Incidence and Etiology of Microinfarcts in Patients with Ischemic Stroke

ABSTRACT BACKGROUND AND PURPOSE Cerebral microinfarcts (CMI) are associated with intracerebral hemorrhage due to small vessel disease (SVD) in studies not including an ischemic etiologic workup. We aimed to determine their incidence and potential causes in a large ischemic stroke (IS) cohort. METHODS Consecutive patients with MRI‐confirmed IS within 72 hours of onset were enrolled. Subjects had either single high‐risk embolic source (cardioembolic or large vessel disease) or no embolic source. CMIs were classified by their relationship to the primary infarct as within or outside the same vascular territory. White matter hyperintensities (WMH) and microbleeds were markers SVD severity. Multivariable regression tested the association between CMIs and potential etiologies. RESULTS We analyzed 946 IS patients, mean age 69 ± 15 years, 46% female. We detected CMI (≤5 mm) on diffusion‐weighted imaging in 269 (28%) subjects, 190 (71%) within the vascular territory of the primary infarct. Large‐vessel atherosclerosis (P