The influence of bilateral internal mammary arteries on short- and long-term outcomes: A propensity score matching in accordance with current recommendations

Abstract

We undertook a single-center, 12 years outcomes analysis of the influence of bilateral internal mammary arteries (BIMA) over single internal mammary artery (SIMA) on short-term outcomes and long-term outcomes by means of propensity score matching technique in accordance to current recommendations. A propensity score was generated for each patient from a multivariable logistic regression model based on 20 pretreatment covariates. The study population consisted of 4195 patients undergoing coronary artery bypass graft procedure using SIMA (n = 3445; 78.3%) or BIMA (n = 750; 21.7%). A total of 750 matching sets were derived. The BIMA group was associated with an increased rate of superficial sternal wound infection (5.6% vs 1.7%; P = .0001) but the incidence of deep sternal wound infection was comparable between the 2 groups, at 2.1% and 1.5% in BIMA and SIMA groups, respectively (P = .43). With regard to other postoperative complications the 2 groups were comparable. Operative mortality rate did not significantly differ between the 2 groups, at 0.7% and 1.2% in the BIMA and SIMA groups, respectively (P = .28). After a mean follow-up time of 4.8 ± 3.2 years, BIMA use was associated with a significantly lower risk for late mortality (hazard ratio, 0.61; 95% confidence interval 0.38-0.97; P = .03) and need for repeat revascularization (hazard ratio, 0.75; 95% confidence interval, 0.53-0.96; P = .03). When compared with SIMA grafting, BIMA use did not increase operative morbidity and mortality and was associated with a better long-term survival.