Stroke Subtype Classification to Mechanism-Specific and Undetermined Categories by TOAST, A-S-C-O, and Causative Classification System

Abstract

Background and Purpose-Reliable etiologic classification of ischemic stroke may enhance clinical trial design and identification of subtype-specific environmental and genetic risk factors. Although new classification systems (Causative Classification System [CCS] and ASCO [A for atherosclerosis, S for small vessel disease, C for cardiac source, O for other cause]) have been developed to improve subtype assignment, few comparative data exist from large studies. We hypothesized that both CCS and ASCO would reduce the proportion of patients classified as cause undetermined compared with the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) scheme in a large population-based stroke study. Methods-A single rater classified all first-ever ischemic strokes in the North Dublin Population Stroke Study, a population-based study of 294 529 North Dublin residents. Published algorithms for TOAST, CCS, and ASCO were applied. Results-In 381 first-ever ischemic stroke patients, CCS assigned fewer patients as cause undetermined (26.2% versus 39.4%; PϽ0.000001), with increased assignment of cardio-aortic embolism (relative increase 6.9%; Pϭ0.004), large artery atherosclerosis (relative increase 44.1%; Pϭ0.00006), small artery occlusion (relative increase 27.3%; Pϭ0.00006), and other causes (relative increase 91.7%; Pϭ0.001) compared with TOAST. When ASCO grade 1 evidence was applied, fewer patients were classified as small artery disease (relative decrease 29.1%; Pϭ0.007) and more as large artery/atherothrombotic (relative increase 17.6%; Pϭ0.03). ASCO grade 1 did not reduce the proportion of cause undetermined cases compared with TOAST (42.3% versus 39.4%; Pϭ0.2). Agreement between systems ranged from good (ϭ0.61 for TOAST/ASCO grade 1 small artery category) to excellent (ϭ0.95 for TOAST/CCS and ASCO grade 1/CCS cardio/aorto-embolism category). Application of ASCO grades 1 to 3 indicated evidence of large artery/atherosclerosis (73.3%), cardio-embolism (31.3%), small artery (64.7%), and other cause (12%) in TOASTundetermined cases. Conclusion-Both CCS and ASCO schemes showed good-to-excellent agreement with TOAST, but each had specific characteristics compared with TOAST for subtype assignment and data retention. The feasibility of a single combined classification system should be considered. (Stroke. 2010;41:1579-1586.)Key Words: cerebral infarct Ⅲ subtypes Ⅲ causative classification system Ⅲ TOAST Ⅲ ASCO K ey outcomes such as disability, fatality, and recurrence after ischemic stroke differ according to subtype defined by stroke mechanism. 1,2 Identification of the underlying cause of stroke is an important element of daily clinical practice, guiding treatment decisions and prognosis for individual patients. Accurate and reproducible assignment of the likely mechanism of ischemic stroke is also important in clinical trials investigating benefit in specific patient groups 3 (eg, cardioembolic or atherosclerotic stroke) and in epidemiological studies investigating associations between environ- The Trial of ORG 10172 in Acut...

Incidence and mortality of ischemic stroke subtypes in Joinville, Brazil: a population-based study

“…This was previously reported in epidemiological studies based on the same pathophysiological classification 2, 3,4,10 . Recent studies have chosen different criteria for stroke subtype definition 5,22 . These new criteria, combined with advanced diagnostic techniques, could help reducing the cryptogenic stroke observed in UND subtype 23 .…”

Mechanisms and treatment of ischaemic stroke—insights from genetic associations

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Endovascular Treatment of Carotid Atherosclerosis: Concerns and Perspectives

“…Согласно классификации TOAST (от названия исследования -Trial of ORG 10172 in Acute Stroke Treatment) выделяют следующие подтипы ише-мического инсульта: атеротромботический (патология крупных экстра-и интракраниальных сосудов), кар-диоэмболический, лакунарный (патология мелких ин-тракраниальных сосудов головного мозга), инсульт другой установленной этиологии и инсульт неустанов-ленной этиологии (криптогенный) [5,6]. Впоследствии также появились другие классификации: CCS (Causative Classification System) и A-S-C-O (Atherosclerosis, Small-vessel disease, Cardiac source, Other cause), позволившие бо-лее точно определять подтипы ишемического инсульта и уменьшить количество криптогенных инсультов [7,8]. В отечественной литературе распространена класси-фикация, разработанная сотрудниками Научного цент-ра неврологии (НИИ Неврологии РАМН) [2].…”