Background
Anomalous left coronary artery from the pulmonary artery (ALCAPA), or Bland-White-Garland syndrome, [1] is a rare but very significant lesion that requires prompt recognition and diagnosis. In most patients with this condition, the origin of the left main coronary artery abnormally originates from the posterior or leftward sinus of the pulmonary artery. Less commonly, the anomalous coronary artery arises from the right pulmonary artery. The branching of the anomalous left coronary artery is typically normal, with normal left anterior descending and circumflex coronary arteries. The origin of the right coronary artery is also normal; however, this vessel is usually enlarged and tortuous. With early diagnosis, the prognosis of ALCAPA is excellent after surgical repair.
ALCAPA affects 1 in 300,000 live US births, representing approximately 0.24-0.46% of congenital heart defects. [2, 3] No data are available to suggest variance in the frequency of this condition in different countries or between social, economic, or ethnic groups.
History of the Procedure
Early surgical intervention for repair of an anomalous left coronary artery from the pulmonary artery (ALCAPA) were palliative, including, but not limited to, the following procedures [3] :
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1953: An aortopulmonary anastomosis to increase oxygen saturation in the main pulmonary artery (Potts); a left carotid artery–to–anomalous left coronary artery procedure (Mustard) [4]
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1959: Simple ligation of the proximal origin of the anomalous left coronary artery (Sabiston et al) [5]
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1966: Saphenous vein grafting from the aorta to the anomalous left coronary artery (Cooley et al) [6]
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1968: A left subclavian artery–to–anomalous left coronary artery repair (Meyer et al) [7]
An internal mammary artery–to–ALCAPA procedure has also been performed. [8] Pulmonary artery banding has been attempted to increase perfusion pressure in the anomalous left coronary artery from the pulmonary artery. [9] In addition, procedures to increase collateral circulation, such as poudrage and de-epicardialization, have been tried. [10]
Each of the above procedures has fallen out of favor. At present, establishing a system with today coronary arteries is the goal in definitive surgical repair.
Direct anastomosis of the ALCAPA directly to the aorta has been the procedure of choice since the 1970s. [3] The experience gained in coronary artery transfer during the arterial switch operation has facilitated techniques for coronary transfer to repair the ALCAPA. In most patients, the anomalous left coronary artery is situated in a position that allows for direct transfer of the anomalous coronary artery. When direct transfer of the coronary artery is not feasible, it may be appropriate to create an intrapulmonary aortocoronary tunnel (Takeuchi procedure/repair). [11]
Some patients with ALCAPA and severe cardiac dysfunction may need to undergo cardiac transplantation.
Pathophysiology
The pathophysiology of anomalous left coronary artery from the pulmonary artery (ALCAPA) varies and depends on the patient's age, the pulmonary vascular resistance/pressure, the presence of collateral vessels between the right and left coronary artery systems, and the degree of myocardial ischemia. Four physiologic stages have been described, as outlined below.
Stage 1
In the fetal and early neonatal period, pulmonary vascular resistance is high and pulmonary artery pressure is equal to the aorta pressure. Saturation and perfusion in the ALCAPA are adequate, and no obvious myocardial ischemia or impairment of left ventricular function is observed.
Stage 2
During the first days to weeks of neonatal life, pulmonary vascular resistance normally decreases. The drop in pressure is inadequate to provide prograde flow into the ALCAPA.
Flow to the left coronary system is provided by collateral flow from the right coronary artery system. At this time, flow in the ALCAPA is retrograde.
Collateral flow from the right coronary artery system meets the high resistance of the left ventricular myocardial bed, and preferential flow occurs into the low-resistance pulmonary artery. This leads to the development left ventricular myocardial ischemia. At this time, infants may present with clinical signs of myocardial ischemia.
With the retrograde flow of fully saturated blood into the pulmonary artery, a small left-to-right shunt may be present, detected on cardiac catheterization by a "step up" in oxygen saturation in the pulmonary artery. Usually, the shunt is minimal, and the ratio of pulmonary blood flow (Qp) to systemic blood flow (Qs) ranges from 1 to 1.5.
Stage 3
Rarely, a large collateral circulation may be located between the right and left coronary systems, which may provide adequate myocardial perfusion, allowing infants to have little or no clinical difficulties. These extensive collateral vessels can provide enough coronary flow to allow patients to live to adulthood.
Stage 4
In the final stage, collateral flow is inadequate, retrograde flow into the pulmonary artery persists, and myocardial steal continues. At this stage, adults may present with signs of myocardial ischemia.
Myocardial ischemia
Myocardial ischemia occurs in an anterolateral distribution, resulting in global left ventricular dilatation and dysfunction. Mitral valve regurgitation is common secondary to papillary muscle infarction, mitral annular dilation, or both. Left atrial dilation and pulmonary venous congestion ensue, adding congestive symptoms to those of angina pectoris.
Etiology
The coronary arterial circulation is established by 45 days' gestation in the fetus. Anomalous left coronary artery from the pulmonary artery (ALCAPA) is caused either by abnormal division of the conotruncus or by abnormal involution of endothelial buds that are present on all six sinuses of Valsalva of the great vessels. Usually, all but two of the endothelial buds involute, leaving two buds in the aortic sinuses to eventually become the coronary arteries. With ALCAPA, an endothelial bud sometimes persists on a pulmonary sinus and attaches to the developing left main coronary artery. The left coronary artery can also connect to other locations in the pulmonary artery and has even been reported to connect to one of the branch pulmonary arteries.
