The most common acyanotic congenital heart defects include abnormalities of the heart valves and great vessels, ventricular or atrial communications with left-to-right shunting, and such lesions as partial anomalous pulmonary veins and anomalous coronary arteries.
Congenital Aortic Valvular Disease
- History of murmur since infancy, coarctation repair, or endocarditis.
- Early systolic ejection click, harsh crescendo-decrescendo systolic, or early decrescendo diastolic murmur.
- Left ventricular hypertrophy.
- Abnormal bicuspid or dysplastic aortic valve with stenosis or regurgitation on Doppler echocardiography.
Congenital aortic stenosis is the most common anomaly encountered in the adult population and constitutes approximately 7% of all forms of congenital heart disease. The male:female ratio is approximately 2–3:1. The term “bicuspid aortic valve” is actually a misnomer; a raphe caused by commissural fusion of two leaflets usually exists. The valve is often dysplastic, with thickened, rolled, and calcified leaflets. The predominant pathophysiology results from mildly obstructed nonlaminar (disturbed) flow across the abnormal valve. A left ventricle-to-aorta pressure gradient of variable severity occurs, setting the stage for the inevitable deterioration of the valve with long-term calcium deposition and progressive stenosis or regurgitation. The valve is also at risk for endocarditis, which can lead to early destruction and regurgitation. Congenital aortic valve disease frequently occurs as a developmental “triad” with coincident aortopathy and coarctation, and these conditions should be sought clinically and echocardiographically in patients with congenital aortic valve disease. Familial congenital aortic valve disease occurs occasionally. While the genetics of this are incompletely understood, mutations in the gene encoding Notch 1 have been implicated in a subset of these patients.
The individual with congenital aortic stenosis is usually asymptomatic unless hemodynamically significant stenosis or regurgitation is present. Routine physical examination reveals a normal carotid pulse contour and left ventricular (LV) impulse, a normal S2, an early systolic click or sound, and an early-peaking systolic murmur. Identifying these patients in the asymptomatic stage is important. Current guidelines do not recommend endocarditis prophylaxis for the native valve. Refraining from high-level isometric exercise is generally believed to preserve valve function and limit valve regurgitation. The presence of a diastolic murmur of aortic regurgitation in a patient with a febrile illness should alert the clinician to the possibility of endocarditis and prompt the performance of appropriate diagnostic tests (eg, blood cultures, echocardiogram).
Congenital aortic stenosis is progressive; once hemodynamically significant valvular disease develops in a patient, generally in the fifth or sixth decade of life, the symptoms and signs are identical to those of a patient with acquired aortic valvular disease. Dyspnea, chest pain, and exertional syncope are the classic presenting symptoms. When stenosis predominates, the carotid upstroke is delayed and diminished in volume, the systolic click is no longer present, S2 is single, and the systolic murmur is crescendo-decrescendo, peaking in late systole. The murmur of aortic regurgitation is often present. The finding of upper extremity hypertension should alert the examiner to the possibility of concomitant aortic coarctation.
Electrocardiography and Chest Radiography
The major electrocardiographic (ECG) findings occur in the presence of hemodynamically significant disease and include left ventricular hypertrophy (LVH) with high QRS voltage, left-axis deviation, and repolarization changes; left atrial enlargement may also be present. The chest radiographic findings are nonspecific. With predominant valvular aortic stenosis, the cardiothoracic ratio may be normal, but LV enlargement and calcification may be evident in the region of the aortic valve on the lateral film. A dilated ascending aorta or a prominent aortic knob may be seen. The cardiac silhouette is enlarged in patients with predominant aortic regurgitation. Pulmonary vasculature may be prominent in the presence of congestive heart failure (CHF).
In the child and younger adult, the abnormally thickened leaflets of the congenitally abnormal valve are readily seen, and the bicuspid valve with its ovoid appearance in systole is apparent (Figure 31–1). On M-mode echocardiography, the point of closure may be eccentric. Heavy calcification often obscures the original valve morphology in the older individual with stenosis. The peak systolic gradient in severe aortic stenosis is usually greater than 64 mm Hg (peak velocity > 4 m/s by continuous wave Doppler). Aortic valve area can be accurately calculated by the continuity equation. Severe aortic stenosis is defined as a valve area of less than 1.0 cm2 or 0.5 cm2/m2. The LV shows concentric hypertrophy with thick walls and normal cavity dimensions, and the LV ejection fraction is usually normal. In cases with reduced ejection fraction, however, the peak gradient across the aortic valve is generally lower.
Transesophageal echocardiographic views of a patient with bicuspid aortic valve. A: Systolic frame showing two leaflets of the aortic valve (AV) with an ovoid opening (arrow). B: Diastolic frame showing the single line of coaptation (arrow). LA, left atrium; RV, right ventricle.
In hemodynamically significant aortic regurgitation, the high-velocity diastolic color-flow jet is broad at its site of origin below the aortic valve. Spectral Doppler imaging demonstrates a dense diastolic velocity signal with a short pressure half-time (< 400 ms), and diastolic flow reversal can be recorded in the descending aorta. The LV shows eccentric hypertrophy with normal LV wall thickness and a dilated cavity.
In occasional patients with poor precordial windows, transesophageal echocardiography (TEE) may be required to define valve anatomy by demonstrating commissural fusion and asymmetric sinuses of Valsalva. Systolic doming of the leaflets can be easily seen in the long axis view of the LV outflow tract, which also allows measurements to be taken of the aortic valve annulus, sinuses of Valsalva, sinotubular ridge, and ascending aorta.
Cardiac magnetic resonance angiography (MRA) is a possible alternative imaging technique.
Indications for cardiac catheterization in congenital aortic valve disease have changed significantly because most of the diagnostic data are now available noninvasively. According to current guidelines, however, cardiac catheterization is indicated when noninvasive tests are inconclusive or when there is a discrepancy between noninvasive tests and clinical findings regarding severity of aortic stenosis. It is also indicated preoperatively in patients at risk for atherosclerotic coronary artery disease (men age 35 years or older, premenopausal women age 35 years or older who have coronary risk factors, and postmenopausal women) and in patients for whom a pulmonary autograft (Ross procedure) is contemplated and if the origin of the coronary arteries was not identified by noninvasive techniques.
Magnetic Resonance Imaging
Serial imaging with magnetic resonance imaging (MRI) permits accurate and reproducible follow-up of aortic dilatation and is accepted as the standard of care for follow-up of repaired coarctation, a frequent association with a bicuspid aortic valve.
Valvular aortic stenosis should be distinguished from subaortic stenosis, which may be due to an obstructing fibrous membrane in discrete subaortic stenosis, which is more frequently encountered in adults, or by a tubular fibromuscular channel that usually presents in childhood. Aortic regurgitation, commonly associated with discrete membranous subaortic stenosis (in approximately 60% of cases), increases in frequency with age. Regurgitation may occur due to leaflet thickening induced by direct trauma to the aortic leaflets from the high-velocity jet or by interference with leaflet closure from the membrane. The aortic valve appearance and the severity and mechanism of aortic regurgitation must be carefully assessed.
Recurrent stenosis caused by regrowth following surgical resection of the fibromuscular ridge is sometimes encountered in the adolescent or adult. Discrete subaortic stenosis and congenital valvular aortic stenosis must also be distinguished from dynamic LV outflow-tract obstruction caused by hypertrophic cardiomyopathy (see Chapter 23). Supravalvular aortic stenosis is frequently seen in patients with Williams syndrome.
When aortic regurgitation is the predominant lesion and ascending aorta dilatation is present, the condition must be distinguished from Marfan syndrome and other genetic aortopathies. This latter condition is characterized by dilatation of the aortic root at the level of the sinuses of Valsalva (Figure 31–2). The aortic valve leaflets are not thickened, and regurgitation is caused by failure of leaflet coaptation caused by the root dilatation. With valvular stenosis, the aorta narrows toward normal at the sinotubular junction, and the descending thoracic aorta is spared. In some patients with a bicuspid aortic valve, an underlying abnormality of the medial layer of the aorta above the valve predisposes to the dilatation of the aortic root, which may progress to aneurysm formation or rupture and places the patient at risk for aortic dissection. All components of the vessel wall, smooth muscle, elastic fibers, collagen, and ground substance can be affected and should be recognized as a potential risk in the surgical patient.
Transesophageal echocardiographic (TEE) views of the ascending aorta (Asc Ao) measuring 8 cm in a patient with Marfan syndrome. LVOT, left ventricular outflow tract.
The natural history of aortic stenosis presenting in childhood depends largely on the severity of the stenosis at the time of diagnosis. During a 25-year follow-up period, approximately one-third of the children with a peak systolic gradient of less than 50 mm Hg who were treated medically, required surgery, in contrast to 80% of those with an intermediate gradient (50–79 mm Hg). Of those treated surgically for a gradient of more than 79 mm Hg, approximately one-fourth required reoperation; reoperation was more common in those treated with initial valvotomy (30%) than aortic valve replacement (5%). The overall 25-year survival rate is approximately 85%; sudden death accounts for approximately half of the cardiac-related deaths.
Once symptoms of aortic stenosis develop, the prognosis without valve replacement is poor; the 5-year mortality rate is approximately 90%. Although percutaneous valvuloplasty has been successful in children and adolescents, the results in adults (even those with congenitally abnormal valves) have been disappointing. Therefore, surgery with aortic valve replacement, rather than percutaneous valvuloplasty, is generally mandated. Surgery is indicated in the symptomatic patient with a valve area of less than 1.0 cm2 (or < 0.5 cm2/m2). It should be considered in the asymptomatic patient with critical stenosis when the patient requires cardiac surgery (eg, coronary artery bypass surgery) for another lesion. A particularly difficult management decision ensues in the asymptomatic woman with severe aortic stenosis who is contemplating pregnancy. Valve replacement prior to pregnancy should be considered when there is evidence of LV dysfunction or reduced exercise tolerance on objective stress testing.
