Congenital Heart Disease in the Adult

Primary Congenital Heart Disease

Primary CHD in the adult refers to previously untreated anomalies. These anomalies tend to cause relatively benign pathophysiologic perturbations, allowing survival into adulthood without treatment. Primary CHD is less common than secondary CHD.

Secondary Congenital Heart Disease

Secondary congenital heart disease refers to patients with previously treated CHD, which is more common in the adult than primary CHD. It covers the entire spectrum of congenital anomalies. As illustrated in Fig. 29-1 , some but by no means all patients who have undergone surgery for CHD as infants and children are cured and are not considered to have secondary CHD as adults.

Pregnancy and Contraception

Pulmonary Arterial Hypertension and Eisenmenger Physiology

Irreversible pulmonary arterial hypertension (PAH) associated with CHD usually results from anomalies that allow long-standing left-to-right shunts. All such shunts cause PAH from birth onward; however, initially the PAH is flow related, meaning pulmonary blood flow ( ) is increased and pulmonary vascular resistance (Rp) is low. Over time, PAH may evolve from flow related to resistance related, meaning that Rp becomes elevated and decreases. Flow-related PAH is reversible after eliminating the shunt with surgery or other intervention. Resistance-related PAH is generally irreversible. The shunt's type, size, and duration influence the likelihood that, and rapidity with which, irreversible PAH will develop. Thus, these factors will be important in determining the age at which patients with irreversible PAH present. Type and size of the shunt determine the magnitude of shunt flow, which in turn determines the amount of shear stress on the endothelial surface of resistance-level pulmonary arteries. Shear stress induces vasoactive changes and ultimately permanent obstructive structural changes in these arteries. Pulmonary vascular histology in shunt-induced irreversible PAH resembles that described for idiopathic PAH, with medial thickening and plexiform lesions in severe cases.

Individuals with atrial-level left-to-right shunts are least likely to develop irreversible PAH, those with ventricular-level shunts are more vulnerable, and those with arterial-level shunts are at greatest risk. Whether the variation in risk among these different levels is solely related to shunt flow or to an underlying genetic predisposition is unknown. A number of specific congenital heart anomalies can lead to irreversible PAH. Unrepaired large ASD, VSD, AVSD, and PDA account for most cases, simply because these defects are common. However, many less common complex lesions, such as partial or total anomalous pulmonary venous return, unrepaired or palliated conoventricular defects, including truncus arteriosus or transposition of the great arteries (TGA), and single-ventricle variants, can also result in development of irreversible PAH. Other congenital causes of PAH unrelated to shunting include pulmonary vein stenosis and pulmonary veno-occlusive disease.

Over time, as severe vascular obstructive changes develop, Rp approaches and exceeds systemic vascular resistance (Rs), causing a bidirectional or predominantly right-to-left shunt accompanied by oxygen-unresponsive hypoxemia, identified as Eisenmenger physiology. In patients with large ventricular- and arterial-level left-to-right shunts or unrepaired complex congenital heart defects, irreversible PAH can develop as early as the first year of life and Eisenmenger physiology within the first decade of life (see “Pulmonary Vascular Disease” under Natural History in Section I of Chapter 35 ); however, in patients with medium or larger ASDs, Eisenmenger physiology may not appear at all, but when it does, it typically appears in the second, third, or fourth decade. Pregnancy may unmask pending Eisenmenger physiology.

PAH and Eisenmenger physiology may develop late after surgical repair of left-to-right shunts. The most common explanation is that the repair was performed too late or was incomplete. However, additional factors such as left ventricular hypertrophy and diastolic dysfunction, valve abnormalities, pulmonary venous hypertension or obstruction, restrictive or hypoventilatory lung disease, chronic liver disease, and toxin use must be considered and, if present, addressed to the degree possible.

Dyspnea on exertion is the most common presenting symptom of patients with severe PAH and Eisenmenger physiology, followed by palpitations, peripheral edema, volume retention, hemoptysis, syncope, and progressive cyanosis. Morbidity is progressive and becomes substantial, typically by the third decade of life. Hypoxemia-related secondary erythrocytosis leads to increased blood viscosity and intravascular sludging. Organ damage may result in the brain from cerebrovascular changes brought about by sludging, with resultant stroke, and in the kidneys, with altered renal function. Right heart pressure and volume overload cause elevated systemic venous pressure leading to hepatic dysfunction. Hyperuricemia may result in gout. Hemoptysis is potentially life threatening. Chest pain due to right ventricular ischemia, coronary artery compression by a dilated pulmonary artery, or arteriosclerosis may occur with exertion or at rest. Ultimately, right heart failure is inevitable. Poor functional status is an important predictor of mortality, as are serologic evidence of low systemic organ perfusion, worsening hypoxemia, and left ventricular systemic dysfunction. Premature death is the rule. The immediate modes of death include right ventricular failure, severe hemoptysis from bronchial artery rupture or pulmonary infarction, complications during pregnancy, and cerebral vascular events, including occlusive strokes, systemic paradoxical embolization, and brain abscesses. Death during noncardiac surgery also occurs.