Although ALCAPA typically occurs as an isolated defect, it has been associated with congenital defects, including ventricular septal defect, patent ductus arteriosus, and coarctation of the aorta. [3] One case report documented ALCAPA in a patient with hypoplastic left heart syndrome. [12]
Presentation
Historically, the defect of anomalous left coronary artery from the pulmonary artery (ALCAPA) was termed Bland-Garland-White syndrome. In 1933, Bland et al first eloquently described the clinical presenting signs in infants with ALCAPA. [1] The following description is of a 10-week-old infant:
…while nursing from the bottle, the onset of an unusual group of symptoms occurred, which consisted of paroxysmal attacks of acute discomfort precipitated by the exertion of nursing. The infant appeared at first to be in obvious distress, as indicated by short expiratory grunts, followed immediately by marked pallor and cold sweat with a general appearance of severe shock. Occasionally, with unusually severe attacks, there appeared to be a transient loss of consciousness… [1]
Symptoms
Infants present with respiratory distress, feeding intolerance, or failure to thrive. In the rare case involving an older child or adult, the patient may have exertional chest pain, dyspnea, or syncope. Unfortunately, sudden death occurs in some patients following exertion.
Signs
Upon physical examination, infants have an enlarged heart and displaced apical impulse. A gallop rhythm or the holosystolic murmur of mitral regurgitation may be present. Signs of congestive heart failure may be apparent.
The clinical signs of ALCAPA are nonspecific. Myocarditis and cardiomyopathy are other considerations in infants presenting with left ventricular dilation and heart failure. Careful evaluation for the presence of ALCAPA is necessary in any infant presenting with left ventricular dilatation and heart failure.
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A 3-month-old child presented with anomalous left coronary artery from the pulmonary artery (ALCAPA). Note the large prominent Q waves in leads I, aVL, and V4-V6.
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This is a parasternal long-axis view, two-dimensional echocardiogram of the pulmonary artery. The anomalous left coronary artery and first-order branches of the anomalous left coronary artery (LCA) are identified.
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This is also a parasternal long-axis view, two-dimensional echocardiogram. A very dilated left ventricle (LV) with mitral regurgitation is noted.
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This is a parasternal long-axis view, two-dimensional, color-flow Doppler echocardiogram. Normal flow is noted in the pulmonary artery, but note the abnormal retrograde flow (*) in the anomalous left coronary artery from the pulmonary artery (ALCAPA).
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This is a parasternal short-axis view, two-dimensional, color-flow Doppler echocardiogram. Normal antegrade flow in the proximal right coronary artery (RCA) is observed.
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This is a modified parasternal, long-axis echocardiogram with color-flow Doppler. Abnormal retrograde flow in the left anterior descending (LAD) coronary artery is seen. LV = left ventricle; RV = right ventricle.
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This is an apical four-chamber two-dimensional echocardiogram. Note the very dilated left atrium and left ventricle. LA = left atrium; LV = left ventricle; RA = right atrium; RV = right ventricle.
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This is an intraoperative transesophageal, transverse plane, four-chamber view, two-dimensional, color-flow Doppler sonogram. Note the dilated left atrium, dilated left ventricle, and mitral regurgitation. LV = left ventricle; RV = right ventricle.
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This is an intraoperative transesophageal, transverse plane, two-dimensional sonogram showing the main pulmonary artery (MPA) with origin of the anomalous left coronary artery. Note the first-order branching into the left anterior descending (LAD) and circumflex coronary arteries. LMAC = left main coronary artery.
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This is an intraoperative transesophageal, transverse plane, two-dimensional, color-flow Doppler ultrasound image demonstrating the main pulmonary artery (MPA) with origin of the anomalous left coronary artery. Abnormal retrograde flow is noted in the left anterior descending (LAD) coronary artery. LMAC = left main coronary artery.
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This is an intraoperative transesophageal, transverse plane, two-dimensional ultrasound image. It reveals completed repair of the left main coronary artery (LMCA) anastomosed to the aorta. LAD = left anterior descending coronary artery.
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This is an intraoperative transesophageal, transverse plane, two-dimensional, color-flow Doppler ultrasound image. Note the completed repair with normal antegrade flow in the circumflex and left anterior descending (LAD) coronary arteries. LMCA = left main coronary artery.
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Intraoperative photograph. (1) A cardioplegia catheter in the ascending aorta. (2) A cross-clamp on the ascending aorta. (3) A cross-clamp on the main pulmonary artery. (4) An arterial bypass cannula in the main pulmonary artery. (5) A cardioplegia catheter in the main pulmonary artery. (6) The dilated conal branch of the right coronary artery. (7) A venous bypass cannula in the right atrial appendage. (8) A left heart vent.
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Intraoperative photograph. (1) A transverse anterior incision in the main pulmonary artery trunk. (2) A probe is in the orifice of the anomalous left coronary artery.
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Intraoperative photograph. (1) The divided distal main pulmonary artery. (2) The left coronary artery button. (3) The divided proximal main pulmonary artery.
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Intraoperative photograph. (1) The left coronary artery button. (2) The divided proximal main pulmonary artery. (3) A bypass sucker in the transverse aortotomy (to visualize the aortic sinuses). (4) An incision in the aortic sinus for the site of the aortocoronary anastomosis.
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Intraoperative photograph. (1) Completing the anastomosis of the left coronary artery to the aortic sinus. (2) The divided proximal main pulmonary artery.
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Intraoperative photograph. (1) The completed anastomosis of the left coronary artery to the aortic sinus. (2) The divided proximal main pulmonary artery. (3) The ascending aorta, transverse aortotomy.
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Intraoperative photograph. (1) Suture closure of the aortotomy.
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Intraoperative photograph. (1) The distal divided main pulmonary artery. (2) Beginning the reanastomosis (posterior wall) of the main pulmonary artery. (3) The proximal main pulmonary artery.
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Intraoperative photograph. (1) The completed repair of the main pulmonary artery reanastomosis.