The Core Curriculum: Cardiopulmonary Imaging, 1st Edition (2004)

Chapter 19. Adult Congenital Heart Disease

Advances in the treatment of congenital heart disease over the past five decades have led to significant growth in the number of surviving patients. Accurate statistics are lacking, but estimates of adult patients with congenital heart disease in the United States in the year 2000 were more than 750,000 (1). Most adult cases consist of simple defects such as bicuspid aortic valve, right aortic arch, and atrial septal defect. However, patients with more severe forms of congenital disease, such as pulmonary atresia, Ebstein anomaly, and transposition of the great arteries, can also survive into adulthood. For this reason, radiologists should have a broad understanding of the anatomic and physiologic aspects of congenital heart disease. In this chapter we provide a broad overview of adult congenital heart disease, with an emphasis on chest radiography, computed tomography (CT), and magnetic resonance imaging (MRI). The discussion focuses on patients who have not had prior surgical corrective procedures, cases where radiologists can be the first to provide clues for early diagnosis.

The chapter is divided into two sections (Table 19.1). The first section is a discussion of congenital defects that do not produce cyanosis, such as anomalies of the aorta, left-to-right intracardiac shunts, and other miscellaneous conditions. The second section addresses the more complex cyanotic defects.

Noncyanotic Congenital Heart Disease

Bicuspid Aortic Valve

The congenitally bicuspid aortic valve, after mitral valve prolapse, is the second most common major cardiac malformation (2). The malformation occurs as frequently as 2 in every 100 births (3). The finding sometimes remains clinically silent throughout life, found incidentally at autopsy. However, the tendency is to have progressive thickening and fibrosis of the valve with aging. Valve stenosis is the most common complication of this malformation. When stenosis occurs, virtually all adult patients will have calcification of the valve found at pathologic tissue examination. Abundant aortic valve calcification found on chest radiographs in a patient under the age of 50 should be mentioned in reports as a possible diagnosis of valve stenosis, especially if associated with dilatation of the ascending aortic outline (Fig. 19.1). Incidental identification of abundant aortic valve calcification on chest CT in patients under the age of 55 should also be reported as a possible case of aortic valve stenosis (Fig. 19.2) (4). Congenital subaortic and supraaortic valve stenoses are uncommon conditions in adults shown on occasion on imaging studies (Fig. 19.3).

Bicuspid aortic valve is the second most common major cardiac malformation after mitral valve prolapse.

Table 19.1: Outline of Congenital Heart Disease

Acyanotic Conditions

Cyanotic Conditions

Bicuspid aortic valve
Aortic arch anomalies
Anomalous coronary artery origins
Left-to-right cardiac shunts
Pulmonary valve stenosis
Absent pulmonary valve
Cor triatriatum
Corrected transposition
Left superior vena cava
Azygos continuation of the inferior vena cava

Eisenmenger physiology
Tetralogy of Fallot
Ebstein anomaly
Rare adult conditions
Abnormal situs

Aortic valve calcification, particularly in individuals less than 50 years of age, has a high association with aortic valve stenosis.

Table 19.2: Common Anomalies of the Aortic Arch

Left aortic arch with aberrant right subclavian artery
Right aortic arch with aberrant left subclavian artery
Mirror image right aortic arch
Double aortic arch
Cervical aortic arch

Anomalies of the Thoracic Aorta

The nature of the embryologic development of the aortic arch and its branches leads to rather common malformations that can be clinically silent or can lead to clinical symptoms. Some of the anomalies are common, and others are quite rare (5,6). Table 19.2 outlines some of the common arch anomalies.

The left aortic arch with aberrant right subclavian artery is the most common major arterial anomaly, affecting 0.4% to 2% of the population. In this anomaly, the right subclavian artery takes off as the final branch of the aorta, not as the first branch. Patients with this anomaly are usually asymptomatic or have symptoms of dysphagia. There is no increase in the incidence of other associated congenital defects. Over half of these patients will show an abnormal mediastinal contour at the aortic arch level on frontal chest radiographs representing dilatation of the proximal portion of the aberrant artery, the so-called diverticulum of Kommerell (Fig. 19.4A). Lateral chest radiographs can show the abnormality as opacity projecting in the mediastinum behind the trachea, anterior to the spine, and above the aortic arch (the Raider triangle) (Fig. 19.4B) (7). The retrotracheal opacity represents the subclavian artery as it passes behind the esophagus and trachea through the mediastinum. If desired clinically, CT can prove the diagnosis of the aberrant artery (Fig. 19.4C). On occasion, the aberrant right subclavian artery can be seen as an oblique edge coming off the aorta and as an opacity projecting through the trachea extending to the right on the frontal view (Fig. 19.5) (8).

A right aortic arch identified incidentally in an adult almost always has an aberrant left subclavian artery.

Right aortic arch with mirror image branching has a very high (95%) association with severe congenital heart disease, including truncus arteriosus and tetralogy of Fallot.

The right aortic arch with aberrant left subclavian artery origin is an anomaly that is also generally an incidental finding on chest radiographs. However, there is a small association with other congenital heart defects. Chest radiographs show a right aortic arch with opacity in the Raider triangle on the lateral view representing the aberrant artery (Fig. 19.6).

