Fistula between the left internal mammary artery and pulmonary artery: a rare cause of recurrent angina after coronary bypass grafting

Left internal mammary artery (LIMA) to pulmonary vasculature fistula is a rare complication after coronary artery bypass surgery. In most cases, the duration between bypass grafting and fistula formation ranges from 2 to 5 years. We present a 62-year-old man who presented with anginal symptoms five years after bypass surgery. On coronary angiography, selective catheterization of the LIMA showed fistula formation to the pulmonary artery, which probably led to coronary steal syndrome and myocardial ischemia. He underwent surgery and the connection between the LIMA and pulmonary artery was terminated. After surgery, his anginal complaints improved and echocardiography showed improvement in the wall motion abnormality detected before surgery.