Changes that occur with left-to-right shunt-related PAH can be reversible after eliminating the shunt, provided that the surgery is performed during the vasoactive stage of PAH development, before irreversible obstructive pulmonary vascular changes occur. Catheterization-based calculations of , individualized measurements of resistance in isolated lung segments, and direct measurement of pulmonary venous pressure are typically used to assess PAH reversibility and likelihood of surgical success. One hundred percent inspired oxygen, inhaled nitric oxide, and intravenously administered prostacyclin are frequently used in such investigations to determine the degree of pulmonary vascular reactivity and the potential to subsequently lower pulmonary artery pressure with surgical correction of the shunt. Increasingly, acute and chronic pharmacologic pulmonary vasodilatory and vascular remodeling therapy accompanies surgery in these cases. Specific data are not available that firmly establish the pressures, flows, and resistances that determine if operation to remove the shunt is indicated. Typically, Rp less than 10 to 14 Wood units and a less than or equal to 2/3 are associated with better surgical outcomes. Even less clear is the predictive value of degree of vasodilatation achieved in the catheterization laboratory in response to vasodilatory agents. An additional confounding factor is that calculated Rp itself can vary with based on flow; Rp calculated under shunt conditions with high may actually be lower than that calculated after the high-flow condition is eliminated by surgical repair. Pulmonary vessels that were recruited because of high may be lost after flow is reduced to normal following surgery, resulting in higher postoperative Rp and pulmonary pressure than was anticipated using the catheterization data.

If evaluation determines that surgical closure of the shunt is indicated, a multidisciplinary team approach is mandatory, including an anesthesia team and intensive care team experienced in managing both PAH and the adult with CHD. The surgical procedure itself will often be technically simple; however, pre- and postoperative management will not. The optimal type and mode of anesthetic administration should be individualized (see Chapter 4 ). Risk of right-to-left embolization warrants avoiding bubbles following intravenous catheter placement. Use of inhaled nitric oxide both pre- and postoperatively should be considered.

Diagnosis of Eisenmenger physiology requires a detailed history, documenting all previous cardiac surgical and interventional procedures and medical treatments. Thorough documentation of the current cardiac morphology and cardiopulmonary physiology is mandatory using chest radiography, electrocardiography, echocardiography, cardiac catheterization, computed tomography (CT), pulmonary function studies, and assessment of all end-organ function. Once the diagnosis is made, the option of surgical treatment by repair of the anomaly causing the shunt is no longer an option because this approach will result in physiologic decompensation from severe PAH, right heart failure, and mortality. Proven treatment options are strictly medical, with the exception of lung or heart-lung transplantation (see Chapter 21 ). Transplantation offers a limited survival benefit, given the unpredictability of transplant-free survival and significantly higher perioperative mortality in this cohort of patients, although individual outcomes may warrant individual considerations. Medical treatment options are complex and must be tailored to the individual patient, as discussed in detail in the ACC/AHA 2008 guidelines. The evolving concept of treat and repair , meaning initially using advanced pharmacologic regimens to treat PAH followed by surgical repair of the structural anomaly, has the potential to change some patients from “inoperable” to “operable,” although long-term benefit is currently unknown.

Heart Failure and Transplantation

Endocarditis

As stated earlier in this chapter, most forms of CHD are not cured by surgery or other intervention. Residual defects or surgical and interventional remnants present in most adults with CHD often predispose to infective endocarditis (see Chapter 15 ). More than 10% of patients with endocarditis have a history of CHD, and endocarditis is the cause for 4% of hospital admissions for adults with CHD. Some anomalies carry a higher risk of endocarditis than others, including bicuspid aortic valve, unrepaired VSD, PDA, tetralogy of Fallot, TGA, single-ventricle anomalies with systemic to pulmonary artery shunts, and those whose repair includes a conduit or prosthetic valve. Surgical closure of a VSD reduces the risk of endocarditis, and when endocarditis develops at the site of a surgically repaired defect, a residual patch leak is frequently observed. In a series of adults with CHD admitted for a diagnosis of endocarditis, certain anomalies were underrepresented, including ASD, completely closed VSD, unrepaired Ebstein anomaly, and Mustard and Senning atrial switch repairs.

Definitive diagnosis of infectious endocarditis requires positive blood cultures with appropriate organisms and physical evidence of endocardial involvement (typically identified by echocardiography). Surface echocardiography may be adequate, but transesophageal echocardiography may be particularly helpful, especially when complex structural anomalies are present. Once the diagnosis is made or suspected, further management should occur at a center with an established adult CHD program. Consultation with a cardiac surgeon who has a focus on adult CHD should be undertaken early in the patient's course, because rapid deterioration requiring surgery is common. Relative indications for surgery are :

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  Development of hemodynamic decompensation

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  Evidence of embolic complications

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  Intractable infection despite appropriate antibiotic therapy

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  Infection of prosthetic valves, conduits, or other material

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  Abscess development

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  Contained rupture

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  Development of heart block

The indication to operate may be clear, or it may be ambiguous. Consultation among the cardiologist, infectious disease specialist, and surgeon should take place in all cases under consideration for surgery.

Recommendations for infectious endocarditis prophylaxis have changed in recent years. The 2007 AHA guidelines recommend selective use of preventive antibiotic therapy, but also emphasize behavioral elements. The latter include maintaining daily oral hygiene and skin hygiene, particularly with respect to acne, and avoiding nail biting. Prophylactic antibiotic therapy is confined to dental procedures (no longer gastrointestinal or genitourinary procedures) in patients with prior endocarditis, prosthetic heart valves, conduits, shunts, unrepaired cyanotic CHD, CHD repaired with prosthetic patches or other material within 6 months of surgery, residual defects after reparative surgery for CHD if the residual defect is in the proximity of prosthetic material, and valve lesions in transplant patients.

