Expanded use of the right and left internal mammary arteries for myocardial revascularization.

While the use of the left internal mammary artery (IMA) has become routine in many cardiac surgery units there is some reluctance to utilize the right IMA. The reasons for this are the higher morbidity and mortality observed in the initial experience with bilateral IMA grafting, the limited length of the right IMA, and its potential injury in reoperations when used to revascularize the left anterior descending artery. In this series of 50 patients the right IMA was used as a conduit for myocardial revascularization. One hundred and fifty-nine coronary vessels were grafted (3.2 per patient) 67.3% with IMA and only 32.7% with vein grafts. The right IMA was used for 51 anastomoses and the left for 56, either as simple, sequential or Y type grafts. The refinement of techniques for constructing the IMA grafts used in this series show that the right IMA can reach in most of the cases the anastomotic sites of the right coronary artery beyond the acute margin of the heart, and it is hoped that the lateral positioning of the IMA pedicles will lessen the chance of graft injury at reoperation. On the basis of early clinical results (2% mortality and 4% sternal complications), the application of the right IMA seems justified electively for the revascularization of both left and right coronary artery systems or as a free graft in conjunction with the left IMA.