THE FALL AND RISE OF CAROTID ENDARTERECTOMY IN THE UNITED-STATES AND CANADA

Background Randomized clinical trials have demonstrated the efficacy o f carotid endarterectomy in the prevention of stroke when the procedur e is performed in regional centers of surgical excellence. However, th e relative effects of these studies on the rates of carotid endarterec tomy in the United States and Canada have been unclear. Methods We cal culated the annual rate of carotid endarterectomy in the U.S. states o f California and New York and in the Canadian province of Ontario from 1983 through 1995. We also studied whether patients in the early 1990 s were selectively referred to hospitals with high volumes of procedur es and historically low in-hospital mortality rates. Results Rates of carotid endarterectomy fell in all three regions from 1984 to 1989 (fr om 126 to 66 per 100,000 adults 40 years of age or older in California , from 65 to 40 per 100,000 in New York, and from 40 to 15 per 100,000 in Ontario), after the publication of studies demonstrating that the rates of complications of carotid endarterectomy were unacceptably hig h. However, the clinical trials of the 1990s, which showed benefit fro m carotid endarterectomy, were associated with a dramatic resurgence i n the rates of the procedure from 1989 to 1995 (from 66 to 99 per 100, 000 in California, from 40 to 96 per 100,000 in New York, and from 15 to 38 per 100,000 in Ontario). These increased rates were not associat ed with proportionally greater numbers of referrals of patients to hos pitals with low mortality rates. Conclusions There have been a dramati c fall and a rise in the rates of carotid endarterectomy in both the U nited States and Canada, which correlate with the publication of first unfavorable and then favorable clinical studies. The absence of selec tive referral of patients to centers with the lowest mortality rates r aises questions about whether the benefits of carotid endarterectomy i n the general population are similar to those demonstrated in the clin ical trials. (N Engl J Med 1998;339:1441-7.) (C) 1998, Massachusetts M edical Society.