Independent predictors of early mortality after coronary artery bypass grafting in a single centre experience - does gender matter?

Background: It is commonly believed that women undergoing isolated coronary artery bypass graft surgery (CABG) are subject to a higher risk of perioperative complications and death. Aim: To evaluate the effect of sex as a risk factor on early complications and mortality after isolated CABG performed with cardiopulmonary bypass, and to evaluate the profile of the risk determined by the patient's sex. Methods: Data derived from 2,194 surgical procedures performed in the Department of Cardiac Surgery at the Medical University of Lodz between January 2009 and March 2011 was analysed. The database was constructed on the basis of retrospective analysis of variables contained in a form of the National Registry of Cardiac Surgery. Results: Isolated CABG with cardiopulmonary bypass was carried out in 1,303 patients (59.4% of all procedures). Women constituted the minority of patients (24.2%), and were significantly older (mean age 67.3 vs. 62.8 years, p < 0.001). They more often suffered from concomitant diabetes (43.1% vs. 33.41%, p = 0.003), had impaired renal function (median eGFR 88.5 vs. 95.0 mL/min1/1.73 m(2), p < 0.001), and had a history of smoking in fewer cases (54.1% vs. 83.0%, p < 0.001). Internal mammary artery was more rarely used as arterial graft in the group of women (84.8% vs. 95.0%, p < 0.001). Women were subject to a higher risk of recent postoperative myocardial infarction (5.5% vs. 2.9%, p = 0.03) and required reoperation more rarely than men (4.5% vs. 8.1%, p = 0.04). Higher 30-day mortality was observed among women (7.6% vs. 2.8%, p < 0.001) and female sex appeared to be an independent predictor of death in the multiple logistic regression analysis (OR = 1.8; 95% CI 1.2-2.7). Conclusions: Women undergoing isolated CABG are subject to higher 30-day mortality. Female sex is an independent risk factor for death after isolated CABG. Further studies are necessary to identify causes of differences in prognoses among women.