Chronic GI bleeding includes common clinical scenarios, yet the meaning and diagnostic criteria for the different terms are not well delineated.² Chronic bleeding from the gut is always significant; in particular, malignant tumors of the gut that are curable may be present. There is no universal agreement regarding the nomenclature of GI lesions that can cause chronic bleeding. Development of new technology, mainly wireless video capsule endoscopy and balloon-assisted enteroscopy has provided an opportunity to revisit the traditional classifications of the source of GI bleeding into upper or lower GI bleeding based on the location of the bleeding either proximal or distal to the ligament of Treitz.³

Some authors propose reclassifying GI bleeding into three categories: upper GI, mid-GI, and lower GI bleeding. Bleeding above the ampulla of Vater, within the reach of esophagogastroduodenoscopy (EGD), is defined as upper GI bleeding; small intestinal bleeding from the ampulla of Vater to the terminal ileum, best investigated by capsule endoscopy and balloon-assisted enteroscopy, is defined as mid-GI bleeding; and colonic bleeding, which can be evaluated by colonoscopy, is defined as lower GI bleeding. A simple classification is presented in Table 16.1. This chapter discusses some of the most frequent causes of chronic GI bleeding. Vascular lesions are an important cause of chronic GI bleeding. They may be solitary, multiple, or diffuse and may exist as isolated abnormalities or be part of a syndrome or a systemic disorder. The internationally accepted term for the endoscopic finding of a mucosally based vascular malformation is angiectasis. The categorization of vascular abnormalities in the GI tract has been inconsistent and a source of confusion.^4,⁵ It can be based on histologic characteristics, gross appearance, or association with systemic diseases. These considerations permit categorization into three broad groups, as follows:

Table 16.1 Causes of Chronic Gastrointestinal Bleeding

Gastrointestinal Lesions
Within Reach of Upper Endoscope	May Be beyond Reach of Upper Endoscope
Esophagitis	Celiac sprue
Cameron’s erosions	Crohn’s disease
Peptic ulcer disease	Intestinal lymphoma
Gastritis and erosions	Small bowel angiodysplasia
Duodenitis and erosions	Small bowel tumors
Angiodysplasia	Small bowel ulcers and erosions, including NSAID- and other drug-induced lesions
Portal hypertensive gastropathy	Small bowel diverticulosis
Gastroesophageal cancer	Small bowel varices
Gastric or duodenal polyps	Lymphangioma
Gastroduodenal lymphoma	Radiation enteritis
Partial gastrectomy	Blue rubber bleb nevus syndrome
GAVE	Osler-Weber-Rendu syndrome
Dieulafoy’s lesion	Small bowel polyposis syndromes
	Gardner’s syndrome
	Amyloidosis
	Meckel’s diverticulum
	Hemosuccus pancreaticus, hemobilia
	Klippel-Trénaunay-Weber syndrome

Colonic Lesions

Parasitic infestation

Hemorrhoids

Diverticular bleeding

GAVE, Gastric antral vascular ectasia; IBD, inflammatory bowel disease; NSAID, nonsteroidal antiinflammatory drug.

1 Vascular tumors, which can be benign (e.g., hemangiomas) or malignant (e.g., Kaposi’s sarcoma or angiosarcoma)

2 Vascular anomalies associated with congenital or systemic diseases, such as blue rubber bleb nevus syndrome, Klippel-Trénaunay-Weber syndrome, Ehlers-Danlos syndrome, pseudoxanthoma elasticum, the CREST (calcinosis, Raynaud’s phenomenon, esophageal dysmotility, scleroderma, and telangiectases) variant of scleroderma, and hereditary hemorrhagic telangiectasia

3 Acquired or sporadic lesions, such as angiodysplasias, gastric antral vascular ectasia (GAVE), radiation-induced vascular ectasias, and Dieulafoy’s lesions.

Angiodysplasia of the Gastrointestinal Tract

Vascular ectasia of the GI tract, also referred to as angiodysplasia or less accurately as arteriovenous malformation, is a distinct clinical and pathologic entity.⁶^–⁸ It is the most common vascular abnormality of the GI tract and probably the most frequent cause of lower intestinal bleeding in patients older than 60 years. Although the terms angiodysplasia and arteriovenous malformation have been used synonymously, the term angiodysplasia (Greek angeion, “vessel”; dys, “bad” or “difficult”; plasis, “a molding”), means a poorly formed vessel but with a lesser connotation of congenital origin than with the word malformation. Angiodysplasias are usually distinguished from telangiectasias, which, although anatomically similar, are usually referred to in the context of systemic or hereditary diseases. Because most vascular abnormalities are detected during endoscopy, a classification based on endoscopic appearance has been proposed.⁹ The classification system recognizes the location, size, and number of angiodysplasias.

Pathogenesis

Angiodysplasias are composed of ectatic, dilated, thin-walled vessels that are lined by endothelium alone or by only small amounts of smooth muscle. Their anatomy has been best shown by studies in which casts of the vessels were made by injecting a silicone material.¹⁰ These studies showed that dilated tortuous submucosal veins are the most prominent feature in angiodysplasias. Small arteriovenous communications are present because of incompetence of the precapillary sphincter. Enlarged arteries are also present in bigger angiodysplasias and may be associated with arteriovenous fistulas, which explains why bleeding can be a risk in some patients.

Histologic examination shows dilated vessels in the mucosa and submucosa, sometimes covered by a single layer of surface epithelium. These features are shared by angiodysplasias in the colon and stomach.¹¹ Increased expression of angiogenic factors has been found in human colonic angiodysplasias.¹² The pathogenesis of angiodysplasias is not well understood. Four theories have been proposed, as follows:

1 Angiodysplasias may develop in response to chronic partial, intermittent, low-grade obstruction of the submucosal veins at the point where they penetrate the muscle layers of the colon.¹⁰ Following this logic, the prevalence of vascular ectasias in the right colon can be attributed to a greater tension in the cecal wall compared with other parts of the colon, according to LaPlace’s principle. Over many years, repeated contraction and distention of the cecum results in dilation and tortuosity of the submucosal vein and, later, the venules and capillaries draining into it. Finally, the capillary rings dilate, the precapillary sphincters become incompetent, and a tiny arteriovenous fistula develops.

2 Angiodysplasias may be a complication of chronic mucosal ischemia, which can occur during episodes of bowel obstruction or straining stools.¹³

3 Angiodysplasias may be a complication of local ischemia associated with cardiac, vascular, or pulmonary disease.¹⁴

4 Angiodysplasias may be congenital, which is probably more likely in young patients or patients who have angiodysplasias associated with congenital diseases.

Epidemiology and Natural History

The prevalence of GI angiodysplasias in the overall population is not well known because asymptomatic individuals usually do not undergo endoscopic evaluation. Angiectases have been seen in 0.2% to 2.9% of “nonbleeding persons”^15,¹⁶ and in 2.6% to 6.2% of patients evaluated specifically for occult blood in the stool, anemia, or hemorrhage.¹⁵^–¹⁷ Angiodysplasias occur most often in the colon, where they are an important cause of lower GI bleeding, particularly in patients older than 60,¹⁸^–²⁰ although presentation in patients in their 30s has been described.²¹ There is no gender predilection.

Clinical Manifestations

Angiodysplasias can remain clinically silent or cause bleeding. The estimated incidence of active GI bleed in patients with angiodysplasia is less than 10%. These lesions may be located throughout the GI tract with a variable rate of bleeding associated with them and presentation ranging from hematemesis or hematochezia to occult anemia.^3,²² Bleeding is usually chronic or recurrent and, in most cases, low grade and painless.

GI bleeding from small bowel lesions has occurred in 22% of patients in whom angiodysplasia of the colon was the presumed index source of bleeding. In 40% to 60% of patients with gastric and duodenal angiodysplasia, multiple lesions are observed at endoscopy. Colonic lesions are associated in 15% to 20% of these patients. In addition, angiodysplastic lesions in the colon are frequently multiple. To diagnose and treat patients with suspected angiodysplasia, the propensity for multiplicity at different levels within the gut must be considered. Hematemesis can rarely be observed in patients with angiodysplasia of the upper GI tract. Presentation with hemodynamically well-compensated, chronic bleeding is more typical. Bleeding from colonic lesions most often is chronic, intermittent, and low grade, with 15% of patients presenting with acute hemorrhage.

Patients with colonic angiodysplasia may present with hematochezia (0% to 60%), melena (0% to 26%), Hemoccult-positive stool (4% to 47%), or iron deficiency anemia (0% to 51%). Melena occurs in at least one-fourth of patients with colonic bleeding. The nature and degree of bleeding frequently vary in the same patient with different episodes, and patients may have bright red blood, maroon-colored stools, and melena on separate occasions. In 20% to 25% of episodes, only tarry stools are passed, and in 10% to 15% of patients, bleeding is evidenced only by iron deficiency anemia, with stools that are intermittently positive for occult blood.²³ With effective diagnostic and therapeutic endoscopy, the percentage of patients who have had operations has decreased because most lesions are being identified and treated at the time of the first episode.²⁴ Angiodysplasia can be confidently considered to be a source of GI bleeding in an anemic patient only if it is seen to be actively bleeding. The risk of bleeding in patients who are incidentally found to have nonbleeding colonic angiodysplasia is unknown. The number of lesions and the presence of coexisting coagulopathy or platelet dysfunction may increase the risk for bleeding. Patients who have bled from colonic angiodysplasias are at increased risk for subsequent bleeding.¹⁰

Conditions with Increased Prevalence

End-Stage Renal Disease

Angiodysplasia is the second most common cause of GI bleeding in patients with end-stage renal disease.³⁰ These lesions account for about 20% of upper GI bleeds and 30% of lower GI bleeds³⁰ and approximately 50% of recurrent upper GI bleeds.³¹ In a prospective study of upper GI hemorrhage over a 50-month period, vascular ectasia was the etiology of upper GI hemorrhage in 13% of patients with renal insufficiency and was the etiology of bleeding more often in patients with renal insufficiency than in patients with normal renal function.³² The prevalence of vascular ectasia as a cause of upper GI bleeding was related to the duration of renal failure and the requirement of hemodialysis. The lesions can occur anywhere along the GI tract and are usually multiple.³¹ The reason for the increased prevalence among patients with end-stage renal disease is unknown. One possible explanation is that the lesions are detected more frequently because of the increased risk of bleeding associated with uremia-induced platelet dysfunction.

von Willebrand’s Disease

The association of abnormal von Willebrand’s factor (vWF) is receiving increasing attention in the management of patients with bleeding GI angiectasias. von Willebrand’s disease is a bleeding disorder that results from a qualitative or quantitative defect in vWF. vWF is a complex multimeric glycoprotein present in platelets, plasma, and subendothelium. vWF is essential to platelet adhesion and aggregation at the site of vascular injury. In a study of patients with both bleeding and nonbleeding angiectasias of the GI tract and control patients with colonic diverticular hemorrhage, Veyradier and associates ³³ showed that most patients with bleeding angiectasias of the GI tract lack the largest multimers of vWF induced by a latent acquired form of von Willebrand’s disease. Because these specific multimers are the most effective in inducing platelet aggregation in high shear stress that is commonly present in the microcirculation of angiectasias, it was concluded their deficiency contributes to active bleeding.

An association between angiodysplasias and congenital or acquired von Willebrand’s disease had been reported previously.^34,³⁵ Patients with angiodysplasia found on endoscopy were prospectively tested for von Willebrand’s disease at the Mayo Clinic, but no associations were identified.

Aortic Stenosis

Approximately 50% of patients with bleeding vascular ectasias have evidence of cardiac disease, and 25% have been reported to have aortic stenosis. Bleeding from angiodysplasias in patients with aortic stenosis (Heyde’s syndrome) has been repeatedly reported but is highly controversial.³⁶ In support of this relationship is the observation that bleeding may be improved after aortic valve replacement.³⁷^–³⁹ Two possible explanations have been proposed to explain this observation. Patients with aortic stenosis may develop an acquired form of von Willebrand’s disease, which can be reversed after aortic valve replacement.^33,^40,⁴¹ The mechanism is thought to involve mechanical disruption of vWF multimers during turbulent passage through the narrowed valve.⁴² Patients with aortic stenosis may be more likely to bleed from existing angiodysplasias. The observation that angiodysplasias persist after aortic valve replacement despite the fact that bleeding stops supports this hypothesis.^11,⁴³ Another explanation is that existing angiodysplasias may bleed as a result of ischemic necrosis in patients who have a low cardiac output.^13,⁴³ However, this explanation is inconsistent with the observations that bleeding angiodysplasias have not been observed with other forms of heart disease associated with a low cardiac output and that a low cardiac output is a late complication of aortic stenosis.

Several retrospective, uncontrolled studies ^44,⁴⁵ and a prospective, controlled investigation⁴⁶ do not substantiate a causative role or association of aortic valve diseases with colonic angiectases. Replacement of the aortic valve for control of bleeding secondary to these vascular lesions is not universally accepted.²⁴ A logical approach to patients with both lesions is to treat the colonic lesion first endoscopically, regardless of whether the patient’s cardiac status warrants surgery. If valve replacement is necessary and endoscopic therapy is unsuccessful, further endoscopic or surgical treatment of the colonic angiodysplasia should be delayed until after cardiac surgery. Further attempts at endoscopic treatment or surgical resection are indicated if bleeding recurs.⁴⁷ The association between chronic GI bleeding in elderly patients and aortic stenosis becomes more relevant with the advent of transcatheter aortic valve implantation that can be offered even to elderly patients with comorbidities, which could make conventional surgery impossible.⁴⁸

Progressive Systemic Sclerosis

Vascular lesions are a prominent feature of progressive systemic sclerosis, especially in the CREST variant.⁴⁹ Angiodysplasias are usually distinguished from telangiectases, which, although anatomically similar, are usually referred to in the context of systemic or hereditary diseases. In patients with progressive systemic sclerosis, sites most frequently involved by telangiectases are the hands, lips, tongue, and face, but gastric, intestinal, and colorectal lesions have been reported. These lesions may be the source of occult or clinically significant bleeding and are best treated by endoscopic coagulation.⁵⁰

Diagnosis

Angiectases have a characteristic appearance of a cherry-red, fernlike pattern of arborizing, ectatic blood vessels radiating from a central vessel (Fig. 16.1). This pattern should be specifically looked for because angiectases may be confused with other erythematous mucosal lesions or with normal vessels (Table 16.2).^24,⁵¹ Because traumatic and endoscopic suction artifacts may resemble vascular lesions, all lesions must be evaluated immediately on insertion of the colonoscope, rather than during withdrawal. “Anemic halos” are often seen surrounding angiectases of the bowel. Although these “halos” do not differentiate the various types of vascular lesions, they distinguish true vascular lesions from artifacts.⁴⁷ Newer alternative imaging options, such as narrow band imaging, allow precise discrimination of vascular structures from artifactual mucosal hemorrhage. Punch biopsy samples of vascular lesions obtained during endoscopy are usually nonspecific; the bleeding induced by performing biopsies of these abnormalities is not justified.

