Adult Manifestations of Congenital Heart Disease

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[edit] Adult Manifestations of Congenital Heart Disease

Edgar C. SchickJr.

Congenital heart disease comprises unusual fare for the adult practitioner. Even among major adult cardiology referral centers, congenital defects seldom constitute more than 5% of all cases; of those, atrial septal defects account for about half, and coarctation of aorta, patent ductus arteriosus, and pulmonic stenosis the bulk of the remainder. Unmodified cyanotic congenital disease has all but vanished from adult practice as a result of advances in surgical correction or palliation. The survivors of these procedures often present complex combinations of persistent anatomic abnormalities, as well as a spectrum of iatrogenic problems almost invariably requiring follow-up at specialized centers. The following considerations are limited to those problems most likely to be encountered in the adult.

[edit] ACYANOTIC CONGENITAL DISEASE WITHOUT SHUNT

[edit] Pulmonic Stenosis

Valvular pulmonic stenosis imposes a systolic pressure burden on the right ventricle that leads to right ventricular hypertrophy. Symptoms, when present, reflect limitation of cardiac output because of increased afterload on the right ventricle and the right heart failure that may ensue. Exertional fatigue and dyspnea are common; chest pain and syncope are encountered less frequently. Patients with mild to moderate degrees of obstruction, usually defined as a peak transvalvular gradient of 40 mm Hg or less, may remain asymptomatic through adult life. Those with more severe obstruction are candidates for intervention.

The clinical findings generally correlate well with the hemodynamic measurements. A crescendo-decrescendo murmur most prominent at the upper left sternal edge that ends well before aortic valve closure indicates mild stenosis. A prolonged systolic murmur, which may extend beyond and obscure the sound of aortic closure, suggests more severe obstruction. A pulmonic ejection click is typically present, and with increasingly severe stenosis the click migrates toward the first heart sound. The pulmonic component of the second heart sound, when audible, is delayed; as a result, the second sound is widely split (Fig. 67-1). Further markers of severe stenosis include a prominent jugular a wave, a right ventricular lift, a systolic thrill along the left sternal edge, and an S₄ gallop that intensifies on inspiration.

Figure 67-1 Auscultatory findings in congenital pulmonic stenosis. With increasing severity, the duration of the murmur (SM) is prolonged and the intensity of the pulmonic closure (P₂) diminishes. S₁, First heart sound; E, pulmonic ejection click; A₂, aortic closure. (From Perloff JK: The clinical recognition of congenital heart disease, Philadelphia, 1970, WB Saunders.)

The electrocardiogram (ECG) is usually normal with mild pulmonic stenosis and exhibits evidence of right ventricular hypertrophy and right atrial enlargement with increasing severity. The x-ray may show poststenotic dilation of the main pulmonary artery. Echocardiography provides precise identification of the level of obstruction, accurate characterization of hemodynamic severity, and assessment of right ventricular wall thickness and function (Fig. 67-2).

Figure 67-2 A, Continuous-wave Doppler recording of pulmonic ejection velocity from a patient with pulmonic stenosis. The arrow indicates a peak velocity of nearly 5 M/s, corresponding to a gradient approaching 100 mm Hg. B, An angiographic frame from the same patient. The arrows point to the thickened valve leaflets and the narrow stenotic flow jet. Post-stenotic dilation of the pulmonary artery (PA) is also evident. C, Cine frame showing a balloon catheter positioned across the stenotic valve during valvuloplasty.

Mild pulmonary stenosis carries an excellent prognosis.^[1] Patients with evidence of mild stenosis (peak systolicgradient under 40 mm Hg) during adolescence are unlikely to develop problems later and require only periodic clinical reevaluation and antibiotic prophylaxis. Patients in whom the measured gradient falls in the moderate range (i.e., between 40 and 80 mm Hg) may do well for extended periods; however, natural history studies indicate that most will eventually require intervention, and cardiology evaluation is appropriate, particularly if symptoms are present. Systolic gradients above 80 mm Hg warrant early intervention.

