Bilateral Internal Mammary Artery Use Can Be Safely Taught Without Increasing Morbidity or Mortality

Background: Evidence shows a likely survival benefit with the use of bilateral internal mammary arteries (BIMA) compared with a single internal mammary artery (SIMA). Nonetheless, BIMA use is often not used or taught because of a perceived increase in operative time and complexity. This study aimed to evaluate operative time, morbidity, and mortality in both resident and nonresident cases using BIMA compared with SIMA.

Methods: Consecutive patients undergoing isolated coronary artery bypass grafting (October 2012 to April 2015) at a single institution were reviewed. Cases were stratified on the basis of the use of SIMA versus BIMA and resident teaching versus nonresident teaching cases. Primary outcomes included operative time, postoperative morbidity, and mortality.

Results: A total of 416 patients were identified; 335 of 416 (81%) patients received a SIMA, and 81 of 416 (19%) patients received BIMA. A total of 184 of 416 (44%) were resident cases: 143 of the 335 (43%) SIMA cases and 41 of the 81 (51%) BIMA cases. Use of BIMA in resident cases was associated with a longer operative and cardiopulmonary bypass (CPB) time than resident SIMA cases, but this increased time did not affect morbidity or mortality. Use of SIMA versus BIMA in nonresident cases had no significant difference on total operative time, CPB time, postoperative morbidity, or mortality. Overall, operative and 1-year mortality rates were similar in the SIMA and BIMA groups (SIMA: 1.2%, 1.8%, respectively; BIMA: 0%, 0%, respectively; p = NS).

Conclusions: In the hands of an experienced surgeon, BIMA use can be effectively performed without an increase in operative or CPB time. In resident teaching cases, BIMA use may increase operative time, but it can be safely taught without affecting morbidity or mortality.