Niwa and colleagues reported 69 cases of endocarditis in adults with CHD. Prior cardiac surgery and a history of cyanosis were common. Involvement of the left and right sides of the heart was equally common. Dental procedures, cardiac surgery, and pneumonia commonly preceded endocarditis. Streptococcus and Staphylococcus accounted for 87% of cases, with Streptococcus the most common organism. Surgical intervention was needed in 26% of cases, and the indication for surgery was large vegetations in 45% and heart failure in 29%. Endocarditis-related mortality was 8% in patients treated medically and 11% in those treated surgically. Di Filippo and colleagues note that adults increasingly account for cases of endocarditis in patients with CHD, and that complex cyanotic heart disease is also increasingly common. Streptococcus and Staphylococcus remain the most prevalent organisms. Again, dental procedures and cardiac surgery frequently preceded endocarditis, but these authors note an increasing frequency of cutaneous infections in recent years. A precipitating cause for endocarditis, however, is often not identified. Awadallah and colleagues identified a predisposing event in 56% of cases, but Gersony and colleagues in only 32%.

Arrhythmias

Both atrial and ventricular arrhythmias are a more important source of morbidity in adults with CHD than in infants and children. Ventricular arrhythmias in particular, uncommon in young patients, are frequent in adults. Arrhythmias can be observed in all adult clinical groups: surgically repaired anomalies, surgically palliated and single-ventricle anomalies, and unrepaired anomalies ( Table 29-3 ). Cause of conduction system pathophysiology is multifactorial, including cyanosis, volume and pressure overload, surgical incisions, suture lines, and patches with subsequent scarring; ischemic insults of any etiology, including coronary embolism in patients with left-to-right shunting; and inadequate myocardial protection during previous surgery. In general, the longer the inciting cause is present, such as cyanosis or volume overload, the more likely arrhythmias will occur. It is this cumulative effect that results in the higher prevalence of arrhythmias in the adult population.

Rhythm disturbances may come to the attention of the surgeon in several ways. Most commonly, a patient being evaluated for reconstructive surgery, such as repair of a large ASD or replacement of a right ventricle to pulmonary trunk conduit, will have an associated rhythm disturbance that may influence intraoperative and postoperative care. Antiarrhythmic therapy may be required, and existence of an arrhythmogenic substrate may influence the choice or concentration of inotropic support used.

The arrhythmia may require surgical therapy concomitant with the reconstructive surgical procedure, such as an atrial maze procedure or placement of ventricular cryoablation lesions (see Chapter 16 ). In other circumstances the sole, or primary, indication for surgery may be the rhythm disturbance. The atrial maze procedure, an epicardial pacemaker system for heart block or bradycardia, a biventricular pacemaker system for resynchronization therapy, or placement of an implantable cardioverter-defibrillator (ICD) are examples of surgery that may be needed.

Intraatrial reentrant tachycardia (IART), or atrial flutter, is the most common rhythm disturbance in adults with CHD. It usually develops late postoperatively, most often in patients who have had a right atrial incision or some other right atrial suture line. The amount of right atrial surgery tends to correlate with prevalence of IART, the greatest being in patients who have had Mustard atrial switch intracardiac type Fontan procedures. It can, however, occur after ASD closure. Pharmacologic therapy and catheter ablation are the first- and second-line therapeutic choices. Pacemaker placement to increase baseline heart rate may suppress fibrillation episodes if sinus bradycardia coexists. If a pacemaker is indicated, a transvenous approach is preferred; however, numerous contraindications exist, including presence of any intracardiac shunt (even if trivial, such as a small patent foramen ovale), previous bidirectional Glenn or extracardiac-type Fontan procedure, single-ventricle physiology of any kind, and upper body central venous thrombosis. In these situations, surgical pacemaker placement is indicated. Surgical therapy with a concomitant right atrial maze procedure is indicated if reconstructive intracardiac surgery is planned. Isolated right atrial maze may be considered if IART is poorly controlled by other means. The right atrial maze procedure and its modifications have been shown to be effective in eliminating IART in Fontan patients undergoing concomitant conversion of an intracardiac-type Fontan to an extracardiac type (see Chapter 41 ).

Atrial fibrillation occurs most often in adults with congenital aortic stenosis, congenital mitral valve disease, or single ventricle. Medical therapy includes anticoagulation, pharmacologic ventricular rate control, and electrical cardioversion. There is no role for catheter ablation. Indications for pacemaker therapy if sinus bradycardia coexists are similar to those for IART. A concomitant combined left and right atrial maze procedure may be beneficial and should be considered if reconstructive surgery is planned.

Wolff-Parkinson-White accessory pathway is particularly common in Ebstein anomaly (see Chapter 42 ). Symptoms related to tachycardia increase in frequency and become more problematic in adulthood. Chronic tricuspid regurgitation induces atrial dilatation, leading to atrial flutter or fibrillation and accelerated conduction across the accessory pathway. Catheter ablation in the electrophysiology laboratory is first-line therapy; however, it is less successful and is more likely to recur when structural heart defects are present. Intraoperative ablation of the accessory pathway should be performed in patients not responding to catheter-based therapy and in those undergoing surgery on an Ebstein tricuspid valve. Additionally, an atrial maze procedure is indicated if atrial fibrillation or flutter is present.

Ventricular arrhythmias may develop in the adult with CHD. Macroreentrant ventricular tachycardia can develop late after ventricular surgery, related to ventriculotomy or VSD patching. In repaired tetralogy of Fallot, reentry circuits typically form through narrow conduction pathways created by right ventricular outflow tract scarring. Prevalence of late ventricular tachycardia or sudden death for repaired tetralogy is 0.5% to 6.0%. Older age at repair, right ventricular dilatation, and QRS duration longer than 180 ms have been identified as risk factors for development of ventricular tachycardia and sudden death in tetralogy of Fallot patients. Palpitations, dizziness, or syncope warrant electrophysiologic testing in the adult with repaired tetralogy of Fallot. These symptoms may be elicited at the time of evaluation for surgical therapy for recurrent or residual right ventricular outflow tract disease. Electrophysiologic testing should be performed prior to surgery.

