Mechanisms of Recurrence in Subtypes of Ischemic Stroke: A Hospital-based Follow-up Study

ABSTRACT

BACKGROUND: Great efforts have been devoted to developing a mechanism-oriented classification of ischemic stroke. Information on the subtype of recurrent stroke may tell us whether the classification using the index stroke mechanism is appropriate. Data on the mechanism of recurrence in each stroke subtype are lacking for Asian patients. METHODS: Using the clinical syndrome, diffusion-weighted imaging, and vascular studies, we divided the patients into five groups [large artery atherosclerosis (LAA), cardioembolism (CE), small artery disease (SAD), parent artery disease occluding the deep perforators (PAD), and no determined cause (NC)], and registered recurrent strokes for up to three years. The LAA patients were subdivided into two groups: intracranial (IC-LAA) and extracranial (EC-LAA) LAA. RESULTS: Seventy-six recurrent vascular events (73 strokes and 3 coronary heart diseases) were evaluated in 73 patients. The pattern of recurrent stroke differed for the IC-LAA and EC-LAA groups; unlike the patients with IC-LAA, recurrent strokes in EC-LAA were often unpredictable with respect to the site of recurrence and degree of pre-existing stenosis. None of the patients in the IC-LAA group recurred as EC-LAA, or vice versa. Patients with SAD and NC recurred most frequently as their index stroke subtype, but intracranial stenosis was often found at the time of recurrence. CONCLUSIONS: From a prognostic and therapeutic perspective, patients with atherosclerosis should be divided into IC-LAA and EC-LAA. In addition, intracranial atherosclerosis may be more important in the development of SAD and NC in Asians than in Westerners, due to the high prevalence of intracranial atherosclerosis.