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.