Aneurysm of the Sinus of Valsalva

In aneurysm of the sinus of Valsalva (congenital aortic sinus aneurysm), there is a gradual downward protrusion of the aneurysm into a lower pressure cardiac chamber that eventually ruptures. Most of the aneurysm arises from the right coronary sinus (80%) and less frequently from the noncoronary cusp (20%). When a sinus of Valsalva aneurysm ruptures, a sinus of Valsalva fistula is formed. The fistula communicates most frequently with the right ventricle (RV) (75%) and less frequently with the right atrium (RA) (25%). Associated anomalies are common and include ventricular septal defect (VSD) (50%), aortic regurgitation (AR) (20%), and coarctation of the aorta. This rare anomaly has been reported primarily in the Asian population.

Unruptured aneurysm produces no symptoms or signs. A small sinus of Valsalva fistula may develop without symptoms. The aneurysm usually ruptures during the third or fourth decade of life. The rupture is often characterized by sudden onset of chest pain, dyspnea, a continuous heart murmur over the right or left sternal border, and bounding peripheral pulses. Severe congestive heart failure (CHF) eventually develops. Chest radiography shows cardiomegaly and increased pulmonary vascularity. The ECG may show biventricular hypertrophy (BVH), first- or second-degree atrioventricular (AV) block, or junctional rhythm.

Patients with small- to moderate-sized unruptured aneurysms probably do not need surgery. Unruptured aneurysms of the sinus of Valsalva that produce hemodynamic derangement should be repaired. When the aneurysm of the congenital sinus of Valsalva has ruptured or is associated with a VSD with or without aortic regurgitation, prompt operation is advisable.

Anomalous Origin of the Left Coronary Artery from the Pulmonary Artery (Bland-White-Garland Syndrome, ALCAPA Syndrome)

In anomalous origin of the left coronary artery from the pulmonary artery (PA), the left coronary artery arises abnormally from the PA. Patients usually are asymptomatic in the newborn period until the PA pressure falls to a critical level after birth. The direction of blood flow is from the right coronary artery, through intercoronary collaterals retrogradely, to the left coronary artery, and into the PA. This results in left ventricular insufficiency or infarction.

Symptoms appear at 2 to 3 months of age and consist of recurring episodes of distress (anginal pain), marked cardiomegaly, and CHF. Significant heart murmur usually is absent, with a rare exception of a heart murmur of mitral regurgitation secondary to myocardial infarction. The electrocardiogram (ECG) shows an anterolateral myocardial infarction pattern consisting of abnormally deep and wide Q waves, inverted T waves, and an ST segment shift in leads I and aVL and the left precordial leads (see Fig. 3-27 ). Chest radiography may show cardiomegaly (of the left atrium [LA] and left ventricle [LV]) with or without pulmonary edema in advanced cases. Cardiac enzyme changes probably occur, but the relatively slow development of myocardial infarction and the uncertainty of the exact time of infarction may make it difficult to interpret laboratory data. However, knowledge of cardiac enzyme changes seen in adult cases of myocardial infarction helps in the diagnosis of this condition (see Fig. A-2 ). Cardiac troponin I levels may also increase. The normal level of cardiac troponin I in children is 2 ng/mL or less and is frequently below the level of detection for the assay.

Two-dimensional echocardiography with color-flow mapping is diagnostic and has replaced cardiac catheterization. The presence of normal origin of both the right and left coronary arteries from the aorta should be routinely checked in every echocardiographic study, especially in newborns. The absence of a normal left coronary artery raises the possibility of the condition and thus the diagnosis can be made in the newborn period before symptoms develop. Color Doppler examination may show retrograde flow into the proximal main PA ( Fig. 15-1 ). The right coronary artery may be seen enlarged. The echocardiographic study also shows the size and function of the left heart. Increased echogenicity of papillary muscles and adjacent endocardium suggests fibrosis and fibroelastosis.

Doppler examination in the high parasternal short-axis view (left) and in the high parasternal long-axis view of the right ventricular (RV) outflow tract (right) from an infant with anomalous left coronary artery (ALCA) arising from the pulmonary artery (PA) (thin arrows). Heavy white arrows indicate retrograde (red) flow into the main PA from the ALCA as shown in both the frames. AO, aorta; LV, left ventricle.

(From Snider AR, Serwer GA, Ritter SB. Echocardiography in Pediatric Heart Disease. Second Edition, 1997, Mosby, Philadelphia, Used with permission.) (see Expert Consult for the color figure).

Computed tomography (CT) scans show high-resolution definition of coronary artery anatomy. The use of rapid acquisition (64-detector) scanners and pharmacologic slowing of the heart rate (with beta-blockers), especially in small infants, may be necessary to increase the ability to diagnose the condition.

