Endarterectomy in carotid artery disease. A decision analysis.

Carotid endarterectomy is being performed with increasing frequency, now over 100,000 times annually in the United States. We used the methods of decision analysis to examine the question of when to perform carotid endarterectomy. We developed a model that simulates the possible outcomes for a cohort of patients at risk for stroke. Estimates of surgical risk, surgical efficacy, annual stroke rate, and nonstroke mortality were derived from the literature. Using sensitivity analysis, we found that surgical risk, surgical efficacy, and stroke risk are the most important factors in determining when surgery is appropriate. By examining a series of clinical scenarios, we constructed guidelines for carotid endarterectomy based on the estimated risk of future stroke. The analysis suggests that for patients with a risk of less than 3% per year, surgery is not indicated. For patients with risk between 3% and 5% per year, low-risk surgery can be expected to provide a benefit of at most three months of quality life, depending on the efficacy of surgery. For stroke risk between 5% and 10% per year, even high-risk surgery is favored if surgical efficacy is above 30%. Above a stroke risk of 10% per year, even high-risk, low-efficacy surgery should be considered. The challenge to advocates of carotid endarterectomy is to develop a cost-effective strategy for identifying patients at high risk for stroke.