Survival After Bilateral Internal Mammary Artery In Coronary Artery Bypass Grafting: Are Women at Risk?

Introduction: To compare survival and safety of BIMA versus SIMA CABG between males and females at our tertiary care center.

Methods: Single-center retrospective cohort including consecutive patients with at least 2 left coronary system (LCS) vessel disease who underwent isolated CABG with at least 1 IMA conduit and a minimum of 2 conduits targeting the LCS between 2004 and 2013. All-cause mortality was the primary outcome, secondary outcomes were in-hospital mortality and reoperation due to sternal wound complications (SWC). Kaplan-Meier analysis after inverse probability weighting using propensity score (IPW) was used to compare BIMA and SIMA CABG amongst genders. Results were confirmed by subgroup analysis.

Results: BIMA CABG was performed in 39% out of 2424 eligible procedures and in 27% of 460 females. No differences were found in survival after BIMA and SIMA CABG (median and maximum follow-up of 5.5 and 12 years, respectively) but a statistical interaction was observed with gender (P<0.001). Females who underwent BIMA CABG showed higher mortality (weighted HR in females subset: 3.16; 95%CI: 1.56-6.29, P=0.001). BIMA CABG showed a higher incidence of reoperations due to SWC (IPW adjusted model OR: 1.74; 95% CI: 1.16-2.60) that were mostly ascribable to males (weighted OR in males: 3.10; 95%CI: 1.74-5.51, P<0.001).

Conclusion: Females may experience higher mortality after BIMA CABG which should be further explored.