Figure 19.1 A 37-year-old patient with aortic stenosis and a bicuspid aortic valve. A. Posteroanterior chest radiograph shows a convex opacity along the right side of the mediastinum (arrowheads) representing poststenotic dilatation of the ascending aorta. In this case the left ventricle is enlarged, showing elongation of the heart and pointing of the cardiac apex toward the left costophrenic angle(arrow). B. Lateral chest radiograph demonstrates the dilated ascending aorta (arrowheads) and posterior displacement of the left ventricle at the posterior-inferior cardiac margin (arrow). C. Frame from a cineangiogram of the aortic root shows “doming”(arrowheads) of the stenotic bicuspid aortic valve.

Figure 19.2 A 45-year-old woman with a bicuspid aortic valve and valve stenosis. Computed tomography image at the aortic valve level shows abundant calcification of the valve (arrowhead).

Figure 19.3 A 44-year-old patient with supravalvular aortic stenosis. A. Computed tomography image shows normal size and configuration of the aortic valve (arrow); (B) tubular narrowing of the supravalvular portion of the ascending aorta (arrow) and (C), normal diameter of the ascending aorta (asterisk). There is no poststenotic dilatation.

The mirror image right aortic arch (no aberrant subclavian artery) has a high rate (95%) of association with severe congenital heart disease, usually of the cyanotic type such as tetralogy of Fallot, truncus arteriosus, or pulmonary atresia. However, the anomaly can be seen as an incidental finding on chest radiographs and CT studies. The double aortic arch forms a complete vascular ring, usually presenting in childhood with symptoms of compression of mediastinal structures. On occasion, the double arch first presents in adulthood (Fig. 19.7). Thecervical aortic arch anomaly is relatively rare, usually presenting as an incidental finding (Fig. 19.8).

Figure 19.4 A 77-year-old patient with aneurysmal dilatation of the thoracic aorta and an aberrant right subclavian artery. A. Posterior anterior chest radiograph shows a left aortic arch. A mass-like protuberance projecting to the right of the superior mediastinum(arrowheads) represents an aneurysm of an aberrant right subclavian artery. B. The lateral chest radiograph shows an opacity posterior to the tracheal air column (arrowheads) in Raider’s triangle representing the aberrant subclavian artery shown on end. C. A computed tomography image of the arch demonstrates an aneurysm of the aberrant right subclavian artery. Thrombus is shown in the posterior portion of the aneurysm (arrow).

Figure 19.5 Posterior anterior chest radiograph shows an aberrant right subclavian artery as an oblique opacity (arrowheads) arising from the aortic arch, passing to the right. In this case the artery can be seen through the tracheal air column (arrows).

Figure 19.6 An adult patient with a right-sided aortic arch and an aberrant left subclavian artery. A. Lateral chest radiograph shows the aberrant left subclavian artery as a round opacity in Raider’s triangle. B. Lateral view of an esophagram shows a posterior impression on the barium column caused by the aberrant left subclavian artery.

Figure 19.7 A 63-year-old patient with a double aortic arch. A. Posterior anterior chest radiograph shows a double aortic arch as opacities lying on both sides of the tracheal air column (arrows)B. Computed tomography image shows the double arches coming together posteriorly as a single descending thoracic aorta. The arches arose from a single ascending aortic lumen below this axial section. In this case, the arches are of equal caliber. The left arch is hypoplastic in many cases.

Figure 19.8 A 59-year-old patient with prior surgery for rheumatic heart disease and a right-sided cervical aortic arch. A. Posteroanterior view of the chest radiograph shows the high cervical right arch (arrows) at the thoracic inlet, displacing the trachea to the left. B. Computed tomography section shows the right cervical arch (a) at the thoracic inlet. There is an aberrant left subclavian artery (asterisk).

Figure 19.9 Computed tomography image shows an aberrant anterior descending coronary artery origin (arrow) arising from the right coronary sinus of Valsalva next to the right coronary artery. The left anterior descending artery passes between the aorta (A) and root of the pulmonary artery (PA). (Courtesy of James Mastromatteo, MD, Boston, MA.)

 

Anomalous Coronary Artery Origins from the Aorta

Anomalous origin of a coronary artery can occur from the pulmonary artery or aorta. Patients with ectopic origin of both coronary arteries from the pulmonary artery are discovered early in life because of severe myocardial ischemia. Origin of one main coronary from the pulmonary artery with the other from the aorta is also a serious malformation, but some patients do survive past childhood. Ectopic origin of one or both coronary arteries, or of individual branches, from the aorta is compatible with life, found in 0.6% to 0.9% of the population (9,10). On occasion, CT or MRI can show these aberrant origins as an incidental finding. At other times, patients with unexplained chest pain and abnormal stress tests or a familial history of sudden death at a young age are referred for echocardiography, CT or MRI to show the coronary artery origins. The course of the ectopic coronary arteries can proceed from the origin to its myocardial distribution by several possible routes (11). The artery can pass between the pulmonary artery and aortic root (Fig. 19.9) or can course anterior or posterior to these structures. When a major coronary artery such as the left main or left anterior descending artery passes between the pulmonary artery and the aorta, there is a small risk of sudden death.

Anomalous coronary artery origin may be a cause of unexplained chest pain, particularly in young adults in whom atherosclerotic disease is less likely.