Fig. 16.1 A, Typical angiodysplasia in right colon. Angiodysplastic lesions are seen as slightly dilated tortuous vessels. B, Angiodysplasia in the stomach. C, Narrow band imaging of same lesion.

Table 16.2 Lesions Confused with Angiectasias on Endoscopy

Vascular	Nonvascular	Colitis
Arteriovenous malformations	Trauma	Ischemic
Angiomas	Polyps	Infectious
Phlebectasia	Adenomatous	Radiation (acute)
Varices	Hyperplastic	Inflammatory bowel disease
Venous stars	Lymphoid

Angiectases may be difficult to visualize during colonoscopy in patients who do not have an optimal bowel cleaning. Because the appearance of angiectases is influenced by blood pressure, blood volume, and state of hydration, these lesions may not be evident in patients with severely reduced blood volumes or who are in shock until red blood cell and volume deficits are corrected. Cold water lavage of the colon, as is sometimes done to clean the luminal surface from debris during colonoscopy, reportedly may mask these lesions.⁵² Meperidine also has been implicated in masking lesions because of a transient decrease in mucosal blood flow. Minimizing use of meperidine and reversal with naloxone to increase the yield of detection have been advocated by some clinicians. Naloxone has been reported to enhance the appearance of normal vasculature in about 10% of patients and to cause angiectases to appear (2.7%) or increase in size (5.4%).⁵³ Reversal of narcotic analgesia may affect the comfort of an examination, particularly if therapeutics are performed.

Some patients presenting with GI bleeding have no source found by upper endoscopy and colonoscopy.³ In these cases of obscure chronic GI bleeding, endoscopic examination of the small bowel has been limited by several factors. The length of the small intestine, in addition to its free intraperitoneal location, vigorous contractility, and overlying loops, confounds the usual diagnostic techniques, including barium studies, endoscopic intubation, and identification of specific sites by special imaging techniques of nuclear medicine scans and angiography. The bleeding rate may be slow or intermittent, not allowing identification by either angiography or radionuclide bleeding scan. Because of the inability to localize a bleeding site in the small bowel, patients with obscure GI bleeding from a small bowel source typically presented with prolonged occult blood loss or recurrent episodes of melena or maroon stool without a specific diagnosis. In this group of patients, previous noninvasive tests, such as small bowel follow-through, radioisotope-labeled red blood cell scan, and push enteroscopy, have had suboptimal diagnostic yields of 20% to 40%. Invasive methods, such as laparotomy or intraoperative enteroscopy, may improve the yield up to 70%.⁵⁴

For patients with obscure chronic GI bleeding, an early diagnosis of the bleeding site was the exception rather than the norm until more recently with the development of capsule endoscopy and balloon-assisted enteroscopy. The last American Gastroenterological Association Institute medical position statement on obscure GI bleeding considered that for patients with obscure GI bleeding and associated anemia or overt bleeding, repeat endoscopic examinations can be worthwhile.⁵⁵ Useful adjunctive diagnostic maneuvers include use of a cap-fitted endoscope to examine blind areas, such as the high lesser curve, under the incisura angularis, and the posterior wall of the duodenal bulb; use of a side-viewing endoscope to examine the ampulla in patients with suspected pancreaticobiliary pathology; and use of a push enteroscope to examine the C-loop of duodenum carefully after injection of glucagons. Although the yield is low (6%), repeat colonoscopy may be useful in the setting of prior poor bowel preparation. Use of naloxone may improve the detection of colonic angiectases that were not obvious at the index examination.³

When all the findings on standard examinations (EGD and colonoscopy) are negative, the small bowel may be assumed to be the source of blood loss. Capsule endoscopy should be the third test in the evaluation of patients with GI bleeding.

Capsule Endoscopy

The first capsule endoscope, referred to as the M2A (“mouth to anus”), was approved for clinical use late in 2001. The capsule endoscope is a wireless miniature camera that can be swallowed to obtain images of the GI mucosa; the camera contains a light source, batteries, and a radio transmitter. Video images are transmitted via radiotelemetry to a skin surface patterned antenna that allows images to be captured and localizes the relative position of each image in the abdomen.⁵⁶ In July 2003, the capsule endoscope was approved by the U.S. Food and Drug Administration (FDA) as a first-line tool for the detection of abnormalities of the small bowel, based on evidence provided by a meta-analysis (Fig. 16.2). M2A was renamed PillCam SB (SB means “small bowel”).⁵⁷

Fig. 16.2 Small bowel angiodysplasias in patients with obscure gastrointestinal bleeding. A, Nonbleeding angiodysplasia diagnosed by wireless capsule endoscopy. B, Active bleeding angiodysplasia visualized by capsule endoscopy. C, Small bowel angiodysplasia seen with balloon enteroscopy. D, Same lesion treated with argon plasma coagulation.

Obscure GI bleeding is the main clinical indication for capsule endoscopy; approximately 70% to 80% of patients undergo capsule endoscopy for this indication. The American Society for Gastrointestinal Endoscopy (ASGE) Technology Assessment Committee concluded that capsule endoscopy provided superior yield compared with radiographic contrast studies and push enteroscopy.⁵⁸ Two published meta-analyses support the utility of capsule endoscopy in obscure GI bleeding.^59,⁶⁰ The ASGE Technology Assessment Committee also concluded that capsule endoscopy is indicated not only for evaluating obscure GI bleeding, but also for evaluating unexplained iron deficiency anemia.⁵⁸

The EndoCapsule EC type 1 is another small bowel capsule endoscope, developed by Olympus America (Center Valley, PA). This capsule uses a high-resolution CCD and an external real-time image viewer (External Viewer) monitor.⁶¹ A randomized study comparing these two types of capsule endoscope reported a statistically nonsignificant trend for the EndoCapsule to detect more bleeding sources in patients with suspected small bowel bleeding than the PillCam SB.⁶² Future capsule designs may emerge with expanded capabilities that include fluid sampling, mucosal biopsy, targeted labeling, and controlled movement. With future innovation and study, the indications for capsule endoscopy are likely to expand and become more focused.

Balloon-Assisted Enteroscopy

Push-and-pull enteroscopy with the double-balloon technique (double-balloon enteroscopy [DBE]) for inspection of the entire small bowel was first performed in the Western world in 2003.⁶³ The earliest case report documenting the success of this method was published by Yamamoto and colleagues in 2001.^63a

Double-Balloon Technique

The endoscope is introduced into the small bowel within a soft overtube. The balloon at the tip of the endoscope is inflated to hold it in place while the overtube, with deflated balloon, is passed distally until it reaches the tip of the endoscope. Both balloons are inflated, and the entire system is slowly pulled back; this results in an accordionlike sleeving of the small bowel onto the overtube. In the next step, the overtube balloon is kept inflated while the endoscope balloon is deflated and the endoscope is pushed 40 cm deeper into the small bowel. This method is repeated until the enteroscope has been passed as far as technically possible. In approximately 10% of cases, the entire small bowel can be visualized in a single session, typically via an antegrade approach. Carbon dioxide insufflation improves depth of insertion especially during antegrade approaches.⁶⁴ In most cases, however, antegrade and retrograde examinations are required for the entire small bowel to be visualized. In this setting, the distalmost point in the small bowel that is reached after antegrade passage is tattooed to provide an endpoint during the retrograde examination.

The push-and-pull technique is used in reverse to withdraw the endoscope from the small bowel; while the endoscope is being withdrawn, the small bowel can be carefully reinspected. The enteroscope is 2 m long and has an outer diameter of either 8.5 mm (standard size channel) or 9.5 mm (therapeutic size channel). The endoscope is outfitted with capabilities similar to a conventional endoscope: The endoscope optics or the bowel itself can be rinsed by the instillation of fluid through the device port, biopsy samples can be taken, and a full range of therapeutic interventions can be performed.

Single-Balloon Enteroscopy

Antegrade DBE can examine three times the length of small bowel as push enteroscopy, with a corresponding increase in diagnostic yield.⁶⁵ More recently, single-balloon enteroscopy (SBE) was introduced in the United States (Olympus America, Center Valley, PA).⁶⁶ The single-balloon and double-balloon systems share many features, including scope length, diameter, accessory channel size, and overtube design. The most important design difference between the two systems is that the single-balloon enteroscope does not have a distal balloon on the scope; the only balloon is on the tip of the overtube. As a result, the sequence of steps to advance the scope through the small bowel is simplified in SBE.

Although there are some minor differences between the systems, use of either scope requires a technician to assist with handling of the overtube and balloon inflation and deflation. In addition, both systems require fluoroscopy to monitor scope position and sedation appropriate for prolonged procedures. Early clinical experience using SBE on average reported a depth of insertion (270 cm) and diagnostic yield (54%) similar to DBE with a shorter procedure time.⁶⁷ Comparison studies between DBE and SBE are inherently difficult to design and carry out. For this reason, accurate comparisons are impossible. Choice of procedure has become a user preference.

Complications

Abdominal pain is common after DBE and can be lessened by the use of carbon dioxide insufflation. Diagnostic DBE has an overall complication rate of 1.7% (perforation 0.3%, bleeding 0.8%, pancreatitis 0.3%).⁶⁸ The cause of pancreatitis is uncertain. Advancing the overtube and enteroscope into the jejunum before inflating balloons and avoiding excessive tension on the mesentery during push-pull cycles may limit this risk. Therapeutic DBE has a relatively high complication rate of 4.3% (polypectomy bleeding 3.3%, argon plasma coagulation [APC] perforation 1.2%, dilation perforation 2.9%). DBE evaluation of the entire small bowel is possible in 45% to 84% of patients in whom it is attempted, although it can rarely be achieved with antegrade DBE alone. In the evaluation of obscure GI bleeding, DBE has been reported to identify a bleeding source in 53% to 80% of cases.^69,⁷⁰

Three prospective studies compared capsule endoscopy with DBE. Combining the results of the three studies, capsule endoscopy and DBE agreed in 68% of all cases and in 63% of positive cases. A meta-analysis that included these three prospective studies and results published only in abstract form compared diagnostic outcomes between capsule endoscopy and DBE. There was no difference in diagnostic yield between capsule endoscopy and DBE.⁷¹ Another meta-analysis reached the same conclusion.⁷² A new enteroscopy technology consists of a 48-Fr rotating overtube with spiral threads (Discovery SB; Spirus Medical, Inc, Stoughton, MA). The overtube is backloaded on any enteroscope⁷³ or on a pediatric colonoscope.⁷⁴ After intubation of the stomach with the endoscope, the overtube is rotated clockwise through the upper GI tract until the spiral threads engage in the jejunum; once free in the abdominal cavity, clockwise spinning of the overtube results in rapid pleating of small bowel onto the overtube. In a preliminary report,⁷⁵ average procedure time for spiral enteroscopy was shorter (32 minutes) than times reported for DBE and SBE. The diagnostic yield is lower (32%) compared with balloon-assisted enteroscopy. The depth of insertion into the small bowel and the overall safety of the large twisting overtube have not been shown.

Summary

Balloon-assisted enteroscopy seems to have superior diagnostic capability compared with push enteroscopy and equivalent yield compared with intraoperative enteroscopy without the associated morbidity of the latter procedure. Although balloon-assisted enteroscopy does not allow visualization of the entire small bowel in one examination, compared with capsule endoscopy, it has been shown to be associated with an equivalent detection rate, has the capability to detect lesions missed by capsule endoscopy, and offers the advantages of therapeutic treatment. In patients with a positive finding on capsule endoscopy, balloon-assisted enteroscopy provides a safe method to achieve a favorable clinical outcome, including significant reduction in recurrent bleeding and transfusion requirements.⁷⁶ With the advent of balloon-assisted enteroscopy, intraoperative enteroscopy can be relegated to cases in which the success of balloon-assisted enteroscopy is limited by body habitus, the presence of adhesions, or other anatomic factors.³ Most existing trials have focused on the diagnostic value of capsule endoscopy, with few examining the impact on the long-term outcome of obscure GI bleeding. In a 1-year study based on telephone interviews, the negative predictive value of capsule endoscopy for clinical rebleeding was 87%.⁷⁷ In another more recent report, the negative predictive value was 89%.⁷⁸ Capsule endoscopy can guide the management of these small bowel lesions.

Similar to other authors,^57,⁸⁰ we⁷⁹ recommend capsule endoscopy as a first-line investigation over balloon-assisted enteroscopy in view of its convenience, higher chance to visualize the entire small intestine, and similar diagnostic yield. A proposed algorithm for capsule endoscopy in cases of obscure GI bleeding is shown in Fig. 16.3. No test substitutes for good clinical judgment, however, and all small bowel diagnostic studies must be considered in difficult cases of obscure GI bleeding, particularly in a young patient.⁸¹

Fig. 16.3 Diagnostic algorithm for obscure gastrointestinal bleeding.

(Adapted from Nakamura T, Terano A: Capsule endoscopy: Past, present, and future. J Gastroenterol 43:93–99, 2008.)

