Survival after bilateral internal mammary artery in coronary artery bypass grafting: Are women at risk?

BACKGROUND: Most observational studies support long-term survival benefit after bilateral internal mammary artery (BIMA) compared with single internal mammary artery (SIMA) coronary artery bypass grafting (CABG) but data on females is scarce. We compared 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 in 2004-2013. All-cause mortality was the primary outcome, secondary outcomes were early 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 in 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 reoperation due to SWC (IPW adjusted model OR: 1.74; 95% CI: 1.16-2.60) that was mostly ascribable to males (weighted OR in males: 3.10; 95% CI: 1.74-5.51, P < 0.001). CONCLUSIONS: Females may experience higher mortality after BIMA CABG which should be further explored.

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.

[Do diabetic patients benefit from bilateral internal mammary artery?] / O Benefício na Sobrevida da Dupla Artéria Torácica Interna Prevalece nos Pacientes com Diabetes?

INTRODUCTION: Bilateral internal mammary artery (BIMA) grafting has been associated with increased long term survival when compared to single IMA, but its benefit on diabetic patients remains controversial. AIMS: To compare long-term survival following BIMA versus single internal mammary artery (SIMA) grafting between diabetic and non-diabetic patients. METHODS: We retrospectively reviewed all the patients who underwent isolated CABG and received two or more grafts with at least one IMA graft between 2004 and 2013. Mean follow-up was 4 years and maximum 10. Kaplan-Meier analysis was used to compare long-term survival between BIMA and SIMA in both groups (diabetic vs. non-diabetic). Propensity score matching was used to adjust for treatment selection bias. RESULTS: 1259 out of 3045 eligible patients were diabetic. BIMA was associated with better long-term survival than SIMA on unadjusted analysis in both groups (cumulative survival of 87% vs. 70% in diabetic patients and 89% vs. 79% in non-diabetic patients, respectively). After propensity score matching, BIMA was associated with increased long-term survival in the non-diabetic cohort (n=1042, HR: 0.570 CI95%: 0.342-0.950), but there was no statistically significant difference in the diabetic cohort (n=850, HR: 0.774 CI95% 0.447-1.339). In-hospital mortality and sternal wound infection were low in matching cohorts irrespectively of the number of IMA grafts or diabetes status. CONCLUSIONS: BIMA grafting appears to be safe for diabetic patients, despite the apparent lack of significant survival advantage.

[Bilateral Internal Mammary Artery Versus Single Internal Mammary Artery in Myocardial Revascularization Surgery. Propensity Score - Adjusted Survival Analysis]. / Dupla Artéria Torácica Interna Versus Artéria Torácica Interna Única na Cirurgia de Revascularização do Miocárdio : Análise Ajustada de Sobrevida com Emparelhamento por Propensy Score.

BACKGROUND: Although arterial grafts are superior to venous grafts in terms of long-term patency, single internal mammary artery (SIMA) is still the preferred strategy in most cardiac surgical centres. Our main aim was to compare long- -term survival between BIMA and SIMA at our own tertiary care centre. METHODS: Retrospective cohort including patients referred to Centro Hospitalar São João (CHSJ), from 2004 to 2011, who underwent isolated CABG and received two or more bypass with at least 1 IMA graft. Kaplan-Meier, Cox regression and propensity score matching 2:1 were used to compare long-term survival between BIMA and SIMA. RESULTS: BIMA was performed in 696 (29.3%) out of 2329 eligible procedures. Mean follow-up time was 5.1 years (2-9.9 years). All-cause mortality was superior in patients with only one internal mammary artery - cumulative survival of 75% for SIMA vs 88% for BIMA. Because of discrepancy between groups regarding preoperative and surgical characteristics, we ran a propensity score matching which revealed BIMA as an independent predictor of survival (n=1510, 40.3% BIMA, HR: 0.648, 95% CI: 0.452-0.927). CONCLUSION: BIMA is associated with significantly better long-term survival than SIMA in CABG. A higher sample size might clarify BIMA advantages, discriminating specific groups that might profit the most with this approach.