Management

Medical treatment alone carries an unacceptably high mortality (80%–100%). Therefore, all patients with this diagnosis need operation. The optimal operation in infancy remains controversial, but most centers prefer definitive surgery unless the patient is critically ill.

Palliative Surgery

In critically ill infants, simple ligation of the anomalous left coronary artery close to its origin from the PA may be performed to prevent steal into the PA. This should be followed by a later elective bypass procedure (as described below).

Definitive Surgery

Even for infants who are critically ill, many centers prefer to create a two-coronary system by performing one of the following procedures.

Intrapulmonary Tunnel Operation (Takeuchi Repair)

Intrapulmonary tunnel operation is the most popular among two-coronary repair surgeries ( Fig. 15-2 ). Two circular openings are made in the contiguous wall of the aorta and the pulmonary trunk, and a 5- to 6-mm aortopulmonary window is created by suturing together these two openings. Two horizontal incisions are made in the anterior wall of the PA directly over the aortopulmonary window to create the flap of the PA wall. The flap is sutured in the posterior wall of the PA, and a tunnel is created that connects the opening of the aortopulmonary window and the orifice of the anomalous left coronary artery. The opening in the anterior wall of the PA is closed by a piece of pericardium. The mortality rate is near 0% but as high as more than 20% has been reported. Late complications of the procedure include supravalvular PA stenosis (75%), baffle leak (52%) causing coronary–PA fistula, and aortic insufficiency.

Intrapulmonary artery tunnel repair for anomalous origin of the left coronary artery (LCA) from the pulmonary artery (PA) (Takeuchi repair). A, Two dashed lines on the anterior wall of the PA are the proposed incision sites to create a flap of the PA. B, An aortopulmonary shunt is created after a punch hole (5–6 mm in size) is made in the contiguous wall of the aorta (Ao) and PA. C, The flap of the PA is sutured in place to form the convex roof of a tunnel through which aortic blood passes to the anomalous orifice of the left coronary artery. D, A piece of pericardium is used to close the opening in the anterior wall of the PA. E, Cross-sectional view of the tunnel operation when completed. LV, left ventricle; RA, right atrium; RV, right ventricle.

Left Coronary Artery Implantation

Left coronary artery implantation, with direct transfer of the anomalous left coronary artery into the aortic root, appears to be the most advisable procedure, but it is not always possible. The anomalous coronary artery is excised from the PA along with a button of PA wall, and the artery is reimplanted into the anterior aspect of the ascending aorta. If the direct implantation may result in excessive tension in the coronary artery, flaps can be developed from the anterior main PA wall and ascending aorta. These flaps are sutured to form a tube extension for the left coronary artery, which is then implanted to the aorta. The early surgical mortality rate is 15% to 20%.

Tashiro Repair

Tashiro and colleagues (1993) reported a repair technique that was performed in adult patients. In this procedure, a narrow cuff of the main PA, including the orifice of the left coronary artery, is transected; the upper and lower edges of the cuff are closed to form a new left main coronary artery; and the aorta and the newly created left coronary artery are anastomosed side to end. The divided main PA is anastomosed end to end. This creates no obstruction to the PA. This technique has a potential application in the pediatric population, including small infants.

Subclavian–to–Left Coronary Artery Anastomosis

In subclavian–to–left coronary artery anastomosis, the end of the left subclavian artery is turned down and anastomosed end to side to the anomalous left coronary artery through a left thoracotomy approach. Aortic cross-clamping, which could be the source of ventricular impairment with postoperative low cardiac output and a high mortality rate, is avoided.

The need for simultaneous mitral valve reconstruction at the time of definitive surgery is controversial because spontaneous improvement of mitral regurgitation (MR) occurs after surgical revascularization. After successful two-coronary artery repair, LV systolic function and heart failure improve markedly, and the severity of the MR also decreases. Even the infarct pattern on ECG may eventually disappear.

Aortopulmonary Septal Defect

In aortopulmonary septal defect (also known as aortopulmonary window, aortopulmonary fenestration), a large defect is present between the ascending aorta and the main PA ( Fig. 15-3 ). This condition results from failure of the spiral septum to completely divide the embryonic truncus arteriosus.

Diagram of aortopulmonary window ( A ) and persistent truncus arteriosus ( B ). These two conditions are similar from a hemodynamic point of view. Anatomically, however, there are two separate semilunar valves (aortic valve [AoV] and pulmonary valve [PV]) without associated ventricular septal defect (VSD) in aortopulmonary window, but there is only one truncal valve (TV) with associated VSD in persistent truncus arteriosus. AO, aorta; PA, pulmonary artery.

