Subtyping of Ischemic Stroke Based on Vascular Imaging: Analysis of 1,167 Acute, Consecutive Patients

BACKGROUND AND PURPOSE Knowledge of a patient's cerebral vascular status is essential for accurately classifying stroke. However, vascular evaluations have been incomplete in previous studies, and a stroke registry based on the results of such vascular investigations has not been reported. The purpose of the present study was to classify ischemic strokes based on vascular imaging data. METHODS Between May 2001 and August 2003, 1,264 patients with acute (< 7 days) ischemic stroke were admitted to Asan Medical Center. Among them, 1,167 patients (750 men and 417 women; mean age 63.3 years) underwent an angiogram (mostly a magnetic resonance angiogram) and were included in this study. Electrocardiography and computed tomography/magnetic resonance imaging were performed in all patients, while 31.2% underwent echocardiography. The subtypes were categorized with the aid of a modification of the Trial of ORG 10172 in the Acute Stroke Treatment classification. RESULTS Large-artery atherosclerosis (LAA) was the most frequent subtype (42%), followed by small-vessel occlusion (SVO, 27%), cardiogenic embolism (CE, 15%), undetermined etiology (15%), and other determined etiology (1.5%). Risk factors included hypertension (71%), cigarette smoking (35%), diabetes mellitus (30%), history of previous stroke (22.7%), emboligenic cardiac diseases (20%), and hypercholesterolemia (11%). Hypertension was more common in patients with SVO than in those with other subtypes (p<0.05), and the case-fatality rate was higher in patients with CE than in those with other subtypes (p<0.01). The functional outcome was worse in patients with LAA than in those with other stroke subtypes (p<0.01). CONCLUSION According to the stroke registry based on vascular imaging results, LAA was the most common stroke subtype followed by SVD. The high incidence of LAA is probably related to the increased identification of the presence of intracranial atherosclerosis by MR angiogram.