Balloon pulmonary valvuloplasty, now the procedure of choice, has a high success rate^[2] in reducing the valvular gradient to acceptable levels. Surgical valvotomy is reserved for those with suboptimal results. The pulmonic insufficiency resulting from these procedures is usually mild and well tolerated. Postoperatively, a systolic murmur almost invariably persists, and a low-pitched, rumbling pulmonary regurgitant murmur is common.

[edit] Coarctation of Aorta

Aortic coarctation, a correctable cause of hypertension, refers to a narrowing of the aorta by a fibrous dorsal invagination most often at or just beyond the origin of the left subclavian artery (Fig. 67-3). Coarctation is more common in men and is occasionally associated with Turner's syndrome. Although heart failure may occur during infancy, the condition is frequently well tolerated into adult life. Because of the sustained left ventricular pressure burden, however, symptoms of congestive failure become the rule beyond age 40. In those undetected until adulthood, the most common associated abnormality is a bicuspid aortic valve (see Chapter 66 ). Other complications encountered with coarctation include bacterial endarteritis at the site of the coarctation or endocarditis involving the bicuspid aortic valve, stroke from cerebral aneurysms, aortic dissection, and rupture.

Figure 67-3 Aortogram from a patient with coarctation. The coarctation is well visualized (upper arrow) beyond the origin of the left subclavian artery. A bicuspid aortic valve is also present (lower arrow) with a faint blush of aortic regurgitation (arrows).

Physical examination reveals upper torso hypertension in most patients with coarctation, but this may not be evident in the left arm if the narrowed segment includes the left subclavian artery. Rarely, arm hypertension may be absent altogether if the right subclavian artery arises aberrantly distal to the coarctation. The carotid pulses are bounding, and a prominent suprasternal pulse may be present. Femoral pulses may be reduced or absent, but comparatively delayed arrival of the femoral pulse on simultaneous palpation of the radial artery is the most diagnostically specific characteristic. Additional systolic or diastolic murmurs arising from associated aortic valve disease are common.

The ECG is likely to manifest evidence of left ventricular hypertrophy in adults. On chest x-ray, a dilated transverse aorta and the poststenotic dilation of the descending aorta may create a “figure-three” sign along the upper left cardiac margin (Fig. 67-4). Rib notching related to intercostal collateral development may become apparent after childhood, usually involving the third to eighth ribs posteriorly. Echocardiographic study from a suprasternal transducer position may directly visualize the coarctation, particularly in younger patients; despite difficulty with imaging in older patients, measurement of the gradient is usually possible by Doppler.

Figure 67-4 Chest film from a patient with aortic coarctation illustrating the components that contribute to the “figure-three” sign. The convexity of the left subclavian artery (LSA) and the descending aorta (DA) separated by the indentation of the coarctation create the “3.” The dilated ascending aorta (Ao) is also notable, as well as rib notching (arrows). (From Perloff JK: The clinical recognition of congenital heart disease, 1970, Philadelphia, WB Saunders.)

Since patients with uncorrected coarctation are at risk for serious complications, suspicion of the diagnosis always warrants cardiology evaluation. Currently, repair is recommended when the gradient exceeds 20 mm Hg or when angiography demonstrates severe coarctation with extensive collateralization. Correction during childhood is preferred, but the optimal mode of treatment is controversial. Operative approaches continue to be favored at some centers, but successful use of balloon angioplasty and stenting is increasingly reported, and balloon angioplasty is generally considered to be the approach of choice for recoarctation.

After childhood, because of a progressive increase in the incidence of residual hypertension with age, the earlier the correction the more favorable the results. Studies suggest a 25% incidence of hypertension after correction if performed before age 10 and about 50% thereafter.^[3] Despite correction, coarctation patients remain subject to such problems as cerebral aneurysm rupture, progression of aortic valve disease, and infective endocarditis.

[edit] ACYANOTIC CONGENITAL DISEASE WITH SHUNT

[edit] Atrial Septal Defect

Atrial septal defect (ASD), the most common intracardiac shunt diagnosed in the adult, frequently eludes early diagnosis because its characteristic features are absent at birth and subtle enough to escape recognition in childhood. Symptoms frequently do not emerge until mid-adult life or later. Defects of the atrial septum occur more frequently in women, and may be hereditary in some instances, notably in conjunction with hypoplastic abnormalities of the thumb and forearm as part of Holt-Oram syndrome.

