Table 1. Summary characteristics of randomized controlled trials.
| Study (years) | Asymptomatic patients | Follow-up duration (years) | Diagnosis of carotid stenosis | Stenosis (%) | Previous symptoms (%)* | Excluded medical condition | Definition of medical therapy† | Definition of asymptomatic status | Features of CAS or CEA | |
|---|---|---|---|---|---|---|---|---|---|---|
| CAS vs. CEA | ||||||||||
| Kougias et al.5) (2011–2013) | 27/28 | 0.5 | DUS, CTA, MRA, DSA | ≥80 | Not reported | High surgical risk | Antiplatelet | No symptoms | CAS: routine EPD (100%) | |
| CEA: selective shunt; routine patch closure | ||||||||||
| ACT 16) (2005–2013) | 1,089/364 | 5.0 | DUS, DSA | ≥70 | 12.6 | Age more than 80 years; high surgical risk; contralateral carotid stenosis | Antiplatelet‡ | No ipsilateral symptoms more than 6 months | CAS: routine EPD (97.8%) | |
| CEA: selective shunt; selective patch closure | ||||||||||
| CREST7) (2000–2008) | 594/587 | 7.4 | DUS, CTA, MRA, DSA | ≥60 | 2.5 | Atrial fibrillation; recent MI; unstable angina | Antiplatelet‡; standard medical therapy | No symptoms or ipsilateral symptoms (>6 months) or recent symptoms in a different territory | CAS: routine EPD (96.1%) | |
| CEA: selective shunt (54%); selective patch closure (69%) | ||||||||||
| SAPHIRE8) (2000–2002) | 117/120 | 3.0 | DUS | ≥80 | 24 | Ischemic stroke <48 hours | Antiplatelet‡; standard medical therapy | No symptoms | CAS: routine EPD (95.6%) | |
| CEA: not reported | ||||||||||
| CEA vs. MT | ||||||||||
| Kolos et al.26) (2009–2013) | 31/24 | 3.3 | DUS, CTA, MRA | ≥70 | 16.4 | High surgical risk | Antiplatelet; antihypertensive; lipid-lowering therapy; lifestyle modification | No symptoms | CEA: eversion CEA in most cases | |
| ACST25) (1993–2003) | 1,560/1,560 | 10.0 | DUS | ≥60 | 24 | Recent MI; cardiac source of emboli; CEA and CABG | Antiplatelet; antihypertensive; lipid-lowering therapy in later years of follow-up | No symptoms or ipsilateral symptoms (>6 months) | CEA: selective shunt; selective patch closure | |
| ACAS23) (1987–1993) | 825/834 | 2.7 | CEA: DSA; MT: DUS | ≥60 | 5 | Atrial fibrillation; MI; unstable angina; severe diabetes or hypertension | Antiplatelet; standard medical therapy and lifestyle modification | No symptoms or contralateral symptoms (>1.5 months) or recent symptoms in a different territory | CEA: not reported | |
| VA24) (1935–1983) | 211/233 | 3.9 | DUS | ≥50 | 32 | High surgical risk | High-dose aspirin; standard medical therapy | No symptoms | CEA: not reported | |
ACAS = Asymptomatic Carotid Atherosclerosis Study; ACST = Asymptomatic Carotid Surgery Trial; ACT 1 = Asymptomatic Carotid Trial; CABG = coronary artery bypass grafting; CAS = carotid artery stenting; CEA = carotid endarterectomy; CREST = Carotid Revascularization Endarterectomy Versus Stenting Trial; CTA = computed tomography angiography; DSA = digital subtraction angiography; DUS = duplex ultrasonography; EPD = embolic protection device; MI = myocardial infarction; MRA = magnetic resonance angiography; MT = medical treatment; SAPPHIRE = Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy; VA = Veterans Affairs.
*Can include any 1 or more of the following: symptoms related to contralateral carotid or other vascular territory or endarterectomy in the contralateral carotid artery; †The definition of standard medical therapy was not provided by trials; ‡CAS received dual-antiplatelet and CEA received single-antiplatelet treatment.