Left-to-Right Shunts

Atrial Septal Defect

The isolated small patent foramen ovale or atrial septal secundum defect is the most common postchildhood left-to-right shunt (12), with an estimated prevalence of 0.6 per 1000 (1). Ventricular septal defects are more common in children, but most close spontaneously or are repaired. Large atrial septal defects such as sinus venosus and ostium primum defects or atrial septal defects associated with other anomalies are usually discovered in childhood. Chest radiographs of patients with atrial septal defect show increased pulmonary vascularity and enlarged pulmonary arteries (Fig. 19.10). The heart can be normal in size but can enlarge, particularly in patients who develop mitral and tricuspid valve regurgitation (Fig. 19.11). Right ventricular enlargement is usually evident on the lateral view (Fig. 19.12). The aortic arch is relatively small in many patients with atrial septal defect. Cardiac MRI (Fig. 19.13) and CT (Fig. 19.14) can show the defect, although echocardiography is the primary modality used to confirm the diagnosis. Table 19.3 lists the common differential diagnosis for noncyanotic cardiac shunts.

An isolated arterial septal defect is the most common postchildhood left-to-right cardiac shunt.

Figure 19.10 Posteroanterior chest radiograph shows increased pulmonary vascularity. The central pulmonary arteries are dilated. The rounded right heart border represents right atrial dilatation, and the round left heart margin is secondary to right ventricular enlargement. Many patients, like this one with atrial septal defect, have an associated small aortic arch (arrow).

Figure 19.11 Posteroanterior chest radiograph shows markedly dilated chambers in this 76-year-old patient with an atrial septal defect. Echocardiography revealed tricuspid and mitral valve regurgitation. The aortic arch (arrow) shows atheromatous calcification but remains small in diameter.

Figure 19.12 Lateral chest radiograph of a 49-year-old patient with an atrial septal defect shows fullness posterior to the sternum, representing right ventricular dilatation. There is pectus carinatum deformity of the sternum, an anomaly with known association with septal defects.

Figure 19.13 A 28-year-old patient with a patent foramen ovale. Frame from a cine-magnetic resonance imaging study in the four-chamber view shows a small dark jet of blood (arrow) crossing the interatrial septum from the left atrium (la) to the right atrium through the patent foramen ovale.

Figure 19.14 A 17-year-old girl with an atrial septal defect. A. Computed tomography section through all four cardiac chambers shows the atrial septal defect (asterisk) as interruption of the septum between the two atria. The right atrium (ra) and right ventricle (rv) are dilated, and the ventricular septum is flattened because of high pressure and volume in the right ventricle. B. Reconstructed three-dimensional image of the left atrium and pulmonary veins shows an anomalous course of a vertical vein emptying the posterior segment of the right upper lobe into the left atrium (arrow). Anomalies of pulmonary veins occur frequently in association with atrial septal defect, often emptying into the right atrium or vena cava.

 

Ventricular Septal Defect

Isolated ventricular septal defects are relatively common congenital malformations in children. Many of these shunts close spontaneously. The estimated prevalence in adults is 0.3 per 1000 (1). Adults presenting with ventricular septal defects for the first time can be asymptomatic or can present with pulmonary hypertension and Eisenmenger physiology (13). Eisenmenger physiology occurs when there is pulmonary hypertension secondary to chronic increases in pulmonary blood flow and elevated right ventricular pressure.

Ventricular septal defects are uncommon in adults, usually either closing spontaneously (the majority) or having been closed surgically during childhood.

The elevated right ventricular pressure stifles left ventricular shunting and eventually leads to bidirectional flow across the septum, which in turn leads to cyanosis. Patients with small ventricular septal defects can have normal pulmonary vascularity and heart size. In these cases the diagnosis is made on physical examination and echocardiography. In patients with large shunts or Eisenmenger physiology, chest radiographs show increased pulmonary vascularity, enlargement of the central pulmonary arteries, right ventricular enlargement, and a normal aortic arch (Fig. 19.15). Left atrial enlargement is commonly seen in children but is usually absent in adults unless there is mitral valve regurgitation (14). MRI can show these defects in detail (Fig. 19.16).

Eisenmenger physiology with pulmonary hypertension develops secondary to chronically elevated pulmonary blood flow with elevated right ventricular pressure creating a bidirectional shunt and leading to cyanosis.

Table 19.3: Congenital Noncyanotic Cardiac Shunts

Atrial septal defect
Ventricular septal defect
Patent ductus arteriosus
Partial anomalous pulmonary venous return
Coronary artery fistula
Ruptured sinus of Valsalva aneurysm

Figure 19.15 A 38-year-old patient with a 2:1 left-to-right shunt through a ventricular septal defect. A. A posteroanterior chest radiograph shows shunt vascularity, cardiomegaly, dilated central pulmonary arteries, and normal size of the aortic arch. B. A lateral chest radiograph on the same patient shows dilatation of the left ventricle (LV) posterior to the inferior vena cava. The dilated right ventricle is shown as fullness behind the sternum. This patient shows pectus carinatum deformity of the sternum (asterisk).

Figure 19.16 A 48-year-old patient with a ventricular septal defect. Image from cine magnetic resonance imaging in the double-oblique short-axis view shows blood flow as a black jet (arrow) across the interventricular septum through a high septal defect (asterisk).

