Gender as a primary predictor of outcome after carotid endarterectomy

Post hoc analysis results of the North American Symptomatic Carotid Endarterectomy Trial and the Asymptomatic Carotid Atherosclerosis Study suggest that carotid endarterectomy (CEA) may not be as efficacious in women as it is in men. This study was undertaken for the evaluation of whether there is a difference between men and women in early postoperative outcome after CEA and whether such a difference is consistent across other predictors.

We conducted a retrospective review of all CEAs entered into our departmental registry between January 1, 1989, and November 30, 2000. A total of 3422 CEAs was performed in 3077 consecutive patients. The ratio of men to women was 2:1, and the ratio of patients who were asymptomatic to patients who were symptomatic was 2.3:1. The following in-hospital outcome data were analyzed: transient ischemic attack (TIA), stroke, mortality, combined TIA or stroke, and combined stroke or mortality. Univariate and multivariate analysis results of selected risk factors for an adverse perioperative event were assessed with generalized estimating equation analysis with backwards selection. The following risk factors were considered: gender, preoperative neurologic status, urgency of operation, type of arteriotomy repair, reoperative CEA for recurrent stenosis, history of cardiopulmonary disease, previous coronary artery intervention, simultaneous CEA and coronary bypass grafting surgery, renal failure, and diabetes.

Univariate analysis results of gender differences revealed that women were at higher risk for a postoperative TIA or stroke (3.3% for women versus 2.1% for men; odds ratio [OR], 1.6; confidence interval [CI], 1.04 to 2.5; P =.03) and for postoperative stroke or mortality (3.1% for women versus 2.1% for men; OR, 1.6; CI, 1.04 to 2.5; P =.03). Multivariate analysis results showed that female gender was an independent predictor for a postoperative TIA or stroke (OR, 1.7; CI, 1.1 to 2.6; P =.03). Further analysis disclosed that women who were asymptomatic were at greater risk than were men for postoperative stroke or mortality (OR, 2.3; CI, 1.3 to 3.9; P =.003). Conversely, there was no gender association for postoperative stroke or mortality in the consideration of only patients who were symptomatic (OR, 1.0; CI, 0.45 to 2.1; P =.95). The interaction between women and preoperative symptoms approached significance (P =.07) with respect to postoperative stroke and mortality rate, which suggests that the gender effect could be influenced by the clinical presentation.

The combined TIA or stroke and stroke or mortality rates are higher in women as compared with men in the postoperative period, but these risks remain acceptable when CEA is performed for appropriate indications. The interaction between symptoms and gender suggests that, in patients who are asymptomatic, women are more likely than are men to have early complications. However, there is no gender difference in patients who are symptomatic. Therefore, despite a low postoperative complication rate, CEA is appropriate in both women who are asymptomatic and women who are symptomatic only if the postoperative TIA, stroke, and mortality rates are appreciably lower than in the natural history of medical management of these patients.