[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.