Of the several types of ASD, the septum secundum defect is most common (Fig. 67-5). It is located in the mid-atrial septum, circumscribing the usual site of the fossa ovalis, the landmark corresponding to the fetal foramen ovale. Even in the absence of detectable shunting, the limbs of the foramen frequently fail to fuse and may provide a potential interatrial communication in up to 30% of adults. Defects in the low atrial septum (ostium primum defect) are a form of endocardial cushion defect, and are accompanied by clefts in the atrioventricular valves. Sinus venosus defects, located high in the atrial septum, are associated with both anomalous pulmonary venous return to the right atrium and abnormalities of the sinus node.

Figure 67-5 Location of the four types of atrial septal defect. SVC, Superior vena cava; RA, right atrium; IVC, inferior vena cava; RV, right ventricle; TVL, tricuspid valve leaflet.

Diversion of flow from the left to the right atrium via the ASD produces volume overload of the right heart and the pulmonary circuit. Commensurate with the course of other chronic volume overload states, this burden is usually well tolerated throughout young adult life, but thereafter complications begin to appear. Symptoms predominantly reflect right ventricular decompensation, and are occasionally abetted by development of pulmonary hypertension. Left-to-right shunting may worsen with age, particularly if other conditions, such as hypertension or coronary disease, lead to elevation of filling pressures in the left heart.

Exertional dyspnea, probably caused by the increased lung blood volume, is a frequent complaint of patients with ASD. Overt right heart failure begins to appear after age 30. Supraventricular dysrhythmias, facilitated by atrial enlargement (most importantly atrial fibrillation), contribute substantially to morbidity. Although the incidence of pulmonary hypertension increases with age, obliterative pulmonary vascular disease sufficient to result in shunt reversal (Eisenmenger's syndrome) develops in fewer than 5% of patients. The association between secundum ASD and mitral valve prolapse has received considerable attention, with an incidence in excess of 50% reported in some series. Mitral regurgitation severe enough to warrant consideration of valve repair or replacement is, however, unusual.

On physical examination, a dynamic systolic impulse immediately to the left of the sternum should direct attention to the possibility of increased volume flow through the right heart. A brief, flow-related systolic ejection murmur is usually audible in the pulmonic area. The two components of the second heart sound are widely split during expiration with imperceptible variation on inspiration. This phenomenon, referred to as fixed splitting, constitutes the single most important and most frequently overlooked or misinterpreted clue to the presence of a shunt. Wide, fixed splitting of S₂, a nearly universal finding with ASD in younger patients, may become less consistent in older adults and when pulmonary hypertension develops. However, any expiratory splitting of the second sound in adults unexplained by right bundle branch block should bring suspicion of ASD to the fore. An audible diastolic rumble at the lower left sternal edge, created by torrential flow across the tricuspid valve, almost invariably indicates a significant left-to-right shunt. A midsystolic click may be audible over the apex if mitral valve prolapse coincides, and a murmur of mitral regurgitation may represent either mitral prolapse or a mitral valve cleft in the case of an ostium primum defect.

The ECG pattern of incomplete right bundle branch is present in about 90% of patients with ASD. Associated left axis deviation connotes a defect of the endocardial cushion and predicts the presence of a primum ASD. Marked right axis deviation implies the presence of pulmonary hypertension. The chest x-ray reveals variable enlargement of the right heart chambers, dilation of the central pulmonary arteries, and a pattern of peripheral pulmonary vascular plethora (Fig. 67-6).

Figure 67-6 Posteroanterior chest film from a patient with a secundum atrial septal defect (3.7:1 pulmonary-systemic flow ratio) and normal pulmonary artery pressures. Note the dilation of the main pulmonary artery segment, which obscures the left pulmonary artery, and the prominent right pulmonary artery and branches.

Thanks to recent advances in color flow and transesophageal imaging, echocardiography provides for complete anatomic and hemodynamic characterization of ASD in most patients (Fig. 67-7). These advances have eliminated the need for catheterization in most younger patients with a straightforward anomaly.

