Bilateral vs. unilateral mammary coronary bypass: analysis of age-related evolution

Abstract

The impact of age in the evolution of patients with bilateral mammary coronary bypass (bilateral internal thoracic arteries, BITA), vs. single mammary coronary bypass (single internal thoracic arteries, SITA) has not yet been established, as stated by Gaudino et.al in U.S., United Kingdom and Canada research centers. Researchers analyzed the results of ART (Arterial Revascularization Trial), the only controlled, randomized trial that has compared the evolution of BITA vs. SITA in a large number of participants with follow-up data from of over 97% of patients at 10 years. The analysis found no significant differences in mortality for any cause, stroke or myocardial infarction. However, given the large number of crossover and cointerventions (particularly the use of the radial artery in the control group), a post-hoc analysis was conducted to assess the differences in the number of arterial grafts, finding higher overall survival and eventfree survival rates in the group with multiple grafts.
Observational evidence suggests that the long-term benefits of bypass with the BITA strategy shall only be evident in younger patients. The overall analysis showed no significant differences. However, in conducting the analysis of 50 to 70 year-old patients, those in the BITA group had a significantly lower incidence of major adverse events. These results suggest that younger patients would obtain greater benefit from the bilateral mammary bypass, although the authors maintain that since this is a post-hoc analysis, further randomized studies are required to confirm this hypothesis.