 

Patent Ductus Arteriosus

Most patent ductus arteriosi close spontaneously or are repaired during childhood. For this reason, patients rarely first present with patent ductus as adults. McManus (15) summarized the pathologic findings of 46 patients 50 years of age or older. In this summary, patients generally had cardiomegaly, and calcification was frequently present in the arch and ductus. Pulmonary hypertension was severe. Chest radiographs in adults with patent ductus look much like chronic ventricular septal defect, showing increased pulmonary vascularity, dilated central pulmonary arteries, and dilated cardiac chambers (Fig. 19.17). However, many patients with patent ductus will have a dilated aortic arch (16). The diagnosis of patent ductus can also be suspected when chest radiographs show shunt vascularity and calcification of the ductus (Fig. 19.18). MRI and CT (Fig. 19.19) can confirm the diagnosis.

Ductus calcification (in the aortopulmonary window) with shunt vascularity should raise suspicion for a patent ductus arteriosus in adults.

Partial Anomalous Pulmonary Venous Return

Partial anomalous pulmonary venous return occurs in 0.4% to 0.7% of postmortem studies (17). The condition can be an isolated anomaly or can be associated with the congenital pulmonary venolobar syndrome, a spectrum of anomalies of the lung, cardiovascular structures, and chest wall (18,19). Associated atrial septal defects are common. The anomaly produces physiologic left-to-right shunting of oxygenated blood into the right heart circulation. The “scimitar syndrome” describes the anatomic course of an anomalous pulmonary vein of the right lung that curves inferiorly, disappearing at the diaphragm (Fig. 19.20) as it drains into the inferior vena cava or other nearby venous structures. Atrial septal defects can coexist. This syndrome almost always occurs in association with hypogenetic lung. Anomalous pulmonary veins are more often found as isolated abnormalities, most of the time without significant clinical implication. These venous drainage anomalies can involve either lung (Figs. 19.2119.22, and 19.23).

Partial anomalous pulmonary venous return is commonly associated with an atrial septal defect.

In scimitar syndrome, the “scimitar” (Turkish word for sword-like) vein drains into a vein below the diaphragm, such as an hepatic vein or the inferior vena cava.

Figure 19.17 A 44-year-old patient with 3:1 shunt to the pulmonary arteries through a patent ductus arteriosus. A. Posteroanterior chest radiograph shows shunt vascularity in the lungs, cardiac enlargement, and dilated central pulmonary arteries reflecting increased flow and pulmonary hypertension. The aorta is enlarged, a common finding in patients with this anomaly. B. Digital angiogram in the frontal view after injection of contrast material in the aortic root. The contrast fills the proximal aorta (a), with early filling of the pulmonary arteries (arrows) through the patent ductus. The ductus is not shown directly in this view.

Figure 19.18 Posteroanterior chest radiograph in a 72-year-old patient with a calcified patent ductus arteriosus. The ductus is shown as a calcified tubular structure (arrowheads) projecting between the aortic arch and the pulmonary artery.

Figure 19.19 Images from a computed tomography in a 17-year-old patient who had previous repair of an ascending aortic aneurysm demonstrate incidental finding of a small patent ductus arteriosus. A. The patent ductus (arrows) arises from the junction of the aortic arch and descending thoracic aorta. B. The ductus (arrowheads) extends anteriorly and inferiorly to the top of the pulmonary artery.

Ruptured Sinus of Valsalva Aneurysm

The three sinuses of Valsalva dilate naturally as a consequence of aging. The sinuses also dilate in disease states, such as Marfan syndrome and ankylosing spondylitis. Congenital dilatation of one sinus is a rare condition, probably related to a defect in the media of the aortic wall behind a sinus of Valsalva (20). Seventy percent of these aneurysms involve the right anterior cusp and 29% the posterior cusp. Less than 1% of these aneurysms involve the left cusp. Most ruptured aneurysms empty into the right ventricle and less commonly into the right atrium. A left-to-right shunt is suddenly created with new communication between the aorta and right-sided cardiac chamber. Chest radiographic changes depend on the size of the aneurysm and corresponding shunt. The aneurysm, if large, can be seen as a bulge near the aortic root. Two of our four patients with sinus of Valsalva aneurysm had cardiomegaly on radiographs, and shunt vascularity was shown in one (Fig. 19.24). MRI can be a valuable tool to show the anatomy before surgery (Fig. 19.25).

Figure 19.20 A 50-year-old patient with the “scimitar” syndrome. A. A posteroanterior chest radiograph demonstrates a small right lung and hemithorax with mediastinal shift to the right. The pulmonary vessels in the right lung are hypoplastic. The anomalous right pulmonary vein is hidden behind the heart in this case. Blood flow to the right lung is increased because of the presence of atrial and ventricular septal defects, as well as a patent ductus arteriosus. B. Computed tomography images show the anomalous vein (arrows)extending inferiorly to its point of entry into the inferior vena cava (VC).

Figure 19.21 A 28-year-old patient with sickle cell disease. The patient has an anomalous draining vein from the right upper lobe. Posteroanterior chest radiograph demonstrates a catheter that extends from the left subclavian vein, into the superior vena cava, into the anomalous vein (arrows).

Figure 19.22 A 62-year-old patient with anomalous venous drainage of the left upper lobe. A. A posteroanterior chest radiograph shows an oblique opacity (arrowheads) at the aortopulmonary window representing an anomalous left upper lobe vein. B. A computed tomography shows the anomalous left upper lobe vein (arrows) that drains into the left brachiocephalic vein.