In the setting of obscure overt bleeding, capsule endoscopy should be performed close to the bleeding episode. We recommend that a second endoscopist reread the capsule endoscopy study. We also recommend a second-look EGD with special attention to areas less optimally examined by capsule endoscopy, especially the duodenum, before concluding with a final diagnosis of obscure GI bleeding. Second-look capsule endoscopy has also been suggested for patients with a prior nondiagnostic capsule endoscopy. Bar-Meir and associates ⁸² reported that 7 of 20 patients (35%) who underwent second-look capsule endoscopy had positive or suspicious findings. Another study showed that patients with a nondiagnostic capsule endoscopy test would benefit from a second-look capsule endoscopy if the bleeding presentation changed from occult to overt or if the hemoglobin value decreased 4 g/dL or more.⁸³

Angiography is used to determine the site and nature of lesions during bleeding. It may permit therapy in patients who are bleeding and can identify some vascular lesions even when bleeding has ceased. The three reliable angiographic signs that help diagnose angiectases are a densely opacified, slowly emptying, dilated, tortuous vein; a vascular tuft, and an early-filling vein.⁸⁴ A fourth sign, extravasation of contrast material, identifies the site of bleeding when bleeding volume is at least 0.5 mL/min but does not contribute to the diagnosis of an angiectasis. Nuclear scan is another diagnostic technique that can be used in selected patients.^85,⁸⁶ Provocative scintigraphy with heparin can enhance diagnosis with further localization of bleeding.⁸⁷

Helical computed tomography (CT) angiography may provide another method to help diagnose angiectases. Accuracy may be high,⁸⁸ although studies are needed to understand the role of this technique better in the management of patients with GI bleeding. In a report of 22 patients with obscure GI bleeding, CT enteroclysis was found to be inferior to capsule endoscopy in the detection of potential bleeding lesions such as angiectases in the small bowel.⁸⁹ In another more recent study performed in 28 patients with obscure GI bleeding, capsule endoscopy detected more lesions (72%) than CT angiography (24%) or standard mesenteric angiography (56%).⁹⁰ The aggressiveness of the approach should be individualized depending on the clinical circumstances. Evaluation of the small bowel may be deferred in patients with negative upper and lower endoscopy until or unless the patient is bleeding severely enough to require a transfusion.⁵⁵

Management

Management of bleeding angiectases consists of three phases ²⁴: (1) diagnosis; (2) conversion of acute bleeding manifesting as an emergency to elective care by control of the acute hemorrhage; and (3) definitive treatment of the lesions by endoscopic ablation, angiography, or surgical removal. The natural history of colonic angiectases is benign in healthy, asymptomatic individuals, and the risk of bleeding is small.²⁹ It is estimated that only about 50% of colonic lesions ever bleed. There is a risk of bleeding and perforation following attempts at endoscopic obliteration. For all these reasons, in incidentally found angiectases at all levels of the gut, endoscopic therapy is not warranted.⁹¹

Pharmacologic Treatment

Iron Formulations

Nonbleeding angiodysplasia detected during evaluation of occult bleeding or iron deficiency anemia should be considered to be causative. In patients with occult bleeding, bleeding from angiodysplasia may be more likely in patients who have multiple lesions and a bleeding diathesis (e.g., anticoagulation). As a result, a graduated approach with primary or adjunctive iron replacement therapy may be initiated, with pursuit of more aggressive therapeutic options guided by the clinical circumstances.⁹¹^–⁹³ The aims of iron replacement therapy should be to restore hemoglobin levels and mean corpuscular volume to normal and to replenish body stores.

Laboratory measurements of body iron stores such as serum ferritin are helpful to assess the effectiveness of iron supplementation. Iron supplementation is achieved most easily with oral iron supplementation. Numerous oral iron preparations are available, although ferrous sulfate and ferrous gluconate are preferred forms of oral iron because of low cost and high bioavailability. A liquid preparation often is tolerated better. Ascorbic acid enhances iron absorption. Parenteral iron should be used when there is intolerance to at least two oral iron preparations or noncompliance, when there is a suboptimal clinical response secondary to suspected iron malabsorption, and when blood transfusion becomes difficult to achieve because of excessive antibodies that challenge crossmatching.

Some patients with obscure GI bleeding are managed clinically with intermittent blood transfusions along with other nonspecific supportive measures, such as avoidance of aspirin, avoidance of anticoagulants, and oral iron supplementation. These patients often do not have a definite diagnosis despite extensive work-up, have diffuse GI angiectases often in inaccessible locations, have failed endoscopic or surgical or other specific therapies, or are elderly with many comorbid conditions and the risk of further diagnostic evaluation is considered to be greater than the risk of nonspecific management.

Hormonal Therapy

Estrogen-progesterone combination hormonal therapy has been used to treat patients with angiectases of the GI tract.^94,⁹⁵ The effect, which is not immediate, seems to be estrogen dose–dependent. Hormonal therapy acts by enhancing microvascular circulation, coagulation, and vascular endothelial integrity. The most common combination schedule has been ethinyl estradiol 0.01 to 0.05 mg and norethisterone 1 to 3 mg. This therapy should be used in 6-month courses with pauses to reduce the incidence of adverse effects, mostly secondary to the estrogen component. The results of several prospective, controlled trials examining hormonal therapy have been divergent.⁹⁶^–⁹⁹ In a long-term observational study, combination hormonal therapy was shown to stop bleeding in patients with occult GI bleeding of obscure origin, likely to have resulted from small bowel angiodysplasias.⁹⁸ Although uncontrolled studies suggest that combination estrogen-progesterone therapy prevents bleeding episodes secondary to angiodysplasia, the evidence from the largest placebo-controlled trial to date suggests that this therapy is ineffective.¹⁰⁰ These authors considered that efficacy of hormonal therapy in these patients remains to be proven by a large, randomized, placebo-controlled trial with long-term follow-up.

This pharmacologic therapy is not without complications. The main side effects include fluid retention, uterine bleeding, increased plasma triglycerides, pancreatitis, hypercoagulability, breast tenderness or enlargement, headache, and increased incidence of gallbladder disease. Contraindications for hormonal therapy include thromboembolic disease, cholestatic jaundice, endometrial hyperplasia, known or suspected breast cancer or estrogen-dependent neoplasia, vaginal bleeding, and gynecomastia. In clinical practice, estrogen-progesterone therapy should be used for patients with symptomatic recurrent episodic bleeding in which other therapies have failed.

Octreotide

Reports of efficacy of octreotide in the treatment of angiodysplasia have been limited to case reports and small series in which a response has been reported in some patients.^95,¹⁰¹^–¹⁰³ Octreotide produces vasoconstriction secondary to inhibitory effects on growth hormone and multiple GI vasodilator hormones and markedly reduces splanchnic blood flow. Its antiangiogenic properties have been shown in different tissues (eye, placenta, liver, and GI neuroendocrine tumors); however, applicability and utility in obscure GI bleeding remain unknown.

The dosage of octreotide can be tapered to the lowest quantity that prevents rebleeding. Response is immediate, and the drug can be administered intravenously (50 µg/hr) or subcutaneously (50 to 100 µg two or three times a day).⁹⁵ Its subcutaneous administration and its longer half-life (90 to 100 minutes) make octreotide superior to somatostatin and allow use in the outpatient setting. A 6-month course of therapy has been used to treat most patients. The first comparative cohort study showing the benefit of long-term octreotide compared with placebo in preventing bleeding from angiodysplasia was reported more recently.¹⁰⁴ Compared with placebo, octreotide markedly reduced the risk of rebleeding with a significant decrease in iron requirements, but there were no differences in hemoglobin levels or transfusion requirements between the two groups.

Mild GI side effects have been reported with octreotide. Inflammation at the injection site has been noted. Mild steatorrhea and mild hyperglycemia may result from the inhibition of pancreatic exocrine and endocrine secretion. Octreotide therapy alters gallbladder contractility, inducing biliary sludge. A few patients develop acute cholecystitis. Cost-effectiveness of this treatment has not been shown to date.

Sandostatin LAR Depot is a depot formulation of octreotide for long-term maintenance therapy currently approved for acromegaly and GI and pancreatic neuroendocrine tumors. Compared with conventional octreotide, Sandostatin LAR Depot is administered intramuscularly once a month with a similar efficacy and safety profile and does not require hospital admission, which makes it an attractive outpatient option for long-term therapy in patients with chronic GI bleeding. The effectiveness of Sandostatin LAR Depot at a dose of 20 mg intramuscularly once a month for obscure GI bleeding has been described in several small series.^95,^102,¹⁰⁵^–¹⁰⁷ The main disadvantage of this drug formulation may be its cost compared with conventional octreotide. However, in very specific cases, it may prove to be cost-effective. The appropriate dose and schedule required for long-term therapy are unknown.

Nonselective β Blockers

Nonselective β blockers aim to control hemorrhage by reducing GI blood flow secondary to splanchnic vasoconstriction and reduction of cardiac output. The benefit of nonselective β blockers in primary and secondary prophylaxis of variceal bleeding in portal hypertension has been shown in many studies, sometimes for portal hypertensive gastropathy (PHG) and colopathy; however, its use in obscure GI bleeding is anecdotal.

Thalidomide

Thalidomide is a drug with powerful immunomodulatory, antiinflammatory, and antiangiogenic effects that was withdrawn from the market in the 1960s because of its teratogenicity; it has been reintroduced more recently for the treatment of leprosy, multiple myeloma, and various tumors. Vascular endothelial growth factor (VEGF) has been identified as the key mediator for endothelial vessel formation in early phases of angiogenesis. High concentrations of VEGF result in aberrant angiogenesis with formation of angiectasias that lack a smooth muscle cell layer and are more susceptible to rupture and bleeding. VEGF-dependent angiogenesis is inhibited by thalidomide. Thalidomide is an innovative and promising therapeutic option for GI bleeding associated with angiodysplasia and can be used in refractory cases or when other drugs or therapies are contraindicated.⁹⁵

Thalidomide is administered orally at a variable dose of 100 to 300 mg/day.⁹⁵ No significant adverse effects have been reported except transient fatigue; however, thalidomide is contraindicated in patients with peripheral neuropathy and pregnant women and women with childbearing potential because of its teratogenic effects, and it should be used cautiously in patients with cardiovascular or neurologic disorders and hepatic or renal impairment. Owing to its immunosuppressant activity by blocking tumor necrosis factor, use of thalidomide may be also discouraged in patients at risk for infection or chronic infectious disease, especially patients with human immunodeficiency virus (HIV) infection. In all these clinical settings, Sandostatin LAR Depot may be safer than thalidomide.

There are few reports in the literature about the effectiveness of thalidomide for chronic GI bleeding. It was successfully used in a patient with von Willebrand’s disease and life-threatening bleeding caused by small bowel angiodysplasia refractory to other pharmacologic treatments and endoscopic cauterization with argon beam laser.¹⁰⁸ It has also been proven effective in controlling bleeding from diffuse idiopathic angiodysplastic lesions in the small bowel.^109,¹¹⁰ Bauditz and coworkers¹¹¹ studied the effect of thalidomide at a dose of 100 mg daily for 3 months in three patients with chronic bleeding from small bowel angiodysplasia as evidenced by wireless capsule endoscopy. Bleeding was controlled in all cases for a median follow-up of 34 months despite drug discontinuation. Repeat capsule endoscopy after therapy revealed a substantial reduction in lesion numbers, size, and color intensity.

Miscellaneous Agents

Antifibrinolytics

Tranexamic acid is a synthetic lysine analogue that inhibits the conversion of plasmin to fibrinogen. It has been used successfully for chronic bleeding from angiodysplasia in patients with end-stage renal failure at doses of 10 to 20 mg/kg every 48 hours; it remains unclear whether long-term therapy or as-needed therapy is preferable during hemorrhagic crises.^95,¹¹² The main risk derived from the use of antifibrinolytics is thrombosis, so thrombophilia should be ruled out before prescribing them. Adverse events associated with tranexamic acid may be frequent, and use of these drugs is not supported by randomized controlled trials, which makes antifibrinolytics a last option for chronic GI bleeding. Because of their mechanism of action, antifibrinolytics may have a more important role in the treatment of patients with hematologic disorders.

Danazol

Danazol is an antigonadotropin drug with weak androgenic activity that blocks pituitary secretion of follicle-stimulating hormone and luteinizing hormone, leading to ectopic and normal endometrial tissue atrophy. It has been used for endometriosis and uterine bleeding disorders. Anecdotal reports suggest a partial improvement in patients with GI bleeding and hereditary hemorrhagic telangiectasia.^44,⁴⁵ Cosmetic stigmata (acne, hair loss, mild hirsutism) and uncommon but severe adverse effects (intracranial hypertension, peliosis hepatis, thrombosis, seizures) consign danazol to a secondary role in chronic GI bleeding, to be used when other therapies have failed.

Desmopressin

Desmopressin is a synthetic analogue of the antidiuretic hormone vasopressin that lacks vasopressor activity. It increases vWF and factor VIII levels and enhances hemostasis in patients with defective platelet function. It is indicated as a hemostatic agent for patients with hemophilia A and von Willebrand’s disease, and it can be administered intravenously, subcutaneously, or by intranasal spray. An isolated report showed a benefit of intravenous desmopressin for life-threatening GI bleeding in a patient with hereditary hemorrhagic telangiectasia and vWF deficiency, allowing elective colectomy and bleeding resolution.¹¹³

Recombinant Activated Factor VII

Recombinant activated human factor VII is a novel drug that strongly promotes hemostasis and is currently indicated for patients with hemophilia A and hemophilia B with antibody inhibitors to coagulation factors VIII or IX, congenital deficiency of factor VII, and Glanzmann’s thrombasthenia. This drug has been used for controlling hemorrhage, with or without hematologic disorders, in massive or uncontrollable bleeding at any location. Its short half-life of 2 hours requires frequent boluses or continuous infusion to achieve hemostasis, and it can induce definitive control of bleeding or be a bridge until a causal therapy can be instituted.

Recombinant activated human factor VII has been used mainly in upper GI hemorrhage related to cirrhosis or acute liver failure,^114,¹¹⁵ although it has been used in other settings, including refractory bleeding after endoscopic sphincterotomy in patients with preexisting coagulopathy.¹¹⁶ Sporadic reports have shown the effectiveness of factor VIIa in patients with von Willebrand’s disease for chronic GI bleeding secondary to small bowel angiodysplasia or of unknown origin.¹¹⁷ Secondary myocardial and cerebrovascular infarctions have been described while using factor VIIa owing to its marked prothrombotic activity,¹¹⁸ so particular care should be taken in patients with a high-risk cardiovascular profile, and the indication should be assessed for each individual case.

