Hormone replacement therapy is safe in women undergoing coronary artery bypass grafting.

In postmenopausal women, hormone replacement therapy (HRT) does not substantially reduce the incidence of cardiovascular disease and may produce a short-term increase in risk. Therefore, we investigated whether HRT increased risk in patients with severe coronary artery disease necessitating surgery. We prospectively studied 4,782 patients undergoing coronary artery bypass grafting at 70 centers in 17 countries from November 1996 through June 2000. Patients were selected using a systematic sampling technique. Mortality, major morbidity, and transfusion requirements were compared among 3 groups: men (n = 3,840), women receiving HRT (n = 144), and women not receiving HRT (n = 798). Women actively receiving HRT, compared with women not receiving HRT or with men, were at no greater risk of developing the following fatal or non-fatal complications: death (2.8% vs 4.4% vs 2.8%, respectively; P = 0.05), myocardial infarction (6.3% vs 7.0% vs 7.7%; P = 0.67), central nervous system complication (2.1% vs 2.8% vs 2.9%; P = 0.85), or renal dysfunction (0.7% vs 5.3% vs 4.8%; P = 0.06). Incidence of postoperative congestive heart failure was significantly lower in men (7.7%) than in women receiving HRT (12.5%; P = 0.04) and in women without HRT (12.8%; P <0.0001). Fewer men (61%) needed red blood cell transfusion than did women receiving HRT (79%) and women without HRT (88%) (P < 0.0001 compared with both other groups). However, the need for fresh frozen plasma transfusions was significantly less in women receiving HRT (16%) than in women not receiving HRT (25%; P = 0.01). We conclude that HRT administration before coronary artery bypass grafting does not increase women's risk of any adverse outcome.