Is sex a risk factor for death in patients with bilateral internal thoracic artery grafts?

Abstract

BackgroundMortality after coronary artery bypass grafting (CABG) has been reported to be higher in women. The aim of this study was to evaluate whether bilateral internal thoracic artery (BITA) grafting in women has a long-term survival benefit over single internal thoracic artery grafting, possibly equivalent to the male population. MethodsA retrospective review was undertaken of our prospectively collected database. We included 4406 consecutive patients who underwent isolated CABG, who received their operation between January 2000 and April 2017. From the entire series, 2979 patients (67.6%) received exclusively BITA grafts; 299 (10.1%) were female. The primary end point was follow-up mortality, independently from cause. In-hospital mortality and during follow-up were analyzed. Substratification according to age was performed to answer whether it has an effect. Multivariable Cox proportional hazard analyses was performed to investigate the significant predictors of late mortality. ResultsThe median follow-up was 5.1 ± 3.9 years. Female BITA patients were older (P < .001), had nonelective surgery (P < .001), more on-pump CABG (P = .015), fewer number of grafts (P < .001) versus male BITA patients. BITA grafting in women had a long-term survival equivalent to that of men (P = .784).In a Cox proportional hazard model, female sex was not an independent risk factor for late death (B, −0.303; hazard ratio, 0.739; 95% confidence interval, 0.470-1.16; P = .189). The stratification analysis showed that the beneficial effect of BITA remained similar among sexes and was not modified by age even after adjusting for confounders. In a risk-adjusted sample, patients older than 65 years with BITA grafting showed superior long-term survival than those with single internal thoracic artery grafting (P = .019). ConclusionsAlthough there are some differences between sexes, BITA grafting in women was associated with similar 10-year survival compared with men, and female sex was not an independent risk factor for late death. Among women, the BITA group had better survival, especially those older than 65 years.