Patients with a bicuspid aortic valve and concomitant annuloaortic ectasia may show a more rapid progression of aortic regurgitation and require surgical intervention earlier than those patients with pure aortic stenosis.
An ideal substitute for replacing the aortic valve does not exist. Homografts and bioprosthetic valves can develop rapid calcific degeneration, causing valve dysfunction, particularly in the younger cohort of patients. Mechanical valves, although extremely durable, require anticoagulation to reduce the complication of thromboembolism. The risks associated with long-term anticoagulation have made surgical options to avoid the use of mechanical valves desirable alternatives. This is particularly germane to the choice of prosthetic valve in young women of childbearing age, in whom management of anticoagulation can be problematic. The Ross procedure (in which the autologous pulmonary valve replaces the aortic valve, and an aortic or pulmonary homograft replaces the pulmonary valve) has been increasingly performed for a variety of LV outflow tract diseases, including aortic insufficiency and valvar aortic stenosis with or without other forms of obstruction (eg, subaortic stenosis, supravalvar stenosis, and arch hypoplasia). Although the Ross procedure is more complex than simple aortic valve replacement, it can be performed with a low mortality rate in selected patients. Advantages of the pulmonary valve autograft include freedom from anticoagulation and the absence of compromise from host reactions and autograft growth, making it an attractive option for aortic valve replacement in infants and children. It is recognized, however, that the pulmonary homograft will require replacement for degenerative disease and size restriction in children. In adults who are confronting surgery for a stenotic aortic valve in the fifth or sixth decade of life, the Ross procedure has shown to be an acceptable alternative to the usual mechanical or bioprosthetic valve. However, recently recognized problems associated with the Ross procedure include progressive dilatation of the neo-aortic root, pulmonary conduit stenosis, and neo-aortic valve regurgitation. Contraindications to the Ross procedure include advanced three-vessel coronary artery disease, poor LV function, a severely calcified or dilated aortic root, or pulmonary valve pathology.
American College of Cardiology/American Heart Association Task Force on Practice Guidelines; Society of Cardiovascular Anesthesiologists; Society for Cardiovascular Angiography and Interventions; Society of Thoracic Surgeons; Bonow RO, et al. ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing committee to revise the 1998 guidelines for the management of patients with valvular heart disease): developed in collaboration with the Society of Cardiovascular Anesthesiologists: endorsed by the Society for Cardiovascular Angiography and Interventions and the Society of Thoracic Surgeons. Circulation
Knott-Craig CJ, et al. Aortic valve replacement: comparison of late survival between autografts and homografts. Ann Thorac Surg
Lambert V, et al. Long-term results after valvotomy for congenital aortic valvar stenosis in children. Cardiol Young
Masani N. Transesophageal echocardiography in adult congenital heart disease. Heart
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Niwa K, et al. Structural abnormalities of great arterial walls in congenital heart disease: light and electron microscopic analyses. Circulation
Raja SG, et al. Current outcomes of Ross operation for pediatric and adolescent patients. J Heart Valve Dis
Siu SC, et al. Bisucpid aortic valve disease. J Am Coll Cardiol
- History of systolic murmur since infancy.
- Systolic ejection click and an early systolic murmur in the second left intercostal space with transmission to the back. S2 may split widely.
- ECG evidence of right ventricular hypertrophy.
- Dilatation of main and left pulmonary arteries on chest radiograph.
- Right ventricular hypertrophy, systolic doming of the pulmonary valve, and a transpulmonic gradient by Doppler echocardiography.
Pulmonary valve, or pulmonic stenosis (PS), is the second most common form of congenital heart disease in the adult. Although many cases are so mild that they require no treatment, it often coexists with other congenital cardiac abnormalities (atrial septal defect [ASD], ventricular septal defect [VSD], patent ductus arteriosus, or tetralogy of Fallot [TOF]). Pulmonary valve stenosis is characterized by a conical or dome-shaped pliant valve with a narrow outlet at its apex. Right ventricular (RV) outflow is obstructed depending on the size of the orifice, and RV stroke volume may not rise appropriately during exercise. In response to the pressure overload, the RV hypertrophies, with an increase in wall thickness. This compensatory hypertrophy can involve the infundibulum and potentially lead to reversible dynamic subpulmonic stenosis once the valvular stenosis is relieved. If severe stenosis remains untreated, RV failure may ensue. It is important to differentiate pulmonary valve stenosis from stenoses of the peripheral pulmonary arteries and primary infundibular stenosis, often associated with VSD (see Tetralogy of Fallot). Pulmonary stenosis from a thickened, dysplastic valve is seen in patients with Noonan syndrome (a heterogeneous malformation syndrome with autosomal dominant inheritance).
The patient with PS usually has exercise intolerance in the form of exertional fatigue, dyspnea, chest pain, or syncope. RV failure with systemic venous congestion occurs late in the course of the disease. If the foramen ovale is patent or a concomitant ASD exists, shunting of blood from the right atrium to the left may occur, causing cyanosis and clubbing. The volume overload of pregnancy may precipitate right heart failure in patients with severe PS, although mild and even moderate stenosis are usually well tolerated.
In significant PS, the physical examination demonstrates a parasternal RV heave, a delayed and diminished or absent P2, and a late-peaking crescendo-decrescendo murmur that increases in volume with inspiration. If the valve is pliable, an ejection click precedes the murmur. This pulmonic ejection sound, best heard in the second left intercostal space, is the only right-sided event that decreases in intensity during inspiration and increases during expiration. As the stenosis becomes more severe, the systolic murmur will peak later in systole and the ejection click moves closer to the first heart sound, eventually becoming superimposed on it. The jugular venous pulse shows a prominent a wave, as a result of the diminished RV compliance, but jugular venous pressure is increased only in the late stages when RV failure occurs. Similarly, there may be an RV S4 gallop early in the course of the disease and a right-sided S3 in the later stages.
Electrocardiography and Chest Radiography
The ECG demonstrates evidence of right ventricular hypertrophy (RVH) with right-axis deviation, prominent R waves in the right precordial leads, and deep S waves in the left precordial leads (Figure 31–3). There may also be evidence of right atrial enlargement with peaked inferior (II, III, aVF) P waves.
Electrocardiograph in congenital pulmonic stenosis with severe right ventricular hypertrophy and marked right-axis deviation.
The cardiac silhouette on the chest radiograph is normal in mild-to-moderate PS but may become enlarged in severe stenosis when right heart failure occurs. The main and left pulmonary arteries are often dilated. In addition to this “poststenotic dilatation,” dilatation may be seen even in cases of mild PS and may be related to intrinsic abnormalities of the pulmonary artery (idiopathic pulmonary artery dilatation).
The poor near-field resolution of transthoracic echocardiography (TTE) often limits definition of pulmonary valve morphology in the adult patient. When examined from the parasternal short-axis view, the valve may appear thickened (rarely calcified) and usually manifests systolic doming. In the absence of right heart failure, the RV dimension is normal or only mildly increased, but the RV wall thickness is increased (> 5 mm). In severe cases, the septum may be deviated toward the LV from the pressure overload of the RV. The right atrium and ventricle dilate late in the course of the disease. Saline contrast echocardiography should be performed in all patients with pulmonary valve stenosis to exclude an ASD or a patent foramen ovale.
Color-flow Doppler imaging demonstrates high-velocity flow within the pulmonary artery and is helpful in excluding a VSD or a patent ductus arteriosus. Continuous wave Doppler demonstrates a high-velocity jet across the RV outflow tract (Figure 31–4B). This signal is best obtained from the parasternal short-axis or subcostal short-axis views where flow is axial to the Doppler beam. PS is classified as mild when the RV systolic pressure is < 50 mm Hg, moderate when the gradient is 50–79 mm Hg, and severe when the gradient is > 80 mm Hg. Unfortunately, because of the lack of range resolution, continuous wave Doppler cannot localize the level of the obstruction. The morphology of the valve by echocardiography and pulsed wave Doppler mapping may provide localizing information, but additional diagnostic procedures are often necessary.
A: Transesophageal echocardiographic views of a pregnant woman with severe pulmonary valve (PV) stenosis. The left image demonstrates the doming pulmonary valve in systole. The right frame illustrates the severe infundibular hypertrophy. B: Continuous wave Doppler recording from the same patient demonstrated a peak velocity of 6 m/s corresponding to a peak transvalvular gradient of 144 mm Hg.
TEE provides excellent definition of the RV outflow tract and pulmonary valve in the basal longitudinal views and excellent images of the atrial septum. As a result, noninvasive methods may now be adequate for establishing the diagnosis, even in adults.
In most patients, cardiac catheterization is therapeutic as well as diagnostic because percutaneous balloon valvuloplasty has virtually replaced surgery for treatment of pulmonary valve stenosis (see below). During right-heart catheterization, the level of the stenosis can be confirmed by pressure monitoring during pullback from the pulmonary artery and supplemented by RV angiography. In valvular stenosis, there is a rise in peak systolic pressure as the catheter tip passes from the pulmonary artery into the infundibulum. In contrast, when the stenosis is in the infundibulum, the systolic pressure increases when the catheter is pulled into the body of the RV. As mentioned earlier, in PS, secondary hypertrophy may result in some degree of infundibular stenosis, and a pressure differential may be demonstrated at both levels on pullback (Figure 31–5). If the level of obstruction is still uncertain, cine-angiography may show the hypertrophied infundibulum or, alternatively, the domed and thickened pulmonary valve. Of course, both levels of obstruction may coexist.
