Miscellaneous Congenital Heart Diseases

A. Pathology and Pathophysiology

The left coronary artery (LCA) arises abnormally from the main PA. Postnatal decrease in the PA pressure results in ineffective perfusion of the LCA, producing ischemia and infarction of the LV that is normally perfused by the LCA.

B. Clinical Manifestations

• 1.

  The newborn patient is usually asymptomatic until the PA pressure falls to a critical level. Symptoms appear at 2 to 3 months of age and consist of recurring episodes of distress (anginal pain) with signs of CHF. Heart murmur usually is absent.

• 2.

  Chest radiographs show cardiomegaly. The ECG shows anterolateral myocardial infarction pattern consisting of abnormally deep and wide Q waves, inverted T waves, and ST-segment shift in leads I, aVL, and most precordial leads (V2 through V6).

• 3.

  Two-dimensional echo with color flow mapping is diagnostic and has replaced cardiac catheterization. The absence of normal LCA arising from the aorta raises the possibility of the condition. Instead, the LCA is seen to connect to the main PA. Color Doppler examination may show retrograde flow into the main PA from the LCA. The right coronary artery may be enlarged. The left ventricle may enlarge with reduced LV systolic function. Increased echogenicity of papillary muscles and adjacent endocardium suggests fibrosis and fibroelastosis.

• 4.

  Computed tomography (CT) scans show high-resolution definition of coronary artery anatomy.

• 5.

  Cardiac troponin I level may be increased.

C. Management

Medical treatment alone carries a very high mortality (80% to 100%). All patients with this diagnosis need surgery.

• 1.

  Palliative surgery (simple ligation of the anomalous LCA close to its origin from the PA) may be performed in very sick infants to prevent steal into the PA. This should be followed later by an elective bypass procedure.

• 2.

  Most centers prefer definitive surgery unless the patient is critically ill, but the optimal operation remains controversial. One of the following two-coronary system surgeries may be performed.

  • a.

    Intrapulmonary tunnel operation (Takeuchi repair). Initially a 5- to 6-mm AP window is created between the ascending aorta and the MPA at the level of the takeoff of the LCA. In the posterior wall of the MPA, a tunnel is created that connects the opening of the AP window and the orifice of the anomalous LCA. The mortality rate is near 0%, but a rate as high as over 20% has been reported. Late complications of the procedure include supravalvar PA stenosis by the tunnel (75%), baffle leak (52%) causing coronary-PA fistula, and AR.

  • b.

    LCA implantation. In this procedure, 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. The early surgical mortality rate is 15% to 20%.

  • c.

    Tashiro repair. A narrow cuff of the main PA, including the orifice of the LCA, is transected. The upper and lower edges of the cuff are closed to form a new left main coronary artery, which is anastomosed to the aorta. The divided main PA is anastomosed end-to-end.

  • d.

    Subclavian-to-LCA anastomosis. In this technique, the end of the left subclavian artery is turned down and anastomosed end-to-side to the anomalous LCA.

A. Pathology and Pathophysiology

In aortopulmonary septal defect (also known as aortopulmonary [AP] window), a large defect is present between the ascending aorta and the main PA. This condition results from failure of the spiral septum to completely divide the embryonic truncus arteriosus. Unlike persistent truncus arteriosus, two separate semilunar valves are present in this condition.

B. Clinical Manifestations

• 1.

  Clinical manifestations are similar to those of persistent truncus arteriosus and are more severe than those of 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.

• 2.

  The natural history of this defect is similar to that of a large untreated PDA, with development of pulmonary vascular obstructive disease in surviving patients.

C. Management

Prompt surgical closure of the defect under CPB is indicated. The surgical mortality rate is very low.

A. Pathology and Pathophysiology

Coronary artery fistulas occur in one of two patterns:

• 1.

  True coronary arteriovenous fistula. It represents a branching tributary from a coronary artery coursing along a normal anatomic distribution, with blood emptying into the coronary sinus. This type occurs in only 7% of patients.

