Sex differences in resource use after on-pump and off-pump coronary artery bypass surgery: A propensity score-matched cohort

BACKGROUND: Previous studies have demonstrated that off-pump coronary artery bypass surgery (OPCAB) is associated with less use of hospital resources compared with on-pump coronary artery bypass surgery (ONCAB). OBJECTIVE: To determine whether there is a sex effect between the two procedures regarding resource utilization. METHODS: Between 1996 and 2004, 13,522 patients (10,637 men and 2885 women) underwent coronary artery bypass grafting surgery at the Toronto General Hospital (Toronto, Ontario). Among the men, 10,121 patients underwent ONCAB and 516 underwent OPCAB. The female population consisted of 2723 ONCAB and 162 OPCAB patients. Both groups were matched to standard preoperative risk factors. A propensity score macro-matched 471 OPCAB men to 471 ONCAB men, and 148 OPCAB women to 148 ONCAB women. RESULTS: The mean (+/- SD) postoperative length of stay (7.5 +/- 6.5 days versus 6.4 +/- 5.5 days; P<0.0001) was significantly higher in ONCAB compared with OPCAB in the male population. The mean length of stay in the intensive care unit and the mean ventilation time was similar between the groups. However, in the female population, there were no differences in mean posoperative length of stay (8 +/- 5.9 days versus 8 +/- 6 days; P=0.4), mean length of stay in the intensive care unit (43 +/- 38 h versus 53 +/- 81 h; P=0.4) or mean ventilation time (9.8 +/- 9.7 h versus 11 +/- 13 h; P=0.8). CONCLUSION: These results suggest that the benefits of OPCAB in terms of hospital resource use are influenced by sex. The potential beneficial effects are not demonstrated in the female population.