Gender and mortality risk on the waiting list for coronary artery bypass grafting

There are gender differences in clinical presentation, treatment and outcome of patients with coronary artery disease. We investigated whether there is also a gender difference in terms of mortality risk on the waiting list in patients accepted for coronary artery bypass grafting (CABG).

All our patients accepted for elective CABG 1995-1999 (1303 women and 4561 men) were included. Prospectively registered preoperative characteristics and mortality were compared between men and women. Hazard functions for death on the waiting list were calculated using Poisson regression.

At acceptance, women were older (68+/-9 vs 65+/-9 years, P<0.001), had a higher Cleveland risk score (2.4+/-1.8 vs 1.8+/-1.8, P<0.001) and a better left ventricular ejection fraction (60+/-14 vs 57+/-14%, P<0.001). More women had unstable angina pectoris (33 vs 20%, P<0.001), diabetes mellitus (23 vs 17%, P<0.001), chronic obstructive pulmonary disease (8 vs 5%, P<0.001), hypertension (47 vs 37%, P<0.001) and planned concomitant aortic valve surgery (13 vs 4%, P<0.001) while more men had three vessel disease (70 vs 66%, P=0.001). Median waiting time (55 vs 54 days, P=0.19) and unadjusted mortality (1.4 vs 1.0%, P=0.25) on the waiting list did not differ significantly between men and women but in a multivariate hazard analysis, female gender was associated with a lower risk than men of death on the waiting list (risk ratio 0.42, 95% confidence interval 0.19-0.93, P=0.032).

Women have a lower risk of death on the waiting list for CABG, in spite of more advanced age, more co-morbidity, and a higher percentage of unstable angina pectoris.