CHAPTER 28 Congenital Cardiac Surgery

Pediatric cardiology as a specific discipline can track its beginnings to the first ligation of a patent ductus arteriosus by Gross in 1938.¹ Much anatomic research had been done up to that time, but surgical treatment was now an option (Table 28-1). In 1945, Crafoord and Nylin² reported the first surgical repair of coarctation of the aorta, and in the same year, surgical palliation of tetralogy of Fallot with an aortopulmonary shunt was described by Taussig and Blalock.

TABLE 28-1 Chronology of Selected Milestones in Pediatric Cardiology

1936	Maude Abbott publishes landmark atlas with historical data on patients with congenital heart disease.
1939	Gross and Hubbard publish case reports of a -year-old patient with successful ligation of a patent ductus.
1945	Crafoord and Nylin publish report of successful coarctation repair in two patients.
1945	Blalock and Taussig publish report of successful shunts in three tetralogy patients.
1949	Janeway invites Nadas to develop pediatric cardiology at Boston Children’s Hospital.
1955	Kirklin and associates report open heart surgery in eight patients with congenital heart disease.
1964	Mustard reports atrial repair of transposition of the great vessels in a 23-month-old.
1966	Raskind and Miller report balloon atrial septostomy in three infants.
1966	Ross and Somerville report homograft repair of pulmonary atresia in an 8-year-old.
1968	McGoon and associates report repair of truncus in an 8-year-old.
1971	Fontan and Baudet report successful repair of tricuspid atresia in two of three patients aged 12, 23, and 35 years.
1975	Jatene and associates report arterial switch for transposition of the great arteries.
1975	Norwood and associates report successful palliatives of hypoplastic left heart syndrome in two of three patients. Early 1970s M-mode echocardiography begins widespread use.
1975	Elliot and associates report ductal dilation with prostaglandin E in two patients.
1976	Bargeron and associates describe axial cineangiography; late 1970s, echocardiography is introduced.
1982	Kan and associates report percutaneous valvuloplasty for valvular pulmonary stenosis.
1980s-1990s	Doppler studies, color flow, fetal studies, and transesophageal echocardiography become vital part of pediatric cardiology.
1980s	Explosion of studies show possibility and success of percutaneous treatment of pulmonary artery stenosis, coarctation, and aortic stenosis.
1990s	Interventional catheterization therapy for patent ductus arteriosus, pulmonary and aortic stenosis, pulmonary artery stenosis, and many atrial septal defects becomes standard part of management.

From Graham TP Jr. Minimizing the morbidity of pediatric cardiovascular disease—historical perspective; pediatric cardiology. Prog Pediatr Cardiol 2005; 20:1-6.

For the repair of intracardiac defects, cardiopulmonary bypass was needed, and in 1955, Lillehei³ reported successful repair of ventricular septal defect, atrioventricular septal defect, and tetralogy of Fallot with use of this human cross-circulating technique. Kirklin⁴ demonstrated the successful use of mechanical cardiopulmonary bypass, reporting eight cases in 1955.

The development of prostaglandins has had an impact on pediatric cardiology and cardiac surgery most significantly. The introduction of prostaglandin E₁ in routine clinical use in the mid-1970s⁵ has allowed proper diagnosis in a timely fashion of a child with congenital heart disease while permitting further clinical stabilization and refinement of the medical management and surgical intervention.

With imaging, cardiac catheterization was a necessary advance for the diagnosis and treatment of congenital cardiac defects, and by the 1950s,⁶ many centers were routinely studying children with heart defects and planning surgical interventions on the basis of these studies. However, the development of two-dimensional echocardiography and color flow Doppler imaging by the 1980s significantly changed the ability to diagnose infants and children with heart disease and refined the ability of surgeons to perform more complex procedures in infants and young children. Three- and four-dimensional multiplanar echocardiography is a developing imaging modality that is affecting how we visualize intracardiac anatomy and great vessel disease, and it is rapidly becoming an expectation of the surgeon as surgical intervention is planned.

