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Background: Prospective population-based studies are important to accurately determine the incidence and characteristics of stroke associated with atrial fibrillation (AF), while avoiding selection bias which may complicate hospital-based studies. Methods: We investigated AF-associated stroke within the North Dublin Population Stroke Study, a prospective cohort study of stroke/transient ischaemic attack in 294,592 individuals, according to recommended criteria for rigorous stroke epidemiological studies. Results: Of 568 stroke patients ascertained in the first year, 31.2% (177/568) were associated with AF (90.4%, i.e. 160/177 ischaemic infarcts). The crude incidence rate of all AF-associated stroke was 60/100,000 person-years (95% CI = 52–70). Prior stroke was almost twice as common in AF compared to non-AF groups (21.9 vs. 12.8%, p = 0.01). The frequency of AF progressively increased across ischaemic stroke patients stratified by increasing stroke severity (NIHSS 0–4, 29.7%; 5–9, 38.1%; 10–14, 43.8%; ≥15, 53.3%, p < 0.0001). The 90-day trajectory of recovery of AF-associated stroke was identical to that of non-AF stroke, but Rankin scores in AF stroke remained higher at 7, 28 and 90 days (p < 0.001 for all). Discussion: AF-associated stroke occurred in one third of all patients and was associated with a distinct profile of recurrent, severe and disabling stroke. Targeted strategies to increase anticoagulation rates may provide a substantial benefit to prevent severe disabling stroke at a population level.

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...

Background and Purpose-Transient ischemic attack (TIA) etiologic data and the ABCD 2 score may improve early stroke risk prediction, but studies are required in population-based cohorts. We investigated the external validity of the ABCD