Figure 67-7 A, Transesophageal echocardiogram from a patient with a secundum atrial septal defect. The large arrows indicate a large defect in the atrial septum (small arrow).B, Doppler recording demonstrating left-to-right flow through the ASD. LA, Left atrium; RA, right atrium; Ao, aorta.

To deter late complications of ASD, repair is recommended for all patients with evidence of a physiologically significant shunt (e.g., right atrial and right ventricular enlargement). Recent studies indicate that ASDs may be safely corrected in patients over age 60 even when pulmonary resistance is markedly elevated, as long as a net left-to-right shunt is present; shunt reversal, however, is a contraindication to closure. Despite evidence that normal right ventricular function is unlikely to be fully restored and that atrial fibrillation may not be prevented, overt right ventricular failure should not deter surgery, which arrests an otherwise progressive process.^[4][5]

Increasingly, attention in the literature has focused on the use of percutaneous devices for closure of secundum ASDs. Although a number of devices are currently under investigation, none have been approved for routine clinical use in the United States.

[edit] Ventricular Septal Defect

The ventricular septum may be divided into inlet, membranous, trabecular, and outlet (infundibular) regions. Perimembranous septal defects, either directly involving or immediately adjacent to the membranous septum, are by far the most common. They are found at the base of the interventricular septum immediately behind the septal leaflet of the tricuspid valve and below the crista supraventricularis, a muscular bar that separates the right ventricular inflow and outflow tracts. Typically, these defects lie subjacent to the right coronary cusp on the left side of the septum. Muscular defects, the second most common ventricular septal defect (VSD), may involve any of the other three segments and are often multiple.

A spectrum of physiologic derangement is possible with a defect in the interventricular septum, ranging from pure volume overload of both ventricles to pure pressure overload of the right ventricle (Eisenmenger's syndrome). The governing features are the size of the defect and pulmonary outflow (vascular) resistance. Volume effects predominate when large defects concur with low pulmonary resistance, whereas both pressure and volume overload of the right ventricle ensue if pulmonary resistance increases.

As a result of improved diagnosis and emphasis on correction of significant defects during childhood, experience with VSD in adult practice is generally limited to patients with small, hemodynamically insignificant shunts (maladie de Roger) or those with minor residual shunting following surgical correction. Physical examination may reveal a harsh holosystolic murmur along the left sternal border radiating to the right; rarely, a systolic thrill may be evident in the same region. Echocardiography provides complete physiologic characterization in most instances (Fig. 67-8). Patients in whom findings suggest a significant left-to-right shunt or pulmonary hypertension should always be referred for cardiology evaluation.

Figure 67-8 A, Parasternal long-axis echocardiographic image from a patient with a small, perimembranous VSD. B, Doppler image from the subsector outlined in A, showing flow across the septum (arrow) immediately below the aortic valve. C, Doppler recording of the VSD jet velocity. The peak velocity of 5 M/s indicates a 100-mm Hg gradient across the ventricular septum and implies normal right ventricular and pulmonary artery pressures. LV, Left ventricle; LA, left atrium; Ao, aorta.

The asymptomatic patient with the murmur of VSD without symptoms, evidence of significant volume overload, or pulmonary hypertension requires only endocarditis prophylaxis. The risk of endocarditis is low, as indicated by the 1.9 cases per 1000 patient-years found in a large cooperative study.^[1] About 5% of VSD patients develop aortic regurgitation, partly because of abnormal tissue support for the aortic cusps. The regurgitation may progress irrespective of VSD closure; in fact, the regurgitation may first appear after repair of the defect. Successful aortic valvuloplasty has been combined with VSD repair, but the management of aortic regurgitation in combination with a small VSD is the same as aortic regurgitation alone.

ECG abnormalities are common after VSD repair. Complete heart block, once a frequent manifestation of surgical trauma to the conduction system, which courses in proximity to the inferior margins of the perimembranous defect, now occurs only rarely. Right bundle branch block is common following right ventriculotomy for surgical closure and is less common following repair via the right atrium, the preferred approach. Ventricular dysrhythmias, which are evident in 40% to 50% of patients after surgical repair, are more likely after ventriculotomy. Late sudden death occurs in approximately 4% of the patients. Management of these dysrhythmias is identical to that for ventricular dysrhythmias of other etiologies in the adult (see Chapter 61 ).

