Coronary artery to main pulmonary artery fistulae via a Vieussens' arterial ring

Coronary artery fistulae are rare abnormal communications between a coronary artery and a cardiac chamber or a great vessel which may shunt blood flow away from the myocardial capillary network. Vieussens arterial ring is usually described as a collateral pathway between the left anterior descending and right coronary arteries, pathology of Vieussens arterial ring are exceedingly rare. We present a case of a complex coronary artery to pulmonary artery fistula via an aneurysmal Vieussens arterial ring, with emphasis on computerized tomography and invasive angiography findings and management.