Our objective was to answer the following key questions regarding the treatment strategies involved in the management of asymptomatic carotid stenosis. These key questions were formulated in consultation with CMS and AHRQ.

1. In asymptomatic patients with carotid artery stenosis, what is the evidence on long-term clinical outcomes (at least 12 months of followup), including stroke, death, myocardial infarction, and other cardiovascular events, for the following interventions and comparisons?
   1. Medical therapy alone
   2. CEA and medical therapy versus medical therapy alone
   3. CAS and medical therapy versus medical therapy alone
   4. CAS and medical therapy versus CEA and medical therapy
2. Among comparative studies (CEA and medical therapy versus medical therapy alone, CAS and medical therapy versus medical therapy alone, CAS and medical therapy versus CEA and medical therapy), what is the impact of the following patient, intervention, and study characteristics on treatment efficacy?
   • Demographic and other baseline features of studied patients, including applicability of studies to patients ≥ 65 years with asymptomatic carotid artery stenosis, subgroup of patients ≥ 80 years, and sex
   • Clinical, and anatomic features of carotid artery stenosis in the studies
   • Average or high risk for carotid endarterectomy due to comorbid diseases
   • Types of the stents used and use of embolic protection devices
   • Concurrent and postoperative treatments
   • Length of followup
   • Methodological quality of studies
3. Among comparative studies (CEA and medical therapy versus medical therapy alone, CAS and medical therapy versus medical therapy alone; CAS and medical therapy versus CEA and medical therapy), what is the evidence on adverse events and complications during the periprocedural period?