A meta-analysis comparing bilateral internal mammary artery with left internal mammary artery for coronary artery bypass grafting.

BACKGROUND

Increasing evidence continues to demonstrate a survival advantage for bilateral internal mammary artery (BIMA) over left internal mammary artery (LIMA) for coronary artery bypass grafting (CABG). We performed an updated meta-analysis of published studies comparing BIMA versus LIMA in CABG operations and assessed differences in long-term survival.

METHODS

Electronic searches for studies comparing BIMA versus LIMA were performed using three databases from 1972 to December 2012. Studies with at least four years of follow-up and at least 100 patients in each group were included for review. We used a random-effect model and pooled hazard ratios from across all included studies.

RESULTS

No randomized controlled trials and 27 observational studies totaling 79,063 patients (19,277 BIMA, 59,786 LIMA) were included for final analysis. The BIMA group demonstrated significantly better long-term survival than the LIMA group [hazard ratio, 0.78; confidence interval, 0.72-0.84; P<0.00001].

CONCLUSIONS

In an updated meta-analysis, we demonstrate an increase in long-term survival in patients receiving BIMA as a primary grafting strategy over those receiving a LIMA. Although no randomized controlled trials were included in this meta-analysis, the survival benefit seen with a BIMA cannot be overlooked when determining which operation to perform in CABG patients. Until the long-term results of the ART trial are published, we offer best available evidence in favor of BIMA over LIMA for CABG surgery.