Stroke recurrence after primary intracerebral haemorrhage: a population-based study of clinical and MRI factors associated with recurrence.

BACKGROUND: Survivors of primary intracerebral haemorrhage (ICH) face competing risks of recurrent ICH and ischaemic stroke. We quantified ischaemic stroke recurrence (ISR) and haemorrhagic stroke recurrence (HSR) and examined associated imaging factors. METHODS: We analysed 30-day survivors of primary ICH in the Brest Stroke Registry (2008-2020). Cumulative incidence was estimated with death as a competing event. Cause-specific Cox models were fitted in the cohort and MRI subgroup. RESULTS: Among 806 survivors, 118 experienced recurrence: 437 died without recurrence. The overall incidence rate was 3.2 per 100 person-years (95% CI 2.7 to 3.9). At 8 years, cumulative incidence was 15.4% (95% CI 12.1% to 19.5%). HSR was higher after lobar than non-lobar ICH (10.1% vs 5.1%), whereas ISR was higher after non-lobar than lobar ICH (10.3% vs 4.8%). ISR was associated with systolic blood pressure, CT leukoaraiosis and atrial fibrillation/flutter. Among 416 participants with MRI, probable cerebral amyloid angiopathy (CAA) was associated with HSR (HR 4.54, 95% CI 1.78 to 11.62). In an exploratory model adjusted for systolic blood pressure and atrial fibrillation/flutter, centrum semiovale perivascular spaces (HR 3.94, 95% CI 1.11 to 13.98) and cortical superficial siderosis (HR 2.96, 95% CI 1.05 to 8.36) were associated with HSR. Brainstem leukoaraiosis was associated with ISR (HR 2.18, 95% CI 1.10 to 4.31). CONCLUSIONS: Recurrence patterns differed by index ICH location. CAA-related MRI markers were associated with HSR, whereas ISR was associated with vascular risk and brainstem small-vessel disease. These findings identify candidate predictors for the development of recurrence prediction models, with potential utility in supporting clinical decision.