Figure 19.23 An adult patient with a large anomalous vein of the right lung. A. Posteroanterior chest radiograph shows a large anomalous draining vein (arrow) of the right lung. B. Reconstructed contrast-enhanced coronal magnetic resonance image shows the anomalous right pulmonary vein emptying into the right atrium (ra).

Pulmonic Valve Stenosis

Congenital stenosis of the pulmonic valve is a common anomaly, comprising about 6% to 10% of all congenital heart disease. There are several different types of stenosis, including the typical domed valve, the dysplastic valve, and the bicuspid valve (21). Pulmonic valve stenosis can go undetected until adulthood, when the defect is an isolated finding and when the degree of stenosis is not severe. The diagnosis is made if right heart failure occurs, if a murmur is found on physical examination, or on occasion when a radiologist discovers the diagnosis as an incidental finding. The chest radiographs of these patients show dilatation of the main and left pulmonary arteries and normal heart size until right heart failure intervenes (Fig. 19.26). Poststenotic turbulent blood flow causes dilatation of the main pulmonary artery and the directly aligned left pulmonary artery. The nondilated right pulmonary artery is protected from the effect of turbulent flow as it extends perpendicular to the flow through the main pulmonary artery.

Isolated dilation of the main and left pulmonary arteries, sparing the right pulmonary artery, should raise suspicion of pulmonic valve stenosis.

Absent Pulmonic Valve

Congenital absence of the pulmonic valve is a rare anomaly, found in a small percentage of patients with tetralogy of Fallot. It is even more unusual to see absence of the valve as an isolated defect. In this condition, a ring of thickened tissue is present at the expected location of the valve leaflets (21). Patients have wide-open pulmonic regurgitation with a dilated right ventricle and atrium (Fig. 19.27).

Cor Triatriatum

In this condition, the common pulmonary vein fails to incorporate into the upper posterior portion of the left atrium during fetal development of the heart chambers. As a consequence, the left atrium is subdivided into two portions by a septum with a perforation (Fig. 19.28). The upper “chamber” receives the pulmonary veins, whereas the lower “chamber” communicates with the left atrial appendage and empties through the mitral valve. If the opening of the septation is small, pulmonary venous and capillary pressures are elevated. Most cases are discovered in infancy or childhood, but adult patients can present with chronic and recurrent heart failure (22).

Figure 19.24 Posteroanterior chest radiograph in a 20-year-old patient with sudden rupture of a sinus of Valsalva shows shunt vascularity and upper normal heart size.

Figure 19.25 Magnetic resonance images of a 74-year-old patient with a huge, nonruptured, sinus of Valsalva aneurysm. A. Coronal view shows the large sinus of Valsalva aneurysm (arrows) occupying the entire right margin of the mediastinum adjacent to the heart.B. Axial view shows the aneurysm (arrowheads) arising from the right side of the aortic root. The origin of the aneurysm could arise from either the right or noncoronary sinus. C. Axial view shows the aneurysm compressing the right atrial and ventricular chambers(arrowheads).

Corrected Transposition of the Great Vessels

Patients with congenitally corrected transposition of the great vessels, unassociated with other cardiac defects, can survive into adulthood without detection. Patients with this anomaly have atrioventricular and ventriculoarterial discordance. In other words, the right atrium empties deoxygenated blood into the left ventricle, which in turn pumps blood into the transposed pulmonary artery. Oxygenated blood returns from the lungs though the pulmonary veins into the left atrium, which empties into the right ventricle, which in turn pumps the blood into the transposed aorta. Thus, blood is oxygenated and pumped to the systemic circulation in a normal sequence. With advancing age, the systemic ventricle (anatomic right ventricle) begins to fail.

In corrected transposition, deoxygenated blood from the systemic venous circulation flows in the lungs, is oxygenated, and flows into the aorta without a shunt lesion; however, the order of the chambers it passes through is abnormal (right atrium → left ventricle → pulmonary artery → left atrium → right ventricle → aorta).

Figure 19.26 A 51-year-old patient with pulmonic valve stenosis. A. Posteroanterior chest radiograph shows a dilated left pulmonary artery (arrows) projecting above the left main bronchus. Heart size and pulmonary vascularity are normal. B. Lateral radiograph shows dilatation of the left pulmonary artery (arrows).

Figure 19.27 Posteroanterior chest radiograph of a 28-year-old patient with absence of the pulmonic valve. The outflow portion of the right ventricle (arrow) and the main and left pulmonary arteries are markedly dilated. The right pulmonary artery has a normal diameter.

Figure 19.28 Magnetic resonance cardiac angiogram in the coronal view of a 68-year-old patient with cor triatriatum. A web(arrowhead) projects within the left atrium (la), above the mitral valve (arrows).

 

The onset of failure of the systemic ventricle can be attributed to myocardial ischemia in the hypertrophied right ventricular myocardium during periods of high oxygen demand such as stress or exercise (23). Incompetence of the left atrioventricular valve and conduction disturbances also contribute to the development of heart failure. Detection of an abnormally configured cardiovascular outline could be the first clinical clue in making this diagnosis. The classic configuration of the cardiovascular outline was described in 1978, with further description in 1985 (24,25). Many patients will show a convex outward configuration of the left cardiovascular margin caused by levopositioning of the ascending aorta (Fig. 19.29).

With age, the morphologic right ventricle that pumps blood into the aorta, thereby pumping against higher systemic arterial pressure (versus lower pulmonary artery pressure), begins to fail.

