4
Preoperative assessment and perioperative management in oesophageal and gastric surgery
Introduction
Perioperative management strategies have been shown to be important in postoperative outcome following oesophageal and gastric surgery.1 Structured pre- and perioperative management has also been shown to have an important role in outcome from a number of other major surgical procedures.2 The overriding principle of preoperative assessment is to identify comorbidities that may complicate the patient’s operative intervention and perioperative recovery. Identification, recognition and treatment of these comorbidities allow the patient to be optimised prior to undergoing surgery in an effort to reduce the incidence of perioperative mortality and postoperative complications.
Perioperative management is another critical factor that can have a significant impact upon clinical outcome following oesophagectomy or gastrectomy.3 This includes selection of surgical and anaesthetic techniques, methodology of intraoperative monitoring, minimising blood losses and perioperative fluid management, as well as lung isolation techniques and intraoperative organ support. Thus, although surgical technique plays an important role in determining outcome following oesophagectomy and gastrectomy, it remains only one variable amongst many others that play a significant part.4
Recently the role of the multidisciplinary team has become increasingly important in the care of this complex cohort of patients. A collaborative approach fosters an open dialogue between surgeons, anaesthetists, oncologists, radiologists, cancer specialist as well as ward nurses, nutritionists, physiotherapists and critical care teams. This dialogue allows the patient to work with highly specialised medical professionals and ideally be included in validated clinical pathways, in order to provide a high-quality service and successful outcome.5 In this chapter, we will review some of the governing principles of preoperative assessment and perioperative management in the context of oesophagogastric surgery, and examine recent developments in this field.
Physiological stress during the treatment of oesophagogastric malignancy
The multimodal nature of treatment of oesophagogastric malignancy imparts significant physiological stress. There are specific issues that can affect a patient’s tolerance to treatment. These issues classically include cardiac and pulmonary reserve, renal function and any other conditions that limit patient mobility and the potential for patients complying with standardised postoperative goals. Clinical outcome following major surgery involves interplay between patient characteristics (e.g. comorbidities), disease characteristics (e.g. tumour stage, grade and cell type), choice of treatment modality (e.g. surgery, chemotherapy, radiotherapy or combination of several modalities) and postoperative recovery.6,7 The results and interpretation of preoperative testing may affect a patient’s treatment course at multiple levels. Thus the goal of preoperative assessment is to identify relevant risk factors in patients, in order to provide a tailored patient-centred approach to the management of oesophagogastric malignancy.
Surgical resection is one modality in the treatment of oesophagogastric malignancy and remains the most commonly applied approach in physiologically appropriate patients with early and locoregional cancer. Surgery does, however, involve a significant physiological challenge.8 Prolonged operations with blood loss and fluid shifts, large thoracic and abdominal incisions, extensive lymph node and tissue dissection around vital organs, and the potential requirement for single lung ventilation are some of the intraoperative factors that can place significant strain upon the cardiorespiratory system of the patient undergoing surgery.9 Adjunctive therapy, including chemo- and radiotherapy in selected patients, can also result in significant physiological impact.10,11 Prediction of patients with sufficient reserve to undergo multimodality therapies is the most important factor when assigning a treatment approach.
Diagnosis
Clinical assessment undertaken at primary care consultation must highlight important symptoms including dysphagia and odynophagia to trigger further investigation. Studies have shown that an under-appreciation of the importance of dysphagia in younger patients can lead to a delay in presentation and an advanced tumour stage, resulting in a poorer prognosis in younger patients.12,13
Standard staging investigations for oesophagogastric malignancy (Box 4.1) include endoscopy, endoscopic ultrasound (EUS), computerised tomography (CT) and positron emission tomography (PET) with or without staging laparoscopy (for oesophagogastric junctional, cardial or gastric tumours). Among the currently available staging modalities, EUS is considered the best for T stage and assessment of regional lymph nodes, whereas PET is the most accurate for the detection of distant nodal and metastatic spread.14 Apart from being increasingly useful in initial staging of oesophageal cancer, [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) scanning has been identified as a potential tool for assessing the therapeutic response after neoadjuvant therapy and detection of recurrent malignancy.15,16
Multidisciplinary team evaluation
Centralisation of oesophagogastric cancer treatment has further improved the opportunities for informed multidisciplinary discussion through increasing specialisation and higher volume centres, resulting in improved clinical outcomes.17,18 This has in turn led to increased recruitment to clinical trials, a process that has been further facilitated by the presence of clinical oncologists as part of the MDT discussion.
