Long-term clinical and angiographic outcomes in symptomatic patients with 70% to 99% carotid artery stenosis

Background and Purpose-In 1991, the North American Symptomatic Carotid Enda rterectomy Trial (NASCET) reported the benefit of carotid endarterectomy fo r 659 patients with 70% to 99% stenosis. Follow-up continued until 1997. Methods-The present study examined the risks and causes of ipsilateral stro ke in the randomized groups and in those who had delayed endarterectomy or continued on medical therapy and also examined the evolution of carotid dis ease on follow-up imaging. Results-By on-treatment (efficacy) analysis, the risk of any ipsilateral st roke at 3 years was 28.3% for medically randomized and 8.9% for surgically randomized patients (19.4% absolute risk reduction, P<0.001). For combined disabling or fatal ipsilateral stroke, the risks were 14.0% and 3.4%, respe ctively (10.6% absolute risk reduction). In medical patients, >80% of the f irst strokes at 3 years were of large-artery origin. After February 1991, 1 16 suitable medical patients underwent endarterectomy within 6 months, and 115 continued on medical therapy. The 3-year risk of any ipsilateral stroke in the groups of 116 and 115 patients was 7.9% and 15.0%, respectively (7. 1% absolute risk reduction). During follow-up, 81 patients had angiograms c omparable to the baseline images. Progression by greater than or equal to 1 0% occurred in 7 patients; regression, in 8; no change, in 39; and occlusio n, in 27. By use of both angiography and ultrasound, 63 (25.5%) of the 247 medically treated patients progressed to occlusion, of whom 31.7% had an ip silateral stroke before or on the day of occlusion. Conclusions-Endarterectomy for patients with 70% to 99% stenosis and recent symptoms was efficacious in the long term. Compared with patients who cont inued on medical therapy, medical patients with delayed endarterectomy expe rienced a moderate benefit. Medically treated patients experienced a high r isk of occlusion.