Is there any further advantage of using more than one internal mammary artery? Literature review and analysis

The use of the internal mammary artery reduces the incidence of late adverse effects and improves survival after coronary artery bypass grafting. Therefore, internal mammary artery grafts ought to be used in all patients undergoing coronary artery bypass grafting (level II evidence), although in the UK, only 95% of the patients receive an internal mammary artery graft. This is due to factors such as poor left ventricular function, old age, previous radiation to the thoracic cavity, or emergency surgery. As there are biological similarities between the left and right internal mammary artery, one can extrapolate that the use of 2 internal mammary artery grafts may provide additional benefits. Bilateral internal mammary artery grafting can be safely performed in most patients (level II evidence). The late survival in patients with bilateral internal mammary artery grafts is favorable. However, there is as yet no completed randomized trial on this subject. Thus the lack of robust data makes previous reports amenable to criticism. This review examines published data on bilateral internal mammary artery revascularization spanning the last 15 years, and addresses the advantages and disadvantages of arterial conduits in coronary surgery.