Changing clinical characteristics of coronary surgery patients. Differences between men and women

There is uncertainty as to the relative efficacy of coronary artery bypass graft surgery (CABG) in men and women. Differences between sexes may be of greater importance than heretofore because of increased frequency of risk factors for adverse outcome. It is the purpose of this study to examine the changing clinical characteristics of patients undergoing CABG and to determine the influence of these changes on the results of CABG in men and in women.

The source of data was the clinical database at Emory University Hospitals. The population comprised 13,368 patients (2648 women, 10,720 men) who had cardiac catheterization followed by CABG between 1974 and 1991. The patients were divided into the time periods 1974 through 1979 (532 women, 2792 men), 1980 through 1983 (727 women, 3151 men), 1984 through 1987 (695 women, 2619 men), and 1988 through 1991 (694 women, 2158 men). Data were collected prospectively and entered into a computerized database. The women were older (63 +/- 10 versus 58 +/- 10 years, P < .0001) and more frequently had diabetes (26.0% versus 15.4%, P < .0001). The in-hospital mortality was 3.8% in women and 1.6% in men. The multivariate correlates of death were older age, emergent surgery, reduced ejection fraction, female sex, diabetes, and more severe distribution of coronary arterial narrowings. Each of these risk factors for death became more prevalent, such that the mortality in men increased from 1.0% in 1974 through 1979 to 2.7% in 1988 through 1991, whereas the mortality in women increased from 1.3% in 1974 through 1979 to 5.4% in 1988 through 1991.

The population undergoing CABG has aged, with correlates of in-hospital death becoming more common. The higher mortality in women could only partially be explained by other clinical variables. In addition, the risk of death after CABG has increased in women more than in men because women have consistently been older, have more emergent surgery and diabetes, and in recent years more women undergoing CABG have three-vessel or left main disease.