Neoadjuvant therapy
Radiotherapy
Several studies have demonstrated a survival benefit in the use of neoadjuvant chemoradiotherapy in oesophageal cancer.19,20 Although this combination therapy has been shown to be effective, it may result in a significant physiological impact on the patient.21 Changes in myocardial perfusion have been reported following chemoradiotherapy for oesophageal malignancy.22 Hence it is important to identify patients with cardiac comorbidities and impaired preoperative cardiac testing that may be more at risk from resultant myocardial ischaemia. Respiratory reserve as measured by pulmonary function testing can also be adversely affected by the use of thoracic radiotherapy.23 Some chemotherapeutic agents, including 5-fluorouracil and cisplatin, have a radiosensitising effect by decreasing the ability of DNA damage repair mechanisms, thus potentiating both therapeutic and toxic effects of radiotherapy.24 This illustrates the importance of reassessment following completion of neoadjuvant therapy, prior to undertaking surgical resection of the gastro-oesophageal cancer. Timing of surgery around neoadjuvant chemoradiotherapy is also an important consideration as in our institution we would recommend surgery 4–6 weeks following the cessation of radiotherapy; however, surgery within 4–10 weeks would be acceptable.
Chemotherapy
Previous studies have shown a clear benefit to the use of adjunctive chemotherapy in the treatment of advanced stage oesophagogastric malignancy.25 Chapter 9 will discuss in more detail the merits of chemotherapy in this disease. However, it is important to note that chemotherapeutic agents can cause significant side-effects, including vomiting, bleeding, malnutrition, compromised immunity, etc. Thus patients undergoing neoadjuvant chemotherapy must be re-evaluated from a physiological and immunological standpoint prior to undergoing surgical resection.
Nutrition
Nutritional assessment and optimisation is a cornerstone of good pre- and perioperative care in cancer surgery. Preoperative malnutrition and associated immunosuppression have been shown to be well correlated with septic complications and mortality following oesophageal cancer surgery.26 The mechanism of malnutrition (Box 4.2) is often related to dysphagia, disease cachexia or neoadjuvant chemotherapy. Nutritional assessment should be a component of the MDT review.
The relative merits of enteral over parenteral methods of feeding in the malnourished patient have been the subject of debate for several years. The proposed benefits of enteral feeding include improved gut oxygenation, colonisation with gut flora serving to reduce septic complications and a reduced cost compared to parenteral feeding.27 There are several potential approaches to enteral feeding (Box 4.3).
At the time of surgery many surgeons would advocate the routine placement of a feeding jejunostomy to ensure nutrition through the perioperative period and allow a more measured approach to reinstating oral nutrition. This can simplify discharge and avoid postoperative problems during the critical healing period, as in our patients jejunal tube feeding is initiated on postoperative day 1. It is important to emphasise that feeding jejunostomies can still be associated with complications in a proportion of cases,28 which should be discussed with the patient prior to placement. In our own experience, we have found that placing a large 14Fr feeding tube decreases problems with tube obstructions.
Although percutaneous endoscopic gastrostomy (PEG) feeding provides a good method of nutritional supplementation, in oesophageal cancer patients it may compromise the gastric conduit used in surgery. In recent years the development of endoscopic stents has served as a well-tolerated treatment modality to bypass obstructing oesophageal lesions and allow oral enteral feeding either for preoperative optimisation or as a palliative measure. However, despite these benefits, fully covered oesophageal self-expanding metal stents (SEMS) are associated with an increased risk of migration (6–43.8%)29 that may significantly impact upon the patient’s nutritional status and surgical resection. Furthermore, many clinical oncologists are hesitant to use radiotherapy in a patient with an oesophageal metal stent. Thus the future of stents as a nutritional bridge during neoadjuvant therapy remains inconclusive, with further studies required.
Preoperative assessment
In general terms, the most familiar and simple classification of preoperative physical status and risk is that of the American Society of Anesthesiologists (ASA) (Table 4.1). Although the correlation of ASA grade with perioperative risk has limitations, it does provide a useful global assessment tool and its use is universal and familiar. Several other clinical risk indices have been developed, including the Eastern Cooperative Oncology Group (ECOG) performance status, the Karnofsky performance scale index and the Charlson comorbidity index. ECOG performance status allows assessment of the effect of oesophagogastric cancer on the daily living abilities of the patient. The Karnofsky performance scale index allows patients to be classified by their functional impairment, in a similar manner to the ECOG score. The Charlson comorbidity index predicts the 10-year mortality for a patient who may have a range of comorbid conditions such as heart disease, AIDS or cancer (22 conditions in total). This index allows quantitative scoring of a patient’s comorbidities and may provide a useful tool in the preoperative assessment.
