Classification and 90-day outcome of mild ischemic stroke subtypes according to TOAST criteria:a prospective cohort study

Objective To determine the classification of TOAST subtypes and 90-day outcome of different TOAST subtypes among mild ischemic stroke.Methods Mild ischemic stroke patients admitted to the department of Neurology of Zhongda Hospital affiliated to Southeast University between May 2012 and July 2013 were prospectively enrolled in the present study.Cerebral imaging examinations were performed for each subject.Stroke pathophysiology was assigned by TOAST criteria.Modified Rankin Scale(mRS)scores≥3on day 90 of follow-up was defined as unfavorable outcome.Disability rates of different TOAST subtypes were compared.Results Eventually 288 mild ischemic stroke patients were enrolled.The ischemic stroke subtypes according to TOAST criteria were as follows:small-artery occlusion(39.2%),large-artery atherosclerosis(29.9%),stroke of undetermined etiology(22.6%),cardiogenic embolism(8.0%),and acute stroke of other determined etiology(0.3%).Disability rates were 52.3%in large-artery atherosclerosis,13.3%in small-artery occlusion,17.4%in cardioembolism,and 23.1% in stroke of undetermined etiology on day 90 of follow-up.The mRS score and disability rates of large-artery atherosclerosis patients were significantly higher than those of other TOAST subtypes(all P0.05).After adjusted for confounding factors,disability risk for mild stroke patients of large-artery atherosclerosis was significantly higher compared to that of small-artery occlusion(OR=7.1,95%CI:3.4-14.9,P=0.000).Conclusion Small-artery occlusion is the most predominant subtype of mild ischemic stroke.Largeartery atherosclerosis also accounts for a large part of mild ischemic stroke and has a poor outcome.