Impact of white matter lesions on associations between prehospital blood pressure and outcomes in spontaneous intracerebral hemorrhage.

Introduction: There are concerns about the safety of intensive blood pressure (BP) lowering in intracerebral hemorrhage (ICH) patients with white matter lesions (WML). We explored the impact of WML on associations between i) prehospital BP, and ii) BP change, and outcomes in acute, spontaneous ICH.

Patients and methods: This retrospective study included consecutive patients with acute spontaneous ICH, admitted 2011-2020. WML on non-contrast computed tomography were categorized as none-to-mild (0-1) or moderate-to-severe (2-3) on the Fazekas scale. The first systolic BP (SBP) and mean arterial pressure (MAP) from the ambulance and admission, and absolute BP change between these time points, were collected. The outcomes were in-hospital mortality, mortality at 180 days, modified Rankin Scale (mRS) scores at 3 months, and hematoma expansion.

Results: Of 548 patients, 260 (47%) had moderate-to-severe WML. Compared to patients with none-to-mild WML, these patients had a stronger association between higher prehospital MAP and in-hospital mortality (p interaction 0.017). WML did not modify associations between prehospital BP and other outcomes. WML modified associations between MAP change and in-hospital mortality (p interaction 0.049), MAP change and mRS score 3-6 at 3 months (p interaction 0.032), and SBP change and mRS score 3-6 at 3 months (p interaction 0.022). These outcomes were poorer with greater BP decrease in patients with moderate-to-severe compared to none-to-mild WML.

Discussion and conclusion: In acute ICH, WML modified the influence of prehospital BP and BP change on clinical outcomes, with a trend toward worse outcomes associated with higher prehospital BP and greater spontaneous BP decrease.