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Etiology

Women had a lower risk than men for mortality after coronary revascularization

ACP J Club. 1999 Mar-April;130:49. doi:10.7326/ACPJC-1999-130-2-049


Source Citation

Jacobs AK, Kelsey SF, Brooks MM, et al. Better outcome for women compared with men undergoing coronary revascularization. A report from the Bypass Angioplasty Revascularization Investigation (BARI). Circulation. 1998 Sep 29;98:1279-85.


Abstract

Question

In patients who have symptomatic multivessel coronary disease, do women have a less favorable long-term outcome after coronary revascularization than men?

Design

Subgroup analysis of a randomized controlled trial with a mean follow-up of 5.4 years (Bypass Angioplasty Revascularization Investigation [BARI]).

Setting

16 centers in the United States and 2 centers in Canada.

Patients

489 women (mean age 64 y) and 1340 men (mean age 61 y) who had severe angina or myocardial ischemia and multivessel coronary disease and were candidates for CABG or PTCA.

Assessment of risk factors

Patients were allocated to CABG { n = 914}* or PTCA { n = 915}*. Sex differences in outcomes were assessed.

Main outcome measures

Procedural factors; in-hospital mortality, myocardial infarction (MI), and major complications; long-term mortality and MI after hospital discharge; symptoms of angina; and repeated revascularization procedures.

Main results

At baseline, women were older than men (mean age 64 vs 61 y, P < 0.001) and were more likely than men to have congestive heart failure (14% vs 7%, P < 0.001), diabetes mellitus (31% vs 15%, P < 0.001), a history of hypercho-lesterolemia (54% vs 40%, P < 0.001) or hypertension (68% vs 42%, P < 0.001), unstable angina (67% vs 61%, P < 0.02), and comorbid conditions (29% vs 23%, P < 0.01). Internal mammary artery conduits were used in fewer women than men (72% vs 85%). Mean number of grafts was similar for men and women. More women than men had multilesion angioplasty (80% vs 76%, P = 0.03) and more congestive heart failure or pulmonary edema in the hospital (9.8% vs 1.8%, P < 0.001 for the CABG group and 4.8% vs 1.4%, P = 0.005 for the PTCA group). At 6 months and at 5 years, angina rates did not differ between women and men. In the PTCA group, women were less likely than men to have repeated revascularization (relative risk [RR] 0.74, P = 0.01), whereas those in the CABG group had more revascularization (RR 1.74, P = 0.04). No differences between women and men existed for in-hospital Q-wave MI or death, for 5-year survival, or in the rate of survival free of MI. A multivariate regression model, which adjusted for baseline characteristics and treatment assignment, showed that women had a lower mortality risk than men (RR 0.60, 95% CI 0.43 to 0.84).

Conclusion

After adjustment for baseline characteristics and type of treatment in patients who had symptomatic multivessel coronary disease, women had a lower risk than men for death after coronary revascularization.

Source of funding: National Heart, Lung, and Blood Institute.

For correspondence: Dr. A.K. Jacobs, Section of Cardiology, Boston Medical Center, 88 East Newton Street, Boston, MA 02118, USA. FAX 617-638-8712.

*The Bypass Angioplasty Revascularization Investigation (BARI) Investigators. N Engl J Med. 1996;335:217-25.


Commentary

The BARI study is the largest recent multicenter trial to compare PTCA with CABG, and the results showed no survival advantage of either treatment except in diabetic patients who had better survival after CABG. Jacobs and colleagues completed a subgroup analysis of BARI. The data showed that overall survival (by Kaplan-Meier curves) was identical in men and women. However, after adjustment for baseline risk factors, the mortality rate in women was 40% (CI 16% to 57%) lower than that in men.

In the National Heart, Lung, and Blood Institute's registry of coronary angioplasty, the initial mortality rate was higher in women (2.6% vs 0.3% for men, P < 0.001), but subsequent survival to 4 years did not differ (1). This is an old study (1985 to 1986), and it does not represent current status. In this study, all patients had vessels > 1.5 mm and similar operative mortality. The Cleveland Clinic reported that higher operative mortality in women was eliminated as a risk factor when body size was considered (2). They reported no sex differences in long-term survival after CABG. Vessel size is an important determinant of short- and long-term progression. Some of the differences between men and women may result from the difference in vessel size at baseline.

It seems that despite more comorbid conditions, women with larger coronary vessels have similar operative mortality rates and have at least similar and possibly better long-term survival rates than men. The coronary anatomy (particularly vessel size), left ventricular function, and severity of symptoms—not the patient's sex—should influence the decision for CABG.

Jai B. Agarwal, MD
UMDNJ Robert Wood Johnson Medical SchoolNew Brunswick, New Jersey, USA


References

1. Kelsey SF, James M, Holubkov AL, et al. Results of percutaneous transluminal coronary angioplasty in women. 1985-1986 National Heart, Lung, and Blood Institute's Coronary Angioplasty Registry. Circulation. 1993;87:720-7.

2. Loop FD, Golding LR, MacMillan JP, et al. Coronary artery surgery in women compared with men: analyses of risks and long-term results. J Am Coll Cardiol. 1983;1:383-90.