CT-Visible Convexity Subarachnoid Hemorrhage is Associated With Cortical Superficial Siderosis and Predicts Recurrent ICH

Objective To investigate whether acute convexity subarachnoid hemorrhage (cSAH) detected on CT in lobar intracerebral hemorrhage (ICH) related to cerebral amyloid angiopathy (CAA) is associated with recurrent ICH. Methods We analyzed data from a prospective cohort of consecutive acute lobar ICH survivors fulfilling the Boston criteria for possible or probable CAA who had both brain CT and MRI at index ICH. Presence of cSAH was assessed on CT blinded to MRI data. Cortical superficial siderosis (cSS), cerebral microbleeds, and white matter hyperintensities were evaluated on MRI. Cox proportional hazard models were used to assess the association between cSAH and the risk of recurrent symptomatic ICH during follow-up. Results A total of 244 ICH survivors (76.4 +/- 8.7 years; 54.5% female) were included. cSAH was observed on baseline CT in 99 patients (40.5%). Presence of cSAH was independently associated with cSS, hematoma volume, and preexisting dementia. During a median follow-up of 2.66 years, 49 patients (20.0%) had recurrent symptomatic ICH. Presence of cSAH was associated with recurrent ICH (hazard ratio 2.64; 95% confidence interval 1.46-4.79; p = 0.001), after adjusting for age, antiplatelet use, warfarin use, and history of previous ICH. Conclusion cSAH was detected on CT in 40.5% of patients with acute lobar ICH related to CAA and heralds an increased risk of recurrent ICH. This CT marker may be widely used to stratify the ICH risk in patients with CAA. Classification of Evidence This study provides Class II evidence that cSAH accurately predicts recurrent stroke in patients with CAA.