Convexity Subarachnoid Hemorrhage in Cerebral Amyloid Angiopathy-related Lobar Intracerebral Hemorrhage: A Systematic Review and Meta-analysis of Recurrence Risk
Sangharsha Thapa1, Anish Thapa2, Prateek FNU3, Sangam Shah4, NIRAJ GAUTAM5
1Westchester Medical Center, 2University of Buffalo, 3AIMS, 4Tribhuvan University, Institute of Medicine, 5Institute of Medicine
Objective:
To evaluate whether convexity subarachnoid hemorrhage (cSAH) in CAA-related lobar ICH predicts higher risk of recurrence, and to examine the impact of cortical superficial siderosis (cSS) on recurrence, mortality, and outcomes, identifying imaging markers such as CT-visible cSAH or disseminated cSS as predictors of hemorrhagic instability.
Background:
Cerebral amyloid angiopathy (CAA) is a leading cause of spontaneous lobar intracerebral hemorrhage (ICH) in older adults. Convexity subarachnoid hemorrhage (cSAH) and cortical superficial siderosis (cSS) represent imaging biomarkers of CAA-related vascular fragility and disease activity. Although both are increasingly recognized, their prognostic value for recurrent hemorrhage remains uncertain. This meta-analysis aimed to determine the association between cSAH and the risk of recurrent ICH in patients with CAA.
Design/Methods:
We systematically searched PubMed and Embase (1980–May 2025) for studies of adults (≥18 years) with CAA-related lobar ICH that reported recurrence outcomes by presence of convexity subarachnoid hemorrhage (cSAH) or cortical superficial siderosis (cSS). Eligible cohort and registry studies were analyzed using random-effects models to estimate pooled hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs).
Results:
Four studies including patients with CAA-related lobar ICH and imaging evidence of cSAH/cSS were meta-analyzed. The pooled risk of recurrent ICH was significantly higher in those with cSAH or cSS (pooled HR 2.67; 95% CI 1.86–3.84; I² = 0%). These findings demonstrate a robust and consistent association between superficial hemorrhagic markers and recurrent CAA-related bleeding.
Conclusions:
Convexity subarachnoid hemorrhage and cortical superficial siderosis strongly predict recurrent hemorrhage in cerebral amyloid angiopathy, identifying a high-risk subgroup for early rebleeding and disability. Integrating these imaging markers may enhance risk stratification and preventive care.
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