Hemodynamic tracings in pulmonic stenosis. A: Predilation: Peak gradient of 65 mm Hg between right ventricle (RV) and pulmonary artery (PA). B: Postdilation: Residual gradient of 20 mm Hg between RV infundibulum and pulmonary artery.
Unlike aortic valve stenosis, the valve area is not calculated from the Doppler or invasive hemodynamic data, and the gradient alone is used to determine the severity of the obstruction and guide therapy.
In severe untreated pulmonary valve stenosis, the average life expectancy is approximately 30 years. The natural history of medically treated mild (gradient < 50 mm Hg) or moderate (gradient 50–79 mm Hg) PS and surgically treated severe (gradient > 80 mm Hg) PS is excellent with a 25-year survival rate of 95%. Surgical valvotomy via a pulmonary artery incision has been extremely effective in long-term relief of pulmonary valve obstruction. Although approximately 50% of patients have mild-to-moderate regurgitation following surgery, it is seldom of hemodynamic significance, and reoperation is rarely necessary.
In children treated conservatively for PS, the likelihood of eventually requiring surgery is dependent on the initial gradient: less than 25 mm Hg, 5%; 25–49 mm Hg, 20%; and 50–79 mm Hg, 76%. In the adult, the indication for treatment of pulmonary valve stenosis is a peak systolic gradient in excess of 50 mm Hg. When the gradient is between 40 and 50 mm Hg, the decision to treat is based on the presence of symptoms, the age of the patient, and the degree of RVH (by echocardiography or ECG). Echocardiography, before and after exercise, may be an important technique to assess RV function in the presence of an increased gradient.
As mentioned earlier, most patients (including adults) with pulmonary valve stenosis are currently treated with percutaneous balloon valvuloplasty. The Registry of the Valvuloplasty and Angioplasty of Congenital Anomalies has listed 35 patients over the age of 20, among them a 76-year-old man. No significant complications occurred in adult patients, and the gradient was reduced from approximately 70 mm Hg to 30 mm Hg, with about 50% of the residual gradient caused by infundibular hypertrophy. Ongoing assessment of these patients indicate sustained long-term relief of the pulmonary valve gradient with progressive infundibular remodeling causing further reduction in the outflow tract gradient over time. Recent technical improvements leading to the development of low-profile balloon have decreased the risk of pulmonary regurgitation after dilatation. Based on these results, percutaneous balloon valvuloplasty appears to be the treatment of choice in adults with pulmonary valve stenosis. Severe pulmonary valve insufficiency after either balloon or surgical valvotomy is uncommon, but patients should be evaluated every 5–10 years for this complication. Even when PS is associated with severe infundibular stenosis and tricuspid regurgitation, the long-term results from balloon valvuloplasty are excellent.
Bashore TM. Adult congenital heart disease: right ventricular outflow tract lesions. Circulation
Baumgartner H, et al. Guidelines on the management of valvular heart disease (version 2012): the Joint Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS). Eur J Cardiothorac Surg
Fawzy ME, et al. Long-term results (up to 17 years) of pulmonary balloon valvuloplasty in adults and its effects on concomitant severe infundibular stenosis and tricuspid regurgitation. Am Heart J
- A widely split S2 without respiratory variation (“fixed split”) and a midsystolic murmur are characteristic.
- RV conduction delay (“incomplete right bundle branch block”) with vertical QRS axis (ostium secundum ASD) and superior axis (ostium primum ASD) on ECG.
- Prominent pulmonary arteries and RV enlargement (decreased retrosternal air space) on chest radiograph. Increased pulmonary vascular markings.
- RV dilatation, increased pulmonary artery flow velocity, and left-to-right atrial shunt by contrast and Doppler echocardiography.
- Oxygen step-up within the right atrium; right-sided catheter can pass into the left atrium across the defect.
ASDs make up 10% of congenital heart disease cases in newborns and are regularly encountered as new diagnoses in adults. The defects vary in size from the smallest fenestrated ASD (a few millimeters) to the largest defect—the complete absence of the atrial septum, or common atrium. The most common interatrial communication is a patent foramen ovale that is anatomically and physiologically not classified as an ASD.
Classification of ASDs is according to location (Figure 31–6): ostium secundum in the region of the fossa ovalis, ostium primum in the lower portion of the atrial septum (actually part of an atrioventricular [AV] canal defect, discussed later), sinus venosus in the upper part of the septum near the entrance of the superior vena cava or at the entrance of the inferior vena cava, and unroofed coronary sinus (communication between the coronary sinus and left atrium). Important associated abnormalities include anomalous drainage of the right upper pulmonary vein into the superior vena cava associated with a superior sinus venosus ASD, a persistent left superior vena cava draining to the coronary sinus with secundum or primum ASDs, and a cleft anterior mitral leaflet and mitral regurgitation associated with an ostium primum ASD. Ostium primum ASD is a common cardiac anomaly in trisomy 21 (Down syndrome) and is part of the spectrum of AV septal “canal” defects (discussed later). There is an approximately 2:1 female predominance for ostium secundum ASDs, while the sex ratio for ostium primum and sinus venosus ASDs is approximately 1:1. An autosomal dominant inheritance pattern has been demonstrated in some patients with ostium secundum ASD with associated first-degree AV block, and cases of ASD in monozygotic twins have been reported. Recent studies have implicated mutations in the genes gata4, and nkx2-5 in nonsyndromic ASDs, whereas point mutations in the gene tbx5 are known to cause the Holt-Oram syndrome (ASD and limb defects).
Anatomic location of atrial septal defects.
The pathophysiologic consequences of an ASD depend on the quantity of blood shunted from the systemic to pulmonary circulation. The size of the shunt is in turn dependent on the size of the defect and the relative compliance of the RV and LV. Little or no shunting occurs immediately after birth because of the high pulmonary vascular resistance (PVR), but as resistance falls, the more compliant RV receives the shunted blood mainly in diastole, when all four chambers are in communication. In the compensated patient with ASD, pulmonary resistance is usually low. The older adult with the LV diastolic abnormalities of hypertension, coronary artery disease, and aging may experience increased left-to-right shunting and, consequently, right heart failure. While pulmonary resistance may increase, the development of Eisenmenger physiology is unusual after the age of 25. Atrial arrhythmias, especially atrial fibrillation, are common over the age of 50.
The young adult with an uncorrected ASD and normal pulmonary artery pressures is usually asymptomatic, with normal or minimally diminished exercise tolerance. After the age of 30, however, exertional dyspnea and atypical chest pain increase in frequency. As mentioned earlier, the frequency of atrial arrhythmias increases with age and occurs in a high percentage of patients over the age of 50 who have not been treated surgically. Signs and symptoms of RV failure may occur because of pulmonary hypertension or as a result of long-standing volume overload.
Important findings of the physical examination in an uncomplicated ASD include a prominent RV impulse along the lower left sternal border; a palpable pulmonary artery; a systolic ejection murmur, caused by increased flow across the pulmonic valve, which does not vary in intensity with respiration; and the almost pathognomonic fixed split second heart sound. When the Qp:Qs exceeds 1.5-2:1, there may be an associated right-sided diastolic flow rumble and S3 gallop from increased flow across the tricuspid valve. The patient with ostium primum ASD usually has a holosystolic murmur of mitral regurgitation. If pulmonary hypertension is present, P2 is increased and a high-pitched murmur of pulmonary regurgitation (Graham Steell murmur) may be audible. Signs of RV failure with elevated jugular venous pressure and venous congestion may be apparent in the later stages of this disease.
Electrocardiography and Chest Radiography
The ECG shows an RV conduction delay (“incomplete right bundle branch block” [IRBBB]) in 90% of cases (Figure 31–7). In ostium secundum and sinus venosus ASDs, the QRS axis is vertical or rightward. In the patient with ostium primum ASD, the axis is superior and leftward. Abnormal sinus node function in patients with sinus venosus ASD often results in an ectopic atrial rhythm with a superior P-wave axis.
Electrocardiograph in atrial septal defect with right-axis deviation, incomplete right bundle branch block, and right ventricular hypertrophy.
The chest radiograph shows prominent main and branch pulmonary arteries with a small aortic knob and RV enlargement. The right atrium may appear enlarged. In the absence of pulmonary hypertension, the lung markings are increased as a result of increased pulmonary blood flow.
The findings on TTE include right-heart enlargement and increased pulmonary artery flow. Color-flow Doppler often can identify the interatrial flow, especially in the subcostal four-chamber view. An intravenous saline contrast injection should be used in all patients with these findings to exclude an unsuspected ASD. In the presence of an ASD, a negative contrast effect can be seen in the right atrium as the unopacified left atrial blood is shunted from left to right. A small degree of bidirectional shunting nearly always is present, and microbubbles can be seen in the left atrium as a result of right-to-left shunting. The shunting across a patent foramen ovale is purely right to left and occurs only during transient (eg, Valsalva maneuver, coughing) or persistent elevations in right atrial pressure.
Pulmonary artery pressure can be estimated from the peak velocity of the tricuspid regurgitant jet. Echocardiographic measurements may be used to determine shunt flow, eliminating the need for an invasive assessment. In adults, however, the TTE is somewhat limited in quantifying the magnitude of shunts and the size of the defect and in locating sinus venosus defects or anomalous pulmonary veins. As noted earlier, TEE has been found to be more accurate in determining the size and location of atrial communications (Figure 31–8). Biplanar and multiplanar transesophageal views are particularly useful in identifying sinus venosus type ASD (Figure 31–9).
