Minimally invasive direct coronary artery bypass: technical considerations and instrumentation

Minimally invasive coronary artery bypass is defined as any maneuver or modification of conventional coronary bypass that decreases adverse effects. These adverse effects fall into three broad categories, which are access trauma, consequences of cardiopulmonary bypass, and aortic manipulation. In the minimally invasive direct coronary artery bypass (MIDCAB) approach, coronary revascularization is performed via a limited access incision, usually a left anterior thoracotomy, through which a left internal mammary artery is anastomosed under direct vision to the left anterior descending artery on a stabilized beating heart. Harvest of the left internal mammary artery can be performed with video assistance (two- or three-dimensional or under direct vision). A variety of offset chest wall retractors that allow internal mammary artery harvest under direct vision have simplified the procedure, and several mechanical stabilization devices (with or without suction) allow local wall immobilization for a target vessel anastomosis. Graft patency data from early series of stabilized MIDCAB procedures and published series of left internal mammary artery graft patency with conventional bypass grafting appear to be comparable. Current indications for MIDCAB include restenosis of the left anterior descending artery after catheter-based therapy and the necessity for target vessel revascularization in elderly high-risk patients with multivessel disease. Limitations of the MIDCAB procedure include mostly single vessel revascularization of the anterior aspect of the heart.