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Late Presentation of an Anomalous Origin of the Left Coronary Artery from the Pulmonary Artery: Case Report and Review
ABSTRACT: Anomalous origin of the left coronary artery (LCA) from the pulmonary artery (ALCAPA) is a rare cause of ischemia, heart failure and/or sudden death. A premortem diagnosis beyond early childhood is exceedingly rare because over 90% of untreated infants die in the first 12 months of life. We present a case of an asymptomatic fourteen-year old male with ALCAPA diagnosed by multidetector computed tomography (MDCT) angiography, who was successfully treated by surgical coronary transfer of the ALCAPA with reimplantation of the LCA to the aortic root.
J INVASIVE CARDIOL 2008;20:564–566
Case Report: A 14 year-old male without significant past medical history was referred to our clinic for evaluation of a 3-month history of intermittent atypical, brief, stabbing left-sided chest pain not associated with exertion. He reported being an active child and had no previous limitations of chest pain or dyspnea during moderate exercise activity. He was not taking any medications and denied tobacco, alcohol or illicit drug use. There was a significant family history of early coronary artery disease, but no heart failure or sudden death. Physical examination revealed a well-developed, well-nourished, normotensive male in no apparent distress. Cardiopulmonary examination revealed a regular rate and rhythm without a gallop. There was a soft, systolic murmur and a holodiastolic murmur noted at the mid-left sternal border. His lungs were clear bilaterally and peripheral pulses were normal in all extremities. A 12-lead electrocardiographic transthoracic echocardiogram showed normal biventricular systolic function with mild right ventricular enlargement. Both right and left coronary arteries appeared significantly dilated with turbulent, increased flow apparent on color Doppler interrogation. The origin of the left main coronary artery (LMCA) was not visualized. Cardiac CTA was performed, which clearly demonstrated an anomalous origin of the left coronary artery (LCA) from the posterior aspect of the main pulmonary artery (MPA) (Figure 1) and significant dilatation of the epicardial coronary vessels. The patient underwent a standard Bruce-protocol treadmill stress test with significant >2mm ST-segment depression during exercise and into recovery. The patient underwent coronary angiography which further confirmed that the LCA was supplied through aneurysmal collateral branches from the RCA with retrograde filling of the LCA and MPA (Figure 2).
At the time of surgery, following introduction of antegrade cardioplegia, the MPA was opened anteriorly and the LCA was identified. A generous “button” of tissue was taken around the LCA and was re-implanted at the posterior sinus of the aortic valve. The MPA was reconstructed using a piece of autologous pericardium. There were no peri- or post-operative complications and the patient was discharged home in stable condition on the sixth day following surgery. A follow-up treadmill myocardial perfusion stress test five months following the surgery was normal, and the patient remains asymptomatic one year later.
Discussion. Congenital coronary artery anomalies occur in less than 1–2% of births and are seen in approximately 1% of adults undergoing coronary arteriography.1,2 Many of these variations are benign and are discovered incidentally, but others have been implicated in chest pain, dyspnea, cardiomyopathy, myocardial infarction, ventricular fibrillation and sudden death.3–5 Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA), often referred to as Bland-Garland-White syndrome,6 is a rare cause of heart failure, angina or sudden death as it occurs in approximately 1 in 300,000 children.7 If undiagnosed or untreated, most infants die within the first year of life, and untreated survival beyond infancy is dependent upon adequate collateral circulation from the RCA or another source. Rarely, these lesions are tolerated well in the neonate, as the pulmonary vascular resistance is still elevated, leading to high-pressure antegrade flow down the LCA. However, as the pulmonary vascular resistance decreases between 6 to 12 weeks of life, coronary perfusion reverses, and the LCA perfusion becomes retrograde from the RCA and various collateral circulations with poorly-oxygenated blood and/or via a coronary steal phenomenon.4,5
Infants then present with failure to thrive, profuse sweating, dyspnea and/or pallor. Patients with ALCAPA often present with heart failure (mitral valve insufficiency and left ventricular dysfunction) during the first several weeks of life, but some may remain symptomatic if sufficient collateral blood flow from the RCA or other sources is available. Yet, even in patients who survive into adulthood, malignant arrhythmias leading to sudden death is common.7,8
Upon diagnosis, ALCAPA mandates surgical correction regardless of the presence of symptoms, yet carries a high risk of postoperative heart failure and death.9 Previous surgical approaches included ligation of the anomalous LCA with subclavian artery bypass grafting10 or creation of an intrapulmonary conduit/baffle from the anomalous left coronary ostia to the aorta (Takeuchi procedure).11,12 Current surgical technique favors establishment of two “normal-configuration” main epicardial coronary vessels via reimplantation (coronary transfer) of the LCA to the aorta, with or without elongation with a pulmonary artery or pericardial patch or tunneling of the LCA to the aorta.13–17 The operative mortality rate of current techniques range from 0–23%,14 but the natural history of these “corrected” ALCAPAs is still unknown.
In conclusion, ALCAPA is an uncommon congenital anomaly of coronary arteries that is associated with a high degree of morbidity and mortality. An asymptomatic presentation after infancy is very rare. To our knowledge, this is the first reported case of diagnosis of ALCAPA in an asymptomatic young adult by multidetctor CT angiography. This case demonstrates: 1) the importance of a detailed cardiopulmonary physical examination, even in an asymptomatic young adult; 2) the ability of MDCT angiography to accurately delineate this complex anatomy;18 and 3) excellent surgical results from a direct anastomosis of the ALCAPA to the aortic root.