Background and purpose: Patients with cerebral amyloid angiopathy (CAA) are at high risk for intracerebral hemorrhage (ICH), but no effective prevention strategies have been established. The objective is to determine whether lowering of blood pressure (BP) provides protection for this high-risk patient group.
Methods: This study is a subsidiary analysis of the PROGRESS trial-a randomized, placebo-controlled trial that established the beneficial effects of BP lowering in patients with cerebrovascular disease; 6105 patients were randomly assigned to either active treatment (perindopril for all participants plus indapamide for those with neither an indication for nor a contraindication to a diuretic) or matching placebo. Outcomes were probable CAA-related ICH as defined by the Boston criteria, probable hypertension-related ICH, and unclassified ICH.
Results: Over a mean follow-up of 3.9 years, 16 probable CAA-related ICH, 51 probable hypertension-related ICH, and 44 unclassified ICH occurred. Active treatment reduced the risk of CAA-related ICH by 77% (95% CI, 19%-93%), that of hypertension-related ICH by 46% (95% CI, 4%-69%), and that of unclassified ICH by 43% (95% CI, -5%-69%). There was no evidence of differences in the magnitude of the effects of treatment among different types of ICH (P homogeneity=0.4).
Conclusions: BP-lowering treatment is likely to provide protection against all types of ICH.