Congenital Atresia of the Ostium of Left Main Coronary Artery:A Rare Coronary Anomaly, Diagnostic Difficulty and SuccessfulSurgical Revascularization

Philip Varghese, MRCS, Ranjit U. Leanage, FRCP, and Giles J. Peek, FRCS, CTh

University Hospital of Leicester NHS Trust—Department of Cardiothoracic Surgery, Leicester, UK

A B S T R A C T

We report the case of an 8-month-old infant who was referred for mechanical circulatory support (extracorporealmembrane oxygenation). Aortogram was compatible with the diagnosis of anomalous origin of left coronary arteryto pulmonary trunk. A definitive diagnosis of atresia of the left coronary ostium was only established intraoperatively.Patient underwent successful surgical angioplasty with an autologous pericardial patch.

Key Words. Coronary Arteries; Congenital Anomalies; Coronary Ostial Atresia; Myocarditis; Cardiomyopathy;Surgical Coronary Angioplasty

Introduction

Anomalies of the coronary arteries areextremely rare, occurring in only 0.2–1.2% of

the population.1 Isolated atresia of the ostium ofthe left main coronary artery is a rare cardiacanomaly with an incidence of 0.01–0.04%.2

We report the case of an infant referred to ourcenter for mechanical circulatory support (extra-corporeal membrane oxygenation—ECMO).

An 8-month-old, male infant was referred toour intensive care unit with a diagnosis ofmyocarditis/cardiomyopathy. Over the preceding4 weeks, he had a constant cough, attributed to aviral illness, but remained well. There was suddenrapid deterioration in his clinical condition withrespiratory distress requiring admission. ChestX-ray on admission showed pulmonary edema andechocardiography demonstrated a dilated, poorlyfunctioning left ventricle. He was referred to ourunit for further investigation and treatment with adiagnosis of viral myocarditis. Electrocardiograph(ECG) showed sinus rhythm and right bundlebranch block. While in hospital, he sustained 2cardio respiratory arrests. There was initial im-provement with positive pressure ventilation andionotropes. Eleven days after initial presentation,he developed sudden crashing left heart failurewith frank pulmonary hemorrhage, needingurgent cannulation for veno-arterial ECMO (VA

ECMO) and urgent balloon atrial septostomy todecompress the left atrium. There was no changein the ECG following ECMO cannulation.Although a previous echocardiogram had excludedanomalous origin of left coronary artery to pulmo-nary trunk (ALCAPA), repeat echocardiogramshowed some dropout between the aorta and theleft coronary. An aortogram performed showed asingle large right coronary artery arising from theaorta with collaterals filling the left main coronaryartery and no filling of the pulmonary artery, find-ings consistent with diagnosis of ALCAPA in apatient on ECMO (Figure 1). A surgical correc-tion of the anomaly was undertaken.

The operation performed under cardiopulmo-nary bypass using VA ECMO cannula revealedapical myocardial infarction, a large right coronaryartery, normal-sized left main coronary arterybranching to circumflex, and left anterior descend-ing artery. The site of left coronary artery origincould not be clearly seen. Transection of the mainpulmonary artery distally failed to reveal the coro-nary ostium; however, reflecting the main pulmo-nary artery anteriorly to expose the left maincoronary artery revealed it to be arising posteriorlyfrom the aorta. The aorta was transected to displaya dimple in the position of the normal left coro-nary ostium. The aorta was split down to theostium and the incision extended across thestenotic area down to about half the length of

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the left main coronary artery (Figure 2). Theatretic membrane was excised and an autologouspericardial patch was sewn into the arteriotomy toreconstruct the atretic ostium of left main coro-nary artery. Further cardioplegia, administeredintraoperatively by direct cannulation of the rightcoronary could be seen refluxing from the leftcoronary ostium. The restrictive persistent fora-men ovale in the atrial septum was enlarged byresecting a small wedge of the limbus with the aimof future interventional correction.

He required 144 hours on ECMO, 39 days ofintensive care, and 46 days in hospital. At a monthof follow-up, he remained well. Follow-up aorto-gram at 3 months showed good filling of bothcoronary arteries (Figure 3).

