Case report

A male patient, aged 2.5 years, was admitted to our department. During his initial visit at the age of 6 months, he was diagnosed to have congenital severe mitral regurgitation, with a deformity of the valve noted on echocardiography. He was treated conservatively with anticongestive medication and followed up. On his last admission, at the age of 2.5 years, we found a systolic thrill and a pansystolic murmur, graded at 4 from 6, in the left parasternal area. There was no electrocardiographic evidence of ischaemia, infarction, or ventricular hypertrophy. The chest radiograph revealed cardiomegaly. Echocardiography revealed severe mitral regurgitation with a mildly dilated left ventricle, albeit with good contractility, but showed abnormal, mainly diastolic, flow in different parts of the ventricular septum, seen in both short and long axis cuts (Fig. 1). No significant diastolic flow was observed in the pulmonary trunk. Echocardiographic examination in the short axis view showed that both coronary arteries were patent, albeit with dilation of the right coronary artery. When we checked his echocardiographic examination retrospectively from his first visit, we noted that the dimensions of the left ventricle had increased with time. Based on the above findings, and with a presumptive diagnosis of possible anomalous origin of a coronary artery, we performed a coronary angiogram, which revealed anomalous origin of a giant anterior descending coronary artery from the pulmonary trunk, with collateral filling from the right coronary artery. A patent but small circumflex coronary artery took its normal origin from the aorta (Fig. 2). During right heart catheterization, a step-up in saturations of oxygen was also noted, from 68% in the right ventricle to 76% in the pulmonary trunk. Left ventriculography did not reveal any regional abnormalities of mural motion. We found neither electrocardiographic changes nor any rise in troponin. Surgical repair was recommended because of the possibility of ischaemia and infarction developing slowly without symptoms, and also because some of the left ventricular dilattion, and even contractility, could be ameliorated. During the operation, a large and tortuous anterior descending artery was found arising from the leftward adjacent sinus of the pulmonary trunk. The circumflex and right coronary arteries took their normal origin from the aorta. On aorto-atrial cardiopulmonary bypass, a coronary button incorporating the anomalous artery was fashioned from the pulmonary trunk. The trunk itself was anastomosed end-to end using a pericardial patch, the anterior descending artery being anastomosed end-to-side to the aortic root. The mitral valve was repaired by stitch annuloplasty through a left atriotomy. The postoperative course was uneventful, with echocardiography showing normal ventricular function with patent coronary arteries. Doppler echocardiography showed that mitral regurgitation had been reduced, and the diastolic flow in ventricular septum had disappeared.

Figure 1 Echocardiographic view showing abnormal diastolic flow within the ventricular septum, the arrows indicating the abnormal flow. RV, right ventricle; LV, left ventricle; IVS, interventricular septum.

Figure 2 Injections in the right coronary artery, profiled in anteroposterior and lateral projections, show retrograde filling of anterior descending artery via collateral vessels, and retrograde filling of the pulmonary trunk. The arrows indicate the collateral vessels. RCA, right coronary artery; PA, pulmonary trunk.

Disscussion

Anomalous origin of the anterior descending artery from the pulmonary trunk is a rare congenital defect. Although sudden cardiac death in the setting of this anomly may occur at a young age,Reference Morentin, Pecina and Anguilera² survival is higher than for those with anomalous origin of the main stem of the left coronary artery from the pulmonary trunk, the extent of ischaemia being less. Despite the fact that such anomalous origin of the anterior descending artery from the pulmonary trunk is unequivocally a congenital anomaly, review of the literature reveals that presentation is mostly in adults, usually between the ages of 16 and 55 years. This late presentation may be because of the persiting dual arterial supply from the aorta, and sufficient development of collateral circulation. To our knowledge, cases described in children are scarce, and include a 17-month-old who had asymptomatic cardiomegaly,Reference El Habbal, De Leval and Somerville³ a 7-year-old investigated for severe dyspnea,Reference Kaushal, Radhakrisnan, Dagar, Shrivastava and Iyer¹ a seven month old infant who presented with cardiac failure and died from acute myocardial infarction,Reference Schwartz and Robicsek⁴ and three children, 2 of whom developed cardiac failure in infancy.Reference Tamer, Mallon, Garcia and Wolf⁵ There are few other reports in association with other cardiac defects, such as aortic coarctation,Reference Tsuchiya, Arakaki, Takahashi, Kamiya, Kimura and Yagihara^6, Reference Clarke, Radford and Jaldi⁷ and tetralogy of Fallot.Reference Yamaguchi, Tsukube, Hosokawa, Ohashi and Oshima⁸

When a child of less than two years of age presents with unexplained left ventricular failure or dilation, the possibility of an anomalous origin of a coronary artery must always be considered. In our case, mitral regurgitation was initially thought to be due to a mitral valvar deformity. The presence of some echocardiographic findings, such as left ventricular dilation refractory to medication, mitral regurgitation, and diastolic flow in different parts of the ventricular septum, nonetheless,were highly suggestive of the coronary arterial anomaly even in the absence of an electrocardiographic pattern of myocardial ischaemia. Cross-sectional echocardiography is unreliable for making the definitive diagnosis because two coronary arteries often appear to arise from the root of the aorta, as in our patient. Angiography of the aortic root or the coronary arteries is the most certain method of diagnosis. Treatment remains a matter of controversy, since the rarirty of this finding means that there is no data from large series of patients. Surgical establishment of a dual coronary arterial system has been suggested as the treatment of choice.Reference Barth, Allen, Gulecyuz, Chiemmongkoltip, Cuneo and Ilbawi⁹ Intrapulmonary tunnel repair, and coronary arterial reimplantation, are the common procedures. Other repairs iclude interposition grafts using saphenous vein or other conduits, and grafting the left internal thoracic artery to the anterior descending artery. In our case, it proved posibble directly to implant the anomalous artery into the aortic root.

Patients with a dual coronary arterial supply but with anomlous origin of one major coronary artery from the pulmonary trunk, therefore, usually present in adulthood with subtle symptoms. Because this diagnosis may be difficult to make during childhood, patients with clinical findings such as exertional angina, myocardial infarction, dyspnea and severe fatigue attributable to mitral regurgitation, and typical electrocardiographic and echocardiographic findings, may require selective coronary arteriography to exclude the anomaly.