Left Circumflex Coronary-to-Pulmonary Artery Fistula as the Exclusive Collateral to the Occluded Left Anterior Descending Artery

A 64 year-old male presented with a five month history of effort angina. Non-invasive studies demonstrated preserved left ventricular function and a modest stress-induced myocardial perfusion defect at the anterior wall. Coronary angiography revealed occlusion of the proximal left anterior descending coronary artery with its distal segment well supplied by collaterals branching from a left circumflex-to-main pulmonary artery fistula. The occluded left anterior descending coronary artery was recanalised by percutaneous interventions, the collaterals vanished immediately, and the patient lived free of symptoms for the following five months.