Transesophageal echocardiogram in a patient with an ostium secundum atrial septal defect (ASD). A: The image clearly demonstrates the position of the ASD in the midportion of the interatrial septum (IAS). B: The image is obtained after intravenous injection of agitated saline, which opacifies the right atrium (RA). The negative contrast effect produced by the unopacified left atrial blood entering the RA is clearly demonstrated (double arrow). TV, tricuspid valve.
Transesophageal echocardiography in a 50-year-old man with a sinus venosus atrial septal defect. A: Horizontal view showing the defect (arrow) in the superior portion of the interatrial septum. B: The defect (arrow) is clearly demonstrated in this longitudinal plane view. Ao, aorta; LA, left atrium; RA, right atrium; SVC, superior vena cava.
In some younger individuals with unequivocally large defects on noninvasive imaging, diagnostic cardiac catheterization may be avoidable. In others, however, invasive studies may be necessary to accurately quantitate the shunt, measure PVR, and exclude coronary artery disease. Right-heart catheterization with repeated blood sampling for oxygen saturation demonstrates an oxygen step-up (ie, an increase in saturation) from the vena cava to the right atrium. In general, the higher the pulmonary arterial oxygen saturation, the greater is the shunt, with a value greater than 90% suggesting a large shunt. The ratio of pulmonary to systemic flow can be calculated by the following formula:
Where Sao2, Mvo2, Pvo2, and Pao2 are systemic arterial, mixed venous, pulmonary venous, and pulmonary arterial blood oxygen saturations, respectively. Mvo2 is calculated using the Flamm equation, [(3 × SVC) + IVC]/4, where SVC is the oxygen saturation of blood from the superior vena cava and IVC is the oxygen saturation of blood from the inferior vena cava.
A PVR that is more than 70% of the systemic vascular resistance suggests significant pulmonary vascular disease, and closure is best avoided. Pulmonary vasodilator therapy may be used, and occasionally, pulmonary resistance decreases enough to consider closure.
Although patients with an uncorrected ostium secundum ASD generally survive into adulthood, their life expectancy is not normal; older natural history studies showed a 50% survival beyond age 40. The mortality rate after the age of 40 is about 6% per year. Small ASDs (a Qp:Qs < 1.5–2:1) may cause problems only in the advanced years, when hypertension and coronary artery disease cause reduced LV compliance, resulting in increased left-to-right shunting, atrial arrhythmias, and potential biventricular failure. Severe pulmonary hypertension develops during young adulthood in only 5–10% of patients with large shunts (Qp:Qs > 2:1). Although most adults with ASDs have mild-to-moderate pulmonary hypertension, the late development of severe pulmonary hypertension in older adults appears to be quite rare. Pregnancy, in the absence of pulmonary hypertension, is usually uncomplicated. Another potential complication of ASD (including even the smallest patent foramen ovale) in the adult patient is paradoxical embolization. Endocarditis is rare in patients with ASD, and prophylaxis is not routinely recommended unless associated lesions with higher risk exist.
The natural history of sinus venosus ASDs is similar to that of ostium secundum defects, although many of these patients have associated partial anomalous pulmonary venous connection. Adults with an ostium primum ASD are less commonly encountered and may have additional complications resulting from mitral regurgitation caused by the cleft leaflet (see the discussion on AV canal defects, later in this chapter).
Ostium secundum ASDs have been surgically repaired for more than 40 years. No late cardiac deaths occurred in those who had early surgical repair of ASDs (before the age of 18) among patients in a large registry. Patients with elevated pulmonary systolic pressure (> 40 mm Hg) at the time of surgery have the poorest survival rate, especially if they are older than 40 at the time of operation.
Despite the poorer surgical results in adults older than 40 years, closure is superior to medical therapy and is recommended in patients with predominant left-to-right shunts (Qp:Qs > 1.5–2:1) and PVR less than 10 units/m2. Although mortality rates increase when the resistance exceeds this level, surgery can be performed safely in many patients with PVR between 10 and 15 units/m2; pulmonary vasodilator therapy should be considered in these patients before closure. Surgery will improve functional class and eliminate the risk of paradoxical embolization, but closure does not reduce the incidence of atrial arrhythmias.
Percutaneous device closure is widely available, and retrospective studies have suggested comparable results with device closure and surgical closure. Therefore, device closure has become the standard of care for appropriately selected adolescents and adults with ostium secundum defects.
Adult patients with initially small shunts (Qp:Qs < 1.5) should undergo continued echocardiographic surveillance because the shunt may increase over time owing to a progressive decline in LV compliance.
In patients with patent foramen ovale who have suffered embolic phenomena, device closure has become a standard intervention, although evidence from a randomized controlled trial is lacking.
Attie F, et al. Surgical treatment for secundum atrial septal defects in patients > 40 years old. A randomized clinical trial. J Am Coll Cardiol
Garg V, et al. GATA4 mutations cause human congenital heart defects and reveal an interaction with TBX5. Nature
Patel A, et al. Transcatheter closure of atrial septal defects in adults > or = 40 years of age: immediate and follow-up results. J Interv Cardiol
Webb G, et al. Atrial septal defects in the adult: recent progress and overview. Circulation
Ventricular Septal Defects
- History of murmur appearing shortly after birth.
- Holosystolic murmur at left sternal border radiating rightward.
- Left atrial and LV or biventricular enlargement.
- High-velocity color-flow Doppler jet across VSD.
- Increased pulmonary flow velocities.
Because of the tendency for many VSDs to close spontaneously (see later discussion) and the tendency of larger defects to produce CHF in early childhood, it is relatively uncommon to encounter adults with previously undiagnosed VSDs of hemodynamic consequence. In adults, VSDs are usually either small and hemodynamically insignificant or large and associated with Eisenmenger syndrome. The importance of identifying the former is that they pose an ongoing risk of endocarditis and the potential complication of progressive aortic regurgitation. Eisenmenger syndrome is discussed later in this chapter.
Classifications of VSDs can be based on anatomic location or physiology. The anatomic classification includes defects of both the membranous and muscular portions of the ventricular septum (Figure 31–10). Membranous VSDs can be subdivided into supracristal (also known as doubly committed subarterial), perimembranous (the inlet portion of the membranous septum), and malalignment (found in TOF with an overriding aorta) defects. The muscular VSDs, often multiple, may be located in the inlet or outlet regions or within the trabecular portion of the septum. Classifying VSDs physiologically is based on the size of the defect as well as the relative vascular resistances within the systemic and pulmonary circulation. A high-pressure gradient exists across a small restrictive VSD, with normal or mildly elevated pulmonary artery pressure and predominant left-to-right shunting. A large nonrestrictive VSD permits equalization of RV and LV pressures with obligatory pulmonary hypertension (in the absence of RV outflow-tract obstruction) and bidirectional shunting. The smallest VSD (maladie de Roger) is characterized by a hemodynamically insignificant shunt, a loud murmur, and an intermediate to high risk of endocarditis.
Anatomic location of ventricular septal defects (VSDs).
In the infant, left-to-right shunting occurs only when PVR falls below systemic vascular resistance, and the murmur usually becomes audible in the first month of life. With a large nonrestrictive defect, PVR may not fall; if the defect is not surgically closed by age 2, irreversible pulmonary hypertension may ensue. The volume overload caused by a large restrictive VSD may cause CHF in the first 6 months of life. Approximately 40% of VSDs close spontaneously by age 3, and a smaller percentage close before age 10. Generally, the smaller defects are more likely to close, but even in infants with heart failure, 7% will experience spontaneous closure.
Three late complications of VSD are worth mentioning. Tricuspid regurgitation may rarely result when the septal leaflet of the tricuspid valve is deformed by the ventricular septal aneurysm that causes spontaneous closure of a perimembranous VSD. Aortic regurgitation is common in patients with doubly committed subarterial VSDs (supracristal, or outlet, VSDs), as a result of herniation of the right aortic sinus into the defect; it also occurs in those with perimembranous VSDs. Infundibular PS from hypertrophy of the RV outflow tract can develop, functionally dividing the RV into inflow and outflow segments, a condition termed “double-chambered right ventricle.” If a sufficient pressure gradient develops, RV systolic pressure can exceed LV systolic pressure, and right-to-left shunting can occur across the VSD. The resultant hypoxia may only occur during exercise.
The young adult with an uncorrected VSD and normal pulmonary artery pressures is usually asymptomatic, with normal or minimally diminished exercise tolerance. Like those with ASDs, exertional dyspnea often develops in patients with VSDs after the age of 30 when the Qp:Qs exceeds 2–3:1. Individuals with smaller shunts rarely report symptoms. The most disabled group with pulmonary hypertension and cyanosis (Eisenmenger physiology, or syndrome) will be discussed later.
Physical findings depend on the size of the VSD. The patient with uncomplicated VSD is acyanotic, and the LV apical impulse is displaced laterally, suggesting LV volume overload, and may be hyperdynamic. A holosystolic murmur occurs, often associated with a systolic thrill, heard best in the fourth or fifth intercostal space along the left sternal border, with radiation to the right parasternal region. Because of the increased flow across the mitral valve, an S3 gallop and a diastolic rumble may be present. Additional signs of tricuspid insufficiency (prominent jugular venous v wave and systolic murmur) or aortic valve regurgitation (diastolic blowing murmur, increased arterial pulses) will be present in patients with these complications.