Summary

Pharmacotherapy should be considered whenever endoscopic therapy, surgical intervention, or angiographic therapy is impractical or ineffective, such as in patients in whom the source and the etiology of bleeding are unknown or the pathology is too diffuse to be amenable to ablative therapies. Combined hormonal therapy and other miscellaneous treatments (antifibrinolytics, desmopressin, danazol, recombinant activated factor VIIa) should be considered currently useful for chronic GI bleeding in patients with hereditary hemorrhagic telangiectasia, von Willebrand’s disease, and end-stage renal disease. In patients with bleeding from small bowel angiodysplasia or of unknown origin without the above-mentioned diseases, octreotide is effective and safe, but it requires administration several times a day. In the future, Sandostatin LAR Depot, oral thalidomide, and nonselective β blockers are likely to become the pharmacologic cornerstone replacing hormonal therapy and conventional octreotide, owing to easy administration, good tolerability, and absence of major adverse effects. Further studies are needed to confirm this hypothesis and to elucidate the adequate dose and schedule needed for these novel and promising drugs.

Endoscopic Treatment

The goal of endoscopic therapy is thrombosis of the bleeding vessel. Studies directly comparing the effectiveness of the different approaches have not been performed. The approach depends on the location of the lesion, the experience of the endoscopist, and the availability of equipment.

Bipolar Or Heater Probe Coagulation

Bipolar or heater probe coagulation is said to be effective for treatment of angiodysplasia,^119,¹²⁰ and these modalities have replaced monopolar coagulation.^14,¹²¹

Sclerosant

Injection of a sclerosant, such as ethanolamine, has been used to obliterate lesions.¹²² Epinephrine injection works by volume tamponade of the bleeding vessel and transient vasoconstriction.¹²³ Sclerosants should probably be avoided, however, because of the risk for bleeding from injection site ulceration and perforation.⁴⁷

Band Ligation

Band ligation has been used to treat angiectasia of the stomach.^124,¹²⁵ The relatively small surface area incorporated into the ligation site (e.g., in GAVE or “watermelon stomach”) and, more so, the expense of the therapy outweigh any perceived benefits. The walls of the small and large intestine above the rectum (especially the right colon) are thinner than the stomach. For this reason, band ligation therapy cannot be advocated owing to the recognized risk for perforation.^126,¹²⁷

Lasers

Argon and neodymium:yttrium-aluminum-garnet (Nd:YAG) lasers have been used in the past.¹²⁸^–¹³⁰ These techniques require expensive equipment and specific training. More convenient and safer coagulation options have replaced laser therapy except for treatment of “watermelon stomach” (GAVE). APC has become the dominant therapy for GAVE. A few patients are refractory to this therapy. These patients most often respond to treatment with Nd:YAG laser.

Argon Plasma Coagulation

APC is a monopolar electrosurgical procedure in which electrical energy is transferred to the target tissue using ionized and conductive argon gas (argon plasma).¹³¹ The plasma beam follows the path of least electrical resistance. This phenomenon permits the argon plasma to be applied both en face and tangentially, allowing treatment of regions that are normally difficult to access. A second-generation APC (VIO APC; Erbe Elektromedizin, Tuebingen, Germany; and Beamer, Con Med, Utica, NY) offering a broader bandwith of APC modes compared with the earlier generators has been introduced more recently to GI endoscopy. The optional coagulation modes (e.g., “forced,” “pulsed,” and “precise”) of second-generation devices provide different coagulation tissue effects. These effects include a continuous energy output, pulsed energy (with high energy per pulse with longer pauses per pulse or a greater number of pulses with a lower energy per pulse with a constant voltage maintained for each pulse option).

The newer power applications such as “forced” and “pulsed” of second-generation APC devices have been reported to be 30% to 50% higher compared with the ICC/APC300 system. Another power delivery mode (“precise”) uses an integrated regulation system that adjusts the argon plasma regardless of impedance and is characterized by continuous application of energy and by an increase of plasma intensity. In this application, the tissue effect becomes independent of the distance between the APC probe and the target tissue (within 5 mm). The three most important factors influencing the thermal impact of APC are the duration of application, the power setting, and the probe-to-tissue distance. The lowest power settings and the shortest duration of coagulation energy applied to a focal point have the lowest risk of deep tissue injury.

APC has been used for various bleeding lesions, including angiectases.^132,¹³³ Its great advantage over laser or photodynamic therapy is the limited depth of tissue injury and lower cost. Shallow tissue injury is due to the fact that the argon stream always seeks electrically conductive areas of tissue, avoiding the coagulated zones, which have lost their electrical conductivity as a result of desiccation. Perforation of the cecum has been reported.¹³² APC seems to be most effective¹³¹ in the treatment of vascular lesions (GAVE, angiodysplasias, and Dieulafoy’s lesions).

The utility of obtaining a submucosal saline solution cushion before APC therapy to prevent deep tissue injury has been shown in a porcine model.¹³⁴ Before APC, it is recommended to collapse the lumen partially while maintaining the treatment site in view. It is important to avoid thinning of the colonic wall with excessive air insufflation because this increases the risk for perforation during therapy, especially in the cecum.¹²³

Cryotherapy

Safety and efficacy of cryotherapy have been reported for treatment of diffuse mucosal lesions of the GI tract.¹³⁵ The effectiveness of endoscopic treatment of angiectases is difficult to assess owing to the absence of prospective controlled trials. Recurrent bleeding from cecal angiodysplasia seems to be reduced after laser photocoagulation or thermal ablation via heater probe or bipolar electrocoagulation, with long-term control of bleeding requiring more than one treatment.¹³⁶ Aside from perforation, the main risks of thermal therapy for colonic angiectases are bleeding in 5% of patients and postcoagulation syndrome in 1.7% of cases.¹²⁰ Endoscopic treatment of vascular lesions in patients known to have coagulation disorders carries an increased risk of procedure-induced hemorrhage.

When treating large lesions, some experienced endoscopists recommend ⁴⁷ to ablate first the periphery of the lesion to create a collar of edema that theoretically reduces the vascular supply to the lesion and diminishes the potential for immediate or delayed hemorrhage. Some clinicians have placed mechanical clips around the margins of large lesions also to reduce the blood supply and facilitate effective coagulation. Others typically target the central portion of the angiodysplasia because ensuing coagulation and edema obstruct the peripheral branches and limit the extent of coagulation needed. Also, for a very large angiodysplasia, epinephrine injection may contract the lesion and reduce the amount and area of coagulation needed for eradication.¹²³ Recurrent bleeding can be expected in approximately 20% of patients with colonic angiectases and in a greater percentage of patients with associated coagulopathies, renal failure, portal hypertension, or additional upper GI vascular lesions.⁴⁷ It is reasonable to attempt endoscopic therapy in patients with accessible lesions despite various coexisting morbidities that may allow only short-term success. Patients with multiple lesions or an underlying bleeding diathesis are less likely to benefit long-term from endoscopic therapy and are at increased risk of complications, especially delayed bleeding from treatment site thermally induced ulceration. Such patients benefit from any attempts to improve their underlying bleeding tendency.

In preparation for endoscopic ablation of vascular lesions, aspirin, nonsteroidal antiinflammatory drugs, anticoagulants, and antiplatelet agents should be withdrawn at least 1 week to 10 days before the procedure. Care should be taken not to distend the cecum fully because the wall would be thinned further, and the risk of perforation would be increased.^24,¹²³ After therapy, patients must be cautioned not to resume full doses of anticoagulants or antiplatelet agents for at least 1 week. Coagulated tissues are at their maximum of thermal injury by 5 to 10 days, and the onset of hemorrhage may be delayed.

Angiography

Localization of active bleeding permits embolization or infusion of vasopressin. Because angiography occasionally causes serious complications, such as arterial thrombosis, contrast reactions, and acute renal failure, its use before definitive surgical therapy has been questioned.¹³⁷ Angiography should be reserved for patients with life-threatening bleeding, patients who are not surgical candidates, and patients in whom localization of lesions is desired before surgical resection. Intravenous or intraarterial vasopressin infusions through the angiographic catheter successfully arrest hemorrhage from vascular ectasias in more than 80% of patients in whom extravasation is demonstrated.¹⁶ The intravenous route seems to be as effective as the intraarterial route when the bleeding is in the left colon, but intraarterial administration is more successful when the bleeding is from the right colon or small bowel. Infarction of the sigmoid colon and severe arterial spasm and lower extremity ischemia have resulted from vasopressin infusions into the inferior mesenteric artery given at the same rate as used in the superior mesenteric artery. These complications may be avoided by infusing less than 0.4 U/min (the dose of superior mesenteric artery infusions), recognizing the lesser blood flow of the inferior mesenteric artery.

Surgery

Surgical resection is definitive for lesions that have been clearly identified as the source of bleeding. Recurrent bleeding may occur, however, from lesions elsewhere in the GI tract. Preoperative or intraoperative enteroscopy and wireless capsule endoscopy are helpful for localizing lesions. Right hemicolectomy remains the treatment of choice for a patient who has bled and whose right colonic angiectases have been identified by either colonoscopy or angiography if:

1 The bleeding is refractory (especially with redevelopment of recurrent lesions).

2 Endoscopic ablation is unavailable.

3 Endoscopic ablation has been unsuccessful or is not feasible for technical reasons.

In the latter two situations, right hemicolectomy is done as an elective procedure after active bleeding is controlled. The entire right half of the colon needs to be removed to ensure that no angiectases are left behind. Recurrent bleeding can be expected in 20% of patients. Subtotal colectomy should be performed only as a last resort in circumstances in which colonic bleeding is strongly suspected but the site and cause are unknown.²⁴ Richter and colleagues¹⁶ studied the course of 101 patients with angiodysplasias to determine the natural history and compare the efficacy of medical therapy, endoscopic electrocoagulation, and surgery (right hemicolectomy). Similar rates of recurrent bleeding were observed for medically and endoscopically treated groups during a mean follow-up of 22 months. Surgically treated patients had a frequency of recurrent bleeding less than half that of the other groups.

Hereditary Hemorrhagic Telangiectasia

Hereditary hemorrhagic telangiectasia, or Rendu-Osler-Weber disease, is an uncommon, autosomal dominant disorder characterized by telangiectases and arteriovenous malformations that affect many organs, including the skin, periungual areas, lips, oral and nasopharyngeal membranes, tongue (Fig. 16.4A), lungs, GI tract (Fig. 16.4B), liver, and brain,^138,¹³⁹ and can result in bleeding. Lesions consist of irregular, ectatic, tortuous blood spaces lined by a single layer of endothelial cells and supported by a fine layer of fibrous connective tissue. In these vessels, no elastic lamina or muscular tissue is present, so they cannot contract; this property may explain why these lesions tend to bleed.²⁴

Fig. 16.4 Hereditary hemorrhagic telangiectasia, or Rendu-Osler-Weber syndrome. Patient with multiple telangiectases involving the tongue (A) and the stomach (B).

Clinical Manifestations

Manifestations of hereditary hemorrhagic telangiectasia are not generally present at birth but develop with increasing age. Epistaxis is usually the earliest sign of disease, often occurring in childhood; pulmonary arteriovenous malformations become apparent from puberty; mucocutaneous and GI telangiectases develop progressively with age; and, finally, GI bleeding occurs well into adulthood.¹⁴⁰ A family history has been reported in approximately 80% of patients with this disease¹⁴¹ but is less common in patients who manifest bleeding after age 50 years.⁴⁷ Severe GI bleeding is unusual before the 5th or 6th decade¹⁴²; occurs in 25% to 33% of patients with hereditary hemorrhagic telangiectasia; is challenging to treat; and can cause significant morbidity, resulting in severe anemia and high blood transfusion requirements.^143,¹⁴⁴

Endoscopy may reveal telangiectases in the stomach (see Fig. 16.4B), duodenum, small bowel, or colon that are punctiform, discrete, red spots or with a classic fernlike border similar to all other angiectases. Lesions are usually flat, although they may be slightly raised 1 to 3 mm, similar in size and appearance to angiectases of the nasal and oral mucosa.¹⁴² Telangiectases are more common in the stomach, duodenum, or jejunum than in the colon.¹⁴⁰ They also may have a characteristic pale mucosal halo. Capsule endoscopy contributes significantly to defining the extent of small intestinal telangiectases and can be used to stage the disease to decide on the extent and form of endoscopic therapy.¹³⁹ Selective mesenteric arteriography may localize the precise bleeding site, but in most cases this is unnecessary.¹⁴⁵

Management

Therapies for GI bleeding range from various pharmacologic agents to endoscopic and surgical treatment. Drug therapies include ethinyl estradiol and norethisterone,⁹⁶ danazol,¹⁴⁶ and aminocaproic acid.¹⁴⁷ Endoscopic therapy is the most effective form of treatment in stopping hemorrhage from actively bleeding lesions. Because of the multiplicity of lesions and the redevelopment of lesions, sometimes within weeks, bleeding recurs at varying intervals after therapy, depending on the extent and thoroughness of ablative therapies.¹⁴¹ There are several reports of endoscopic therapy, including sclerotherapy with sodium morrhuate,¹⁴⁸ ethanol, and polidocanol¹⁴⁹; monopolar and bipolar coagulation and heater probe^150,¹⁵¹; APC¹⁴⁹; YAG laser¹⁵²; and clip application.¹⁵³ Surgical therapy with resection of involved bowel has limited success because of recurrent disease¹⁴⁰ but may be useful for emergency control of hemorrhage from discrete lesions identified as the source of the bleeding that do not respond to medical or endoscopic therapy.¹⁴¹ Surgical intervention has otherwise been more common owing to excessive bleeding from thermally induced ulcerations after endoscopic therapy and perforation.

Gastric Vascular Lesions in Patients with Cirrhosis

After variceal bleeding, hemorrhagic gastritis is the most frequent cause of upper GI bleeding in cirrhotic patients with portal hypertension.¹⁵⁴ The term hemorrhagic gastritis has included bleeding from various nonvariceal mucosal lesions, such as multiple ulcerations, PHG, and GAVE.¹⁵⁴^–¹⁵⁶ PHG and GAVE can cause acute and chronic upper GI blood loss.¹⁵⁷ These conditions frequently, but not invariably, are diagnosed by upper endoscopy. Although they are fairly prevalent, only 15% to 20% of affected individuals experience symptomatic GI blood loss.