Table 4.1
The American Society of Anesthesiologists’ assessment of physical status
| Grade | Definition |
| ASA 1 | Normal healthy patient |
| ASA 2 | Patient with mild systemic disease |
| ASA 3 | Patient with a severe systemic disease that limits activity but is not incapacitating |
| ASA 4 | Patient with incapacitating disease that is a constant threat to life |
| ASA 5 | Moribund patient not expected to survive 24 hours with or without surgery |
Cardiac assessment (Box 4.4)
As described previously, oesophagectomy or gastrectomy places significant physiological stress upon the cardiovascular system. Up to 10% of patients undergoing oesophagectomy will have a significant cardiovascular complication.30 Furthermore, with increasing oesophagogastric surgery being undertaken in the elderly population, accurate identification of patients at risk from cardiovascular complications (associated with ischaemia or dysrhythmia) can help guide treatment planning.
History
A thorough history and appropriate clinical examination will help identify major cardiovascular risk factors. These include ischaemic heart disease, valvular abnormalities, arrhythmias, heart failure, etc. Ischaemic heart disease has been identified as a crucial risk factor predicting severe complications following major surgery.31 Identification of atrial or ventricular tachyarrhythmias can also help identify patients at risk for the most common postoperative complication, atrial fibrillation. Any pertinent findings will help guide further investigations that may be required, including a full cardiology assessment prior to undertaking major surgery.
Functional capacity
Exercise capacity provides a useful measure of functional cardiorespiratory reserve. Poor exercise tolerance correlates with an increased risk of perioperative complications that are independent of age and other patient characteristics.32 However, the ability to climb a flight of stairs does not preclude a patient from having underlying cardiorespiratory disease, and prior to undertaking surgery the majority of oesophagogastric surgeons and most anaesthetists would advocate the use of further cardiac investigation in all elderly patients or patients with multiple risk factors. In the absence of an agreed protocol, exercise testing for oesophagogastric cancer surgery patients remains an important consideration during preoperative evaluation; however, it should not be used as the sole criterion for denying a patient an operation.
Investigations (Box 4.4)
Electrocardiogram (ECG): ECG is the most basic objective cardiac assessment, usually as part of any preoperative work-up prior to major surgery. It remains a useful baseline test to identify electric conductional abnormalities within the heart that may indicate further structural abnormalities that warrant further investigations. Patients with no prior history of cardiac disease but with an abnormal ECG represent a group that must undergo a higher level of investigation and are potentially amenable to intervention and risk reduction prior to surgery.
Cardiopulmonary exercise testing (CPX): The relative merit of cardiopulmonary exercise testing in the setting of oesophagogastric surgery remains controversial. Some surgeons propose the view that CPX testing is expensive, time-consuming and unreliable for the prediction of cardiorespiratory complications following oesophagectomy or gastrectomy. The literature on this subject also fails to resolve the debate. In a retrospective cohort study, Nagamatsu et al.33 divided patients into two groups based on the presence or absence of cardiopulmonary complications. Nagamatsu et al. found significant differences between the two groups in their preoperative VO2max (P < 0.001) and anaerobic threshold (AT; P < 0.001). In the follow-up to this study, Nagamatsu et al.34 performed a retrospective study of CPX testing in 91 patients who underwent radical oesophagectomy with three-field lymphadenectomy. They found VO2max closely correlated with the occurrence of postoperative cardiopulmonary complications. On the basis of their results, Nagamatsu et al. chose a minimally acceptable value of 800 mL/m2 for the VO2max for patients undergoing curative transthoracic oesophagectomy. Forshaw et al.35 undertook a similar study to determine the usefulness of CPX testing before oesophagectomy in a cohort of 78 patients. The study demonstrated there was a significantly reduced VO2peak (P = 0.04) and a non-significant trend towards a reduced AT (P = 0.07), in patients who developed postoperative cardiopulmonary complications following oesophagectomy. Areas under the curve for AT and VO2peak were 0.63 and 0.62, respectively, suggesting that CPX testing did not perform well in predicting postoperative cardiopulmonary complications.
Stress testing: Cardiac stress testing is a well-validated non-invasive modality that has been shown to accurately predict patients at risk of cardiac complications following non-cardiac surgery.36 In addition, stress testing has been shown to identify patients with inducible ischaemia that may benefit from preoperative beta-blockade.37 Preoperative non-invasive stress testing has been recommended for patients with cardiac risk factors (Table 4.2) by the American College of Cardiology and American Heart Association guidelines.38 Exercise-induced hypotension is a sign of possible ventricular impairment secondary to coronary artery disease and warrants further investigation with a coronary angiogram or myocardial perfusion imaging. Several exercise methods for cardiac stress testing exist, including stair climbing, treadmill and shuttle walk testing. Further investigation in patients who are unable to complete exercise testing due to reduced mobility secondary musculoskeletal disease may include pharmacological to stress testing. Commonly used pharmacological agents include adenosine, dipyridamole, dobutamine and propanolol. The choice of pharmacological drug used in stress testing usually depends upon potential drug interactions with other treatments and concomitant diseases. Cardiac stress echocardiography and radioisotope investigation (to measure cardiac perfusion) are also used to provide a more detailed cardiac assessment. The identification of reduced left ventricular ejection fraction by the latter modalities has been significantly associated with the development of cardiac complications following major surgery.39
Optimisation
Preoperative physical cardiopulmonary rehabilitation: Preoperative cardiopulmonary fitness has been shown to be well correlated with postoperative outcome following major surgery.40 The use of intensive preoperative exercise has been shown to improve cardiopulmonary fitness prior to major surgery.41 Although intensive preoperative exercise improves cardiopulmonary fitness, this short-term improvement has not been conclusively shown to correlate with postoperative outcome following major surgery and cancer resection.
