The left internal mammary artery is a vessel with relatively constant anatomical features and which in almost all subjects is congruent with their own anterior interventricular artery. In addition, atheromatous lesions of this artery are exceptional; when grafted onto the anterior interventricular artery, it adjusts itself to the diastolic coronary flow. Finally, and this is remarkable, once grafted onto the anterior interventricular artery it virtually never undergoes long-term alterations in contrast with the internal saphenous vein. For these reasons, the left internal mammary artery should be used as often as possible to revascularize the anterior intraventricular artery. Preoperative angiography of the left internal mammary artery to evaluate its quality does not seem to be necessary; what is important in the choice of a graft is the quality of the spurt after the vessel is dissected and its distal end is severed. However, the left internal maxillary artery is smaller and more friable in women, in hypotrophic subjects and in elderly people, especially when hypertensive. In these cases, it should be used with caution or not at all, particularly for bypass with a fairly wide, atheromatous and calcified anterior intraventricular artery. Accounting for these restrictions and with some experience at least 90% of anterior interventricular arteries can be revascularized by the left internal mammary artery.