Early risk of recurrence by subtype of ischemic stroke in population-based incidence studies.

To study the early risk of recurrent stroke by etiologic subtype. The authors studied risk of recurrent stroke by etiologic subtype (Trial of ORG 10172 in Acute Stroke Treatment [TOAST] classification) in patients in two population-based studies: the Oxford Vascular Study and the Oxfordshire Community Stroke Project. A meta-analysis was performed with data from the only two other published studies reporting equivalent data. The four studies included 1,709 strokes with 30 recurrences at 7 days, 72 at 30 days, and 113 at 3 months. Recurrent stroke risk varied between subtypes (p < 0.001). Compared with other subtypes, patients with stroke due to large-artery atherosclerosis (LAA) had the highest odds of recurrence at 7 days (odds ratio [OR] = 3.3, 95% CI = 1.5 to 7.0), 30 days (OR = 2.9, 95% CI = 1.7 to 4.9), and 3 months (OR = 2.9, 95% CI = 1.9 to 4.5). Odds of recurrence at 30 days for other subtypes were cardioembolic (OR = 1.0, 95% CI = 0.6 to 1.7), undetermined (OR = 1.0, 95% CI = 0.6 to 1.6), and small-vessel stroke (OR = 0.2, 95% CI = 0.1 to 0.6). There was no significant heterogeneity between the studies. Although only 14% of strokes were associated with LAA, this subtype accounted for 37% of recurrences within 7 days. The risk of early recurrent stroke is highest in patients with LAA. This supports the need for urgent carotid imaging and prompt endarterectomy.