Microbleeds and the risk of recurrent stroke.

BACKGROUND AND PURPOSE: We studied the risk of recurrent cerebrovascular events in patients who had a transient ischemic attack or ischemic stroke and who had evidence of microbleeds on MRI.

METHODS: A prospective follow-up study was performed on hospitalized patients who were at least 50 years old with a transient ischemic attack or an ischemic stroke. The presence and number of microbleeds were assessed on gradient echo MRI and the presence of white matter disease on fluid-attenuated inversion recovery imaging using a semiquantitative scale. Patients were followed up by phone every 6 months. End points were intracerebral hemorrhage, ischemic stroke, and unclassified stroke. Cerebral events were adjudicated by 2 independent neurologists blinded to the presence of microbleeds. Cox regression analysis was performed.

RESULTS: A total of 487 patients with a mean age of 72 years were followed up for a median of 2.2 years (25th to 75th percentile 1.9 to 2.7 years). Microbleeds were identified in 129 patients (25.6%). Two patients developed intracerebral hemorrhage during follow-up, 32 patients developed recurrent ischemic stroke, and 3 patients had unclassified strokes. Microbleeds were not independent predictors of recurrent stroke (P=0.2) or intracerebral hemorrhage (P=0.43). Lobar microbleeds or combined lobar and deep microbleeds were independently associated with recurrent stroke (P=0.018).

CONCLUSIONS: In this European cohort, patients with microbleeds who have had cerebral ischemia have a higher risk of developing new ischemic strokes than of intracerebral hemorrhage. Lobar microbleeds or combined lobar and deep microbleeds might be independent predictors of recurrent stroke.