BACKGROUND:

Coronary atherosclerosis is a major cause of death in women in the United States. Although coronary artery bypass surgery decreases symptomatic and clinical evidence of ischemia, it does not alter the underlying process. Patients may present several years later with recurrent symptoms that may be a result of occlusion of saphenous vein grafts, development of atherosclerotic disease in vein grafts, or progression of underlying disease. Any intervention that can reduce the rate of progression of coronary atherosclerosis following bypass surgery would provide significant benefit for women following bypass surgery and possibly for other women with atherosclerotic disease. Observational studies suggest that postmenopausal estrogen replacement therapy is associated with a reduction in cardiac morbidity.

DESIGN NARRATIVE:

The study was a randomized, double-blind, controlled trial. Subjects were randomized to conjugated estrogen with daily medroxyprogesterone or placebo within two weeks of bypass surgery. Graft occlusion and development of vein graft atherosclerosis were measured by comparing quantitative coronary angiographic and vascular ultrasonic assessment of disease severity and extent performed at six months and three and a half years after randomization. The primary outcome variables included the occurrence of graft occlusion at six months and the change in severity and extent of atherosclerosis in the saphenous vein grafts over three years. The trial determined the influence of hormone replacement therapy on the primary outcome variables.