Background and Purpose-We systematically compared and appraised contemporary guidelines on management of asymptomatic and symptomatic carotid artery stenosis. Methods-We systematically searched for guideline recommendations on carotid endarterectomy (CEA) or carotid angioplasty/stenting (CAS) published in any language between January 1, 2008, and January 28, 2015. Only the latest guideline per writing group was selected. Each guideline was analyzed independently by 2 to 6 authors to determine clinical scenarios covered, recommendations given, and scientific evidence used. Results-Thirty-four eligible guidelines were identified from 23 different regions/countries in 6 languages. Of 28 guidelines with asymptomatic carotid artery stenosis procedural recommendations, 24 (86%) endorsed CEA (recommended it should or may be provided) for ≈50% to 99% average-surgical-risk asymptomatic carotid artery stenosis, 17 (61%) endorsed CAS, 8 (29%) opposed CAS, and 1 (4%) endorsed medical treatment alone. For asymptomatic carotid artery stenosis patients considered high-CEA-risk because of comorbidities, vascular anatomy, or undefined reasons, CAS was endorsed in 13 guidelines (46%). Thirty-one of 33 guidelines (94%) with symptomatic carotid artery stenosis procedural recommendations endorsed CEA for patients with ≈50% to 99% average-CEA-risk symptomatic carotid artery stenosis, 19 (58%) endorsed CAS and 9 (27%) opposed CAS. For high-CEA-risk symptomatic carotid artery stenosis because of comorbidities, vascular anatomy, or undefined reasons, CAS was endorsed in 27 guidelines (82%). Guideline procedural recommendations were based only on results of trials in which patients were randomized 12 to 34 years ago, rarely reflected medical treatment improvements and often understated potential CAS hazards. Qualifying terminology summarizing recommendations or evidence lacked standardization, impeding guideline interpretation, and comparison. This systematic review of contemporary international guidelines was performed to compare and appraise recommendations for the management of patients with ACS and SCS (including accessibility, organization, clarity, and consistency) and the evidence used in making these recommendations. Conclusions-This Methods Guideline SearchesGuidelines with recommendations on the use of CEA or CAS or both patients with ACS or SCS or both were sought systematically using popular search engines, bibliographies, and author professional networks. PubMed and ISI Web of Knowledge were searched independently and synchronously by 2 authors on September 9, 2013 (A.L.A., K.I.P.). PubMed was searched using carotid guideline and then stroke guideline in the title, yielding 91 references after duplicate removal. ISI Web of Knowledge was searched using carotid and guideline and then stroke and guideline in the title, yielding 422 references after removal of duplicates, abstracts, reference materials, letters, corrections, meetings, news, and case reports. Wider searches using the words carotid or stroke and guideline in any ...

Previous studies have addressed the differences in risk factors and stroke mechanisms between ICAS and ECAS, 2,3 but the results are inconsistent. Whereas some reported that hypertension, diabetes mellitus, and metabolic syndrome (MetS) are more closely associated with ICAS, 4-8 this was not confirmed by others. 9-11 It also remains unclear whether the risk factors and stroke mechanisms differ between anterior and posterior circulation atherosclerosis. 12Previous studies examined a small number of patients at single hospitals. 6,7,11 Most importantly, prospective studies that used detailed examinations, including advanced brain and vascular imaging, are scarce. The purpose of this study was to elucidate the differences in the risk factors and mechanisms of stroke between ICAS and ECAS, and between anterior and posterior circulation atherosclerosis. We developed a Background and Purpose-The aim of this study was to investigate differences in risk factors and stroke mechanisms between intracranial atherosclerosis (ICAS) and extracranial atherosclerosis (ECAS) and between anterior and posterior circulation atherosclerosis. Methods-A multicenter, prospective, Web-based registry was performed on atherosclerotic strokes using diffusionweighted magnetic resonance imaging and magnetic resonance angiography. Stroke mechanisms were categorized as artery-to-artery embolism, in situ thrombo-occlusion, local branch occlusion, or hemodynamic impairment. Results-One-thousand patients were enrolled from 9 university hospitals. Age (odds ratio [OR]