Hemodynamic abnormalities are similar to those of persistent truncus arteriosus and are more severe than those of patent ductus arteriosus (PDA). CHF and pulmonary hypertension appear in early infancy. Peripheral pulses are bounding, but the heart murmur is usually of the systolic ejection type (rather than continuous murmur) at the base.

The natural history of this defect is similar to that of a large untreated PDA, with development of pulmonary vascular disease in surviving patients. This defect has no known tendency to close spontaneously. Prompt surgical closure of the defect under cardiopulmonary bypass is indicated when the diagnosis is made. The surgical mortality rate is very low.

Arteriovenous Fistula, Coronary

Coronary artery fistulas are the most common congenital anomalies of the coronary artery, representing nearly half of all coronary artery anomalies. It can be isolated or associated with other CHDs, such as tetralogy of Fallot (TOF), atrial septal defect (ASD), PDA, and VSD. The right coronary artery is much more frequently involved than the left, and rarely both coronary arteries are involved.

These fistulas occur in one of two patterns.

• 1.
  

  “True” coronary arteriovenous fistula. This pattern occurs in only 7% of the cases of coronary fistulas ( Fig. 15-4 ). This fistula involves a branching tributary from a coronary artery coursing along a normal anatomic distribution and eventually entering into the coronary sinus.

  
  

  
  

  
  

  

  
  

  
  

  Aortogram showing coronary arteriovenous fistula in the distribution of the left circumflex artery (solid arrows). A, Anteroposterior projection. B, Lateral projection. The fistula empties through the coronary sinus (cs) and eventually into the right atrium (RA). The point of entry into the RA is marked by an open arrow. AO, aorta.

  
  
  
  
• 2.
  

  Coronary artery fistula (or coronary-cameral fistula). In the majority of cases (>90% of patients), the coronary fistula results from an abnormal coronary artery system with aberrant termination rather than true arteriovenous fistula. The right coronary is most commonly involved in coronary artery fistula. In more than 90% of reported cases, the fistula terminates in the right side of the heart (either to the RV or the PA; less commonly to the RA). It rarely terminates in the left side of the heart, but when it does, the majority enters the LA.

Patients usually are asymptomatic. However, congestive heart failure may develop if the shunt through the fistula is large. With a significant shunt, a continuous murmur, similar to the murmur of PDA, is audible over the precordium (rather than in the left infraclavicular area). The ECG usually is normal but may show right ventricular hypertrophy (RVH) or left ventricular hypertrophy (LVH) if the fistula is large. Chest radiography shows a normal heart size.

Echocardiographic studies usually suggest the sites and types of the fistulas. The presence of a massively dilated proximal portion of one coronary artery while the other coronary artery is of normal size suggests coronary artery or arteriovenous fistula. The dilatation is usually uniform. One can follow the course of the dilated coronary artery to its site of entry. The site of entry can usually be located with the help of color Doppler echocardiography by the detection of either continuous or diastolic high-velocity flow. Often selective coronary artery angiography is necessary for an accurate diagnosis before the intended intervention. If the flow through the fistula is large, then the chamber or vessel receiving the fistula will be dilated.

A tiny coronary artery fistula to the PA (coronary artery–to-PA fistula) that produces no symptom can only be detected incidentally by an echocardiographic study. Most children with this condition are asymptomatic. Spontaneous closure may occur in small fistulae. However, some patients may present with symptoms of dyspnea on exertion, increased fatigability, and possibly signs of high-output congestive heart failure. Rarely, adult patients may present with angina, palpitation, or signs of exercise-related coronary insufficiency.

Small fistulous connections in the asymptomatic patient may be monitored. For a moderate or large coronary artery fistula, transcatheter occlusion is reasonable using coils or other occluding devices. Elective surgery is indicated if not amenable to catheter occlusion. Using cardiopulmonary bypass, the fistula is ligated as proximal as can be done without jeopardizing flow in the normal arteries, and it is ligated near its entrance to the cardiac chamber. The surgical mortality rate is 0% to 5%.

Arteriovenous Fistula, Pulmonary

In this condition, the pulmonary arteries and veins communicate directly, bypassing the pulmonary capillary circulation. The fistulas may take the form of either multiple tiny angiomas (telangiectasis) or a large PA–to–pulmonary vein (PV) communication. About 60% of patients with pulmonary arteriovenous fistulas have hereditary hemorrhagic telangiectasis (Rendu-Osler-Weber syndrome), and 5% to 15% of patients with the syndrome have the fistula (see Table 2-1 ). Patients who have undergone a bidirectional Glenn operation are at risk of developing multiple pulmonary arteriovenous fistulas, although these malformations rarely occur after completion of a Fontan operation. This finding suggests that pulmonary circulation requires as yet undetermined hepatic factors, possibly vasoconstrictor prostaglandins, to suppress the development of arteriovenous malformations. Similarly, chronic liver disease can rarely be the cause of the arteriovenous fistula.