Electrocardiography and Chest Radiography
In the presence of a large shunt, the ECG is suggestive of LVH or biventricular hypertrophy, with biphasic QRS complexes in the transitional precordial leads. Evidence of left or right atrial enlargement is present in only about 25% of patients.
Cardiac enlargement with an increased cardiac silhouette is evident on chest radiograph only in the presence of a large left-to-right shunt. In the absence of pulmonary hypertension, there is evidence of pulmonary vascular engorgement with a plethora of the peripheral vasculature as well as enlargement of the proximal vessels. Left atrial enlargement may be evident on the lateral chest radiograph.
It is important to remember that in most adults with a small VSD (< 1.5–2:1 shunt), both the ECG and radiograph are normal, even in the presence of a loud murmur. On the other hand, the presence of pulmonary hypertension alters the ECG and radiograph findings.
Two-dimensional and Doppler echocardiography can usually define the location and often the size of a VSD, although accurate Doppler shunt quantitation may not be possible in the adult. There is evidence of left atrial and LV dilatation. The right-heart chamber dimensions are usually normal, although the main pulmonary artery may appear dilated. The presence of RVH usually signifies pulmonary hypertension or associated PS (with right-to-left shunting and cyanosis). Usually only the largest defects, often located in the membranous septum, can actually be visualized echocardiographically (Figure 31–11). The aneurysmal pouch of a ventricular septal aneurysm may be seen in the parasternal short-axis view just below the aortic valve in the inlet portion of the septum near the septal leaflet of the tricuspid valve. Saline contrast administration shows a negative contrast effect within the RV, and a small degree of bidirectional shunting is sometimes present, with microbubbles appearing in the LV.
Transthoracic echocardiogram in a 40-year-old woman with a large membranous ventricular septal defect (double arrow). The right ventricle (RV) was enlarged because of pulmonary hypertension. AV, aortic valve; LV, left ventricle.
Color-flow Doppler imaging demonstrates a high-velocity (aliased) systolic jet across the ventricular septum into the RV. The location of the jet provides the best guide to the location of the defect. In the parasternal short-axis view, the jet from a membranous VSD may be seen in the region of the tricuspid valve (perimembranous) or toward the pulmonary artery (doubly committed subarterial, or supracristal). Muscular VSD jets are best seen in the apical or subcostal four-chamber views (Figure 31–12).
Transthoracic echocardiogram in a 45-year-old woman with a small muscular ventricular septal defect (VSD). LV, left ventricle; RV, right ventricle.
In continuous wave Doppler, the peak velocity of the jet across the ventricular septum provides the peak systolic LV-RV gradient (using the modified Bernoulli equation). Subtracting this gradient from the systolic blood pressure gives the peak RV systolic pressure. In the absence of a pressure gradient across the RV outflow tract—including the pulmonary valve (which should be carefully sought)—the RV systolic pressure is equivalent to the pulmonary artery systolic pressure. Additional Doppler evidence of the left-to-right shunt is found in the increased pulmonary artery flow velocity.
In the postrepair patient, the VSD patch may or may not be apparent, depending on the size of the original defect. Once endothelialized, the patch may not cause acoustic shadowing (or distal echo blockout). Color-flow Doppler may demonstrate patch leaks at the peripheral suture lines of the patch in a small percentage of patients. Spontaneous closure of a VSD involving juxtaposed tricuspid valve tissue may cause significant tricuspid regurgitation. Varying degrees of aortic regurgitation may be present and are most often associated with membranous or supracristal VSDs.
Although the diagnosis is often made noninvasively, the decision to close a VSD rests on accurate measurements of the shunt ratio and the level of PVR. Catheterization is therefore often necessary for therapeutic decision making.
Right-heart catheterization with sequential measurements of oxygen saturation reveals a step-up within the body of the RV. As with an ASD, the higher the RV oxygen saturation, the greater is the degree of shunting. For the calculation of Qp:Qs, the same formula is used as for ASD, except that the mixed venous blood sample is drawn from the right atrium. Pulmonary artery pressures and vascular resistance should be measured, and a gradient across the RV outflow tract, including the infundibulum and the pulmonary valve, must be excluded. Left ventriculography in the cranial left anterior oblique projection will reveal the location of the defect as contrast enters the RV.
As previously mentioned, adults with large, uncorrected VSDs are uncommonly encountered. With an uncorrected VSD, the overall 10-year survival rate after initial presentation is 75%. Survival is adversely affected by functional class greater than New York Heart Association class I, cardiomegaly, and elevated pulmonary artery pressure (> 50 mm Hg). As in patients with ASD, surgery is generally recommended when the magnitude of the systemic-to-pulmonary-shunt ratio exceeds 2:1. Other indications for surgery may include recurrent endocarditis and progressive aortic regurgitation.
In patients with small VSDs treated either conservatively or with surgery, outcomes are identical for patients with a Qp:Qs < 2.0, normal PVR, no LV volume overload or VSD-related aortic regurgitation, and no symptoms of exercise intolerance.
Surgery for closure of VSDs has been available for more than 50 years, and long-term follow-up data are available. Surgery prior to age 2—even in infants with a large VSD, high pulmonary blood flow, and preoperative pulmonary hypertension—almost always prevents the development of pulmonary vascular obstructive disease. In patients who underwent surgery during the 1960s and 1970s, there is an approximately 20% incidence of residual left-to-right shunt and a persistent risk of endocarditis. Ventricular arrhythmias and right bundle branch block (RBBB) are more common with a repair performed via right ventriculotomy (eg, muscular or subarterial VSD); when possible, the right atrium is the preferred approach. The risk of sudden death and complete heart block is low. Most patients who have VSDs repaired in childhood survive to lead normal adult lives.
Devices have been developed for percutaneous closure of both muscular and perimembranous VSDs. Muscular VSD occluders have been approved by the U.S. Food and Drug Administration and are commercially available in the United States. Initial case series suggest high success rates and low complication rates. Reported complications (in nine patients) include conduction anomalies and aortic or tricuspid regurgitation. More extensive follow-up data are needed before device implantation becomes routine.
Aboulhosn J, et al. Common congenital heart disorders in adults: percutaneous therapeutic procedures. Curr Probl Cardiol
Gabriel HM, et al. Long-term outcome of patients with ventricular septal defect considered not to require surgical closure during childhood. J Am Coll Cardiol
Penny DJ, et al. Ventricular septal defect. Lancet
. 2011;377(9771): 1103–12.
- Continuous machinery-like murmur, loudest below the left clavicle.
- Left ventricular hypertrophy.
- Pulmonary plethora, left atrial and ventricular enlargement; in older adults, calcification of the ductus on chest radiograph.
- Left atrial and ventricular dilatation with normal right-heart chambers on echocardiography.
- Continuous high-velocity color Doppler jet with retrograde flow along lateral wall of main pulmonary artery near left branch.
The patent ductus arteriosus (PDA) is a remnant of the normal fetal circulation. In the fetal circulation, superior vena cava blood enters the right atrium and characteristically is directed across the tricuspid valve into the RV. It is then delivered into the systemic circulation via the ductus arteriosus, which connects the left pulmonary artery to the descending aorta just distal to the insertion of the left subclavian artery (Figure 31–13). In the normal full-term newborn, the ductus closes within the first 10–15 hours following birth. If the ductus fails to close after birth when PVR falls, the direction of blood flow within the ductus reverses, producing a left-to-right shunt. CHF usually develops within the first year of life in patients with nonrestrictive PDA (large left-to-right shunts). As with VSD, it is relatively unusual—but by no means rare—to encounter an adult with uncorrected PDA.
Anatomic locations of patent ductus arteriosus (A) and aortopulmonary window (B), with multiple distinct anatomic locations possible.
An anatomic variant of the PDA is the aortopulmonary window (see Figure 31–13), which is usually a relatively large communication between the ascending aorta and the main pulmonary artery. The pathophysiology is similar to that of the PDA and is dependent on the size of the shunt and the level of PVR. The degree of pulmonary hypertension depends on the directly transmitted aortic pressure, which in turn depends on the size of the channel and the amount of pulmonary blood flow. If LV failure occurs, pulmonary venous hypertension may contribute further to the pulmonary hypertension. In a small number of patients, PVR rises above systemic vascular resistance and the shunt reverses. Because the site of the PDA is distal to the left subclavian, the head and neck vessels continue to receive oxygenated blood—but the descending aorta receives the desaturated blood, with the development of differential cyanosis.
When present in isolation, the PDA may lead to heart failure from pulmonary overcirculation. In conjunction with other defects, however, it may represent the sole pulmonary (eg, pulmonary atresia with intact ventricular septum) or systemic (eg, aortic atresia) blood supply, and survival may depend on persistent patency.
The mothers of patients with PDA may have a history of maternal rubella, and the patient may have had a murmur since infancy. If CHF has not developed by age 10, most patients will be asymptomatic as adults. CHF develops in a few patients in their 20s and 30s, however, and presents as exertional dyspnea, chest pain, and palpitations.
The patient is almost always acyanotic; but when cyanosis and clubbing are present, the upper extremities are usually spared. Thus, the lower extremities and sometimes the left hand may show clubbing and cyanosis, but the right hand and head are always pink. The pulse pressure may be widened, and the pulses are collapsing. The LV impulse is hyperdynamic and often laterally displaced. The classic murmur of the uncomplicated PDA is best heard below the left clavicle and gradually builds to its peak in late systole; it is continuous through the second heart sound and wanes in diastole. There may be a pause in late diastole or early systole. With a significant LV volume overload caused by a large shunt, an S3 gallop and a diastolic murmur of relative mitral stenosis (similar to that of the large VSD) may be present. The murmur varies as PVR increases and shunting reverses, first with a decrease in the diastolic component and then a decrease in the systolic component. Finally, the murmur is silent and the physical findings are consistent with pulmonary hypertension (see Eisenmenger Syndrome).
