Sex differences in carotid plaque and stenosis

Background and Purpose - Women are relatively protected from cardiovascular events; they are 3 times as likely as men to survive to age 90 years. Although clinical trials show an excess of thrombotic events with estrogen/progestin hormone replacement therapy, much experimental and epidemiological evidence suggests that estrogen may have beneficial effects on endothelial function and atherosclerosis, raising the possibility of sex differences in arterial remodeling. We studied sex differences in carotid plaque and stenosis in relation to survival free of stroke, death, and myocardial infarction. Methods - A total of 1686 patients from an atherosclerosis prevention clinic were followed annually for up to 5 years (mean, 2.5+/-1.3 years) with baseline and follow-up measurements; there were 45 strokes, 94 myocardial infarctions, and 41 deaths. Results - Carotid stenosis and plaque increased with age. Women had greater stenosis compared with men (P=0.001), whereas men had greater plaque area than did women at all ages (P<0.0001). Stroke, myocardial infarction, and death combined were predicted significantly by plaque area (P=0.004) but not by stenosis (P=0.042). Conclusions - Women have more stenosis but less plaque than men, suggesting that differences in sex hormones may affect remodeling of atherosclerosis. Plaque area was a stronger predictor of outcomes than was stenosis.