Desaturated systemic blood from the PAs reaches the PVs, bypassing the lung tissue, resulting in systemic arterial desaturation, cyanosis, and clubbing. The pulmonary blood flow and pressure remain unchanged, and there is no volume overload to the heart, unlike in systemic AV fistulas.

Physical examination may reveal cyanosis and clubbing. The peripheral pulses are not bounding. A faint systolic or continuous murmur may be audible over the affected lung in about 50% of patients. Polycythemia usually is present, and arterial oxygen saturation runs between 50% and 85%. Chest radiography shows normal heart size because there is no volume overload to the heart in pulmonary AV fistulas. One or more rounded opacities of variable size may be present in the lung fields. The ECG usually is normal. Occasional complications include stroke, brain abscess, rupture of the fistula with hemoptysis or hemothorax, and infective endocarditis.

The diagnosis can be made through contrast two-dimensional echocardiography by the appearance of microcavitations (bubbles) in the LA. In this technique, 4 to 10 mL of saline that has been agitated is injected into a peripheral vein while the appearance of bubbles in the atria is monitored. The bubbles appear first in the RA, and within 2 cardiac cycles, they appear in the LA. CT typically shows one or more enlarged arteries feeding a serpiginous or lobulated mass and one or more draining veins. Magnetic resonance imaging (MRI) has not been studied as much as CT in children. Pulmonary angiography remains the gold standard to determine the position and structure of abnormal vascular lesions in the lung before treatment.

Transcatheter occlusion is recommended for all symptomatic patients and for asymptomatic patients with discrete lesions with feeding arteries 3 mm or larger in diameter. Transcatheter occlusion has been proved to be effective with excellent long-term results. Diffuse microscopic pulmonary AV malformations are not amenable to transcatheter occlusion. Surgical resection of the lesions, with preservation of as much healthy lung tissue as possible, may be attempted in symptomatic children, but the progressive nature of the disorder calls for a conservative approach.

Arteriovenous Fistula, Systemic

Systemic arteriovenous fistulas may be limited to small cavernous hemangiomas or may be extensive. In large AV fistulas, there is direct communication (either a vascular channel or angiomas) between the artery and a vein without the interposition of the capillary bed. The two most common sites of systemic arteriovenous fistulas are the brain and liver. In the brain, it is usually a large type occurring in newborns in association with a vein of Galan malformation. In the liver, either localized or generalized hemangioendotheliomas (densely vascular benign tumors) are more common than fistulous arteriovenous malformations. With a large fistula, because of decreased peripheral vascular resistance, an increase in stroke volume (with a wide pulse pressure) and tachycardia result, leading to increased cardiac output, volume overload to the heart, and even CHF.

Physical examination reveals a systolic or continuous murmur over the affected organ. An ejection systolic murmur may be present over the precordium because of increased blood flow through the semilunar valves. The peripheral pulses may be bounding during the high-output state but weak when CHF develops. A gallop rhythm may be present with CHF. Chest radiography may show cardiomegaly and increased pulmonary vascular markings with a large fistula. The ECG may show hypertrophy of either or both ventricles.

Most patients with large cerebral arteriovenous fistulas and CHF die in the neonatal period, and surgical ligation of the affected artery to the brain is rarely possible without infarcting the brain. Surgical treatment of hepatic fistulas is often impossible because they are widespread throughout the liver. However, hemangioendotheliomas often eventually disappear completely. Large liver hemangiomas have been treated with corticosteroids, aminocaproic acid, local radiation, or partial embolization, but the beneficial effects of these management options are not fully established. Catheter embolization is becoming the treatment of choice for many symptomatic patients with AV fistula.

Atrial Septal Aneurysm

An aneurysmal tissue is present in part or all of the atrial septum that shows phasic septal excursion (of 10–15 mm in an adult) protruding into either atria. Atrial septal aneurysm (ASA) is present in 4% of the neonate using a different criterion (of marked mobility of the atrial septum). The prevalence of ASA varies between 0.2% and 1.9% of normal adult patients and up to 8% to 15% of adult stroke patients by transesophageal echocardiographic studies. It is commonly associated with patent foramen ovale (PFO), and together they might play a role in cryptogenic stroke in adult patients. ASA may prove to be a cause of atrial arrhythmias in some patients. See the section on PFO later in this chapter for further discussion of PFO or ASA versus stroke.