Portal Hypertensive Gastropathy

PHG describes the endoscopic appearance of gastric mucosa, with a characteristic mosaiclike pattern with or without red spots, seen in patients with cirrhotic or noncirrhotic portal hypertension. The mosaiclike pattern appears as a white reticular network separating areas of raised red or pink mucosa, resembling the skin of a snake (“snakeskin appearance”). PHG is seen mainly in the body and the fundus of the stomach but is also seen rarely in the gastric antrum (Fig. 16.5). These changes are not unique to gastric mucosa. Similar changes are rarely seen in the small intestine and colon, especially in the presence of extrahepatic portal hypertension. With the broad use of capsule endoscopy, different manifestations of portal hypertension have been reported, although their clinical implications are uncertain to date.^158,¹⁵⁹ When PHG is severe, it can include discrete cherry-red spots, fine pink speckling, or scarlatina-type rash, collectively called red marks.¹⁶⁰ The characteristic histologic finding of PHG is dilated capillaries and venules in the mucosa and submucosa without erosion, inflammation, or fibrinous thrombi.¹⁶¹

Fig. 16.5 Portal hypertensive gastropathy with mosaic pattern and cherry-red spots in the body of the stomach (A) and localized in the antrum of a cirrhotic patient (B).

Classification

There is no general consensus on the endoscopic classification of PHG. The most widely used classification is the one recommended by McCormack and colleagues,¹⁶¹ who classified PHG into mild and severe (Table 16.3). Mild PHG is defined by the presence of only a mosaiclike pattern, whereas severe PHG is diagnosed when red point lesions, cherry-red spots, or black-brown spots are present. The popularity of this classification relates in part to its simplicity and its ability to predict the risk of bleeding, with an increased risk of gastric hemorrhage in severe cases (38% to 62%) compared with mild cases (3.5% to 31%).^155,¹⁵⁶ Observed endoscopic findings often are of an intermediate severity, however, and are not well represented as being either mild or severe. Tanoue and colleagues¹⁶² and the New Italian Endoscopy Club^162,¹⁶³ have described a more detailed scoring system. Tanoue and colleagues¹⁶² classified PHG into four grades (grade 0 = none, grade 1 = mild, grade 2 = moderate, grade 3 = severe). This grading permits more informative description of the observed endoscopic findings. A simpler classification system such as recommended by McCormack and colleagues¹⁶¹ has a better intraobserver and interobserver agreement and reproducibility.¹⁶⁴ Further work needs to be done to improve the currently available grading system.

Table 16.3 Classification of Portal Hypertensive Gastropathy

McCormack et al¹⁶¹	Tanoue et al¹⁶²	Primignani et al (NIEC)¹⁶³
Mild	Grade I	Mosaic pattern
Fine pink speckling (scarlatina-type rash)	Mild reddening	Mild—diffuse pink areola
Superficial reddening	Congestive mucosa	Moderate—flat red spot
Mosaic pattern		Severe—diffuse red areola
Severe	Grade II	Red mark lesion
Discrete red spots	Severe redness and fine reticular pattern separating areas of raised edematous mucosa	Discrete
Diffuse hemorrhagic lesion		Confluent (diffuse)
	Grade III	Black brown spot
	Point bleeding + grade II

NIEC, New Italian Endoscopic Club.

Prevalence

Prospective studies have reported that PHG is present in more than 50% of patients with cirrhosis.^165,¹⁶⁶ The reported prevalence varies widely because of patient selection, absence of uniform criteria and classification, and, more importantly, the differences in interobserver and intraobserver variation.¹⁶⁷ Although PHG is usually seen in association with either esophageal or gastric varices, there is no direct linear correlation between portal pressure and the presence or severity of PHG.¹⁶⁸ The cause of portal hypertension is unlikely to be a significant factor.¹⁶⁹^–¹⁷¹ The prevalence of PHG does not seem to have a linear relationship with the severity of liver disease, as reported by one study that showed the lowest prevalence of severe PHG in Child C patients.¹⁶³ This finding may suggest that other, hitherto unidentified factors may play a role in the pathogenesis of PHG. There is general agreement, however, that the prevalence of PHG increases with variceal obliteration.¹⁷⁰

Pathogenesis

Portal hypertension, and not liver disease, seems to be the key factor for the development of PHG because PHG is equally common in patients with portal hypertension with or without liver disease.^172,¹⁷³ The improvement or disappearance of PHG in many patients after transjugular intrahepatic portosystemic shunt (TIPS) and shunt surgery suggests that there is a significant association between PHG and portal hypertension. However, the severity and the presence of PHG do not have a linear correlation with the severity of portal hypertension.¹⁶⁸ Chronic elevation in portal pressure and increased splenic circulation may increase gastric mucosal blood flow; this may be one explanation for the development of PHG, but actual measurement of gastric blood flow using Doppler has shown variable results, suggesting that there may be other explanations for the pathogenesis of PHG.^174,¹⁷⁵

The severity of PHG may increase with more advanced liver disease as shown in some studies, but the results are inconsistent.^163,^168,¹⁶⁹ Many other explanations have been offered for the pathogenesis of PHG. Experimental evidence suggests that gastric mucosal defense mechanisms are impaired in the presence of portal hypertension.¹⁷⁶^–¹⁷⁸ Aggravation of PHG after variceal banding or sclerotherapy might be caused by alterations in local hemodynamics after obliteration of the esophageal varices.^179,¹⁸⁰ Hepatofugal flow velocity is increased in the left gastric vein in direct relationship with the enlarging size of esophageal varices. Gastric mucosal blood flow is higher in cirrhotic patients whose extrahepatic collaterals are predominantly via esophageal varices. Obliteration of the esophageal collateral venous network may cause higher flow velocity in the gastric vascular bed. It has been speculated that the extravasation of sclerosant into the mediastinum during sclerotherapy may result in chemical vagotomy, and this may cause esophageal dysmotility and delayed gastric emptying, leading to the development of PHG.¹⁸¹ However, there is no direct evidence to suggest that delayed gastric emptying causes PHG.

Natural History and Complications

The overall incidence of acute bleeding from PHG is low, and acute bleeding is seen mostly in patients with more severe PHG. Bleeding is often mild, and transfusion requirement is usually limited to 1 to 2 U of blood. The prevalence of chronic bleeding cannot be reliably estimated because of the uncertainty of making a firm diagnosis. Major determinants of bleeding from PHG are length of time the patient had PHG and the extent and severity of lesions. The mortality associated with bleeding from PHG is very low because most bleeds are minor compared with variceal bleeding. Death caused by PHG is unusual, and PHG is not an independent risk factor for survival.

The presence and severity of PHG seem to change with time. Although some authors believe that PHG is a progressive lesion,^166,¹⁸² others have observed that it may regress in a fair proportion of patients. In one study, during a follow-up of 2 years, the severity of PHG fluctuated with time in 25%, improved in 23%, remained stable in 29%, and deteriorated in 23%.¹⁶³ The variability in results can be due to differences in the patient population, the time when the lesions appear, or the influence of endoscopic intervention for varices. Endoscopic sclerotherapy and banding seems to worsen the severity of PHG and increases the risk of bleeding.^161,^162,^179,¹⁸⁰ In one study, 44% of patients developed PHG after variceal eradication by sclerotherapy compared with only 9% before sclerotherapy.¹⁷⁰ The results in this prospective study suggested that if gastropathy persists for more than 3 months, it is likely to persist for longer periods. In a few patients, PHG lesions may still regress within 6 months but are unlikely to regress beyond this period; when PHG was present before endoscopic therapy for varices, the lesions often persisted or progressed after obliteration of esophageal varices. The frequency of bleeding from PHG in these circumstances was high. For these reasons, the study investigators recommended that such patients be followed with serial endoscopies and that the benefits of β blocker therapy be evaluated as prophylaxis against PHG bleeding.¹⁷⁰ However, the efficacy of serial endoscopies simply for monitoring of the progression of PHG remains to be proven.¹⁸³

Management

Clinically significant bleeding is seen only in association with severe PHG. Effective treatment requires a reduction in the portal pressure.

Pharmacologic Treatment

The aim of pharmacologic treatment is (1) to control hemorrhage in patients with actively bleeding PHG and (2) to prevent rebleeding in patients with known PHG.

Nonselective β Blockers

Nonselective β blockers, such as propranolol and nadolol, have been shown to reduce portal pressure and gastric mucosal blood flow. In small studies, propranolol has been shown to reduce bleeding related to PHG.^184,¹⁸⁵ In a randomized, controlled trial of 56 patients with PHG, multivariate analysis showed that absence of propranolol treatment was the only predictive variable for rebleeding.¹⁶⁵ The use of propranolol in PHG leads to endoscopic improvement, a cessation of bleeding in acutely hemorrhaging patients, and a decreased incidence of rebleeding from severe PHG. Pharmacologic therapy is typically long-term because of evidence that discontinuation of therapy can lead to rebleeding from PHG. Other medications, such as prednisone, estrogen, and progesterone, are ineffective for bleeding-related PHG.

Vasoactive Agents

Given the proven beneficial effects of vasoactive agents such as somatostatin, octreotide, and terlipressin in variceal bleeding, their role in the management of PHG has also been evaluated. Somatostatin has been shown to reduce gastric mucosal blood flow by decreasing splanchnic blood flow.¹⁸⁶ Similar effects are seen with vasopressin and terlipressin. In patients with acute bleeding, an uncontrolled study showed efficacy with somatostatin and octreotide.¹⁸⁷ A more recent study showed that the decrease in portal pressure is only transient, however, and use of somatostatin or octreotide is unlikely to benefit patients with chronic PHG bleeding.¹⁸⁸ Use of these agents should be limited to patients with acute bleeding. There are no clinical trials directly comparing the efficacy of propranolol versus octreotide for active hemorrhage related to PHG. Some authors use octreotide first in patients with acute bleeding because it is better tolerated than propranolol in this setting.¹⁸⁹

Endoscopic Treatment

Endoscopic treatment does not have a significant role in the management of PHG bleeding because the bleeding is often mild and diffuse. If an active bleeding site is identified, it could be managed by injection of sclerosant or cauterization using the heater or bipolar probe. Although laser therapy has been shown to be safe and effective in reducing GAVE-associated bleeding, it is unknown whether laser therapy is effective or safe in patients with severe PHG when the predominant lesion is in the gastric antrum.¹⁹⁰

Noninvasive And Invasive Surgery

Both TIPS and shunt surgery have been shown to be effective for PHG bleeding in anecdotal reports. In a study by Orloff and coworkers,¹⁹¹ portacaval shunting successfully controlled bleeding, and the gastric mucosa had reverted to normal on follow-up gastroscopies in all 12 patients with repeated bleeding unresponsive to propranolol. TIPS was shown to improve PHG in 9 of 10 patients.¹⁹² TIPS successfully stopped recurrent bleeding refractory to medical therapy in one of these patients. TIPS offers another therapeutic option for patients who have bleeding refractory to medical therapy, especially if they are poor candidates for surgical shunts.¹⁹³ Despite these encouraging anecdotal reports, most authors believe¹⁸⁹ that TIPS or shunt surgery should be used only as the last resort in these patients because the risks outweigh the benefits. Currently, the only treatment that could be recommended for prophylaxis of PHG bleeding is nonselective β blockers such as propranolol or nadolol. Pharmacologic therapy is typically long-term because of evidence that discontinuation of therapy can lead to rebleeding from PHG.¹⁹³ Efficacy of therapy can be followed clinically and endoscopically; efficacy is evidenced by improved mucosal appearance and diminished portal hypertension.

Gastric Antral Vascular Ectasia

GAVE was first described in 1984 by Jabbari and colleagues.¹⁹⁴ These authors coined “watermelon stomach” to describe GAVE because of its resemblance to the skin of a watermelon. GAVE describes vascular lesions of the antrum organized in a linear array on top of raised convoluted folds radiating outward from the pylorus, similar to spokes from a wheel, and resembling the dark stripes on the surface of a watermelon (Fig. 16.6A). The typical histologic appearance of GAVE includes marked dilation of capillaries and collecting venules in the gastric mucosa and submucosa with areas of intimal thickening characterized by fibromuscular hyperplasia, fibrohyalinosis, and thrombi.^155,^156,¹⁹⁴ An increasing number of reports of GAVE have included some cases in which the endoscopic appearance showed spotty erythemas diffusely scattered in the antral area and coalesced (diffuse antral vascular ectasia or “honeycomb stomach”).^4,²⁵ Diffuse antral vascular ectasia is now recognized as the same entity as “watermelon stomach,” and both are regarded as GAVE (Fig. 16.6B).²⁶

Fig. 16.6 Two different forms of gastric vascular antral ectasia: “watermelon stomach” (A) and diffuse vascular antral ectasia (B).

The diffuse form is the predominant pattern in patients with cirrhosis. Noncirrhotic patients with GAVE are typically middle-aged or older women; in these patients, GAVE is associated with achlorhydria, atrophic gastritis, CREST syndrome, and post–bone marrow transplantation.^26,^49,¹⁹⁵

Pathogenesis

The pathogenesis of GAVE is poorly understood, and there is no single unifying hypothesis. Possible mechanisms include humoral factors and mechanical causes.^155,^156,¹⁹⁶ Spahr and coworkers¹⁹⁷ observed that GAVE was not improved by successful portal decompression after TIPS (one patient) or by endoscopic laser therapy (one patient), whereas the antral mucosal lesions disappeared completely after liver transplantation. GAVE could be related to increased secretion of yet unidentified vasoactive substances in the presence of liver disease; for example, glucagon and nitric oxide were found to be increased in cirrhotic patients. Local disturbances in vascular tone must be involved to explain that vascular ectasias develop specifically in the antrum. The proponents of a “mechanical” theory have suggested that chronic intermittent venous obstruction associated with powerful muscular contractions of the antrum and pylorus or repeated trauma associated with a loosely attached antral mucosa and prolapse of the antral mucosa through the pylorus may cause GAVE.^194,^198,¹⁹⁹ The fibromuscular hyperplasia seen at histology in GAVE supports the hypothesis of repeated mechanical stress induced by gastric peristalsis.

