Hematoma Expansion Shift Analysis to Assess Acute Intracerebral Hemorrhage Treatments

Abstract

OBJECTIVE: Hematoma expansion (HE) is commonly analyzed as a dichotomous outcome in intracerebral hemorrhage (ICH) trials. In this proof-of-concept study, we propose an HE shift analysis model as a method to improve the evaluation of candidate ICH therapies. METHODS: Using data from the Antihypertensive Treatment of Acute Cerebral Hemorrhage II (ATACH-2) trial, we performed HE shift analysis in response to intensive blood pressure lowering by generating polychotomous strata based on previously established HE definitions, percentile/absolute quartiles of hematoma volume change, and quartiles of 24-hour follow-up hematoma volumes. The relationship between blood pressure treatment and HE shift was explored with proportional odds models. RESULTS: The primary analysis population included 863 patients. In both treatment groups, approximately one-third of patients exhibited no HE. With the use of a trichotomous HE stratification, the highest strata of ≥33% revealed a 5.8% reduction in hematoma growth for those randomized to intensive therapy (adjusted odds ratio [aOR] 0.77, 95% confidence interval [CI] 0.60-0.99). Using percentile quartiles of hematoma volume change, we observed a favorable shift to reduce growth in patients treated with intensive therapy (aOR 0.73, 95% CI 0.57-0.93). Similarly, in a tetrachotomous analysis of 24-hour follow-up hematoma volumes, shifts in the highest stratum (>21.9 mL) were most notable. CONCLUSIONS: Our findings suggest that intensive blood pressure reduction may preferentially mitigate growth in patients at risk of high volume HE. A shift analysis model of HE provides additional insights into the biological effects of a given therapy and may be an additional way to assess hemostatic agents in future studies. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov Identifier:NCT01176565.

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