Earlier Blood Pressure-Lowering and Greater Attenuation of Hematoma Growth in Acute Intracerebral Hemorrhage INTERACT Pilot Phase

Background and Purpose-The INTEnsive blood pressure Reduction in Acute Cerebral hemorrhage Trial (INTERACT) pilot study showed that early intensive blood pressure-lowering can attenuate hematoma growth in acute intracerebral hemorrhage. The present analysis aimed to determine the treatment effects on hematoma growth by time from intracerebral hemorrhage onset to randomization. Methods-Patients (N = 404) with acute intracerebral hemorrhage and elevated systolic blood pressure were randomly assigned to intensive or guideline-based blood pressure management. Baseline and repeat CT (24 and 72 hours) were performed and changes in hematoma volume were assessed using generalized estimating equations. Results-Among 296 patients with all 3 CT scans available for analysis, reductions in proportional hematoma growth produced by randomized intensive blood pressure-lowering treatment over 72 hours decreased progressively with delays in initiation of study treatment: 22%, 17%, 9%, and 3% for quartile groups defined by time from onset to randomization of <2.9, 2.9 to 3.6, 3.7 to 4.8, and >= 4.9 hours, respectively (P trend = 0.001). There were also smaller absolute reductions in hematoma growth with delays in initiation of study treatment (6.5 mL, 3.3 mL, 0.9 mL, and 0.6 mL), although the trend did not reach statistical significance (P trend = 0.12). Conclusions-Earlier initiation of intensive blood pressure-lowering treatment is likely to provide greater protection against hematoma growth in acute intracerebral hemorrhage.