Relationship between Portal Hypertensive Gastropathy and Gastric Antral Vascular Ectasia

Some researchers believe that GAVE and PHG are different manifestations of the same pathogenetic process, whereas others view them as separate entities.¹⁵⁶ These lesions can be differentiated by endoscopic and histologic findings. PHG is always associated with cirrhosis and is observed mostly in the fundus and corpus of the stomach; mucosal red spots and the so-called mosaic pattern are present, and the histologic examination shows only microvascular ectasia in the mucosa without signs of inflammation. By contrast, GAVE can occur in cirrhotic and noncirrhotic patients. Lesions are found almost exclusively in the antrum, and the mucosal microvascular ectasias are either aggregated in linear stripes (as in “watermelon stomach”) or diffusely spread. Histologically, true ectasia of the mucosal microvasculature is present and associated with fibrin thrombi, fibrohyalinosis, and spindle cell proliferation. This constellation of findings can be identified within the body of the stomach in a patient with PHG but not a patient with GAVE.

In severe PHG, the mucosal vascular ectasias are linearly arrayed in the antrum and resemble GAVE. A GAVE-like appearance is commonly seen in patients with portal hypertension.¹⁶⁴ The dilemma is whether this appearance is GAVE or severe PHG. As mentioned earlier, the histologic appearance of GAVE is confined to the antrum. Similar histologic examination of random biopsy specimens in the body of the stomach in patients with severe PHG can serve to discriminate between the two. In contrast to PHG, bleeding from GAVE is not known to respond to nonselective β blockers.^156,²⁰⁰ However, a therapeutic challenge is not clinically useful to differentiate these two entities because the response to β blockers is variable in patients with PHG. Kamath and associates²⁰¹ showed that compared with patients with PHG, patients with GAVE, in the absence of background mosaic appearance, did not respond to TIPS.

It has been suggested that the same gastric vascular alteration related to portal hypertension may appear grossly and histologically different depending on the anatomic location in the stomach.¹⁶⁶ The hemodynamics of venous drainage of the antrum are different from the body or the fundus of the stomach. It can be argued that the “typical” histologic changes, fibrosis and thrombosis, seen in GAVE are also seen with more chronic and severe PHG confined to the antrum. The variable response to β blockers and TIPS may be a reflection of the advanced histologic changes.¹⁵⁶ Some authors believe that the diagnosis of GAVE should be reserved for patients with the presence of typical, linear red lesions in the gastric antrum without the mosaiclike appearance of mucosal background in the rest of the stomach. When there is evidence of a mosaiclike pattern or evidence of more severe PHG in the body and fundus, some authors favor classifying it as a spectrum of PHG.¹⁶⁴

Management

Bleeding from gastric mucosal lesions in patients with portal hypertension is a serious complication, although bleeding is usually slow and insidious and rarely massive and life-threatening. However, multiple transfusions may be required during follow-up. Endoscopic therapy generally is preferred because of its efficacy, but pharmacologic treatment may be used as adjunct therapy or in patients with persistent bleeding from mucosal areas not amenable to endoscopic therapy.

Pharmacologic Treatment

Combination Hormonal Therapy

Combination hormonal therapy has been shown to be effective in controlling bleeding from GAVE in some case reports and small trials.²⁰²^–²⁰⁵ Hormonal therapy does not improve the endoscopic appearance of this lesion. As with other pharmacologic therapies, hormonal therapy provides an alternative to endoscopic therapy when extensive vascular abnormalities are present. It also eliminates the risk of circumferential scarring and stenosis, which can occur with the endoscopic modalities discussed.

Tranexamic Acid

One case report described the use of tranexamic acid for GAVE.²⁰⁶ Given the limited experience with antifibrinolytics for GI bleeding, the use of this agent should be reserved for refractory patients who have failed other measures.¹⁸⁹

Octreotide

Octreotide was used in one trial with successful results.¹⁰¹ However, at least one case report failed to show a response of GAVE to octreotide.²⁰⁷

β Blockers

Treatment with β blockers has been reported to be successful in controlling bleeding from gastric mucosal lesions in cirrhotic patients. However, it is unclear in these reports whether patients bled from PHG or from GAVE.^165,¹⁸⁵ In the study from Spahr and coworkers,¹⁹⁷ treatment with the nonselective β blocker nadolol did not control chronic bleeding from GAVE. In addition, the results of this study clearly showed that the decrease in portal hypertension after TIPS or shunt surgery was not effective in controlling chronic blood loss related to GAVE.¹⁹⁷

Endoscopic Treatment

The current first-line therapy for GAVE consists of endoscopic coagulative ablation. The aim of endoscopic therapy is to eliminate completely or reduce significantly the blood transfusion requirements of a patient with bleeding.

Neodymium:Yttrium-Aluminum-Garnet Laser Coagulation

In a trial by Bourke and associates,²⁰⁸ Nd:YAG laser coagulation was used in 11 consecutive patients with GAVE. Transfusion dependence was eliminated in two-thirds of the patients and decreased in the remaining patients. In this trial, an average of three sessions per patient was required; sucralfate was used to prevent iatrogenic ulceration. Endoscopic laser therapy is repeated every 8 to 12 weeks until most of the lesions disappear and the hemoglobin remains stable. Sufficient time must be allowed after laser photocoagulation therapy for healing of the thermally induced ulcers to occur and to maximize the assessment of residual vascular lesions. One study indicated that the mean number of treatments needed to obliterate the vascular lesions and eliminate the need for transfusions was less for Nd:YAG laser compared with APC (2.33 ± 0.27 vs. 5.75 ± 0.89).²⁰⁹

Heater Probe

The heater probe uses a thermal element that heats the device tip and results in tissue coagulation. Petrini and Johnston ²¹⁰ described the successful use of a heater probe for management of GAVE. An average of four sessions was required to eliminate the transfusion requirements and improve endoscopic appearance in 8 of 10 patients.

Argon Plasma Coagulation

As with the Nd:YAG laser, large surface areas of involved mucosa can be adequately treated with APC during a single endoscopic session. Several case reports have described the successful use of APC for the management of GAVE.^211,²¹²

Compared with Nd:YAG laser, APC is more convenient to use. The tangential approach to the vascular lesions, especially along the posterior wall of the antrum, makes APC an attractive tool for use compared with the laser device, which requires a more perpendicular approach. Among noncontact thermal endoscopic treatments for GAVE, APC has gained popularity in recent years and is now widely available in endoscopy units. The results from several small series and case reports so far have been similar to the results achieved with the Nd:YAG laser but with a superior safety profile.²¹³ Long-term efficacy remains suboptimal, however, with a 22% incidence of recurrent bleeding and with up to 31% of patients requiring ongoing transfusions.^156,^214,²¹⁵ Long-term sequelae of ablation include antral scarring and hyperplastic polyps.²¹⁶ Most rebleeding episodes respond to repeated treatment, but these patients may require multiple sessions and commitment to ongoing endoscopic treatments.²¹³

Higher power settings should be used for patients with GAVE to provide ablation of the mucosal and submucosal vascular abnormalities. Nd:YAG laser therapy provides a viable option for patients with refractory bleeding and should be offered to these patients. The major problem with GAVE is continued blood loss requiring repeated blood transfusions. Ikeda and colleagues ²¹⁷ presented a 10-year endoscopic follow-up study from discrete initial lesions to the full picture of GAVE. They reported that latent hemorrhage occurred at an early stage as the coalesced lesions formed and that the vascular lesions of GAVE should be eradicated at this stage. The underlying pathophysiology is unclear, and endoscopic ablative methods do not affect the origins of the problem, so there is a long-term potential for recurrent vascular lesions and bleeding.

Generally, Nd:YAG laser and APC are preferred over heater probe for the treatment of GAVE because of their ability to cover a greater surface area. However, the endoscopic therapeutic modality chosen also depends on the individual experience of the endoscopist and local availability.¹⁸⁹

Other Endoscopic Techniques

Band Ligation

A retrospective study of thermal therapy (APC or multipolar electrocoagulation probe) compared with band ligation found that band ligation may offer a therapeutic option.²¹⁸ The use of band ligation requires meticulous efforts to band ligate all of the involved mucosa, which is technically challenging and expensive. At the present time, this form of therapy cannot be advocated as superior to existing therapies. Newer mucosal ablation techniques,²¹⁹ such as radiofrequency ablation and cryotherapy, have also been used to ablate GAVE in small pilot studies.

Cryotherapy

A study of 26 patients with various bleeding lesions (e.g., GAVE, arteriovenous malformations, radiation proctitis, radiation gastritis) were treated with cryotherapy with a mean of 3.6 sessions.¹³⁵ These patients had previously undergone treatment with multipolar electrocoagulation and heater probe but continued to have bleeding. Cryotherapy with nitrous oxide was efficacious in causing hemostasis in 77% overall, with follow-up of 6 months. Another report included 12 patients with a diagnosis of GAVE and documented iron deficiency anemia. Eight patients had a history of overt GI bleeding. Eight patients (67%) had previously been treated with APC (median 6 sessions, range 1 to 10 sessions) and failed to respond or had a recurrence. Six patients (50%) had a complete response, and six patients (50%) had a partial response.²²⁰

Preliminary data suggest that cryotherapy may be a reasonable option for diffuse GAVE lesions. Although the etiology of GAVE is poorly understood, histopathology results show distinct abnormalities limited to mucosa and lamina propria, including superficial fibromuscular hyperplasia with capillary ectasia and microvascular thrombosis. Cryotherapy seems to work in GAVE by causing a deeper injury compared with APC with necrosis of mucosa and superficial submucosa, followed by reepithelialization. A major advantage of cryotherapy over APC is its ability to treat large areas of mucosa relatively quickly because ice formation occurs after 2 to 3 seconds of spraying the mucosa and is quickly followed by thawing.¹³⁵

Effective and safe APC treatment requires an experienced endoscopist who is able to target the lesions accurately while maintaining a 1- to 3-mm distance from the mucosa for effective coagulation and avoidance of transmural injury especially because high-power settings are used. Cryotherapy treatment times for GAVE have not previously been reported. Cho and associates ²²⁰ were able to treat greater than 90% of affected mucosa in 89% of cases, with a mean of 5 minutes. Because of its ability to spray a large area quickly, there was no significant difference in the duration with respect to the extent of GAVE. A reduction in the duration of treatment was observed with subsequent cryotherapy sessions, which may reflect the endoscopists’ learning curve with cryotherapy, the use of an overtube, and the reduction in the extent of the lesions to be treated. Limitations of cryotherapy include the need for specialized equipment and training. An overtube has been used to enable passive venting of carbon dioxide to reduce patient discomfort and the risk of perforation. The requirement for an overtube extends the duration of the procedure and adds technical difficulty and risk to the procedure.

The promising benefits of cryotherapy would suggest that a randomized controlled trial that compares endoscopic cryotherapy with APC is warranted. Documentation of different patterns of GAVE, patient characteristics, and histopathology of lesions before and after treatment for both responders and nonresponders to different treatment modalities may provide useful information regarding the optimal endoscopic management of this condition.

Radiofrequency Ablation

A pilot study of six patients with GAVE treated with the HALO90 device (Barrx Medical, Sunnyvale, CA) showed improved hemoglobin concentrations in all patients after one to three treatments. Five of six patients were no longer dependent on transfusions.²²¹ This device provided very superficial coagulation injury. Considerably more experience is needed to determine if this expensive form of therapy is justified.

Surgery

In the study from Spahr and coworkers,¹⁹⁷ chronic bleeding was never controlled in one patient who underwent a surgical shunt despite a complete normalization of portal pressure. Similarly, it has been reported that portacaval shunt surgery proved ineffective in treating chronic GI blood loss related to GAVE in a patient with portal hypertension as a result of nodular regenerative hyperplasia.²²² Antrectomy provides the most definitive therapy for GAVE as illustrated by low rates of rebleeding and anemia recurrence.²²³^–²²⁵ Surgery carries a significant risk of mortality, however, in cirrhotic patients with portal hypertension. TIPS placement may make antrectomy easier and faster by avoiding operative blood losses related to the presence of collaterals secondary to portal hypertension. However, TIPS should be restricted to cirrhotic patients with good liver function, owing to the risk of TIPS-induced progressive liver failure.¹⁹⁷ Given the comorbid illnesses typically associated with GAVE and the advanced age of most patients, surgery is considered salvage therapy for patients who have not responded to a reasonable trial of endoscopic or pharmacologic therapies.¹⁸⁹

Portal Colopathy

Clinical Manifestations

Over the past 2 decades, awareness of the association between portal hypertension and changes in the intestinal circulation has increased. The fundamental pathologic change is a vasculopathy. Portal hypertensive vasculopathy most often involves the stomach (PHG) and can be a source of bleeding. The significance of small bowel involvement (enteropathy) is unknown. Colonic involvement (colopathy) has been associated with bleeding. Several studies have described the colonic findings associated with cirrhosis and portal hypertension.²²⁶^–²³⁵ Colorectal lesions associated with portal hypertension and cirrhosis include hemorrhoids, varices (portosystemic collaterals that develop because of portal hypertension; Fig. 16.7A), focal and diffuse angiectases, and spiderlike vascular lesions. The term portal colopathy has been used to describe colonic lesions resembling the vascular lesions of portal gastropathy and the diffuse colitislike appearance seen in patients with portal hypertension (Fig. 16.7B).^226,²²⁷ There is confusion regarding the diagnostic criteria and clinical significance of this condition. This confusion might be attributable to imprecise terminology, lack of uniform endoscopic descriptions, interobserver variability, and the absence of distinctive histopathologic features.²³⁶

Fig. 16.7 Portal colopathy. A, Portal hypertension causing collateral circulation in the rectum. B, Colitis with granularity, erythema, friability, and cherry-red spots.

