Interactions Between Acute Infarcts and Cerebrovascular Pathology Predict Poststroke Dementia.

BACKGROUND Chronic cerebrovascular pathology accelerates the incidence of poststroke dementia (PSD). Whether the risk of PSD varies according to different types of chronic cerebrovascular pathology remains unclear. OBJECTIVES We investigated whether PSD is associated with a unique pattern of interactions between chronic cerebrovascular pathologies and acute stroke lesions. MATERIALS AND METHOD In this case-control study of acute mild stroke patients (n=185), cases included patients who developed PSD at a 6-month poststroke follow-up, and controls included patients who remained nondemented at 6 months, matched on prestroke cognitive status. Magnetic resonance imaging was performed at initial stroke presentation; neuropsychological assessments were performed 6 months after the stroke. RESULTS White matter hyperintensities (WMH), chronic lacunes, microbleeds, and acute infarcts were not associated with PSD after controlling for demographics, cardiovascular risk, and global cortical atrophy. The risk of PSD was largest for patients with acute large subcortical infarcts (>15 mm) and concomitant periventricular WMH compared with patients with large subcortical infarcts and punctate/absent periventricular WMH [odds ratio (OR)=5.85, 95% confidence interval (CI)=1.85-40.04]. A moderate risk of PSD was observed for patients with acute multiple small infarcts (3 to 15 mm) and concomitant lacunes (OR=2.48, 95% CI=0.94-6.51) or concomitant lobar microbleeds (OR=2.20, 95% CI=0.89-5.41), compared with patients with acute multiple small infarcts and absent lacunes or microbleeds. Single small infarcts did not interact with cerebrovascular pathology to affect PSD. CONCLUSIONS The risk of PSD varies depending on the presence of chronic cerebrovascular pathologies and type of acute infarcts. Clinical implications support a precision medicine approach for stratifying those at highest risk of PSD.