Discussion

Congenital atresia of the ostium of left main coro-nary artery is an extremely rare condition. Thereare only 42 cases (including the present case)reported so far in the literature.

In congenital atresia of the ostium of left maincoronary artery, a single right coronary artery sup-plies the entire heart with the flow in the leftanterior descending and the circumflex arterybeing centripetal and therefore retrograde depen-dent on collateral supply from the right coronaryartery. The collateral channels are through thecircle of Vieussens, which include the conal artery,interseptal, apical-anterior, and posterior ven-tricular anastomosis.3 The ostium of the left coro-

Figure 1. Preoperative aortogram—single large right coronary artery (RCA) with collaterals filling the left main coronaryartery (LMCA) and no filling of the pulmonary artery.

Figure 2. Scheme of angioplasty for atresia of the ostium of left main coronary artery—incision in the aorta extending acrossthe atretic ostium into the LMS, closed with an autologous pericardial patch after excision of the atretic membrane. LCA, leftcoronary artery; LMS, left main stem; RCA, right coronary artery.

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nary artery is absent and the proximal left maintrunk ends blindly. The left anterior descendingand the circumflex arteries are located in thenormal anatomic position and connect in the usualfashion.

There is debate on the etiology with systemic orinfectious etiologies suggested for both the con-genital and even the acquired cases. It may beassociated with other cardiac defects. From clinicalviewpoint, congenital atresia of the ostium of leftmain coronary artery can be classified as infantileor adult. Koh et al.4 found only 1/12th of thesymptomatic cases presented during childhoodwith half of these seen during infancy and adoles-cence and 1/3rd in adult life. Infants mostly pre-sented with failure to thrive, cardiomyopathy5 andmyocardial infarction where as children and ado-lescents often have syncope and tachyarrhythmia.Adults usually became symptomatic at an ad-vanced age with angina pectoris.

In true congenital atresia of the ostium of leftmain coronary artery, there is no coronary orificeand the left main trunk with a blind proximalsegment continues as the anterior descending andthe circumflex arteries.3,4 The main segment mayconsist of a fibrous band,6 an impervious cord or adiminutive twig. The ostium may be entirely absentwithout a trace,4 or represented by a dimple in theinner aspect of the aorta,6 or as a blind pouch.

It would seem logical from a functional viewpoint to consider the condition to fit into the des-ignation of single coronary artery;7 however, some

would differ.3 The view is based on the differencein clinical presentation and the different patternsof myocardial perfusion. In single coronary artery,there is adequate perfusion because of major anas-tomosis in the atrio ventricular groove with theblood flow to the left main coronary artery beingcentrifugal or anterograde. The condition is usu-ally asymptomatic in the absence of coexisting ath-erosclerosis or aortic stenosis. With congenitalatresia of the ostium of left main coronary artery,the collateral supply from the right coronaryartery to the left main coronary artery territorytakes place in the region of the apex of the heart.The flow between the distal small vessels is inad-equate leading to ischemia and symptomaticcardiac disease or sudden death.

Congenital atresia of the ostium of left maincoronary artery carries an unfavorable prognosis.Surgical revascularization is the best choice forboth symptomatic and asymptomatic patients.Coronary artery bypass graft (CABG) seems to bethe procedure of choice in adults. Long-termresults of CABG in children in questionablealthough good response have been reported.8,9

Surgical angioplasty in children is possibly a moresuitable alternative technique for coronary revas-cularization.10 Our patient had good outcome afterthe operation and the postoperative aortogramshowed good filling of both the coronaries. Thepreliminary results are encouraging; however,long-term patency and reoperation rates are yet tobe determined.

Figure 3. Postoperative aortogram—3 months: good filling of right and the reconstructed left coronary artery.

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Coronary Vessel Anomalies 349

Corresponding Author: Mr Philip Varghese, Depart-ment of Cardiothoracic Surgery, University Hospital ofLeicester NHS Trust Groby Road, Leicester LE3 9QP,UK. Tel: (+44) 116-250-2796; Fax: (+44) 116-232-1720; E-mail: drphilipv90@yahoo.com

Accepted in final form: June 14, 2007.

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