Figure 19.29 A 30-year-old patient with congenitally corrected transposition of the great arteries. A. Posteroanterior chest radiograph shows widespread pulmonary edema. B. Follow-up frontal chest radiograph after treatment demonstrates a convex left cardiac margin(arrows) representing the levopositioned ascending aorta. C. Frame from a cine-angiogram shows levopostioning of the ascending aorta that exits from a trabeculated ventricle, with the configuration of an anatomic “right ventricle.”

Figure 19.30 An adult patient with passage of a left subclavian catheter into a left superior vena cava. A. Posteroanterior chest radiograph shows a left subclavian catheter extending down the left side of the mediastinum. B. Digital subtraction angiogram shows the connection of the superior vena cava (SVC) and the coronary sinus (CS).

Persistent Left Superior Vena Cava

Cases of persistent left superior vena cava are usually discovered incidentally at chest CT or as a result of an abnormal catheter position on a chest radiograph (Fig. 19.30). This anomaly is the most common congenital abnormality of the thoracic veins, occurring in about 0.3% of the population. The left vena cava extends down the left side of the mediastinum and empties into the coronary sinus. Thus, a left paramediastinal position of a catheter is seen on chest radiographs (26). The differential of left-sided catheters on chest radiographs is shown on Table 19.4.

A duplicated superior vena cava is more common than an isolated left superior vena cava.

Table 19.4: Left Paramediastinal Catheter Position

Left superior vena cava
Left superior intercostal vein
Left pericardiophrenic vein
Left internal thoracic vein
Left subclavian artery to descending thoracic aorta

Azygos Continuation of the Inferior Vena Cava

If the right subcardinal vein fails to form the suprarenal segment of the inferior vena cava, the result is congenital absence and azygos continuation of the inferior vena cava (27). In these patients, the azygos and hemiazygos veins dilate in response to increased venous blood flow. This anomaly is often associated with abnormalities of situs. Chest radiographs show dilatation of the azygos vein, and problems such as situs inversus can be observed in some patients (Fig. 19.31).

With azygos continuation of the inferior vena cava, the azygos vein is dilated, and the inferior vena cava opacity on the lateral view of the chest radiograph may be absent.

Figure 19.31 A 37-year-old patient with azygos continuation of the inferior vena cava. Posteroanterior chest radiograph shows situs inversus and a dilated azygos vein.

Cyanotic Congenital Heart Disease

No data are available that describe the numbers of and frequency of occurrence of complex congenital heart disease in adults. It is estimated that about 117,000 of these patients were alive in the United States in the year 2000 (1). Cyanotic congenital heart disease can be categorized by the presence or absence of shunt vascularity. This type of classification aids radiologists in deriving lists of differential diagnosis (Tables 19.5 and 19.6). The most common forms of adult congenital cyanotic disease are left-to-right high volume shunts resulting in Eisenmenger physiology, tetralogy of Fallot, and Ebstein anomaly. Rarely, adults with other forms of severe cyanotic disease without prior surgical treatment present for treatment and diagnosis.

Eisenmenger Physiology

Many adults presenting with cyanotic congenital heart disease suffer from chronic uncorrected left-to-right shunts, resulting in Eisenmenger physiology. In these cases, patients have severe pulmonary hypertension with markedly elevated right heart pressures. The pulmonary hypertension is caused by chronic exposure of the pulmonary vessels to marked increases in blood flow, resulting in pulmonary vascular obstructive disease (28). The systemic type pressure in the right chambers causes admixture shunting of desaturated blood to the systemic circulation, producing clinical cyanosis. Chest radiographs of these patients show marked dilatation of the central pulmonary arteries, associated with enlargement of the right ventricle and right atrium (Figs. 19.32 and 19.33).

 

On occasion, the central pulmonary arteries show peripheral calcification (Fig. 19.34). The pulmonary vessels in the mid-lungs are enlarged, reflecting the chronic increase in pulmonary blood flow and pressure.

Table 19.5: Cyanosis with Shunt Vascularity

Eisenmenger physiology of left-to-right shunts
Transposition of the great vessels
Truncus arteriosus
Total anomalous venous return
Single ventricle
Tricuspid valve atresia with transposition

Table 19.6: Cyanosis without Shunt Vascularity

·         Tetralogy of Fallot

·         Hypoplastic right heart syndrome
   Tricuspid valve atresia
   Pulmonic valve atresia
   Hypoplastic right ventricle

·         Ebstein anomaly

Figure 19.32 A 42-year-old patient with atrial septal defect and gradual onset of cyanosis secondary to Eisenmenger physiology. A.Posteroanterior chest radiograph shows marked dilatation of the central pulmonary arteries. The aortic arch is small, a common finding in patients with atrial septal defect. B. Lateral view of the chest shows dilated right (arrowheads) and left (arrows) pulmonary arteries. Pectus deformity of the sternum obscures the enlarged right ventricle.

Figure 19.33 Posteroanterior chest radiograph of a 63-year-old patient with an atrial septal primum defect and Eisenmenger physiology. The central pulmonary arteries and all cardiac chambers are dilated.

Figure 19.34 Anteroposterior bedside chest radiograph of a 58-year-old patient with marked pulmonary arterial hypertension and Eisenmenger physiology. The patient had an uncorrected 4-cm ventricular septal defect and an atrial septal defect. The markedly dilated central pulmonary arteries have curvilinear peripheral calcification.