In previously published studies, the prevalence of colonic abnormalities in patients with cirrhosis varied widely (Table 16.4), and the true prevalence of portal colopathy is unknown. Because all patients in some studies were referred for colonoscopy based on clinical indications,²³⁷ these reviews may have overestimated the true prevalence of portal colopathy. Conflicting data have been published regarding the relationship between the prevalence of portal colopathy and Child-Pugh classification in cirrhotic patients.²²⁶^–²²⁸ ^,233 ^,235 ^,237 ^,238

Table 16.4 Published Studies on the Prevalence of Colonic Abnormalities in Patients with Cirrhosis

In the study from Bini and associates,²³⁷ portal gastropathy, 2+ or larger esophageal varices, Child-Pugh class C cirrhosis, and the use of β blockers were independent predictors of portal colopathy; the use of β blockers was protective. Portal hypertensive colopathy and gastropathy might not be distinct entities but rather regional manifestations of portal hypertension. These entities might share similar mechanisms with regard to pathogenesis. The histology of the colitislike mucosal abnormalities from most patients with portal hypertension is nonspecific, mild inflammation. Several studies have shown that the endoscopic appearance of colonic mucosal edema and erythema is not associated with significant inflammatory infiltrates but rather mucosal vessel changes.^227,^237,^239,²⁴⁰ Based on these findings, some authors suggest the use of the term colopathy when referring to the mucosal abnormalities of the colon in patients with cirrhosis.²³⁷ This term avoids the suggestion of the involvement of inflammatory cells in the pathogenesis of a disease that lacks a definitive etiologic mechanism.

Several endoscopic classification systems exist to grade the severity of mucosal changes in patients with portal gastropathy.^161,¹⁶³ To date, no classification systems exist for grading the severity of mucosal abnormalities in cirrhotic patients with portal colopathy, making comparisons between studies difficult. Based on their findings, Bini and associates²³⁷ proposed that portal colopathy could be classified into three grades: grade 1, erythema of the colonic mucosa; grade 2, erythema along with a mosaiclike appearance of the mucosa; and grade 3, vascular lesions of the colon, including cherry-red spots, telangiectases, or angiodysplasialike lesions. The same authors²³⁷ observed for the first time an increase in the prevalence of portal colopathy in cirrhotic patients who had undergone band ligation or sclerotherapy, or both, of esophageal varices. They suggested that, similar to PHG, it may be that portal colopathy is related to the levels of portal pressure and that obliteration of esophageal varices may cause a redistribution of blood flow in similar ways in the stomach and colon. Prospective studies are necessary to validate this observation.

Management

β-adrenergic blockers are usually the first-line therapy in patients with portal colopathy. The vascular lesions of portal colopathy are considered amenable to the same thermal therapies as GAVE and PHG, although no trials have been published at this time.^24,²²⁶ TIPS may be useful as a second-line treatment in patients with recurrent portal hypertensive bleeding from colonic angiodysplasialike lesions who do not tolerate or are unresponsive to treatment with β-adrenergic blockers.²⁴¹

Hemangiomas

Clinical Manifestations

Hemangiomas are the second most common vascular lesion of the colon. Considered by some investigators to be true neoplasms, they are generally thought to be hamartomas because most are present at birth. They may be solitary or multiple lesions limited to one segment of the GI tract, or they may be part of diffuse GI or multisystem angiomatoses. Individual hemangiomas may be classified as cavernous, capillary, or mixed types. Most are small (Fig. 16.8), ranging from a few millimeters to 2 cm, but larger lesions do occur, especially in the rectum (see section on cavernous hemangioma of the rectum). In the presence of GI bleeding, hemangiomas of the skin should suggest the possibility of associated bowel lesions.⁴⁷ Hemangiomas causing upper GI hemorrhage are most commonly identified in the upper small intestine. These benign vascular tumors, almost all of which are cavernous hemangiomas, appear as single or multiple red, purple, or blue nodular lesions.

Fig. 16.8 A, Solitary hemangioma of the colon. B, Narrow band imaging of hemangioma of the colon.

These lesions generally should not be treated endoscopically because they may be transmural, and treatment would result in perforation and induce bleeding from larger vascular elements. Angiographic therapy may stop bleeding; however, the most effective treatment is surgical. Bleeding from colonic hemangiomas usually is low in volume, producing occult blood loss with anemia or melena. Hematochezia is less common except in large, cavernous hemangiomas of the rectum, which may cause massive hemorrhage. Diagnosis is best established by endoscopy, including enteroscopy, because radiologic studies, including angiography, frequently are normal, although the presence of calcifications representing phleboliths within hemangiomas has been described.

Management

Hemangiomas that are small, solitary, or few in number can be treated by colonoscopic coagulation using laser or other thermal mode. Colonoscopic excision of small lesions has been described,²⁴² including removal of small lesions for the purpose of diagnosis in patients with multiple hemangiomas.²⁴³ Amano and colleagues²⁴⁴ reported electrosurgical snare polypectomy of a large, pedunculated, polypoid cavernous hemangioma that arose in the sigmoid colon in a 28-year-old man who presented with prolapse of the lesion through the anus. Although complications of colonoscopic excision of hemangiomas seem to be rare, the number of reports is small, and it is difficult to determine the safety of colonoscopic treatment. Safety may depend on size and gross morphology of the lesion (e.g., sessile vs. pedunculated) and the technical feasibility of endoscopic treatment. Large or multiple lesions usually require surgical resection of either the hemangioma alone or the involved segment of colon.

Cavernous Hemangioma of the Rectum

A distinct form of colonic hemangioma is cavernous hemangioma of the rectum.⁴⁷ These lesions are usually not associated with other GI hemangiomas and are extensive, involving the entire rectum or portions of the rectosigmoid colon. The massive bleeding resulting from these rectal hemangiomas often necessitates excision of the rectum by either abdominal-perineal or low-anterior resection; ligation and embolization of major feeding vessels have been employed successfully. Attempts at local control have been valuable in some instances, but mostly these have been only temporarily effective.

Blue Rubber Bleb Nevus Syndrome

Clinical Manifestations

Blue rubber bleb nevus syndrome (BRBNS), also known as Bean’s syndrome, is a rare entity, characterized by cutaneous hemangiomas and vascular tumors of the GI tract, that can also involve other organs such as the brain, kidneys, lungs, eyes, oronasopharynx, parotids, liver, spleen, heart, pleura, peritoneum, pericardium, skeletal muscles, bladder, penis, and vulva.²⁴⁵^–²⁴⁷ Although a familial history is infrequent, a few cases of autosomal dominant transmission have been reported,²⁴ and one analysis identified a responsible locus on chromosome 9. The lesions were thought to be hemangiomas, but they are now considered to be venous malformations,^24,²⁴⁸ which usually appear in early childhood and tend to increase in size and number with age. They are usually blue and raised, vary from 0.1 to 5 cm in diameter, have a wrinkled surface, and are easily compressible with light palpation. The contained blood can be emptied by direct pressure, leaving a wrinkled blue sac that slowly refills over several seconds or minutes.²⁴ Skin lesions may be present throughout the body, particularly predominating on the upper limbs (Fig. 16.9A), trunk,²⁴⁹ and face.

Fig. 16.9 Multiple hemangiomas of blue rubber bleb nevus syndrome. Typical dark blue nodular lesions of the skin (A) and involving the colon (B and C).

GI lesions are usually multiple and may involve any portion of the GI tract but are most common in the small bowel and in the distal part of the colon.²⁴ The characteristic GI lesion is a discrete mucosal nodule with an overlying central bluish red cap resembling a nipple, but a lesion may be a flat macular, dark bluish red spot or a frankly polypoid nodule with a central venous colored portion (Fig. 16.9B and C).^246,²⁵⁰ Most patients are asymptomatic. Loss of blood from the GI tract is the major problem and commonly causes chronic anemia.^250,²⁵¹ The onset of GI bleeding may be at any time from early childhood to middle age.¹⁴⁵ The lesions can also cause intestinal intussusception²⁵² and numerous extraintestinal problems, such as orthopedic deformities associated with bone involvement,²⁴⁵ neurologic defects secondary to central nervous system involvement²⁵³ and spinal cord compression,²⁵⁴ pulmonary hypertension owing to vascular obliteration, hemothorax and hemopericardium,²⁵⁵ exophthalmos and loss of vision secondary to eye involvement,²⁴⁷ and disseminated intravascular coagulation and thrombocytopenia.²⁵⁶

Diagnosis

When blue rubber bleb nevus syndrome is suspected and depending on the clinical manifestations, diagnostic studies should include gastroscopy, colonoscopy, capsule endoscopy,²⁵⁷ enteroscopy,²⁴⁶ intraoperative enteroscopy,²⁴⁸ endoscopic ultrasound,²⁵⁸ enteroclysis, ultrasound, CT,²⁵¹ magnetic resonance (MR) imaging,^249,^253,²⁵⁹ radionuclide tagged red blood cell scan,²⁵⁵ and angiography.²⁶⁰

Treatment

Most patients respond to supportive therapy, such as iron supplementation and blood transfusion when required.²⁵⁰ For recurrent bleeding, medical, endoscopic, and surgical therapies have been used. Medical therapy includes the use of corticosteroids,^256,²⁶¹ antifibrinolytic agents,²⁶² γ-globulin,²⁵⁶ interferon,^248,²⁶¹ and octeotride.²⁶² Endoscopic management seems to be safe and useful, although the lesions can be transmural, which implies a theoretical increase in risk for bowel perforation as a complication. There are several reports of endoscopic therapy, including sclerotherapy with absolute alcohol,²⁶³ sodium morrhuate,²⁶⁴ epinephrine and polidocanol,²⁶⁵ band ligation,^251,²⁶⁵ polypectomy,^249,^251,²⁶⁶ bipolar coagulation,²⁶⁷ and laser therapy.^267,²⁶⁸

Angiographic embolization can be useful for treating acute bleeding and preventing further bleeding.²⁶⁹ Successful surgical excision of the bleeding lesions or segmental resection of the involved bowel segment has been performed^248,²⁷⁰ and can be aided by intraoperative endoscopy.^248,²⁷¹ Patients with an overwhelming number of lesions may require staged operative procedures.²⁴⁸

Klippel-Trénaunay-Weber Syndrome

Clinical Manifestations

Klippel-Trénaunay-Weber syndrome, also known as nevus vasculosus hypertrophicus, is a rare congenital vascular malformation, secondary to a generalized mesodermal development abnormality.²⁷² Originally described by Klippel and Trénaunay in 1900, it is characterized by bony or soft tissue hypertrophy, usually affecting one extremity (Fig. 16.10A); hemangiomas or lymphangiomas or both; and varicosities or venous malformations, appearing at birth or in childhood.

Fig. 16.10 Klippel-Trénaunay-Weber syndrome involving gastrointestinal tract. A, Hypertrophic leg caused by venous hypertension and stasis. B, Rectal hemangioma in the same patient. C, Rectal hemangiomas and venous varicosities in another patient with Klippel-Trénaunay-Weber syndrome.

Visceral hemangiomas have been described involving organs such as the GI tract (Fig. 16.10B), liver, spleen, bladder, kidney, lung, and heart.^273,²⁷⁴ Involvement of the GI tract may be more common than previously believed, occurring in 20% of patients.²⁷⁴ GI hemorrhage is a potential serious complication secondary to diffuse vascular malformations involving the GI tract. GI bleeding usually begins in the 1st decade of life and may be recurrent and mild or severe.²⁷³ The severity may be enhanced by a consumption coagulopathy owing to intravascular clotting within the venous sinusoids of the hemangiomas.⁴⁷ The most common reported cause of GI bleeding is attributed to diffuse cavernous hemangiomas of the distal colon and rectum,²⁷⁵ found in 1% to 12.5% of cases.^273,²⁷⁶ Less frequent causes of GI bleeding are rectal or rectovaginal varices caused by obstruction of the internal iliac system, esophageal varices secondary to prehepatic portal hypertension owing to cavernous transformation or hypoplasia of the portal vein,²⁷⁷ and jejunal hemangiomas.²⁷⁸ Colonic obstruction and ascites secondary to massive hemangiomatous-lymphangiomatous retroperitoneal masses may occur.²⁷⁹

Diagnosis

Radiologic investigations play an important role in assessing colorectal involvement in Klippel-Trénaunay-Weber syndrome and occasionally finding the specific bleeding site. The presence of phleboliths on a plain abdominal radiograph in these very young patients suggests that they have angiomatosis.²⁷³ Barium studies can show luminal distensible narrowing, with a scalloped mucosal outline caused by the presence of varicosities or submucosal hemangiomas.^47,²⁸⁰ CT and MR imaging of the abdomen and pelvis provide a simple, noninvasive means of assessing visceral hemangiomatous masses and identifying upward extension in the pelvis and abdomen.^274,²⁸⁰ Abdominal angiography is required preoperatively for defining the anatomy and extent of the intestinal involvement to guide surgical intervention.²⁷⁸ At colonoscopy, the rectum and the lower part of the colon may show visible mucosal vessels or compressible nodules and extensive bluish angiomatous submucosal lesions. Biopsy of the lesions should be avoided because it may precipitate severe hemorrhage.²⁷³ Lesions in deeper layers of the wall can be assessed by endoscopic ultrasound.²⁸¹

Treatment

Treatment varies from conservative to surgical measures, depending on the clinical symptoms and risk of complications. Transfusion dependency, life-threatening bleeding episodes, and poor quality of life require definitive surgical therapy.^273,²⁷⁴ When the entire rectum is severely involved, surgery is sometimes necessary via an abdominoperineal resection of the involved rectum and colon, with a permanent colostomy²⁷⁶ or with a colon pouch anal anastomosis.²⁸² Angiographic embolization may be useful if a specific active bleeding site is found²⁷³ or preoperatively.²⁸² Endoscopic therapy has a limited role because of the commonly diffuse nature of the intestinal hemangiomas²⁸³ and is reserved for management of localized lesions or ablation of postoperative residual disease. The use of argon²⁸⁴ and Nd:YAG laser,²⁸³ sclerosis with formaldehyde and absolute alcohol,²⁸⁵ and placement of hemostatic clips in the rectum combined with arterial embolization²⁸⁶ have been reported with success. APC and photodynamic therapy²⁷³ may be very efficient, but their use in Klippel-Trénaunay-Weber syndrome has not yet been reported.

