ABSTRACT
Atherosclerosis from supra-aortic vessels and especially from the common carotid bifurcation accounts for approximately 15% of all strokes (1,2). The benefit of carotid endarterectomy (CEA) in reducing the risk of stroke in symptomatic and asymptomatic patients with carotid artery (CA) stenosis has been established in randomized trials. In The North American Symptomatic Carotid Endarterectomy Trial (NASCET), the risk of any ipsilateral stroke was reduced significantly in patients with carotid stenosis of 70-99% (absolute risk reduction [ARR] ±SE: 17 ± 3.5% in 2 years) and with stenosis of 50-69% (ARR of 6.5% in 5 years) (3-6). This risk reduction did not extend to patients with <50% stenosis (6-8). In the European Carotid Surgery Trial (ECST), CEA led to a reduction in the 5-year risk of any stroke by 5.7% [95% confidence interval (CI), 0 to 11.6] in patients with 50% to 69% stenosis and by 21.2% (95% CI, 12.9 to 29.4) in patients with 70% to 99% stenosis (9-11). In both the NASCET and the ECST, randomization within 2 weeks of the last ischemic event contributed to an increase in the effectiveness of surgery in the number needed to treat to prevent one ipsilateral stroke (p = 0.009) (12). Randomized trials in asymptomatic patients with stenosis >60% showed an ARR for ipsilateral stroke at 5 years of 5.9% in the Asymptomatic Carotid Atherosclerosis Study (ACAS) and 5.4% in the Asymptomatic Carotid Surgery Trial (ACST), with a net gain of 4.6% at 10 years according to the results of ACST (13-16).
