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Aortopulmonary window with anomalous origin of the right coronary artery from the pulmonary artery: Two cases highlighting the importance of complete pre-operative echocardiographic evaluation of the coronary arteries in all conotruncal anomalies

Steven C. Greenway, Timothy J. Bradley, Christopher A. Caldarone, Norman H. Silverman, Frank L. Hanley, Jeffrey F. Smallhorn
DOI: http://dx.doi.org/10.1016/j.euje.2005.10.010 379-382 First published online: 1 October 2006

Abstract

This report describes two infants with an aortopulmonary window in association with anomalous origin of the right coronary artery from the pulmonary artery. In both cases the diagnosis was made pre-operatively by transthoracic echocardiography, with the initial clue being extensive collateral flow within the myocardium. In each case there was surgical confirmation of the echocardiographic findings. These two cases demonstrate that coronary artery evaluation should be an integral part of every new echocardiographic evaluation, particularly in the setting of conotruncal anomalies.

Keywords
  • Aortopulmonary window
  • Anomalous origin of the coronary artery from the pulmonary artery
  • Echocardiography

Introduction

Aortopulmonary window with anomalous origin of a coronary artery from the pulmonary artery, is a rare but important lesion.1,2 If left undiagnosed, the potential associated myocardial ischemia due to coronary steal, may be further compounded by the additional aortic run-off lesion. Thus far, the majority of cases have been diagnosed at the time of angiocardiography or surgical repair of an associated defect.2–5 We report two infants with an aortopulmonary window, in association with anomalous origin of the right coronary artery from the pulmonary artery (ARCAPA), in whom the diagnosis was made pre-operatively by transthoracic echocardiography.

Case 1

The first case was referred at 6weeks of age to the Division of Cardiology at the Hospital for Sick Children for the assessment of a cardiac murmur. The infant was asymptomatic, with clinical findings suggestive of a patent ductus arteriosus and electrocardiographic evidence of left ventricular hypertrophy in the absence of myocardial ischemia. This case had only echocardiographic evaluation. Of note, there was no evidence of either significant mitral or tricuspid valve regurgitation. There was evidence of collateral coronary artery flow within the myocardium. In the precordial short axis view at the level of the aorta and pulmonary artery, a dilated left coronary system was noted, with antegrade color Doppler flow (Fig. 1A). In the same view the right coronary artery could be identified arising from the posterior and medial sinus of the pulmonary valve and color Doppler flow demonstrated retrograde flow into the main pulmonary artery (Fig. 1B). With angulation in the same transducer location, high velocity continuous color flow could be seen arising from a small (3mm) aortopulmonary window that was located in a more antero-superior location (Fig. 1C). There was no evidence of pulmonary hypertension, with normal septal curvature and a peak instaneous gradient across the aortopulmonary window of 61mmHg while the systemic systolic blood pressure was 96mmHg. At surgery the right coronary artery was directly reimplanted into the facing aortic sinus, with closure of the aortopulmonary window and the post-operative course was uneventful.

Figure 1

Transthoracic echocardiography (2D and color Doppler): (A) high precordial short axis view demonstrating the dilated left coronary system, with antegrade flow; (B) same view showing the origin of the right coronary artery from the pulmonary artery, with retrograde flow into the pulmonary artery indicated by the arrows; and (C) with angulation above the aortic valve sinuses to demonstrate the small aortopulmonary window indicated by arrows. (AO, aorta; CIRC, circumflex coronary artery; LAD, left anterior descending coronary; PA, pulmonary artery; RCA, right coronary artery).

Case 2

The second case was referred at 3months to Stanford University Medical Center with the diagnosis of a patent ductus arteriosus for coil occlusion. This infant was also asymptomatic with electrocardiographic findings of left ventricular hypertrophy. Again by echocardiography, dilatation of the left sided chambers was noted with good biventricular function and no atrioventricular valve regurgitation. Collateral coronary artery flow within the myocardium and a small (2–3mm) aortopulmonary window was seen. In this case cardiac catheterization with angiocardiography was performed prior to surgical intervention and demonstrated mildly increased pulmonary pressures and a dilated left coronary system with retrograde flow in the right coronary artery into the main pulmonary artery. The surgical surface anatomy in the second case is shown (Fig. 2). Surgical reimplantation of the right coronary artery and closure of the aortopulmonary window was similarly performed and the post-operative course was uneventful.

Figure 2

Surgical anatomy. The aortopulmonary window is indicated by the arrow and the anomalous right coronary artery arising from the pulmonary artery runs down beside the two asterisks. Note the dilated left coronary system marked by the smaller arrows. (AO, aorta; PA, pulmonary artery).

Discussion

These two cases demonstrate the importance of performing a complete echocardiographic evaluation in all new patients, including an assessment of the coronary arteries. This is especially important now that echocardiography is often likely to be the only imaging obtained prior to many neonatal and infant repairs. The initial echocardiographic clue to the diagnosis in both of these cases was the extensive collateral flow within the myocardium, which if seen should suggest a coronary artery run-off lesion, be it an anomalous coronary artery or a significant coronary artery fistula. The echocardiographic findings are consistent with reports of isolated ARCAPA, that is a dilated left coronary system with retrograde flow from the coronary artery into the pulmonary artery.6

Anomalous origin of the either the left or right coronary artery may occur in isolation or in association with other forms of congenital heart disease, in particular conotruncal abnormalities.2–5 If coronary abnormalities are not identified prior to surgical correction of an associated lesion, then there may be dire consequences for the patient.2 Both of our cases had acquired coronary collaterals which preserved, but these may have not have been adequate in the post-operative period, if the associated ARCAPA had not been identified.

References

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