Hormone replacement therapy is associated with improved survival in women undergoing coronary artery bypass grafting

The effect of hormone replacement therapy on cardiovascular events in postmenopausal women is controversial. We investigated the roles of sex and hormone replacement status in female patients undergoing coronary artery bypass grafting.

We reviewed the records of 4259 consecutive patients aged 55 years or older who underwent primary elective isolated coronary artery bypass at our hospital between May 1996 and September 2001.

Female sex with hormone replacement therapy was an independent predictor of decreased mortality, regardless of age. Mortality was 6.7% (61/905) for women not receiving hormone replacement therapy, 2.3% (6/256) for hormone replacement therapy recipients, and 2.7% (82/3098) for men (P <.01 for all comparisons). Of the characteristics examined, multivariate analysis indicated that independent predictors of mortality were advanced age, previous congestive heart failure, class IV angina, and female sex without hormone replacement (P <.005). Independent predictors of survival included use of an internal thoracic artery graft and white ethnicity. There were no significant intergroup differences in the incidence of nonfatal, morbid postoperative events.

Postmenopausal women undergoing coronary artery bypass had a significantly improved in-hospital survival if they had been receiving hormone replacement therapy. The improved survival might be related to one or more of the numerous cardiovascular effects of estrogen that are considered beneficial. A prospective randomized trial is needed to validate the observation that hormone replacement therapy is protective in this setting.