Avoidable errors in cardiac surgery: anastomosis of the left internal mammary artery to a vein.

We report the case of a patient who had undergone a three-vessel coronary artery bypass graft surgery 6 years earlier, during which the left internal mammary artery was erroneously anastomosed to an epicardial vein instead of the intended target, an intramyocardial left anterior descending artery. Visually distinguishing artery from vein can be occasionally challenging and can lead to errors in distal anastomosis. This case report identifies two difficult problems in cardiac surgery and discusses the techniques to differentiate between arterial and venous targets.