The more intriguing aspect of congenital heart disease is the fact that within the next few years, there will be more adults with congenital heart disease than children with congenital heart disease (Table 28-2).⁷ Survival to adulthood with a diagnosis of congenital heart disease is now an expectation.

This chapter serves as a general overview of congenital heart disease, surgical considerations, and imaging strategies. More detailed aspects of these defects (Table 28-3) are addressed in subsequent chapters.

TABLE 28-3 Relative Frequency of Major Congenital Heart Lesions*

* Excluding patent ductus arteriosus in preterm neonates, bicuspid aortic valve, physiologic peripheral pulmonic stenosis, and mitral valve prolapse.

SURGERY FOR ACYANOTIC CONGENITAL HEART LESIONS WITH A SHUNT

Description and Special Anatomic Considerations

Acyanotic congenital heart disease (Table 28-4) is characterized by a lack of cyanosis. In further defining these disorders, they are often classified on the basis of the presence or absence of left-to-right shunt.

TABLE 28-4 Acyanotic Congenital Heart Disease with a Left-to-Right Shunt

Atrial-Level Shunt Atrial septal defect: causes diastolic overload of the right ventricle and increased pulmonary blood flow Ostium secundum, the most common defect, involves fossa ovalis in midseptal location. Ostium primum anomalies, a form of atrioventricular septal defect, occur immediately adjacent to atrioventricular valves, either of which may be deformed and incompetent. Sinus venosus type occurs high in the atrial septum, near entry of the superior vena cava. Partial anomalous pulmonary venous connection Atrial septal defect with mitral stenosis (Lutembacher syndrome) Ventricular-Level Shunt Ventricular septal defects: either isolated defects or one component of a combination of anomalies Usually one opening situated in the septum membrane Functional disturbance depends on size and pulmonary vascular bed status rather than on defect location. Ventricular septal defect with aortic regurgitation Ventricular septal defect with left ventricular–to–right atrial shunt Aortic Root–to–Right Heart Shunt Ruptured sinus of Valsalva aneurysm with fistula Coronary arteriovenous fistula (unusual) Consists of communication between a coronary artery and another coronary chamber, usually the coronary sinus, right atrium, or right ventricle Anomalous origin of left coronary artery from pulmonary trunk Aortopulmonary-Level Shunt Patent ductus arteriosus Failure of the ductus arteriosus to close after birth Aortopulmonary window Multiple-Level Shunts Complete common atrioventricular canal (endocardial cushion defect with atrial and ventricular septal defect) Ventricular septal defect with atrial septal defect (unassociated with endocardial cushion defect) Ventricular septal defect with patent ductus arteriosus

Ventricular septal defect (VSD), the most common form of congenital heart disease, represents approximately one third of all major congenital cardiac defects. VSDs are generally classified into one of four groups, depending on their location in the interventricular septum (Fig. 28-1). These may be associated with other cardiac defects, such as atrioventricular valve defects, coarctation of the aorta, and other left-to-right shunts. The ventricular septum anatomy is complex, and many associated anatomic structures are key in the consideration of the repair, such as location of the conduction system of the heart.

FIGURE 28-1 The classic anatomic nomenclature assigning VSDs to one of four anatomic types.

(Redrawn from Wells WJ, Lindesmith GG. Ventricular septal defect. In Arciniegas E [ed]. Pediatric Cardiac Surgery. Chicago, Year Book Medical, 1985.)

Atrial septal defects, which usually cause volume overload of the right ventricle and increased pulmonary blood flow, are also categorized on the basis of their location within the atrial septum. These defects can go undiagnosed for decades and can be associated with other defects, such as partial anomalous pulmonary venous return. Unfortunately, when they are undiagnosed for several decades, fixed pulmonary vascular changes may develop that prohibit surgical correction.

