Prevalence, Predictors, and Prognostic Implications of Covert Brain Infarctions in First-Ever Acute Ischaemic Stroke:...

Covert brain infarctions (CBIs) are imaging-detected ischaemic lesions without overt neurological symptoms. Their role in determining short-term outcomes and recurrence risk in acute ischaemic stroke (AIS) remains underexplored. Here, we aimed to evaluate the prevalence, predictors, and impact of CBI on outcomes and recurrence in patients with first-ever AIS in a South Indian cohort.

This was a single-centre ambispective observational study of patients with first-ever AIS who completed 1-year follow-up. Demographics, vascular risk profiles, imaging findings, including covert infarct location and phenotype, and outcome metrics (functional outcome and recurrence) were studied.

We had 350 subjects in our study cohort. CBI was observed in 132 (37.7%) patients. Most common CBI locations were subcortical supratentorial (50.5%) and cortical supratentorial (27.2%). Frequent phenotypes included combined grey and white matter lesions (40%) and cavitatory lacunes (34.5%). CBI was significantly associated with older age (OR 2.38, p = 0.001), vertebrobasilar territory infarcts (OR 2.26, p = 0.004), watershed infarcts (OR 2.21, p = 0.012), and multiple embolic infarcts (OR 2.91, p = 0.001), but not with vascular risk factors or etiological subtypes. Though patients with CBI showed a trend towards increased recurrence risk in the early phase, functional outcomes at 1 year was favourable.

CBIs are prevalent in over one-third of first-ever AIS cases and are linked to specific infarct patterns and advanced age, rather than classic stroke risk factors. Though not associated with long-term disability, their presence may portend early recurrence. Recognition and characterization of CBI should inform post-stroke monitoring strategies and future preventative trials.