Ventricular tachycardia can develop in any form of CHD in the adult, even if there has never been a ventricular incision or suture line. The onset may coincide with deteriorating ventricular function.

Complete hemodynamic and electrophysiologic evaluation is required before therapy for ventricular tachycardia is undertaken. If sustained ventricular tachycardia is documented or the patient has a history of cardiac arrest, the next step is to determine whether there is a physiologically significant residual or recurrent structural anomaly. If there is no structural anomaly, the treatment option of choice is implanting an ICD. A surgically placed ICD is indicated for patients with single-ventricle physiology, obstructed upper body systemic veins, bidirectional cavopulmonary anastomosis, a Fontan procedure, residual intracardiac shunts, or other unusual or distorted intracardiac morphology; otherwise, transvenous systems are available. In selected cases, catheter-based ablation can also be performed to reduce the likelihood or frequency of ventricular tachycardia episodes. Catheter-based ablation is unreliable as sole therapy, with recurrence that may exceed 20%. Pharmacologic therapy alone is currently considered inadequate if sustained ventricular tachycardia or a history of cardiac arrest exists, but may be indicated if less serious ventricular arrhythmias are present.

If structural cardiac anomalies with important hemodynamic impairment are present in an adult with ventricular tachycardia, surgical repair of the anomaly combined with either concomitant surgical ablation or concomitant surgical ICD placement may be indicated. In such cases, it is necessary to map the ventricular tachycardia, either by preoperative electrophysiologic testing or intraoperative mapping. If a discrete focus of ventricular tachycardia is inducible and there is no clinical history of cardiac arrest, surgical ablation may be the best option. A typical situation appropriate for this form of therapy is the patient with tetralogy of Fallot originally repaired with a transanular patch who presents late with severe pulmonary regurgitation, a dilated right ventricle, and inducible ventricular tachycardia mapped to the right ventricular outflow tract. Surgical therapy includes placing a pulmonary valve prosthesis and creating cryoablation lesions from the outflow patch to the pulmonary trunk and from the outflow patch to the tricuspid anulus. Follow-up electrophysiologic evaluation is indicated in all such cases to determine if ventricular tachycardia is controlled. Placement of an ICD is indicated if ventricular tachycardia is inducible at follow-up. In the patient presenting with a history of cardiac arrest whose evaluation reveals structural disease as well as ventricular tachycardia, or the patient with structural disease and poorly localized ventricular tachycardia, the best choice of therapy is probably structural repair and concomitant surgical ICD placement.

Sinoatrial (SA) node dysfunction in adults with CHD typically is acquired, occurring as a result of localized trauma or ischemia following previous cardiac surgery. The most common procedures that result in SA node dysfunction are the Mustard, Senning, Glenn, and Fontan operations. Less frequently, SA node dysfunction is congenital, associated with some forms of heterotaxy syndrome. Patients with SA node dysfunction may be symptomatic as a result of chronotropic incompetence or of development of atrial fibrillation or flutter, which are more likely to occur when SA node dysfunction is present. Ventricular tachycardia can also develop as a result of prolonged sinus pauses. Placing a pacemaker system is indicated in several circumstances. Implantation of an atrial, or atrioventricular sequential, pacing system with activity responsiveness is indicated for symptoms related to chronotropic incompetence, tachy-bradycardia syndrome, recurrent atrial tachycardias, and pause-dependent ventricular tachycardia. It is also indicated for the asymptomatic adult patient with a resting heart rate of less than 40 beats per minute or atrial pauses greater than 3 seconds. Typically, atrioventricular conduction is normal when SA node dysfunction is present; therefore, atrial pacing alone is effective therapy. Nevertheless, atrioventricular sequential pacing systems are recommended in all cases, with appropriate programming of the system such that atrial pacing occurs along with natural atrioventricular conduction. Pacemaker systems can be placed transvenously or surgically. Surgical placement is indicated in the presence of single-ventricle physiology, bidirectional cavopulmonary anastomosis, Fontan surgery, distorted or thrombosed upper body central veins, and any intracardiac shunt; otherwise, transvenous placement is preferred.

Atrioventricular (AV) block in the adult with CHD may be acquired or congenital. Acquired block is more common and results from surgical trauma to the AV node or surrounding tissues during intracardiac repair. Block usually develops during surgery. Typical operations that may result in block include closure of perimembranous or inlet VSDs, resection of left ventricular outflow tract obstruction, and surgery to repair or replace the inlet valves. Transient heart block with full recovery of AV conduction is common after these operations, occurring in over half of all patients who suffer block at surgery. Recovery typically occurs within 10 days. Transvenous or surgical placement (see indications for each in the preceding text) of an AV sequential pacemaker system is indicated if postoperative second- or third-degree block has not recovered after 10 days of observation. A relative indication for pacemaker placement is presence of persistent bifascicular block.

The AV node and bundle of His may also be congenitally abnormal, associated with specific anomalies such as congenitally corrected TGA and AVSD. These patients are more likely to develop block with any form of intracardiac manipulation and to develop spontaneous block either before or after surgery. Spontaneous development of second- or third-degree heart block is an indication for either transvenous or surgical placement of an AV sequential pacemaker system.

