INTERACT (Pilot)
(2008)Objective
Assess the safety and feasibility of early intensive blood pressure (BP) lowering in patients with acute intracerebral hemorrhage (ICH) and its effects on hematoma growth.
Study Summary
• In this pilot trial, early intensive systolic BP lowering (target <140 mm Hg) within 6 hours of ICH onset significantly reduced hematoma growth compared to guideline-based management (target <180 mm Hg), without increasing adverse events. Findings supported the feasibility and safety of intensive BP reduction and laid the groundwork for the larger INTERACT2 trial.
Intervention
Phase 2, randomized, open-label, blinded-endpoint, multicenter pilot trial. N=404 patients with spontaneous ICH <6 hours from onset and SBP 150–220 mm Hg randomized to: • Intensive BP lowering: target SBP <140 mm Hg • Guideline-based BP management: target SBP <180 mm Hg Primary outcome: proportional change in hematoma volume at 24 hours. Secondary outcomes included absolute hematoma growth and safety at 90 days.
Study Design
Arms: Array
Outcome
• Proportional hematoma growth at 24h: 13.7% (intensive) vs. 36.3% (guideline); absolute difference 22.6% (95% CI 0.6–44.5); p=0.04
• Relative risk of hematoma growth ≥33% or ≥12.5 mL: RR reduced by 36%; p=0.05
• Absolute risk reduction for hematoma growth: 8% (95% CI −1.0 to 17); p=0.05
• Adjusted difference in hematoma volume: −1.7 mL (95% CI −0.5 to 3.9); p=0.13
• No increase in adverse events or poor clinical outcomes at 90 days
• BP reduction achieved: −13.3 mm Hg (1h), −10.8 mm Hg (1–24h); both p<0.0001
• Relative risk of hematoma growth ≥33% or ≥12.5 mL: RR reduced by 36%; p=0.05
• Absolute risk reduction for hematoma growth: 8% (95% CI −1.0 to 17); p=0.05
• Adjusted difference in hematoma volume: −1.7 mL (95% CI −0.5 to 3.9); p=0.13
• No increase in adverse events or poor clinical outcomes at 90 days
• BP reduction achieved: −13.3 mm Hg (1h), −10.8 mm Hg (1–24h); both p<0.0001