Coronary artery bypass grafting (CABG) is an established therapy for obstructive cardiovascular disease and ischemic cardiomyopathy. Utilization of the left-internal mammary artery as a graft has been a particularly successful aspect of CABG due to impressively durable patency rates. Despite this, adoption of bilateral mammary artery grafting has lagged in surgical practice.  The Arterial Revascularization Trial (ART) randomized a total of 3102 patients to either single or bilateral mammary grafting. At five years there were no differences between groups in the rates of death (8.7% vs. 8.4%; P=0.77) or major adverse cardiovascular events including myocardial infarction and stroke (12.2% vs. 12.7%; P=0.69).   Rates of sternal wound infections and sternal reconstruction were significantly higher in the bilateral mammary group (P=0.005) while rates of clinical angina were no different at 5 years.

Conclusions

At 5 years there is no difference in clinical efficacy between bilateral and single internal mammary grafting in patients requiring CABG. Long-held concerns regarding immediate post-operative complications when utilizing both mammary arteries were validated.  Based on the modest durability of vein grafts, primary arterial conduits are hypothesized to hold the keys to even better CABG outcomes, but realizing these benefits remain elusive in practice.

Taggart DP, Altman DG, Gray AM, Lees B, Gerry S, Benedetto U,  and Flather M,  for the ART Investigators.   Randomized Trial of Bilateral versus Single Internal-Thoracic-Artery. N Engl J Med. 2016 Nov 14. [Epub ahead of print]

Husain Contractor and James M. McCabe