Other Organ Systems

Other organ systems may be abnormal in the adult with CHD. These abnormalities may result from altered hemodynamics, chronic cyanosis, or associated syndromes (see “ Syndromes Associated with Congenital Heart Disease ” in text that follows), and may contribute important morbidity and mortality risks when cardiac surgery is performed in the adult with CHD.

Altered hemodynamics can lead to pulmonary vascular abnormalities. This subject is discussed under “ Pulmonary Arterial Hypertension and Eisenmenger Physiology ” earlier in this section. An altered hemodynamic state is well documented in patients with coarctation of the aorta, both repaired and unrepaired. Systemic hypertension and decreased systemic vascular compliance contribute to, and may even play a causal role in, development of and morbidity related to intracranial aneurysms. All adults with a history of coarctation should undergo evaluation of the cerebral vasculature to rule out vascular aneurysms, particularly if repeat aortic surgery is being contemplated. Long-standing abnormal right-sided hemodynamics, particularly in patients with tetralogy of Fallot, single-ventricle morphology with Fontan surgery, and Ebstein anomaly, may result in chronic hepatic venous hypertension and hepatic congestion, leading to hepatic dysfunction and cirrhosis, gastroesophageal varices, and even hepatocellular carcinoma. Particularly in Fontan patients, additional problems may include protein-losing enteropathy, plastic bronchitis, and renal compromise.

Chronic cyanosis leads to erythrocytosis, iron deficiency, and clotting disorders. Blood viscosity is increased. Combined erythrocytosis and iron deficiency leading to microcytosis increases risk of thrombosis and stroke, which may be particularly relevant perioperatively. Additionally, cyanosis-related platelet dysfunction and deficiency of plasma and clotting factors due to erythrocytosis combine to increase the risk of hemorrhagic complications, again of particular relevance perioperatively. An additional complication of erythrocytosis is an increased rate of red cell turnover, leading to abnormal bilirubin metabolism and development of gall stones. The risk of cholecystitis and pancreatitis perioperatively is increased. Chronic cyanosis also leads to renal glomerulosclerosis. Glomerular filtration rate is decreased, resulting in creatinine elevation.

Renal dysfunction is found in adult patients with a wide-spectrum CHD.

Scoliosis is common in patients with chronic cyanosis. This may lead to deformity of the thorax, causing ventilatory compromise. Pulmonary function tests are required in all adult patients with CHD and scoliosis who are under consideration for cardiac surgery.

There is a risk of stroke after all cardiac procedures in patients of all ages. It was found to be 0.8% in 124 adults undergoing surgery for CHD. Interestingly, this is lower than the risk of stroke in adults undergoing several different types of surgery for various acquired heart problems.

Syndromes Associated with Congenital Heart Disease

A number of syndromes are associated with CHD, many associated with neurologic, developmental, and cognitive deficits ( Table 29-4 ). Many of these syndromes include other coexisting disease processes in other organ systems that represent specific risks during anesthesia and surgery ( Table 29-5 ).

The deficits may be mild enough in many cases to allow these individuals to live somewhat independently. When the cardiac surgeon is asked to consult on the adult patient with CHD, he or she must keep in mind that the patient may have one of these syndromes. Additionally, many adults with CHD who do not have specific syndromes may be overprotected by caring family members and may not have the emotional or intellectual maturity expected for their age. Accordingly, these patients may have limited ability to fully appreciate the complexities, risks, complications, and alternatives to a proposed surgical procedure. Family members and primary care providers should be included in such consultations.

Repeat Sternotomy

Overview

Many adults undergoing surgery for CHD have had at least one, and often several, previous cardiac operations via median sternotomy. Risk of life-threatening hemorrhage is present with any repeat sternotomy. Other risks include entry of air into the circulation and arrhythmias. Thus, special preparation is required when repeat sternotomy is planned. First, all previous operative notes should be obtained and reviewed. Along with the details of previous cardiac procedures, they may provide important information regarding whether a prosthetic barrier was placed between the sternum and cardiac structures, whether the native pericardium was reapproximated, and whether difficulty was encountered during the previous sternotomy. Also, comments warning about such things as conduit placement in proximity to the posterior sternal border may be given. Second, CT or MRI of the chest can be helpful in defining the position of the anterior border of the heart, ascending aorta, pulmonary trunk, brachiocephalic vein, and conduits relative to the posterior sternal table ( Fig. 29-3 ).

Specific Anomalies

Definition, surgical history, morphology, and natural history, as well as general aspects of pathophysiology, clinical presentation, diagnosis, and treatment of specific anomalies discussed in the remainder of this chapter, are described elsewhere in this book in the specific chapters named for each anomaly. The following sections focus on preoperative, operative, and postoperative care issues that are specifically related to adults with these anomalies.

Several studies provide an overview of the practice of adult congenital cardiac surgery. Putman and colleagues report a single-institution experience with 963 adult congenital cardiac surgical procedures in 830 patients (mean age 39 years, 50% male) between 1990 and 2007. Underlying diagnoses are shown in Table 29-6 ; 51% were primary operations and 49% reoperations. Underlying anomalies tended to be more complex in the reoperation group and simpler in the primary operation group. The most common operations were those involving aortic valve replacement (26%); ASD closure (18%); pulmonary valve replacement (13%); mitral valve operation (7.1%); pacemaker placement (6.4%); VSD closure (5.5%); and coarctation repair (4.6%) ( Table 29-7 ). Concomitant coronary artery bypass grafting was performed in 3.4%. CPB was used in 90%. Overall early mortality was 1.5%, and actuarial survival at 17 years was 71% ( Fig. 29-4 ). Risk factors for mortality are shown in Table 29-8 . Functional status, estimated by NYHA functional classification, was improved in most survivors.

