STUDY OF 340,000 HEART BYPASS PATIENTS FINDS MORTALITY RISK SIGNIFICANTLY HIGHER FOR WOMEN

Findings Of The Society Of Thoracic Surgeons' National Cardiac Surgery Database Reinforce Need For Women's Health Research

(WASHINGTON, DC) - Women with low to moderate risk factors have a significantly higher chance of operative mortality during and immediately after heart bypass surgery when compared to men of equal risk, according to research published in the just released July, 1998 issue of The Annals of Thoracic Surgery.

Fred H. Edwards, M.D., from the University of Florida Health Science Center, Jacksonville, Florida, and colleagues compared more than fifty potential factors affecting the risk of a patient's mortality after heart bypass surgery. The authors write, "For any single risk factor associated with coronary artery bypass graft operations, a direct comparison of operative mortality between males and females confirms a statistically significant higher mortality for women."

In conducting their study, the authors analyzed data reported to The Society of Thoracic Surgeons National Cardiac Surgery Database. The society's database relies upon data from a wide variety of medical centers throughout the United States and is the largest, most comprehensive, and most utilized of all databases tracking the outcomes of patients receiving some form of open-heart surgery in the world.

All 344,913 coronary artery bypass graft surgery patient records reported to the database between 1994 and 1996 were compared. These reports consisted of 97,153 women (28.17%) and 247,760 men (71.83%). A comparison of the risk factors showed significant differences in the two populations. In general, women were older, had a higher incidence of diabetes, hypertension, and peripheral vascular disease, and underwent nonelective procedures more often. Men were more likely to have poor ventricular function, a significant smoking history, and the need for reoperation. Direct comparisons of patients from separate genders with similar body size and disease state found that a female patient's risk of mortality was higher than a male patient's in every classification measured.

Dr. Edwards adds, "Women and men undergoing heart surgery have very different preoperative characteristics. To provide a true 'apples to apples' comparison of the mortality risks facing heart bypass patients, any analysis determining the influence of gender on heart surgery outcomes must take these differences between men and women into consideration.

"Our study design drew upon national statistics and implemented several 'risk models' that analyzed the data reported to the Society of Thoracic Surgeons' National Cardiac Database. The characteristics of this national database allowed us to group male and female patients into categories and populations with virtually identical co-morbid conditions without regard to geographic limitations. Upon conclusion and analysis of this research, we found that women had significantly higher operative mortality in all categories except for those few in the highest risk category.

"The differences in outcomes and survival rates for men and women are likely not explainable by traditional or existing research and surveys. Finding an explanation for these differences will require new research examining and focusing solely upon practices to improve outcomes and prevent mortality after surgery for either women or men."

Richard P. Anderson, M.D., President of The Society of Thoracic Surgeons added, "Thoracic surgeons are committed to improving the lives of all patients receiving and recovering from heart surgery regardless of gender. The research of Dr. Edwards and others demonstrates a clear but unexplained difference in the outcomes between men and women after coronary artery bypass surgery. These findings indicate a need for further study of gender differences among all patients with heart disease. In particular, this research will serve to focus specific attention on women as thoracic surgeons continue working to ensure recovery of all patients after coronary artery bypass surgery."

The Society of Thoracic Surgeons is the membership society for thoracic surgeons in the United States. With over 4,100 members, the society represents the surgical practice areas of cardiac surgery (heart), general thoracic surgery (pulmonary, lung, esophagus, and mediastinum), pediatric thoracic surgery, and transplant surgery. The society is committed to saving, extending, and improving the quality of life for all Americans.