Premorbid Blood Pressure Control Modifies Risk of DWI Lesions With Acute Blood Pressure Reduction in Intracerebral Hemorrhage

BACKGROUND: Hypoperfusion due to blood pressure (BP) reduction is a potential mechanism of cerebral ischemia after intracerebral hemorrhage. However, prior evaluations of the relationship between BP reduction and ischemia have been conflicting. Untreated chronic hypertension is common in intracerebral hemorrhage and alters cerebral autoregulation. We hypothesized that the risk of diffusion-weighted imaging (DWI) hyperintensities from acute BP reduction is modified by premorbid BP control. METHODS: Individuals enrolled in the ERICH study (Ethnic/Racial Variations of Intracerebral Hemorrhage) from 2010 to 2015 were categorized as untreated, treated, or nonhypertensive based on preintracerebral hemorrhage diagnosis and antihypertensive medication use. The percent reduction of systolic BP (SBP) was calculated between presentation and 24 hours from admission. The primary outcome was the presence of DWI lesions. Using logistic regression, we tested the association between chronic hypertension status, SBP reduction, and their interaction with DWI lesion presence. RESULTS: From 3000 participants, 877 with available magnetic resonance imaging met inclusion (mean age, 60.5±13.3 years; 42.5% women). DWI lesions were detected in 25.9%. Untreated, treated, and no hypertension accounted for 32.6%, 47.9%, and 19.5% of cases, respectively. SBP reduction was not directly associated with DWI lesions; however, an interaction effect was observed between SBP reduction and chronic hypertension status ( P =0.036). Nonhypertensive subjects demonstrated a linear risk of DWI lesion presence with greater SBP reduction, whereas untreated hypertension demonstrated a stable risk across a wide range of SBP reduction ( P =0.023). CONCLUSIONS: Premorbid BP control, especially untreated hypertension, may influence the relationship between DWI lesions and acute BP reduction after intracerebral hemorrhage. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01202864.