In a multi-institutional (37 Child Health Corporation of America [CHCA] centers) study of 719 adult congenital cardiac operations performed between 2005 and 2007, Mahle and colleagues report that the most frequent principal procedures were pacemaker placement (29%), pulmonary valve replacement (17%), aortic valve replacement (8.3%), and Fontan revision (5.2%). Early mortality was 1.9%. Among the 37 freestanding children's hospitals that make up this consortium, 0% to 11% of all cardiac operations were performed in adults.

Data from the CONCOR (CONgenital CORvitia) Dutch national registry of adults with CHD show several notable gender-specific outcomes in 7414 patients. Women had a 33% higher risk of pulmonary hypertension, a 33% lower risk of aortic events, a 47% lower risk of endocarditis, and a 55% lower risk of arrhythmias and ICD placement. There were no gender-related mortality differences.

Presentation

The chronic right-sided volume and pressure overload found with large ASDs leads to reduced aerobic capacity, atrial arrhythmias, and respiratory infections. Dyspnea and palpitations are the most common presenting symptoms, typically in the third and fourth decades of life. Atrial fibrillation or flutter and paradoxical embolism may also lead to presentation. Pulmonary arterial hypertension (PAH) is usually mild and primarily flow related; however, severely elevated pulmonary vascular resistance (Rp) and obstructive pulmonary vascular disease leading to Eisenmenger physiology occur in a minority of patients.

Smaller ASDs—those less than 5 mm in diameter—and PFOs do not cause these changes, but can be the source (as can larger ASDs) of paradoxical emboli. Defects smaller than 1 cm may not cause symptoms for many decades, but the left-to-right atrial shunt may increase later in life as left ventricular compliance decreases because of acquired cardiac diseases such as coronary artery disease and hypertension, causing symptoms to develop late.

Diagnosis

The electrocardiographic and chest radiographic findings are the same in the adult as in the child (see Chapter 30 ). The mainstay of diagnosis is echocardiography. In adults, transthoracic studies may produce inadequate images of the atrial septum. Transesophageal studies often produce more accurate atrial septal images and detail the dimensions and position of the defect. PAH is estimated by measuring velocity of tricuspid regurgitation flow, if present. Contrast echocardiography can be used to confirm atrial-level shunting if direct imaging and color Doppler evaluation are not definitive. Both magnetic resonance imaging (MRI) and computed tomography (CT) angiography may be helpful if echocardiography is not definitive, and are particularly helpful in defining the pulmonary venous anatomy in sinus venosus ASD. MRI is preferred to CT, which requires substantial radiation exposure. Cardiac catheterization is reserved for three situations: to assess pulmonary vascular hemodynamics if PAH is suspected or confirmed; to assess presence of coronary artery disease, typically in patients over age 35 (male) and 40 (female); and as a therapeutic procedure if percutaneous device closure is planned.

Presentation

Of the 280,000 individuals who suffer a cryptogenic stroke in the United States every year, a PFO is found twice as often as in the normal population, suggesting an association between PFO and stroke. Nevertheless, three prospective class 1 studies addressing cryptogenic stroke all suggest that when patients who suffer an initial cryptogenic stroke are followed, recurrent cryptogenic stroke has no relationship to the size or presence of a PFO. Yet several longitudinal observational studies examining the likelihood of recurrent stroke in patients with PFO suggest that recurrent strokes occur less often when the PFO is treated with a device or with surgical closure rather than with antiplatelet or anticoagulation therapy. Larger PFO size has also been associated with increased risk of recurrent cryptogenic stroke following an initial event. Thus, cryptogenic stroke has multiple causes, only one of which is paradoxical embolism through a PFO; however, just because a cryptogenic stroke occurs in the presence of a PFO does not mean that the PFO is causative. These studies do not provide definitive enough data to formulate a management plan for preventing recurrent cryptogenic stroke in PFO patients.

Atrial septal aneurysm with or without a PFO has also been found with increased prevalence in patients with cryptogenic stroke, suggesting a possible association between it and cryptogenic stroke.

Presentation

Adults with a history of VSD closure as an infant or child may present with infectious endocarditis in the presence of a small residual defect; distortion of the tricuspid valve septal leaflet due to previous VSD closure, resulting in clinically important tricuspid regurgitation or progressive aortic regurgitation due to surgical injury; distortion of the valve during VSD closure; or prolapse of the valve into the VSD prior to VSD closure that progresses after closure.

Diagnosis

Transthoracic echocardiography is usually diagnostic for patients with unrepaired or previously repaired VSD unless the surface windows do not provide adequate images. In that case, transesophageal echocardiography is usually diagnostic. It is important not only to focus on size and position of the native or residual VSD, but also to rule out aortic valve prolapse and regurgitation, tricuspid regurgitation, double-chamber right ventricle, subaortic membrane, membranous septal aneurysm, primary pulmonary arterial hypertension (PAH), and ventricular dysfunction.

If PAH is suggested by echocardiography, diagnostic cardiac catheterization is indicated to assess status of the pulmonary vascular bed (see “ Pulmonary Arterial Hypertension and Eisenmenger Physiology ” in Section I). Cardiac catheterization may also be indicated in the patient with a small to moderate VSD, either unrepaired or repaired with a residual defect, for whom the indications for surgical closure are equivocal. Specific data obtained at catheterization may assist in the decision to close the VSD, including magnitude of the shunt, left ventricular end-diastolic pressure, pulmonary artery pressure, and pulmonary vascular resistance (Rp). Catheterization and angiography may also be indicated to assess the coronary arteries if arteriosclerotic disease is suspected, if the patient is older than age 35 (male) or 40 (female), or to further characterize unusual structural problems, such as membranous septal aneurysms ( Fig. 29-7 ).

