RECURRENT CAROTID STENOSIS - RESULTS OF THE ASYMPTOMATIC CAROTID ATHEROSCLEROSIS STUDY

Background and Purpose-We sought to determine the incidence of recurre nt carotid stenosis in patients in the Asymptomatic Carotid Atheroscle rosis Study (ACAS) who had undergone carotid endarterectomy and were p rospectively followed with Doppler ultrasound for up to 5 years. Metho ds-The ACAS database was interrogated to determine the rate of recurre nt carotid stenosis (greater than or equal to 60%) based up angiogram- validated Doppler data, with a 90% and a 95% positive predictive value , as well as information concerning the technologists' interpretation of percent stenosis. These 3 parameters are reported for each of 3 tim e intervals: within 3 months of operation (residual disease), between 3 and 18 months (early restenoses), and between 18 and 60 months (late restenosis). Results-Of the 825 patients randomized to the surgical a rm of the study, 720 actually underwent carotid endarterectomy, and 64 5 had complete ultrasound data. The aggregate incidence of residual an d recurrent carotid stenosis for all time intervals ranged from 12.7% to 20.4%, depending on the positive predictive value confidence level desired. Residual disease occurred in 4.1% to 6.5%; true, early resten osis was found in 7.6% to 11.4%; and late restenosis occurred in 1.9% to 4.9%. None of the traditional risk factors showed a statistically s ignificant effect on recurrent stenosis. The use of patch angioplasty closure reduced overall risk of restenosis from 21.2% to 7.1%, from 16 .7% to 4.6%, and from 27.4% to 8.2%, depending on the PPV confidence l evel desired (P<0.001). Of the 136 patients judged to have recurrent s tenosis, only 8 (5.9%) underwent reoperation (only 1 for symptoms). Th ere was no correlation between late stroke and recurrent stenosis. Con clusions-Carotid endarterectomy is a durable procedure with a low rate of true restenosis, particularly when patch angioplasty is used to cl ose the arteriotomy.