Learning curve for carotid endarterectomy.

It is generally accepted that training and experience are necessary to obtain acceptably low perioperative mortality and permanent neurologic morbidity for carotid endarterectomy. To test this hypothesis I analyzed the results of 600 consecutive primary carotid endarterectomies that I performed over a 13-year period beginning with my senior residency. The overall hospital mortality was 9/600 (1.5%), the permanent neurologic morbidity 11/600 (1.8%), and the combined mortality and permanent neurologic morbidity 20/600 (3.3%). The mortality for the first 300 operations was 6/300 (2%) (4/6 from stroke) and for the last 300, 3/300 (1%) (3/3 cardiac). All 11 nonfatal strokes occurred in the first 300 operations. Morbidity and mortality decreased with both cumulative experience and the number of operations done per year. While it is difficult to separate the effect of these two factors, the results suggest that both may be important in obtaining a combined perioperative mortality and permanent neurologic deficit below 3%.