Electrocardiography and Chest Radiography
The ECG is normal when the shunt is small; it shows left atrial and ventricular hypertrophy in the presence of a large shunt. When pulmonary hypertension is present and the shunt is predominantly right to left, the ECG may show P-pulmonale, right-axis deviation, and evidence of RVH.
The chest radiograph is also normal in the presence of a small shunt. With a significant shunt, LV prominence is evident with an enlarged cardiac silhouette and pulmonary vascular plethora. In the presence of pulmonary hypertension, pruning of the peripheral pulmonary vessels is present, with prominence of the central pulmonary arteries. The ductus may be calcified in the older adult.
The two-dimensional echocardiogram shows left atrial and ventricular enlargement, but imaging of the ductus itself is usually difficult in the adult. Color-flow Doppler imaging is diagnostic and reveals continuous high-velocity flow within the main pulmonary artery near the left branch. Flow is predominantly retrograde within the pulmonary artery and can be detected by continuous wave Doppler. In an aortopulmonary window, continuous color flow is detected, but it is most often antegrade, which distinguishes it from the flow through a PDA. Pulmonary artery pressure can be estimated from the almost ubiquitous tricuspid regurgitant jet.
Right-heart catheterization is performed to measure the pulmonary artery pressure, PVR, and flow ratio (Qp:Qs). The oxygen step-up is at the level of the pulmonary artery, and when the ductus is large enough, the descending aorta can be entered from the pulmonary artery. The ductus can also be seen during aortography in the left lateral projection. Because echocardiography is noninvasive and diagnostic, cardiac catheterization may become exclusively therapeutic in the future. Techniques for coil and, more recently, device occlusion are well established and currently represent the treatment of choice for simple PDAs in many institutions. Thus, catheterization should be combined with a therapeutic intervention.
Patients who survive into adulthood with a large uncorrected PDA generally have CHF or pulmonary hypertension (with right-to-left shunting and differential cyanosis) by about age 30. Most adults with PDA and normal or only mildly elevated PVR (< 4 units) are either asymptomatic or mildly impaired and can undergo surgical ligation or percutaneous closure with good results. In the group with severely elevated PVR (> 10 units/m2), survival is poor. Approximately 15% of patients older than 40 years of age may have calcification or aneurysmal dilatation of the ductus, which can complicate surgery. Surgical ligation or percutaneous coil or device occlusion of a PDA can be performed with low morbidity and mortality and is recommended—independent of the size of the shunt—because of the high risk of endocarditis in uncorrected cases. Division of an isolated restrictive PDA in childhood can be curative of congenital heart disease. If repaired after childhood, the morbidity and mortality rates depend on the degree of pulmonary hypertension, LV volume overload, and calcification of the ductus. Unless persistent shunting is present following a surgical ligation, endocarditis prophylaxis is not recommended after the sixth postoperative month.
Masura J, et al. Long-term outcome of transcatheter patent ductus arteriosus closure using Amplatzer duct occluders. Am Heart J
Schneider DJ, et al. The patent ductus arteriosus in term infants, children, and adults. Semin Perinatol. 2012;36(2):146–53. [PMID: 22414886]
- Elevated systolic blood pressure in the upper extremities (always in right arm); normal or diminished systolic blood pressure in lower extremities (and often left arm); radial-femoral pulse delay.
- LVH, LV prominence, “3” sign, rib notching on chest radiograph.
- Visualization of the coarctation by imaging.
- Distal aortic pressure drop by Doppler echocardiography or catheterization.
Coarctation of the thoracic aorta predominates in males, is often associated with a congenitally abnormal aortic valve, and is a congenital narrowing of the aorta, usually in the region of ductal insertion. The most common location is distal to the origin of the left subclavian artery (postductal; Figure 31–14), but the narrowing may also be proximal (preductal). Infrequently, a preductal coarctation is present in combination with an anomalous origin of the right subclavian artery, causing reduced pressures in the right upper extremity. There is considerable variability in the degree and extent of narrowing, ranging from a localized shelf to a long tubular narrowing. Multiple discrete sites are rarely encountered. Coarctation of the abdominal aorta is less common than that of the thoracic aorta; it is found equally in males and females and presents with symptoms of claudication. Additional coexisting problems may include congenital mitral valve disease and aneurysms of the circle of Willis (the latter are present in approximately 25% of patients with coarctation). Coarctation is frequently seen as part of a syndrome. Approximately 50% of patients have an associated bicuspid aortic valve. Long, tubular narrowing should alert the clinician to the possibility of Williams syndrome, whereas preductal coarctation is frequently seen in Turner syndrome. Collateral circulation to the distal aorta develops mainly via the subclavian and intercostal arteries, in addition to the vertebral and anterior spinal arteries.
Anatomic features of aortic coarctation. A: Preductal coarctation, in which differential cyanosis may occur. B: Postductal coarctation.
Aortic coarctation is usually diagnosed during childhood in the asymptomatic phase by routine examination of blood pressure and femoral pulse palpation. Aortic coarctation is approximately two to five times more common in boys than in girls. In cases of severe obstruction, infants may have CHF. Symptoms may arise in the adult during the 20s and 30s, and evidence of coarctation should always be sought in patients of this age group presenting with hypertension. Early detection and repair are highly desirable because repair forestalls the associated accelerated development of coronary artery disease.
The adult with uncorrected coarctation is usually asymptomatic. When symptoms occur, they are nonspecific: exertional dyspnea, headache, epistaxis, and leg fatigue. CHF can occur in the adult with long-standing hypertension secondary to coarctation. Additional significant complications, usually occurring between the ages of 15 and 40, include aortic rupture or dissection of the proximal thoracic aorta or an aneurysm distal to the coarctation, infective endocarditis on an associated bicuspid aortic valve or endarteritis at the site of coarctation, and cerebrovascular accidents, which are most often due to rupture of an aneurysm of the circle of Willis.
The systolic blood pressure is elevated in the right arm and often the left arm, with reduced systolic blood pressures in the lower extremities. Diastolic blood pressures are not usually affected. Simultaneous palpation of the radial and femoral pulses reveals delayed arrival of the femoral pulse. Adult patients with highly developed collateral circulation may no longer exhibit these signs, however, and a clinically recorded difference between upper and lower extremity blood pressure will underestimate the coarctation gradient. The jugular venous pulse is normal, the carotid upstroke is usually brisk, and the aorta may be palpable in the suprasternal notch. Cardiac examination reveals a nondisplaced, but forceful, LV impulse. The first heart sound is normal, and the aortic component of the second heart sound may be accentuated. A late systolic murmur is present (as a result of the coarctation) that is best heard between the scapulae to the left of the spine. The murmur caused by collateral flow through the intercostal and internal mammary arteries is longer, but it is not necessarily continuous. An ejection click and systolic murmur as well as a blowing diastolic murmur of aortic regurgitation may be associated with a bicuspid aortic valve.
Electrocardiography and Chest Radiography
The ECG is nonspecific, with LVH and, in the later stages, left atrial enlargement. As in other patients with long-standing hypertension, atrial fibrillation may occur.
On the other hand, the radiograph finding of rib notching is highly specific, although it is not 100% sensitive even in adults. Notching is present on the bottom of the rib where the intercostal arteries are located. In preductal coarctation (ie, proximal to the left subclavian artery), the rib notching is present only on the right side, and, in abdominal coarctation, it is limited to the lower ribs. Another classic radiograph finding is the “3” sign, with the aortic arch and dilated left subclavian artery forming the upper curvature and the dilated distal aorta forming the lower. There may be radiologic evidence of LV and atrial enlargement.
It is extremely difficult to identify the actual site of the coarctation in the adult patient with precordial two-dimensional echocardiography. Doppler evidence of flow acceleration in the descending aorta from the suprasternal notch, however, can often identify obstruction even when images are suboptimal. The peak systolic velocity can be used to estimate the gradient, but the presence of persistent antegrade flow in diastole (Figure 31–15A) and decreased acceleration time beyond the coarctation provide additional confirmation of hemodynamic significance. Further localization of the coarctation is now possible with imaging of the descending aorta in the longitudinal plane during multiplanar TEE. The anatomy of the aortic valve should be carefully defined, and careful Doppler interrogation for evidence of stenosis or insufficiency is essential.
A: Continuous wave Doppler from transthoracic echocardiogram in a patient with coarctation of the descending aorta (DAO). There was a peak gradient (PK GR) of 51.4 mm Hg with runoff in diastole (arrow). B: Three-dimensional reconstruction of a magnetic resonance angiogram of the thoracic aorta demonstrates a discrete coarctation (lower arrow) in the typical location after the take-off of the left subclavian artery (LSA).
Magnetic Resonance Angiography and Computed Tomography Angiography
MRA can localize and define the extent of narrowing with a high degree of accuracy (Figure 31–15B) and provides estimates of the presence of collateral flow to the distal aorta. Aneurysmal dilatation is visible, and postoperative evaluation is possible. Computed tomography (CT) angiography provides excellent anatomic definition but cannot provide any physiologic information.
Aortography is necessary only when the diagnosis is not adequately confirmed clinically or the anatomy cannot be fully defined noninvasively. Premature coronary disease is common, and if it is clinically suspected, coronary arteriography should be performed. Balloon dilatation with or without stent placement across native and recurrent coarctation has been attempted in cases of discrete narrowing (see later discussion).