Magnetic resonance imaging (MRI) and computed tomography (CT) may play a role in defining anatomic details if echocardiography is not definitive. These imaging modalities may help define multiple VSDs, unusually positioned muscular VSDs, and suspected associated pulmonary artery or vein anomalies.

Presentation

The clinical presentation of repaired AVSD depends on the nature of residual or recurrent lesions after repair, and on development of new lesions. The most common residual or recurrent lesion is left-sided AV valve regurgitation, which presents with left ventricular volume overload and failure, left atrial dilatation, and atrial fibrillation. The next most common lesion is subaortic left ventricular outflow tract obstruction, which may be residual, recurrent, or new onset. Signs and symptoms are the same as for any patient with left ventricular outflow obstruction. Other presentations include signs and symptoms related to left or right AV valve stenosis, right AV valve regurgitation, residual ventricular septal defect (VSD), endocarditis related to any of these residual structural lesions, or PAH, particularly in patients with repaired complete AVSD.

Diagnosis

The electrocardiogram shows typical superior left-axis deviation, and this finding alone in a previously undiagnosed adult is highly suggestive of AVSD. In adults with residual or recurrent lesions, electrical findings of left atrial enlargement, left ventricular hypertrophy, and right ventricular hypertrophy may be present. Atrial fibrillation or flutter may also be present.

The chest radiograph will show a prominent pulmonary artery bulb and distal pulmonary artery pruning if PAH is present, cardiomegaly if valve regurgitation or left-to-right shunting exists, and pulmonary venous congestion if left-sided AV valve regurgitation is present. Echocardiography is diagnostic, just as it is in infants and children. In previously repaired patients, this study should focus on determining presence of residual atrial or ventricular shunts, right and left AV valve function, left ventricular outflow tract patency, and signs of PAH.

Cardiac catheterization is performed in all unrepaired adults under consideration for surgical repair to assess the pulmonary vasculature. Coronary angiography is indicated if the patient is over age 35 (male) or 40 (female) or if coronary insufficiency is suspected. Catheterization may also be indicated to assess PAH in repaired patients and general hemodynamics in patients with equivocal indications for surgical intervention. Magnetic resonance imaging can be helpful in assessing regurgitant fraction when AV valve regurgitation is present in patients with equivocal indications for surgical intervention.

Death

Early mortality for primary repair of partial AVSD in the adult can be less than 1%; however, some older series report early mortality as high as 6%. There was no (CL 0%-4.8%) early mortality in a series of 39 patients (mean age 36 years) in whom the indication for surgery was left-to-right shunt. One patient required concomitant left AV valve replacement and 37 underwent cleft closure, five of whom also underwent reduction anuloplasty. At a median follow-up of 7 years, there were six late deaths, five of which were cardiac in origin. In a series of 132 patients with partial AVSD, 10% of whom were older than age 20 years, early mortality was 4.5% (CL 2.7%-7.2%) and late mortality 3.2%. By univariable analysis, older age (more than 10 years at initial repair) was among the risk factors. By multivariable analysis, however, only preoperative PAH and a grossly deformed left AV valve were risk factors, suggesting that the association of death with older age is due to development of PAH and valve deformity over time. In a series of 31 patients with partial AVSD, all of whom were over age 40, early mortality was 6.4% (CL 2.2%-15%); however, some of the operations were performed as long ago as 1958, and the two deaths occurred in 1967 and 1981. There were nine additional deaths at late follow-up ( Fig. 29-8 ). In a separate report from the same authors, an analysis of all patients with partial AVSD showed that age older than 20 years at repair was a risk factor for death. In a series of 29 adolescents and adults (mean age 28 years) undergoing repair of partial AVSD, early mortality was 3.4% (CL 0.6%-11%), and actuarial survival after 25 years was 79%. There was important left AV valve regurgitation in 68% of the long-term survivors and important arrhythmias in 20%. In a larger series of reoperations in 96 adults (median age 26 years) with prior repair of partial AVSD, early mortality was 5.2% (CL 2.9%-8.7%); however, three of the deaths occurred prior to 1983. Since 1983, 2 of 76 patients experienced early death (2.6%; CL 0.9%-6.1%) ( Fig. 29-9 ).

Primary repair of complete AVSD in the adult is rare; however, there are isolated case reports of such repairs.

Left Atrioventricular Valve and Left Ventricular Outflow Tract Lesions

Early mortality after repair of residual or recurrent left AV valve lesions or left ventricular outflow tract lesions is similar to that after mitral valve or left ventricular outflow tract procedures performed in adults without AVSD. One report describes 11 patients with prior repair of partial AVSD in whom surgery as an adult was required. Indications were left AV valve regurgitation in six (two of whom required valve replacement), subaortic stenosis in three, left AV valve stenosis in one, and atrial shunt in one. There were no early deaths (CL 0%-16%), and at median follow-up of 7 years, there were two late deaths, one of which was cardiac in origin.

In a series of 96 reoperations in adults after partial AVSD repair, indications for reoperation were left AV valve regurgitation in 67%, subaortic stenosis in 25%, right AV valve regurgitation in 22%, residual atrial septal defect in 11%, and other in 6%. About half of the patients requiring reoperation for left AV valve regurgitation underwent valve repair, and the other half underwent valve replacement.

