Epidemiology of carotid endarterectomies among Medicare beneficiaries.

Extensive debates exist in the literature on the indications, effectiveness, and risks of carotid endarterectomy. However, no investigations analyze the procedure's epidemiology. Medicare paid for essentially all carotid endarterectomies on patients over 65 years old, more than two thirds of all such surgery. Accordingly, we identified all 1985 to 1989 Medicare bills for ICD-9-CM code 38.12. This report found an average annual decrease of 6.4% in the frequency of carotid endarterectomies. Higher proportions and incidence rates occurred among 65- to 79-year-old people, men, and whites. Larger, urban, and nonprofit hospitals performed the procedure more often. The number of hospitals performing this procedure has increased over time. Mortality rates within 30 days decreased from 3.0% of procedures in 1985 to 2.5% in 1989. Higher than average death rates occurred among older, male, and black patients, and in low volume hospitals. Clinical trials undertaken in large, urban, teaching, high-volume institutions reported only 1% deaths. The institutions actually performing carotid endarterectomies differ from the clinical trials in their demography and perioperative mortality rates. This difference in community practice may limit the applicability of the clinical trials.