Giant Aneurysmal Left Main Coronary Artery to Right Atrium Fistula. A Case for Surgical Approach

Coronary artery fistulae (CAF) are either congenital or acquired coronary artery abnormalities, that have different anatomical appearance; with varying degree of shunting (Qp/ Qs); and associated cardiac anomalies [1]. Etiologies include high cardiac output state and congestive heart failure with shunting of blood into a cardiac chamber, great vessel, or other structures, bypassing the myocardial capillary network [2]. If the fistula is large, the intracoronary diastolic perfusion pressure diminishes progressively [1-2]. The coronary vessel usually attempts to compensate by progressive enlargement of the ostia and feeding artery. Nevertheless, myocardium beyond the site of the fistula’s origin is at risk for ischemia, most frequently evident in association with increased myocardial oxygen demand during exercise or activity [3]. With time, the coronary artery leading to the fistulous tract dilates progressively, that in turn, may progress to frank aneurysm formation, intimal ulceration, medial degeneration, intimal rupture, atherosclerotic deposition, calcification, sidebranch obstruction, mural thrombosis, and, rarely, rupture [4]. Reports suggested surgical repair or transcatheter embolization in symptomatic patients at risk for fistula aneurysmal rupture and/or obstruction of nearby anatomic structures from its mass effect [5-6].