Radiation Injury of the Gastrointestinal Tract

Radiation Proctopathy

Clinical Manifestations

Radiotherapy is a common treatment modality used for several pelvic malignancies. Despite progress in radiation techniques, adjacent organs are still exposed to chronic radiation injury, which occurs in 2% to 25% of patients.²⁸⁷

The rectum, a fixed organ in the pelvis, has a glandular-type epithelium in which the cells undergo a rapid turnover. This organ is particularly vulnerable to ionizing radiation and to radiation-induced complications. The incidence of such complications is proportional to the dose and its degree of spreading and to the volume and method of irradiation (external or by brachytherapy).²⁸⁷ Intracavitary radiation delivery has been shown to increase the risk of developing chronic radiation proctopathy.²⁸⁸ Risk factors for radiation-induced damage include history of abdominal surgery, arteriosclerosis, obesity, diabetes, and concomitant chemotherapy.^287,^289,²⁹⁰

Radiation injury to the intestine has acute and chronic phases. Acute radiation injury occurs during or immediately after treatment and results from direct cellular damage. This injury inhibits division of the intestinal crypt stem cells, and the lamina propria becomes infiltrated with inflammatory cells resulting in loss of cellular function and mucosal inflammation. Clinical symptoms of acute radiation proctitis—diarrhea and tenesmus—are usually self-resolving, requiring only symptomatic treatment, and are not typically therapeutic challenges.²⁹¹ Chronic radiation proctopathy is histologically characterized by submucosal collagen proliferation, endarteritis of arterioles, and thrombi in vessel lumens, leading to submucosal fibrosis, chronic mucosal ischemia, and progressive epithelial atrophy.²⁹² Clinical symptoms of chronic radiation usually begin months to years after the initial radiation exposure, with a median of 8 to 16 months^292,²⁹³ but with latencies as long as 30 years.²⁹⁴ Symptoms include rectal bleeding, diarrhea, rectal pain, fecal urgency, tenesmus, obstructed defecation (in patients who have developed stenosis), and less commonly fecal incontinence and fistulas. Many patients have multiple symptoms with a significantly negative impact on their daily activities.²⁹¹ Bleeding may be severe enough to require frequent hospitalizations and blood transfusions; 55% of patients may require support with blood transfusions before undergoing definitive therapy.²⁹⁵

Diagnosis

Flexible Sigmoidoscopy And Colonoscopy

Flexible sigmoidoscopy and colonoscopy aid in diagnosis and determine the extent and severity of radiation injury. The findings include distinctive angiectases accumulated in the distal rectum, extending to and often including the dentate line along with friability and spontaneous bleeding (Fig. 16.11). Less frequently, there may be ulceration, stenosis, and fistulas. There is often a distinct margin between normal and abnormal tissue that relates to the edge of the radiation field.²⁹⁵ In some patients, especially women who have undergone radiation therapy after surgery for a gynecologic malignancy, there may be an associated segment of sigmoid colon with identical findings.

Fig. 16.11 Radiation proctopathy with pale mucosa, edema, and angiectasis.

Barium Enema

Barium enema may be helpful in investigating patients suspected to have fistulas or strictures. It may show distortion and narrowing of the colon and rectum, although it tends to underestimate the severity of radiation injury.²⁹⁶

Manometry Studies

Anorectal physiology manometry studies reveal reduced rectal compliance, rectal volumes, and anal resting pressures and reduced internal anal sphincter length.^297,²⁹⁸

Treatment

Medical Therapies

The traditional approach to treatment of radiation proctopathy has been directed toward decreasing any inflammation with the use of antiinflammatory agents such as aminosalicylic acid derivatives and corticosteroids.²⁹¹ The response to such agents is disappointing. Other approaches such as promoting healing in damaged tissue with short-chain fatty acid enemas,²⁹⁹ oral and rectal sucralfate,^293,³⁰⁰ antioxidants and vitamins,²⁹¹ or hormonal therapy with an estrogen-progesterone combination³⁰¹ have been tried without significant success. The use of hyperbaric oxygen has been shown more recently to be helpful in patients who are not controlled with endoscopic techniques such as formalin, laser therapy, and APC. The response rate was 68%.³⁰² The response rate for bleeding was 70% to 76%,^302,³⁰³ 48% showed complete resolution of bleeding, and 28% reported significantly fewer bleeding episodes.³⁰³ Although this therapy is expensive and inconvenient, requiring 20 to 40 treatment sessions,^304,³⁰⁵ it should be offered to patients who fail conventional treatments.³⁰⁶

Endoscopic Therapies

Different endoscopic therapies have been described for rectal bleeding in this condition.

Topical Formalin

Topical formalin application for radiation injury was first reported in radiation-induced cystitis.³⁰⁷ Its mechanism of action is likely to be due to a local chemical cauterization of the inflamed or fragile telangiectatic rectal mucosa.²⁹⁵ The treatment is inexpensive and easy to perform. The technique involves the direct application of 4% formalin to the affected area in the rectum, either with formalin-soaked gauze³⁰⁸ or by direct instillation and timed retention (typically approximately 10 minutes).³⁰⁹ The application continues until mucosal blanching occurs, usually within 2 to 3 minutes.³¹⁰ The perianal area should be protected with careful draping and the application of petroleum jelly around the anus and perianal skin to avoid formalin injury.²⁹⁶ The rectum is irrigated liberally after topical application to remove residual formalin. Formalin is contraindicated in the presence of fissures or ulceration. The short-term success of the technique with complete cessation of bleeding ranges from 59% to 100%.^295,³¹¹ Recurrent symptomatic relapses have been treated successfully with repeated applications.

In patients with severe radiation proctitis, the administration of topical formalin may be more effective than APC.³¹² Complications have been described in 27% to 57% of patients^311,³¹³ and include painful fissures of the anal margins, perianal ulcerations,³¹⁴ stool incontinence, and rectal ulcerations and strictures.³⁰⁹ Some authors think that this technique should be reserved for severe hemorrhagic proctitis refractory to medical or endoscopic treatment and that it should be thoroughly discussed in cases of anorectal radiation–induced stricture, prior anal incontinence, or treated anal cancer.³¹¹ Formalin offers an excellent option for patients who are on anticoagulation and have increased risk for bleeding from thermally induced ulceration after conventional coagulation therapies.

Bipolar Electrocoagulation and Heater Probe

Bipolar electrocoagulation and heater probe are more effective than medical therapy improving the quality of life.³¹⁵

Laser

Argon,³¹⁶ Nd:YAG,³¹⁷ and KTP laser³¹⁸ have been reported to be effective with a marked decrease in bleeding in 87% of treated patients.²⁹⁵ Repeated treatments were needed in the long-term because symptoms tended to recur.³¹⁶ Laser therapy has the advantage of being a precise technique that does not involve tissue contact, is well tolerated, and improves activities of daily life. Disadvantages include its high cost; the need for protective precautions; and the risk of rectal ulcer,³¹⁸ bowel perforation, and rectovaginal fistulas.²⁹⁵

Argon Plasma Coagulation

APC represents a safer, less expensive, and more widely available alternative to laser therapy.³¹³ Many authors consider APC to be first-line therapy for radiation proctopathy. When the lesions are circumferential and numerous, a staged treatment may be useful allowing a sufficient period of time for healing of the previously treated area of at least 4 weeks.²⁸⁷ A median of 1.7 to 3.7 treatment sessions is necessary for control of bleeding.^295,^319,³²⁰ APC is relatively ineffective in patients with excessive bleeding, owing to the absorption of current by blood on the surface. It is important to minimize contact-induced bleeding during endoscopy to maximize access to the vascular lesions.

Care must be taken not to overdistend the bowel with argon gas insufflations.²⁹⁵ In the case of low rectal lesions, the use of a transparent cap at the tip of the colonoscope allows direct viewing of these lesions and of the upper part of the anal canal without the retroflexed position. Thanks to the cap, the endoscope remains close to the lesion but with sufficient distance to allow safe APC.³²¹ One of the most common reasons for failed endoscopic therapy is the failure to coagulate the lesions at and immediately above the dentate line. There was significant improvement in rectal bleeding in many patients, with complete cessation of bleeding in 81% to 98%,^319,^322,³²³ providing long-lasting clinical remission.³²⁴

APC improves symptoms of diarrhea and tenesmus in 60% to 75% of cases ³²⁵ with no obvious reason apparent. Patients with diarrhea and tenesmus should be advised that these symptoms may seem worsened after bleeding is controlled owing to the greater awareness of the symptoms in the absence of bleeding. Because of its limited depth of penetration, morbidity is usually minor and consists of gas bloating, tenesmus, transient abdominal or anal pain, and diarrhea in about 20% of cases.³¹⁹ Major complications are exceptional but include rectovaginal fistula,³²⁶ chronic rectal ulceration, anal or rectal stricture,²⁸⁷ and perforation.³²⁷ Deliberate care should be taken to use the lowest power setting that provides a coagulum and to avoid overtreating, especially with persistent oozing after initial coagulation.

Endoscopic Cryotherapy

Endoscopic cryotherapy using nitrous oxide has been described more recently in a small group of patients with radiation proctitis with complete control of bleeding in all patients.¹³⁵ It was also highly effective in patients with multiple angiectases (86%) and “watermelon stomach” (71%), but less effective in patients with radiation gastropathy and duodenopathy (40%). Cryotherapy was applied every 2 to 3 days until all lesions were ablated. The average number of therapeutic sessions needed to stop the bleeding was 3.6. Cryotherapy resulted in superficial tissue necrosis that was usually completely healed within 3 months after the final treatment sessions. Cryotherapy was remarkably safe with only benign self-limited adverse events.

Surgery

Surgical treatment is now considered a last resort and should be reserved for patients who have intractable symptoms that have failed to respond to medical therapy and patients with rectal strictures and fistulas because it is associated with frequent morbidity (9% to 79%)^295,³¹³ and mortality (3% to 13%).^313,^328,³²⁹ Proctectomy and Hartmann’s procedure, abdominoperianal resection, and coloanal anastomosis are the surgical options. Resection of the affected rectum necessitates dissection in an irradiated field with potential complications that range from bleeding to anastomotic leaks and sepsis.²⁹³

Radiation Gastropathy

Gastric complications secondary to radiotherapy are uncommon, but injury can occur when the stomach lies within the radiation field of an adjacent extragastric tumor.³³⁰ A high total dose, usually greater than 5000 rad, and a high daily fraction seem to be the main risk factors.³³¹ There have been reports of chronic gastroduodenal ulcerations, gastritis, and duodenitis being diagnosed days to months after selective internal radiation therapy with resin-based microspheres loaded with yttrium-90. It is possible to find small spheres located inside the vessels in the biopsy specimens.^332,³³³ Acute vasculopathy may progress to a prolonged and progressive endarteritis obliterans, vasculitis, and endothelial proliferation, leading to mucosal ischemia, ulceration, mucosal angiectases and fibrosis.³³⁴

In contrast to radiation proctopathy, GI bleeding from chronic radiation gastropathy is rare with very few cases reported.³³⁴^–³³⁶ When it is present, there are multiple friable angiectases. These lead to melena and significant blood loss requiring multiple blood transfusions, prolonged hospitalizations, and repeated endoscopies. Endoscopically, the mucosa of the affected stomach (usually antrum) is friable and with multiple angiectases (Fig. 16.12). Other possible severe complications are perforation and gastric outlet obstruction.²⁹²

Fig. 16.12 Radiation-induced gastritis with erythema, friability, and ulcerated mucosa.

There is very little information in the literature on the management of radiation-induced complications in the stomach.²⁹² Prolonged blood loss needs to be treated with iron and folic acid supplements and with transfusions. Aminocaproic acid³³⁴ and hyperbaric oxygen³³⁵ have been reported to be effective in control of bleeding in a few patients. Bleeding can be controlled by any endoscopic coagulation technique, with APC preferred³³⁶^–³³⁸ and cryotherapy.¹³⁵ Surgery may be necessary if other treatment fails,^331,³³⁹ but is associated with high morbidity.³³⁴

Radiation Injury of the Small Bowel

The small intestine is particularly susceptible to radiation injury (Fig. 16.13).³³⁰ Radiation injury to the small intestine most often occurs in the clinical setting of radiotherapy for rectal, urologic, gynecologic, or retroperitoneal malignancies. The degree of injury seems to be proportional to radiation dosage delivered to the segment of small bowel that lies within the radiation field. The relative fixed position of the duodenum and distal ileum within the abdominal cavity make these portions particularly vulnerable to radiation-induced injury. Predisposing factors in the progression of radiation injury include excessive radiation, previous abdominal surgery that fixes loops of bowel in place, underlying cardiovascular disease, and an asthenic habitus.³⁴⁰ The mechanism of injury is vascular damage with progressive localized ischemia. The ischemia leads to angiectases and ulceration of the mucosa, fibrosis with stricturing, and, less frequently, fistula formation or perforation.

Fig. 16.13 Radiation-induced duodenopathy with edema, friability, and diffuse angiectases.

The clinical manifestations of chronic radiation typically occur 1 to 2 years after exposure and range from malabsorption, hemorrhage, bowel obstruction, fistulas, and abscess formation secondary to perforation.³⁴¹ Bleeding can be managed with the same endoscopic techniques that are used in radiation proctitis. Balloon enteroscopy may be needed to access distal small bowel involvement and perform dilation of the diaphragmlike strictures, which resemble strictures seen with long-standing use of nonsteroidal antiinflammatory drugs. The treatment is difficult, and often surgery is necessary.³⁴⁰ Resection of the involved small bowel segment is preferable to bypass.¹³⁷

Cameron Ulcers and Erosions

Patients with large hernias may develop Cameron ulcers or erosions. These mucosal lesions are usually located on the crest of the mucosal folds that make up the distal hiatal hernia rosette, on the lesser curve of the stomach, or at the level of the diaphragmatic hiatus.³⁴² Cameron lesions can be found in 5% of all patients with hiatal hernias.³⁴³ The cause of Cameron lesions is still unclear, but it is thought that mechanical trauma secondary to diaphragmatic contraction from respiratory excursions and, perhaps, ischemia and acid mucosal injury play a primary role in their pathogenesis.³⁴⁴ Cameron lesions manifest clinically with chronic occult GI bleeding and associated iron deficiency anemia. These lesions can also manifest as acute upper GI bleeding in one-third of cases.³⁴³ Treatment includes antisecretory therapy and supplemental iron. In about one-third of patients, Cameron lesions may persist or recur despite antisecretory medication, in which case surgical repair of the hiatal hernia is required.³⁴³

References

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