The importance of identifying coarctation in adults lies in the tendency toward LVH and CHF, premature coronary artery disease, and cerebral hemorrhage. In an autopsy series of uncorrected coarctation, 50% of patients had died by about age 30 and 90% by age 60. Proximal aortic rupture, aortic dissection, and cerebral hemorrhage often occur before the age of 30, and the incidence of CHF continues to increase after the age of 40.
Surgery for correcting coarctation presents a considerable challenge in patients over the age of 15 years because of large intercostal aneurysms and atheromatous changes in the aorta near the shelf. It should be noted that surgical repair even in childhood is often only palliative, and these patients require continued surveillance, particularly in the presence of associated cardiac lesions or preoperative systemic hypertension. Hypertension persists in approximately one-third of patients operated on after the age of 14. The major determinants of long-term survival following repair of aortic coarctation are the presence of associated lesions and the age at operation. The postsurgery cardiac mortality rate after age 20 is approximately 5% in patients with isolated coarctation. Causes of late cardiovascular deaths (in order of frequency) include coronary artery disease, sudden death, aortic regurgitation and heart failure, hypertension and heart failure, and cerebrovascular accidents. Approximately 10% of patients require subsequent cardiovascular surgery, the majority for aortic valve replacement. The incidence of recurrent coarctation requiring surgery or percutaneous intervention varies significantly depending on surgical technique and can be 16–60%, with the highest recoarctation rates generally associated with earlier operation.
The surgical methods of repair have undergone considerable evolution since their initial introduction in the late 1950s. In part this is due to the considerable morphologic variability that has precluded using a single method for correction. The removal of the abnormal coarctation tissue as occurs in an end-to-end anastomosis is most desirable, but depending on other factors, a subclavian flap repair or an interposition graft may be necessary. Less reliance is placed on the patch angioplasty because long-term studies have shown late aneurysm formation due to thinning of the posterior wall.
Over the last 10 years, endovascular repair of coarctation has become a popular treatment option. Furthermore, the advent of balloon-expandable stents has reduced the complication rate associated with balloon angioplasty alone. Complications of stent implantation can be classified into three categories: technical (stent migration or fracture, balloon rupture, and overlap of the brachiocephalic vessels), aortic (intimal tear, dissection, and aneurysm formation), and peripheral vascular (cerebral vascular accident, peripheral embolization, and injury to access vessels). Compared with surgical therapy, endovascular stenting of native coarctation has a similar morbidity and mortality but is associated with a significantly higher incidence of recoarctation, need for reintervention, and persistent hypertension. In light of these differences, there is ongoing controversy about the best treatment approach for adults and adult-sized adolescents with native coarctation of the aorta. There is general agreement, however, that recoarctation in adults can be managed by percutaneous transluminal balloon angioplasty, with or without stent implantation.
Because of the risk of recoarctation and of complications such as aortic aneurysm, periodic surveillance with MRI or with CT aortography is recommended in the adult after repair, irrespective of technique. It is essential to screen women of childbearing age for postrepair aortic dilatation because the risk of aortic dissection or rupture during pregnancy is high. The need to screen for intracranial aneurysms is controversial.
Connolly HM, et al. Intracranial aneurysms in patients with coarctation of the aorta: a prospective magnetic resonance angiographic study of 100 patients. Mayo Clin Proc
. 2003;78 (12):1491–9.
Godart F, et al. Intravascular stenting for the treatment of coarctation of the aorta in adolescent and adult patients. Arch Cardiovasc Dis. 2011;104(12):627–35. [PMID:22152515]
Pádua LM, et al. Stent placement versus surgery for coarctation of the thoracic aorta. Cochrane Database Syst Rev
- History of dyspnea, atypical chest pain, or intermittent cyanosis.
- Palpitations associated with supraventricular arrhythmias and preexcitation syndrome.
- Right parasternal lift, widely split S1, systolic clicks, and systolic murmur of tricuspid regurgitation (without inspiratory accentuation).
- Right atrial enlargement, RV conduction defect of RBBB type, posteriorly directed delta waves with accessory pathway by ECG. Frequent first-degree AV block.
- Normal or reduced pulmonary vascularity without pulmonary artery enlargement, right atrial enlargement, normal left-sided cardiac silhouette on chest radiograph.
- Apical displacement of septal tricuspid valve leaflet; variable degrees of tricuspid regurgitation originating from apical portion of RV; and enlarged right atrium on echocardiography.
Ebstein anomaly is characterized by deformity of the tricuspid valve with apical displacement of the septal and posterior leaflets (Figure 31–16) and their adhesion to the RV wall. The anterior leaflet is elongated and has been described as sail-like. Tricuspid regurgitation arises from the apically displaced site of leaflet coaptation with considerable variability in the extent of tricuspid leaflet displacement and the degree of tricuspid regurgitation. The portion of the RV proximal to the leaflets is atrialized (thinned), and if the remaining RV is diminutive in size, pump function may be inadequate. Cyanosis may be present as a result of right-to-left shunting across an ASD or patent foramen ovale in the presence of significant tricuspid regurgitation or elevated right atrial pressures. Interatrial septal defects, including patent foramen ovales, are the most common associated anomaly, occurring in 80–90% of patients with Ebstein anomaly.
Anatomy of Ebstein anomaly.
Tremendous variability exists in the morphologic abnormalities and clinical presentation of patients with Ebstein anomaly. In severe cases, CHF or cyanosis may be present during infancy. At the opposite end of the spectrum, a mildly affected adult may be asymptomatic or symptomatic only because of supraventricular tachyarrhythmias. The latter are an important feature of Ebstein anomaly, which is associated with preexcitation in 25–30% of patients. The accessory pathway is usually posteroseptal or posterolateral in location.
Cyanosis may be the most important clinical feature in early life, but in older patients, long-standing RV volume overload and right atrial distention result in CHF. Dysrhythmias, including the Wolff-Parkinson-White syndrome, are frequent. Adult patients may have dyspnea, arrhythmias, decreased exercise tolerance, and intermittent or exercise-induced cyanosis (with associated right-to-left shunting across an ASD or patent foramen ovale).
Physical examination reveals right parasternal lift, widely split S1, systolic clicks (from delayed tricuspid valve closure, the “sail” sounds), and the systolic murmur of tricuspid regurgitation. The latter does not usually increase in intensity during inspiration, because the noncompliant RV cannot accept an increase in venous return. On the other hand, the right atrium is compliant, and systemic venous congestion is uncommon; the jugular venous pulse is therefore usually normal. S3 and S4 gallops may be present, as may an early diastolic snap from the opening of the elongated anterior leaflet.
Electrocardiography and Chest Radiography
The ECG shows evidence of right atrial enlargement and an RV conduction defect of the RBBB type. The PR interval may be prolonged, except in the presence of an accessory pathway. In 25–30% of patients, ECG findings are consistent with Wolff-Parkinson-White syndrome; the PR interval is short, and delta waves from a posterolateral or posteroseptal bundle of Kent are evident (Figure 31–17). Atrial fibrillation may be present in older patients.
Electrocardiogram in Ebstein anomaly with associated Wolff-Parkinson-White syndrome.
The chest radiograph shows normal or reduced pulmonary vascularity without pulmonary artery enlargement; it also shows cardiac enlargement to the right of the sternum caused by right atrial enlargement. The LV and left atrium are normal in size.
The classic M-mode description of this anomaly included increased excursion of the anterior tricuspid valve leaflet and delayed tricuspid valve closure (> 40 ms) following mitral valve closure. Two-dimensional and Doppler echocardiography are diagnostic in most adults. The four-chamber apical and subcostal views provide most of the necessary information. The right atrium is enlarged and the RV is usually small, consisting of the atrialized portion and the remaining pumping chamber. The septal, and possibly the posterior, leaflet of the tricuspid valve is apically displaced, and color-flow Doppler imaging shows the regurgitant jet arising from the apical point of coaptation (Figure 31–18). The degree of tricuspid regurgitation can be estimated from the extent of right atrial filling by color flow and from the density of the continuous wave Doppler signal. The pulmonary artery systolic pressure estimated from the continuous wave tricuspid regurgitation jet is nearly always normal.
Transesophageal echocardiogram in a 50-year-old woman with Ebstein anomaly. This four-chamber view shows the apically displaced tricuspid valve (TV) in relation to the normal mitral valve (MV). LV, left ventricle; RV, right ventricle.
Although color-flow imaging may reveal a patent foramen ovale or an ASD, it is mandatory to perform a saline contrast examination to reliably exclude these sources of right-to-left shunting. When precordial echocardiography is inadequate, TEE can be used to exclude associated lesions of the atrial septum.
During right-heart catheterization, simultaneous recordings of an RV electrogram and a right atrial pressure tracing are obtained with a catheter in the atrialized portion of the RV. This finding is considered pathognomonic of Ebstein anomaly, but catheterization is rarely necessary for diagnosis.
The chance of surviving to age 50 is about 50%, with survival dependent on the degree of the anatomic and physiologic abnormalities. As mentioned, 25–30% of patients have supraventricular arrhythmias, many associated with accessory pathways that are now amenable to catheter ablation. Tricuspid annuloplasty and repair with RV plication have been challenging. The success of these approaches has traditionally been limited, with approximately 50% of patients requiring tricuspid valve replacement. Newer techniques, such as the Carpentier and “cone” techniques, promise to reduce further the need for valve replacement. Improvement in exercise tolerance following tricuspid valve replacement or repair has been observed, especially in patients with associated ASD. In patients with severe morphologic variants, a Fontan-like procedure (see Palliative Surgical Procedures) may be the only suitable choice. In patients who are symptomatic predominantly on the basis of exercise-induced cyanosis, device closure of the interarterial septal defect may be adequate treatment.