Beta-blockade: ACC/AHA guidelines (2006) suggested that beta-blockers should be considered in all patients with an identifiable cardiac risk as determined by the presence of more than one clinical risk factor.38 The hypothesis for this beneficial effect is that adrenergic beta-blockade slows the heart rate and as a result improves ischaemic ventricular dysfunction. Patients on long-term beta-blockade exhibit adrenergic hypersensitivity if the therapy is withdrawn and the intravenous route should be utilised until oral intake can be resumed. The cardioprotective effect of beta-blockers has been reported as persisting for up to 6 months following surgery, even after the cessation of therapy.42 In order for beta-blockade therapy to be most effective, patients should be optimally blocked in the weeks preceding surgery and in the immediate postoperative period. Although not conclusively proven, it is believed that long-acting beta-blockers initiated before surgery are superior to shorter-acting agents.38
The 2009 ACCF/AHA focused update on perioperative beta-blockade for non-cardiac surgery43 states that beta-blockers titrated to heart rate and blood pressure are reasonable for patients in whom preoperative assessment identifies coronary artery disease or high cardiac risk, as defined by the presence of more than one clinical risk factor who are undergoing intermediate-risk surgery.44 In addition, this update states: ‘The usefulness of beta-blockers is uncertain for patients who are undergoing either intermediate-risk procedures or vascular surgery in whom preoperative assessment identifies a single clinical risk factor in the absence of coronary artery disease.’45
Other relevant cardiac medication:
Statins: Current ACC/AHA guidelines on perioperative cardiovascular care recommend that patients should continue statin treatment throughout the perioperative period.38 To date the evidence regarding the cardioprotective effects of statins in the perioperative period is controversial,46 with no studies specifically in the setting of oesophagogastric surgery.
Anticoagulants: In performing oesophagogastric surgery on patients on anticoagulation, the major concern is when is it safe to perform surgery without increasing the risk of haemorrhage or increasing the risk of thromboembolism (e.g. venous, arterial) after discontinuing treatment.
Traditionally, patients are advised to stop aspirin or clopidogrel 7–10 days prior to undergoing major surgery. However, in the case of patients who have had a coronary stent placed within 6–12 months of oesophagogastric surgery, the advice of the American College of Chest Physicians is to continue aspirin or clopidogrel through the perioperative period,47 which would be unacceptable to most oesophagogastric surgeons. Some surgeons are prepared to allow continuation of low-dose aspirin over the operative period but not clopidogrel.
Coronary stents include bare metal and drug-eluting stents, and their placement prior to surgery can significantly impact upon timing of surgical resection. Nuttall et al.48 demonstrated an odds ratio of 3.6 for major cardiac events when surgery was performed within 30 days of bare metal stent placement, which was reduced to 1.6 when surgery was performed between 31 and 90 days. The available data suggest that 30 days should be the minimum interval between placement of a bare metal coronary stent and major non-cardiac surgery. Rabbits et al.49 showed the risk of developing cardiac complications following drug-eluting stent placement is increased (6.4% vs. 3.3%) when surgery is performed within 365 days of stent placement. Thus it is clearly important to discuss the patient’s perioperative plan with the consulting cardiologist prior to any percutaneous cardiac intervention or stent placement if a patient is being scheduled for major oesophagogastric surgery. The timing of when to restart anticoagulants is also a subject of debate, with little clear guidance currently present; however, in our institution we typically reinstitute aspirin on postoperative day 1 following oesophagectomy.
Warfarin: Patients on warfarin are typically told to stop this 4–5 days prior to undergoing major surgery, with the acquisition of an international normalised ratio (INR) assay on the day of surgery. Patients with mechanical heart valves, atrial fibrillation or venous thromboembolism should have an anticoagulation bridging plan with heparin for the perioperative period.49 Patients who have recently sustained a venous thromboembolism should be considered for placement of temporary caval filters prior to radical surgery.