Reoperations following prior repair of complete AVSD have been reported in a series of 50 patients.

As expected, the primary repair was performed early in life (median age 1 year), and the median interval between primary repair and reoperation was 15 months. Thus, most reoperations were performed in young children, although some were performed in adults as old as 38 years. Left AV valve regurgitation was the indication for reoperation in 41 patients. There were two early deaths, both in young patients; thus, there were no deaths in adults, although the specific number of adults treated is not designated. In two other series examining long-term outcomes after AVSD repair in infancy and childhood, freedom from reoperation was 80% at 25 years in one and 76% at 20 years in the other. In both studies the majority of first reoperations were for left AV valve problems, and these reoperations occurred relatively early. In one of these studies, mean age at first reoperation was 2 years. Thus, few patients present for their first left AV valve reoperation in adulthood. Second reoperations on the left AV valve are common, with freedom from reoperation after first reoperation of only 42% at 15 years.

Presentation

Small PDA is asymptomatic, causing clinically unimportant left-to-right shunt. A continuous murmur may or may not be detectable, depending on size of the PDA. The patient may present with endocarditis or endarteritis.

Moderate PDA results in restrictive left-to-right shunting of variable magnitude, depending on its size. The larger the PDA, the more likely it will cause shortness of breath, fatigue, a wide pulse pressure, left atrial and ventricular enlargement, and some elevation of pulmonary artery pressure. In some cases, initial presentation is an incidental finding of ductal calcification or aneurysm on chest radiography or other imaging.

Large PDA is nonrestrictive and produces a large left-to-right shunt, pulmonary arterial hypertension (PAH), and almost always Eisenmenger physiology. Lower body cyanosis develops with advanced Eisenmenger physiology. Left and right ventricular failure may be present.

Diagnosis

The electrocardiogram is abnormal with large PDA, showing left atrial enlargement and left (volume-loaded) and right (pressure-loaded) ventricular hypertrophy. Chest radiography varies from normal to abnormal depending on shunt size. With larger shunts, cardiomegaly from left atrial, left ventricular, and right ventricular enlargement is seen. The pulmonary trunk is prominent. Calcification of the ductus may be detected.

Echocardiography confirms the diagnosis by using color Doppler to identify flow across the ductus. If PAH is present, pressure gradient and flow across the ductus are small, and echocardiography may fail to identify the PDA. Cardiac catheterization is performed in most cases of adult PDA, either as a diagnostic tool to assess the state of the pulmonary vasculature in large PDAs, or as a therapeutic tool to close small and some moderate PDAs. Magnetic resonance imaging or computed tomography may be useful if the PDA is complicated by aneurysm. Using these, the specific size and position of the aneurysm and its adjacency to other structures can be determined. Most reported aneurysms are patent at only one end, either aortic or pulmonary, but cases of true patency have been reported ( Fig. 29-10 ).

Presentation

Patients with primary or secondary disease often present with gradual stenosis and/or regurgitation that eventually leads to symptoms or physiologic criteria for surgical intervention. Less often, the primary presentation is ascending aorta dilatation and, rarely, aortic dissection, aneurysm, or rupture. Occurrence of dissection may be tenfold higher than in the normal population. Associated coarctation appears to increase risk of dissection. Occasionally, BAV presents with signs and symptoms of infective endocarditis.

Adults with secondary disease may present with a failed aortic valve repair, failed bioprosthetic aortic valve, failed or outgrown mechanical aortic valve, or failed pulmonary autograft (Ross procedure) in the aortic position. Bioprosthetic valves tend to require earlier replacement in young adults compared with older adults. This is likely due to a combination of patient growth after original placement and more rapid calcific degeneration. Need for replacement of mechanical valves is mostly related to patient growth, but gradual encroachment of pannus may also play a role. After the Ross procedure, neoaortic regurgitation necessitates reoperation in up to 10% of patients within a decade. Neoaortic root dilatation occurs in about half of cases by 7 years and may or may not be associated with neoaortic regurgitation. Risk of dissection or aneurysm formation in the dilated neoaortic root is not clear. Coronary obstruction may also present late after the Ross procedure because of scarring and kinking of the translocated coronary arteries and from compression by the calcified right ventricle to pulmonary trunk conduit. One of the most common late developments after the Ross operation is right ventricular outflow tract conduit failure. Freedom from conduit reoperation is better following the Ross operation than for conduits placed for other congenital heart diseases, such as tetralogy of Fallot. Brown and colleagues demonstrated freedom from conduit reoperation of 96% at 10 years. Raanani and colleagues report one reoperation for conduit failure in 109 patients at a mean follow-up of 39 months, although moderate to severe stenosis was noted in 3.8% and moderate to severe regurgitation in 9.5%.

Diagnosis

Electrocardiography and chest radiography show typical findings associated with aortic valve disease. Echocardiography is the mainstay of diagnosis. It is able to assess the degree of stenosis or regurgitation once the diagnosis is made and can identify when physiologic criteria are met for intervention. Cardiac catheterization is performed when coronary assessment is indicated, primarily in patients over age 40, or if there is concern that primary coronary insufficiency is present or that coronary scarring or compression has developed following a Ross procedure or other aortic root replacement procedure. Magnetic resonance imaging (MRI) and computed tomography are indicated to assess ascending aorta size and to rule out dissection and aneurysm. Additionally, MRI can be used to quantify aortic regurgitation if symptoms and echocardiographic findings disagree.