Coronary-Pulmonary Artery Fistula Provides Collateral Flow to an Occluded Left Anterior Descending Artery.

A 59-year-old man presented with angina. Coronary angiography revealed an occlusion in the proximal left anterior descending artery (LAD), the distal segment of which was supplied by the collateral flow of a coronary-pulmonary arterial fistula (CPAF), originating from the right coronary artery and left sinus of Valsalva. Myocardial scintigraphy revealed ischemia in the anteroseptal region. Coronary artery bypass surgery was performed on the LAD, and the CPAF drains were closed. The CPAF may serve as collateral circulation. Even when CPAF serves as collateral circulation, open surgery could be indicated if the collateral flow is insufficient and the structure is complicated.