Aortopulmonary-level shunts, such as a patent ductus arteriosus, are less common as isolated defects because they typically close spontaneously in the newborn period. However, they are often seen in conjunction with other complex congenital heart disease. If they are undiagnosed during the course of many years, there is some risk for bacterial endocarditis (rare), and if the connection is large, Eisenmenger syndrome or fixed irreversible pulmonary vascular changes may develop. Aortopulmonary windows, which are direct communications between the great vessels, are much more uncommon and can be challenging to diagnose if one is not attentive to subtle echocardiographic findings.

Aortic root–to–right heart shunts, such as a ruptured sinus of Valsalva aneurysm, coronary artery fistula, or anomalous origin of the left coronary artery from the pulmonary artery, are uncommon. However, a high index of suspicion must be present when one evaluates a newborn or older infant with a diagnosis of dilated cardiomyopathy because anomalous origin of the left coronary artery from the pulmonary artery may be difficult to exclude as a source of the dysfunction.

Multiple-level shunts are typified by the complete atrioventricular septal defect (AVSD, previously known as endocardial cushion defect) with a common atrial- and ventricular-level shunt. A variety of any or all of these defects can combine to present with multiple-level shunts. The most challenging aspect for the surgeon in addressing AVSD is often the common valve function and anatomy.

Indications

Surgical intervention for acyanotic heart defects with left-to-right shunt is almost always primarily driven by clinical symptoms and secondarily by risks of not intervening in a timely fashion. Many lesions can be corrected in infancy but do not need to be addressed until the child is older (or larger) to allow better surgical field access or more optimal tissue “durability.” For example, atrioventricular valve tissue is very thin and friable and may be better manipulated at some point later than 1 month of age, if surgery can be safely delayed without resulting in any negative clinical outcomes.

In this broad category of defects, the usual driving indication for early surgical intervention is congestive heart failure and how difficult it is to control with medical management. This is balanced against the surgical risks for the various procedures and the possible comorbidities that may exist as a part of a clinical syndrome or initial clinical presentation. An infant’s weight and gestational age also may play a role in the surgical timing for many of these defects. A typical scenario for surgical intervention based on prematurity and significant lung disease as a result of left-to-right shunt is a patent ductus arteriosus. The advent of indomethacin⁸ as medical management for closure of these defects has significantly reduced the need for surgical intervention.⁹ However, in extreme prematurity, renal disease, and severe diastolic “runoff” through a large patent ductus arteriosus, surgery may be a relative emergency.

For example, surgical timing for closure of a hemodynamically significant VSD may be indicated at a few weeks or as late as a few years. The later closure may be indicated for a late-identified supracristal VSD or a perimembranous VSD with a coexistent subaortic membrane or prolapse of the aortic valve leaflets. Both of these defects have been implicated in progressive aortic valve damage,^10,11 even though they may be quite small and have no risks for long-term pulmonary vascular disease or congestive heart failure.

The diagnosis of anomalous left coronary artery is typically an emergent one; acute surgical intervention is indicated to reestablish appropriate coronary blood flow and to avert continued or permanent myocardial damage or infarction. Less commonly, these anomalies may present after a referral for a murmur in an otherwise normal infant or child. Although they are rare presentations, surgical intervention may be delayed for a few days to allow further diagnostic evaluation, if indicated, or when other medical considerations exist.

With the diagnosis of AVSD, there can be tremendous variability of the surgical timing based on the level of shunting (i.e., atrial vs. ventricular), the complexity of the associated common atrioventricular valve disease, and the associated clinical status (Fig. 28-2).

FIGURE 28-2 Exposure and assessment of anatomy. A, The atrial incision (broken line) is parallel to the right atrioventricular groove. B, The right atrium has been opened after administration of cardioplegia. Note the coronary sinus and the location of the atrioventricular (AV) node. C, Relationship of ventricular septal defect (VSD), atrial septal defect (ASD), and common atrioventricular valve. The valve leaflets are identified as follows: LIL, left inferior leaflet; LLL, left lateral leaflet; LSL, left superior leaflet; RIL, right inferior leaflet; RLL, right lateral leaflet; and RSL, right superior leaflet. IVC, inferior vena cava; LV, left ventricle; PFO, patent foramen ovale; RV, right ventricle; SVC, superior vena cava.

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