Attenhofer Jost CH, et al. Ebstein's anomaly. Circulation
da Silva JP, et al. The cone reconstruction of the tricuspid valve in Ebstein's anomaly: early and midterm results. J Thorac Cardiovasc Surg.
Paranon S, et al. Ebstein's anomaly of the tricuspid valve: from fetus to adult: congenital heart disease. Heart
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Congenitally Corrected Transposition of the Great Arteries
- Prominent left parasternal impulse, soft S1, accentuated A2, soft or inaudible P2.
- PR prolongation, variable degrees of AV block, Q waves in right precordial leads with absence in left precordial leads on ECG.
- Absence of left-sided aortic knob on chest radiograph.
- Rightward and posterior pulmonary artery with leftward and anterior aorta, apical displacement of right-sided AV valve, coarsely trabeculated left-sided systemic ventricle with moderator band (the morphologic RV) on cardiac imaging.
In congenitally corrected transposition of the great arteries (C-TGA, also abbreviated as l-TGA), the visceroatrial relationship is normal with the right atrium to the right of the left atrium (Figure 31–19). The systemic venous blood drains into the right atrium and through a bileaflet (mitral) valve into a morphologic LV pumping into a posterior and rightward pulmonary artery. The pulmonary venous blood drains into the left atrium and through a trileaflet tricuspid valve into a morphologic RV pumping into an anterior and leftward aorta. This occurs because of atrial-ventricular discordance (ventricular inversion), which causes the RV to be located to the left of the LV. The great arteries are transposed, with the aorta arising from the RV and the pulmonary artery rising from the LV. The result is physiologic correction of the circulation, in that oxygenated blood comes into the left atrium, goes to the anatomic right ventricle, and then flows out of the aorta. The patient is acyanotic, and early symptoms typically result from associated lesions such as PS, VSD, and heart block.
Anatomy of congenitally corrected transposition of the great arteries. LV, left ventricle; RV, right ventricle.
The most common complications are complete heart block (occurring with an incidence of approximately 2% per year) and other associated anomalies, most commonly VSD, subvalvular PS, and abnormalities of the systemic AV valve. Coronary anomalies are uncommon, and the coronary circulation is usually concordant; that is, a right coronary artery supplies the RV. Eventually, the systemic ventricle (a massively hypertrophied RV) is subject to pump failure, even in cases of isolated C-TGA. The relative degree of PS and the size of the VSD determine whether cyanosis is present. In the absence of PS, the patient with a large VSD may have CHF due to the volume overload of the systemic ventricle and is at risk for pulmonary vascular disease.
The male:female ratio is approximately 1.5:1. While familial recurrence has been reported, no genetic linkage has been identified.
Most patients with isolated C-TGA are asymptomatic in childhood and young adulthood, although formal cardiopulmonary exercise testing typically reveals lower VO2max than in healthy controls. The highly prevalent complication of complete heart block may present with syncope, sudden death, or, less dramatically, exercise intolerance. More often, the clinical picture is dominated by associated lesions.
Exertional dyspnea and easy fatigability may develop with systemic AV valve regurgitation. Pulmonary venous congestion from pump failure of the anatomic RV may occur in middle age.
The physical examination depends largely on the associated anomalies. The left parasternal impulse is prominent as a result of the hypertrophied systemic ventricle. In the presence of a prolonged PR interval, S1 is diminished in intensity. The proximity of the aorta to the chest wall causes an accentuated A2; conversely, the posterior displacement of the pulmonary valve causes a soft or inaudible P2. Systolic thrills occur in the presence of PS, with and without VSD. If PS is present, the murmur is best heard in the third left intercostal space, radiating to the right. The murmur of a VSD is usually typical, but the murmur of left-sided AV valve regurgitation radiates to the left sternal border in C-TGA.
Electrocardiography and Chest Radiography
The ECG and radiologic findings of C-TGA are dominated by its associated lesions. The ECG shows variable degrees of AV block, from simple PR prolongation to complete heart block. The absence of Q waves in leads I, V5, and V6 or the presence of Q waves in leads V4R or V1 is characteristic of the condition. This pattern results because the ventricular septal depolarization proceeds from the morphologic LV to RV (Figure 31–20). The typical chest radiograph finding in isolated C-TGA is a straight, left upper cardiac border, formed by the ascending aorta and loss of the pulmonary trunk contour.
Electrocardiograph in congenitally corrected transposition of the great arteries with associated pulmonic stenosis and ventricular septal defect.
The anatomic features of isolated C-TGA are usually apparent by TTE, even in adults. TEE may be useful in defining the anatomy of associated lesions such as infundibular obstruction and the severity of left-sided AV valve regurgitation. In the basal parasternal short-axis view, the aortic valve is anterior and usually to the left of the pulmonic valve. Because the two great arteries arise in parallel, there is a “figure-eight” appearance, rather than the usual arrangement of the pulmonary artery in long axis surrounding the aortic valve. On careful inspection, the coronary arteries can be identified as they emerge from the aortic root. In the long-axis view (obtained from a more vertical and leftward scan), the aorta arises from the posterior ventricle, and its valve is not in fibrous continuity with the AV valve. The heavily trabeculated and hypertrophied RV with its moderator band is posterior and to the left, and the smoothly trabeculated LV is anterior and to the right (Figure 31–21). The systemic AV (anatomically a tricuspid) valve has three leaflets and septal attachments, is apically displaced, and may show variable degrees of regurgitation. In contrast, the subpulmonary AV (anatomically a mitral) valve has two leaflets and no septal attachments.
Apical transthoracic echocardiographic views in a patient with congenitally corrected transposition of the great arteries. A: The moderator band is clearly visualized (double arrow) in the left-sided morphologic right ventricle (RV). B: The narrow-based atrial appendage (double arrow) clearly identifies this as a left atrium (LA). The RV is spherically dilated, reflecting the pressure overload of this chamber. The left ventricle (LV) is small and compressed. RA, right atrium. The left-sided atrioventricular (AV) valve is a morphologic tricuspid valve and the right-sided AV valve is a morphologic mitral valve.
It is essential to identify associated lesions because these are the primary determinants of survival, specifically a VSD and infundibular pulmonary valve stenosis. Doppler echocardiography should be used to determine the pulmonary valve gradient and to identify any pulmonary hypertension. Autopsy studies of patients with C-TGA have documented abnormalities of the pulmonary venous AV valve in greater than 90% of cases. The most common of these is an Ebstein-like deformity. The leaflets of this systemic tricuspid valve are displaced apically, and the chordae tendineae are short and thickened. Clinically significant tricuspid systemic AV valve regurgitation has been reported in 20–50% of patients with C-TGA.
When noninvasive data are diagnostically conclusive, the role of cardiac catheterization is for preoperative evaluation in patients with surgically remediable lesions. The pulmonary artery may be difficult to enter; fluoroscopically, the venous catheter is noted to enter a posterior and rightward vessel. The PVR must be measured to rule out irreversible pulmonary vascular disease in patients with VSD. Although angiography can indicate the abnormally positioned great arteries, it is important only for identification of anomalous coronary arteries, which are infrequently encountered.
Survival in C-TGA is usually determined by other associated lesions, but even in its isolated form, survival may not be normal. The natural history and postoperative outcome of patients with C-TGA and the commonly associated lesions of VSD and PS are known to be less satisfactory than those of patients with normal AV connections and similar intracardiac lesions. The propensity for AV conduction abnormalities and for tricuspid valve dysfunction and the much-debated capability of the RV to function adequately in the systemic circulation may all affect survival.
A frequent feature of C-TGA is the development of complete heart block, estimated to occur at a rate of about 2% per year. AV conduction abnormalities of varying degrees are seen in nearly 75% of patients with this anomaly; many will require permanent pacemaker insertion. Periodic surveillance for the development of high-degree AV block is important: sudden death may be the first manifestation of this complication. However, it is the morphologic abnormalities of the tricuspid valve resulting in severe valvular dysfunction/regurgitation that have been shown to be the most critical determinant for survival. The systemic RV in C-TGA appears to be less tolerant than an anatomic LV of similar degrees of valvular incompetence, and there is an acceleration of the usual vicious cycle of ventricular remodeling, hypertrophy, and dysfunction in response to volume overload. The RV's inability to cope with significant tricuspid regurgitation leads to decreased contractility and annular dilation that in turn exacerbates the degree of regurgitation. Theoretically, the anatomic RV is subject to progressive pump failure from the obligatory pressure overload of the systemic circulation, potentially hastened by systemic hypertension, coronary artery disease, and volume overload from a regurgitant AV valve. Because the circulation is functionally corrected, the indications for surgery are those of the associated lesion requiring surgery (eg, VSD with a Qp:Qs of 2:1, VSD with PS causing cyanosis). Repair or replacement of the tricuspid valve may be indicated; however, 10-year survival after surgical intervention is low. A “double switch” operation has been proposed for patients whose tricuspid valves are severely insufficient. An atrial switch combined with an arterial switch (see the section on Transposition of the Great Arteries) in the absence of LV outflow obstruction or with a Rastelli procedure (RV to pulmonary artery conduit) has been successfully performed. After surgery, the LV and mitral valve are restored to systemic circulation. Improvement in tricuspid valve function in a low-pressure RV has been documented after these operations. This procedure carries significant risk, and late complications relating to the atrial switch component (baffle obstruction, sick sinus syndrome) are of additional concern. Heart transplantation remains the final option for patients with C-TGA, intractable tricuspid regurgitation, and RV failure.
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