• 2.

  Coronary artery fistula. In most patients the fistula is the result of an abnormal coronary artery system with aberrant termination. In most cases the fistula terminates in the right side of the heart and the PA (40% in the RV, 25% in the RA, and 20% in the PA).

B. Clinical Manifestations

• 1.

  The patient is usually asymptomatic. A continuous murmur similar to the murmur of PDA is audible over the precordium.

• 2.

  The ECG is usually normal, but it may show T-wave inversion, RVH, or LVH if the fistula is large. Myocardial infarction pattern can occur. Chest radiographs usually show normal heart size.

• 3.

  Echo studies usually suggest the site and type of the fistula. Presence of a massively dilated proximal portion of one coronary artery suggests a coronary artery fistula or an arteriovenous fistula. One can follow the course of the dilated coronary artery to its site of entry.

• 4.

  Often selective coronary artery angiography is necessary for accurate diagnosis before intended intervention.

C. Management

• 1.

  A tiny coronary artery fistula to the main PA (coronary artery-to-PA fistula) that is detected incidentally by an echo study should be left alone. Spontaneous closure may occur in some small fistulae, but some of them may progress and require intervention.

• 2.

  Small fistulous connections in the asymptomatic patient may be monitored.

• 3.

  For moderate or large coronary artery fistula, transcatheter occlusion is reasonable using coils or other occluding devices.

• 4.

  Elective surgery is indicated if not amenable to catheter occlusion. Using CPB, the fistula is ligated as proximally as possible without jeopardizing flow in the normal arteries and also ligated near its entrance to the cardiac chamber. The surgical mortality rate is zero to 5%.

A. Pathology and Pathophysiology

• 1.

  There is direct communication between the PAs and pulmonary veins (PVs), bypassing the pulmonary capillary circulation. It may take the form of either multiple tiny angiomas (telangiectasis) or a large PA-to-PV communication.

• 2.

  About 60% of patients with pulmonary AV fistulas have Osler-Weber-Rendu syndrome. Rarely, chronic liver disease or a previous bidirectional Glenn operation may cause the fistula.

B. Clinical Manifestations

• 1.

  Cyanosis and clubbing are present, with a varying degree of arterial desaturation ranging from 50% to 85%. Polycythemia is usually present. A faint systolic or continuous murmur may be audible over the affected area. The peripheral pulses are not bounding.

• 2.

  Chest radiographs show normal heart size (unlike systemic AV fistula). One or more rounded opacities of variable size may be present in the lung fields. The electrocardiogram (ECG) is usually normal.

• 3.

  The diagnosis can be made through contrast two-dimensional (2D) echo. In this technique, 4 to 10 mL of saline that has been agitated is injected into a peripheral vein while monitoring the appearance of bubbles in the left atrium.

• 4.

  CT typically shows one or more enlarged arteries feeding a serpiginous or lobulated mass, and one or more draining veins. Pulmonary angiography remains the gold standard to determine the position and structure of the fistula prior to intervention.

• 5.

  Stroke, brain abscess, and rupture of the fistula with hemoptysis or hemothorax are possible complications.

C. Management

• 1.

  Transcatheter occlusion is recommended for all symptomatic patients and for asymptomatic patients with discrete lesions with feeding arteries ≥3 mm in diameter.

• 2.

  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.

A. Pathology and Pathophysiology

• 1.

  Systemic AV 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.

• 2.

  The two most common sites of large systemic AV fistulas are the brain and liver.

  • a.

    In the brain, it is usually a large type occurring in newborns in association with a vein of Galan malformation.

  • b.

    In the liver, hemangioendotheliomas (densely vascular benign tumors) are more common than fistulous arteriovenous malformation.

• 3.

  In the large type, cardiomegaly, tachycardia, and even CHF may result because of decreased peripheral vascular resistance and increased stroke volume.