Signs of Eisenmenger physiology are a large right atrium, right ventricle, and central pulmonary arteries (as a manifestation of pulmonary hypertension) and increased pulmonary blood flow (a manifestation of the shunt lesion).

Tetralogy of Fallot

Another common congenital cause of cyanosis in adults is tetralogy of Fallot. The four components of the malformation are pulmonary stenosis, ventricular septal defect, positioning of the aorta over the interventricular septum, and hypertrophy of the right ventricular myocardium. Adult cases differ from cases appearing in childhood because the ventricular septal defects are smaller, and/or right ventricular outflow obstruction is less severe (29). These cases with a milder form of malformation are sometimes referred to as “pink tetralogy.” The radiographic appearance in adults can be similar to that shown in children, showing decreased pulmonary vascularity and a boot-shaped heart due to right ventricular enlargement (Fig. 19.35). However, the configuration is usually not boot shaped in adults, as it often is in infants. In addition, in many instances, adults show normal heart size and pulmonary vascularity because of the milder form of outflow obstruction.

In unusual instances the heart can be markedly enlarged (Fig. 19.36). A collateral blood flow pattern due to systemic-to-pulmonary artery anastomoses is sometimes observed (Fig. 19.37).

Adults presenting with tetralogy of Fallot usually have smaller septal defects than children and may therefore have normal heart size and normal pulmonary vascularity. The classic “boot-shaped” heart may be absent.

Figure 19.35 Posteroanterior chest radiograph of a 28-year-old patient with tetralogy of Fallot and a boot-shaped heart.

Figure 19.36 Posteroanterior chest radiograph of a 61-year-old patient with untreated tetralogy of Fallot. The right atrium (ra) and right ventricle (rv) are markedly dilated.

Ebstein Anomaly

Ebstein anomaly consists of displaced septal and posterior tricuspid valve leaflets into the right ventricle, associated with abnormalities of the wall of the inlet portion of the ventricle.

Only the anterior valve leaflet remains attached to the tricuspid annulus. Blood flow through the right atrium and ventricle is impaired by severe tricuspid regurgitation and by the reduced size of the contracting portion of the ventricular chamber. A right-to-left shunt is produced through a patent foramen of ovale or atrial septal defect. The most severe form of the disease shows extensive thinning of the wall (“atrialization”) of the right ventricle with little remaining functional component of the myocardium. The mildest forms of the malformation have displaced leaflets but little thinning and encroachment into the functional portion of the right ventricle. Patients can present at any age depending on the severity of the malformation. Although cyanosis is common in neonates and infants, adults present more commonly with arrhythmia (30).

Figure 19.37 A 40-year-old patient with tetralogy of Fallot. A. Posteroanterior chest radiograph shows rounding of the cardiac apex because of right ventricular enlargement. B. Magnified view shows an abnormal branching pattern of the pulmonary vasculature, representing systemic-to-pulmonary artery collateral vessels.

Associated electrocardiographic abnormalities include right axis deviation, right bundle branch block, and a high incidence of Wolff-Parkinson-White syndrome. The imaging characteristics of the anomaly vary according to the degree of malformation. Standard radiographs usually show cardiomegaly, with marked enlargement in many cases. The degree of cardiac enlargement can be mild in adults (Fig. 19.38). Radiologic images show right-sided chamber dilatation. MRI is an excellent imaging modality, particularly when surgical correction is contemplated (31). However, MR images can be difficult to obtain if there are conduction abnormalities and arrhythmias because of electrocardiographic gating problems during image acquisition (Fig. 19.39).

Adults with Ebstein anomaly most commonly present with arrhythmias due to conducting system abnormalities.

Rare Cyanotic Heart Disease in Adults

On rare occasions, clinicians request imaging examinations for patients with severe cyanotic malformations that have not had prior surgical correction.

In complete transposition of the great vessels, the atria and ventricles have a normal configuration but the pulmonary artery and aorta switch positions. The pulmonary artery arises from the left ventricle and the aorta from the right ventricle. Thus, oxygenated blood returns from the lungs through the pulmonary veins, through the left atrium and left ventricle, only to be pumped back out of the pulmonary arteries to the lungs once again. This configuration is incompatible with life unless there is shunting of oxygenated blood to the systemic circulation through atrial and/or ventricular septal defects or when there is a single ventricle and/or patent ductus arteriosus. On rare occasion, when the shunt is large, a patient can survive naturally into adulthood without having a corrective procedure (32). Chest radiographs show increased pulmonary vascularity, dilated central pulmonary arteries, and cardiac enlargement with an elongated heart and narrow pedicle, the so-called egg-on-a-string appearance (Fig. 19.40). Pulmonary blood flow can appear decreased if the condition is associated with pulmonic stenosis. Cross-sectional imaging can be used to visualize the arrangement of the pulmonary arteries, aorta, and cardiac chamber configuration (Fig. 19.41).

Rarely, a patient with a large shunt lesion (atrial or ventricular septal defect, patent ductus arteriosus) can present in adulthood with complete transposition of the great arteries.

Figure 19.38 A 35-year-old patient with mild form of Ebstein anomaly. A. Posteroanterior chest radiograph shows rounding and increased circumference of the right heart margin secondary to right atrial dilatation. The pulmonary blood flow pattern is normal to decreased. B. Lateral view of the chest shows retrosternal fullness because of right ventricular dilatation.