[edit] Patent Ductus Arteriosus

The ductus arteriosus, which shunts blood from the pulmonary to the systemic circuit during fetal development, closes functionally within 24 hours of birth in the normal situation. Anatomic obliteration usually follows within the first 2 months, and patency of the ductus beyond this is abnormal. As with VSD, improved detection and treatment have virtually eliminated encounters with patent ductus arteriosus (PDA) and a significant shunt from adult practice. The finding of a continuous murmur to the left of the upper sternum is the distinctive feature on examination (Fig. 67-9).

Figure 67-9 A, Parasternal short-axis view at the level of the great vessels from a patient with a patent ductus arteriosus. B, Doppler image from the subsector outlined in A. The arrow points to the origin of the flow jet from the descending aorta extending into the pulmonary artery. C, Continuous-wave Doppler recording of PDA flow. The continuous line traces the maximum velocity, demonstrating continuous flow with accentuation during systole, which corresponds to the features of the characteristic murmur. Ao, Aorta; LA, Left atrium; PA, pulmonary artery.

All patients suspected to have ductal patency should be referred for cardiology evaluation. Closure, increasingly accomplished by percutaneous techniques, is the preferred treatment of PDA, regardless of shunt magnitude, because of the risk of endocarditis. The patient with a tiny flow jet consistent with ductal patency discovered incidentally on echocardiography is an exception to this rule and requires only endocarditis prophylaxis. Advanced age may also temper the therapeutic approach to the asymptomatic patient with a small shunt in whom ductal tortuosity and calcification may increase the technical difficulty and risks of catheter closure or ligation; preprocedural angiographic definition is a must in these cases. Antibiotic prophylaxis is not required after closure if there is no echocardiographic evidence of a shunt.

[edit] CYANOTIC CONGENITAL DISEASE

Cyanotic congenital disease in the adult is a rarity. Most often, patients with a history of cyanotic heart disease in infancy or childhood will have undergone previous evaluation and either a palliative or corrective procedure. With few exceptions, these patients remain subject to a variety of potential problems and complications that require follow-up at subspecialized centers familiar with their management. Although declining in incidence, Eisenmenger's syndrome remains a not uncommon cardiac cause of cyanosis in the adult. In these patients, a congenital lesion with a left-to-right shunt, often undetected in childhood, leads to the development of irreversible pulmonary hypertension and shunt reversal, which precludes correction of the primary defect. Despite this, many of these patients survive well into adult life, and aspects of their medical management deserve some consideration.

Patients with Eisenmenger's syndrome demonstrate central cyanosis and clubbing on physical examination as well as cardiac findings associated with pulmonary hypertension. Management of patients with mild symptoms is conservative, since prognosis in this group is better than lung or heart-lung transplantation, and consists of avoidance of, or meticulous monitoring during, situations presenting an increased risk of morbidity for these patients. Patients who develop more severe symptoms as a consequence of right heart failure should be considered for transplantation.

Problematic situations in these patients include those associated with vasodilation and volume depletion (e.g., infection, hemorrhage, surgery, angiography), which may intensify the right-to-left shunt, resulting in precipitous deterioration.^[6] Pregnancy is contraindicated by the high risk of both maternal mortality and fetal loss; modes of contraception not associated with an increase in thromboembolic risk are preferred. These patients are particularly at risk for paradoxical embolization, and meticulous attention to intravenous lines is necessary to minimize the chances of air embolization or cerebral abscess. Erythrocytosis is common, and if excessive (e.g., hemoglobin > 20 gm %), symptoms of hyperviscosity may occur. Routine phlebotomy, however, is not recommended, since this may be associated with the development of microcytosis, which has been associated with an increased thromboembolic risk. Additional common problems include hyperuricemia and gout related to increased red cell turnover. A number of coagulation abnormalities and renal dysfunction may also occur. In this regard nonsteroidal antiinflammatory agents are problematic and should be avoided in these patients.

[edit] REFERENCES