Coronary Artery Bypass Graft Surgery with Double Internal Mammary Artery: Effect on Long-Term Survival

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Abstract

Background: Utilization of the left internal mammary artery (IMA) in coronary artery bypass graft surgery (CABG) is associated with long-term survival free from late cardiac events; moreover, use of the right IMA as a complement of the left artery has shown favorable results. However, it is not yet clear whether double IMA revascularization is a better long-term option.
Objective: The aim of this work was to analyze long-term survival of patients with multi-vessel disease undergoing double IMA (2IMA) compared with single IMA (1IMA) CABG.
Methods: Consecutive 2IMA (n=2,098) and 1IMA (n=1,659) CABG surgeries performed between 1996 and 2014 were reviewed, comparing overall long-term survival between groups and between 485 pairs of patients matched by propensity score. Cox proportional hazard models were generated.
Results: Patients with 2IMA CABG were younger (2IMA: 63.7±9.1 years vs. 1IMA: 65.0±9.9 years; p<0.0001). Overall in-hospital mortality was lower in the 2IMA group (2IMA: 1.2% vs. 1IMA: 4.4%; p<0.0001). At 10 years, unadjusted survival was higher in the 2IMA group (2IMA: 82.6%±1.8% vs. 1IMA: 76.1%±1.3%; p=0.001). Overall Cox logistic regression analysis showed higher survival in patients with 2IMA CABG (HR 0.71, 95% CI 0.58-0.87; p<0.001). In the propensity score adjusted analysis, in-hospital mortality was similar in both groups (2IMA: 1.6% vs. 1IMA: 2.9%; p=0.196), but the 2IMA group still had higher long-term survival at 10 years (2IMA: 81.0%±4.1% vs. 1IMA: 71.8%±2.5%; p=0.039).
Conclusion: Patients with 2IMA CABG evidenced better long-term survival than patients with 1IMA plus another type of conduit.