Table 1.

Evidence for the Treatment of Asymptomatic Carotid Stenosis

	Year and location	Patients, n (follow-up time, years)	Stenosis Inclusion	Excluded medical conditions	Composite primary endpoint	Findings	Perioperative risk of stroke or death within 30 days	Major criticisms
ACAS12	1995, United States	1,662 (median 2.7)	≥60% stenosis	TIA or stroke symptoms, lifespan <5 years	Ipsilateral stroke or any perioperative stroke and death	5-year stroke risk of 11% vs 5.1% for medical therapy vs CEA (P=0.004)	1.5%	Medical management not contemporary; surgeon inclusion criteria too stringent
ACST13	2004, Europe	3,120 (mean 3.4)	≥60% stenosis	Previous ipsilateral CEA, poor surgical risk, cardiac source of emboli	Perioperative death, stroke or MI, nonperioperative stroke	5-year stroke risks 11.8% vs 6.4% for medical vs CEA (<75 years old; P<0.0001)	3.1%	Medical management not contemporary
SAPPHIRE80	2008, North America	237 (=3.0)	≥80% stenosis with one or more criteria for high surgical risk	Ischemic stroke <48 hours, intraluminal thrombus, target vessel occlusion, intracranial aneurysm, bleeding disorder, ostial lesion of common carotid or brachiocephalic	Cumulative incidence of death, stroke, or myocardial infarction during follow-up of 3 years	3-year CAS vs CEA, 24.6% vs. 26.9% (no statistical comparison) for high-risk asymptomatic	CAS 5.4%, CEA 4.6% for high-risk asymptomatic	Biased randomization, industry-sponsored, surgeon/interventionalist skills biased
CREST91	2010, United States	1,181 (median 2.5)	≥60% stenosis on angio, ≥70% by ultrasound	Disabling stroke, chronic atrial fibrillation <6 months	Stroke, MI, death 30 days periprocedural or ipsilateral stroke during follow-up	4-year CEA vs CAS, 4.9% vs 5.6% (P=0.56) for asymptomatic	CAS 2.5%; CEA 1.4% for asymptomatic	CAS patients received more intensive antiplatelet therapy, inclusion of asymptomatic patients, age-stratified difference

Abbreviations: ACAS, Asymptomatic Carotid Atherosclerosis Surgery; ACST, Asymptomatic Carotid Stenosis Trial; CREST, Carotid Revascularization Endarterectomy Versus Stenting Trial; CEA, carotid endarterectomy; ASA, aspirin; CAS, carotid artery stent; TIA, transient ischemic attack; CTA, computed tomography angiography; MRA, magnetic resonance angiography; MI, myocardial infarction; SAPPHIRE, Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy; vs, versus.