Surgical strategies for bilateral internal mammary artery grafting

The internal mammary artery is universally recognised as the preferred conduit for coronary artery bypass grafting. Accumulating evidence in recent years has demonstrated the superiority of bilateral internal mammary artery (BIMA) grafting over single internal mammary artery grafting in terms of survival, event-free survival, and freedom from re-intervention. The survival benefit seen with BIMA grafting has been associated particularly to grafting the myocardium supplied by the left coronary artery system. Several surgical strategies have been used to achieve left-sided myocardial revascularisation with BIMA grafting. These include in-situ right internal mammary artery (RIMA) to the left anterior descending and the left internal mammary artery (LIMA) to circumflex marginal branches, directing the RIMA through the transverse sinus in a retroaortic course, and free RIMA graft connected proximally either to the LIMA (composite grafting) or to the ascending aorta. Each one of these surgical strategies for BIMA grafting has its merits and demerits. This review article provides an overview of the various surgical strategies for BIMA grafting focussing on their technical aspects, pros and cons as well as outcomes.