Figure 19.39 Axial magnetic resonance image of a 39-year-old patient with Ebstein anomaly. Anatomic detail is obscured because of difficulty in electrocardiographic capture because of arrhythmia. The right atrium (ra) and ventricle (rv) are dilated. The abnormal tricuspid valve leaflets cannot be identified because of motion artifact.

The “egg-on-a-string” configuration is classic for complete transposition.

Truncus arteriosus is a cyanotic condition characterized by the presence of a single arterial trunk exiting the heart, overriding a high membranous ventricular septal defect. The truncus gives rise to the pulmonary and coronary arteries. Chest radiographs most commonly show shunt vascularity because of the preferential flow to the lower resistance pulmonary vasculature compared with the systemic circulation. The truncus is right-sided in about 25% of cases. Truncus arteriosus can be associated with pulmonic stenosis, in which case the pulmonary vascularity can be normal or decreased (Fig. 19.42). The truncus is dilated, and the heart is usually enlarged with a right ventricular configuration (rounded and uplifted cardiac apex).

Figure 19.40 Posteroanterior chest radiograph of a 38-year-old patient with untreated transposition of the great arteries. The heart is enlarged and elongated with a relatively narrow pedicle, the so-called “egg-on-a-string” configuration.

Figure 19.41 Computed tomography images of a middle-aged patient with transposition of the great arteries. A. The pulmonary artery (Pa) arises from the posterior left ventricle, and the aorta (a) arises from the anterior right ventricle. B. The pulmonary artery (Pa) lies to the right of the aorta (a). The pulmonary artery (Pa) is dilated because of increased pressure and flow from the systemic left ventricle.

Pulmonary atresia can occur as an isolated defect with an intact ventricular septum or can be associated with a ventricular septal defect with or without an overriding aorta. When a ventricular defect is present, the cases can be considered clinically as an extreme form of tetralogy of Fallot. Chest radiographs usually show decreased pulmonary vascularity. However, pulmonary flow can be normal or increased when augmented by flow from a large ductus arteriosus or systemic-to-pulmonary artery collateral vessels (Fig. 19.43). The heart may be normal in size or enlarged. The aorta is usually dilated and left sided. Right arch position is unusual, and if present other diagnoses should be considered (33). MRI can be useful in depicting the pulmonary arteries beyond the point of atresia for planning purposes before surgical bypass (Fig. 19.44).

Figure 19.42 Posteroanterior chest radiograph of an 18-year-old patient with truncus arteriosus. The coronary arteries and pulmonary arteries arose from the proximal truncus in this rare case, and the pulmonary arteries were stenotic. The pulmonary arterial stenosis protected the lungs by allowing adequate, not excessive, pulmonary blood flow. The cardiac apex is rounded, indicating right ventricular dilatation, and the enlarged truncus appears in the usual position of the aortic arch.

Figure 19.43 A 39-year-old patient with pulmonary atresia and a ventricular septal defect. A. Posteroanterior chest radiograph shows cardiomegaly and a dilated aortic arch. The central pulmonary arteries are small as shown, by example, at the left hilum (arrowhead). Systemic-to-pulmonary artery collateral vessels are shown bilaterally (arrows)B. Non–contrast-enhanced computed tomography image at the aortopulmonary window shows dilated ascending and descending aortic segments (a). There are no central pulmonary arteries.

Figure 19.44 A 47-year-old patient with pulmonary atresia and ventricular septal defect. Three-dimensional reconstructed contrast-enhanced magnetic resonance image shows atresia of the main pulmonary artery.

Table 19.7: Situs and Associated Congenital Defects

Situs solitus with:
   Levoversion—no associated defects
   Mesoversion—often no associated defects
   Dextroversion—associated with severe defects
Situs inversus with:
   Dextroversion—associated with less complex defects
   Levoversion—associated with severe defects
   Mesoversion—associated with less complex defects

 

Abnormal Situs

Abnormalities of situs are encountered on occasion in adult patients. Many cases show situs inversus, a mirror image of the normal arrangement of the viscera or situs solitus. Situs inversus is associated with a normal incidence of other cardiac anomalies. In situs solitus the cardiac apex is usually on the left (levoversion), and in situs inversus the apex is usually on the right (dextroversion). Either situs solitus or inversus can have a midline heart (mesoversion). The terms dextrocardia, levocardia, and mesocardia usually refer to the cardiac position in the thorax, unrelated to the visceral situs. Other cardiac apex locations are associated with an increase in congenital heart defects (Table 19.7). Situs solitus with dextroversion of the heart has a high incidence of associated complex cyanotic defects such as pulmonary atresia or tricuspid atresia. Similarly, situs inversus with levoversion of the heart is associated with complex defects (34). Situs ambiguous, or heterotaxy syndrome, applies to patients with discordant thoracic and abdominal situs (35,36). Heterotaxy syndrome can be discovered in adults without any associated cardiac malformation. However, cardiac anomalies are common (Fig. 19.45).

Patients with situs inversus totalis have no increased incidence of cardiac anomalies.

Dextro-, levo- and mesocardia refer to cardiac position, not situs.

Figure 19.45 Anteroposterior chest radiograph of a 35-year-old patient with heterotaxy syndrome. Cardiac anomalies include a single common atrium and a ventricular septal defect. The cardiac apex (long, open arrow) is on the right (dextroversion), whereas the stomach bubble (arrow) and splenic flexure lie on the left side.

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