Five years after receiving CABG or angioplasty, 87 percent of women enrolled in the Bypass Angioplasty Revascularization Investigation (BARI) had survived--a rate nearly identical to the 88 percent survival rate of the men studied. Furthermore, a special statistical analysis found that being female was an independent predictor of higher survival, with women having 60 percent of the risk of death compared with men. The study will be published in the September 29 issue of Circulation.
"This is good news for women with heart disease who may have been concerned about reports that they were at greater risk than men for these procedures. Heart disease remains the number one killer of American women and this study shows that two important treatment strategies are just as safe and effective for them as they are for men," said NHLBI Director Dr. Claude Lenfant.
Previous research on "revascularization" procedures such as bypass surgery and angioplasty has shown higher rates of death and complications among women compared to men. Part of the impetus for conducting the new study, report the authors, was to gauge the effect of advances in technology and surgical technique on outcome in women.
The BARI study is the largest randomized clinical trial to compare bypass surgery and angioplasty in patients with multivessel coronary artery disease who were eligible for either procedure. Between 1988 and 1991, the study enrolled 1, 829 patients who were randomly assigned to either bypass surgery or angioplasty. Twenty-seven percent (489) of the BARI participants were women and 73 percent (1, 340) were men. The main results from BARI, published in 1996, found that both angioplasty and CABG are effective and result in similar mortality rates.
"This is one of the largest studies of women undergoing vascularization," asserted Dr. George Sopko, leader of the Clinical Medicine Research Group at NHLBI and a co-author of the study.
The new study found that not only were long-term survival rates comparable for men and women but in-hospital survival was also similar for men and women in both the bypass and angioplasty groups. As orginally predicted, the authors note that this may be due to improvements in technology and procedures. Five-year survival without a heart attack was also comparable for men and women within both of the treatment groups.
Women in the BARI study were older than the men, had more congestive heart failure, diabetes, high blood pressure, and high blood cholesterol. They also had more unstable angina and other coexisting diseases than the men. Despite these risk factors, the women had a similar degree of heart disease. The meaning of these apparently contradictory findings is unclear and needs further research, according to the authors.
In 1995, the NHLBI issued a clinical alert to U.S. physicians on results from BARI which found that patients with diabetes who were treated with CABG had a markedly lower death rate after 5 years than similar patients treated with angioplasty. The new study did not find a significant difference in survival between the two treatment strategies among women with diabetes. According to the study authors, this may be due to the relatively small number of women with diabetes compared to men.
Dr. Alice K. Jacobs of Boston Medical Center is the lead author of the study. To arrange an interview with co-author Dr. George Sopko, contact the NHLBI Communications Office at (301) 496-4236.
Additional information on women and heart disease can be found on the NHBLI's home page: http://www.nhlbi.nih.gov/nhlbi/nhlbi.htm