Mechanistic Evaluation of Diffusion Weighted Hyperintense Lesions After Large Spontaneous Intracerebral Hemorrhage: A Subgroup Analysis of MISTIE III.

Abstract

Ischemic lesions on diffusion weighted imaging (DWI) are common after acute spontaneous intracerebral hemorrhage (ICH) but are poorly understood for large ICH volumes (> 30mL). We hypothesized that large blood pressure drops and effect modification by cerebral small vessel disease markers on magnetic resonance imaging (MRI) are associated with DWI lesions. This was an exploratory analysis of participants in the Minimally Invasive Surgery Plus Alteplase for Intracerebral Hemorrhage Evacuation phase 3 trial with protocolized brain MRI scans within 7days from ICH. Multivariable logistic regression analysis was performed to assess biologically relevant factors associated with DWI lesions, and relationships between DWI lesions and favorable ICH outcomes (modified Rankin Scale 0-3). Of 499 enrolled patients, 300 had MRI at median 7.5days (interquartile range 7-8), and 178 (59%) had DWI lesions. The incidence of DWI lesions was higher in patients with systolic blood pressure (SBP) reduction ≥ 80mm Hg in first 24h (76%). In adjusted models, factors associated with DWI lesions were as follows: admission intraventricular hematoma volume (p = 0.03), decrease in SBP ≥ 80mm Hg from admission to day 1 (p = 0.03), and moderate-to-severe white matter disease (p = 0.01). Patients with DWI lesions had higher odds of severe disability at 1month (p = 0.04), 6months (p = 0.036), and 12months (p < 0.01). No evidence of effect modification by cerebral small vessel disease on blood pressure was found. In patients with large hypertensive ICH, white matter disease, intraventricular hemorrhage volume, and large reductions in SBP over the first 24h were independently associated with DWI lesions. Further investigation of potential hemodynamic mechanisms of ischemic injury after large ICH is warranted.