Anomalous Origin of Right Coronary Artery Originating from the Pulmonary Trunk (ARCAPA): an Incidental Finding in a Patient Presenting with Chest Pain

Anomalous origin of the right coronary artery originating from the pulmonary trunk (ARCAPA) is a rare congenital coronary anomaly with an estimated prevalence of 0.002%. Most patients are asymptomatic and the anomaly is detected incidentally during evaluation for other problems. Occasionally, ARCAPA may lead to myocardial ischemia and/or sudden cardiac arrest. We present a case of a 55-year-old female with a history of hypertension who presented to the emergency department with intermittent chest discomfort for three days. Laboratory results showed an elevated troponin of 0.18 ng/ml and subsequently increased to 0.39 ng/ml. The initial electrocardiogram study demonstrated sinus tachycardia with no acute changes. The patient was diagnosed with non-ST-segment elevation myocardial infarction. She underwent cardiac catheterization that showed 90% stenosis of the left main/left anterior descending artery. Reflux of contrast from the right coronary artery (RCA) ostium to the pulmonary artery was seen along with left to right collaterals with retrograde filling of the RCA. There was no significant obstruction of the RCA when viewed via left to right collaterals. Right heart catheterization and pulmonary angiography were performed which confirmed the origin of the RCA from the pulmonary trunk. The patient was referred for surgery and ligation of the aberrant RCA originating from the pulmonary artery was performed along with coronary artery bypass grafting x 2, left internal mammary artery to left anterior descending artery (LAD) and saphenous vein graft to the proximal posterior descending artery. The patient was discharged home with marked improvement of her symptoms. Origin of the RCA from the pulmonary artery (ARCAPA) is a rare congenital malformation with a potentially malignant outcome for the patient. The majority of patients with ARCAPA remain asymptomatic. In this case report, the chest discomfort was due to occlusion of the LAD and was probably unrelated to the coronary malformation. However, sudden cardiac death has been linked to ARCAPA and therefore a corrective operation is recommended even for asymptomatic patients. Of the surgical techniques available, which include: simple ligation of the RCA, ligation of the RCA with saphenous vein bypass grafting and re-implantation of the RCA into the aorta, the last method is believed to be superior for the restoration of myocardial blood supply. However, its long-term benefits have not been conclusively demonstrated. Therefore, in our patient, ligation of RCA with saphenous vein bypass grafting was done as it is recognized as a less traumatic surgical alternative to RCA implantation into the aorta.