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Evidence supports early intensive blood pressure (BP) lowering in acute intracerebral hemorrhage, but uncertainty persists over whether potential benefits and harms vary according to the magnitude of BP reduction. We aimed to determine whether larger systolic BP (SBP) reductions were associated with better outcomes in participants of the Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial (INTERACT2). INTERACT2 was an international, open, blinded end point, randomized controlled trial of patients with spontaneous intracerebral hemorrhage (<6 hours) and elevated SBP (150-220 mm Hg) assigned to intensive (target SBP <140 mm Hg) or guideline-recommended (SBP <180 mm Hg) treatment. Associations of BP reduction (baseline minus average of achieved SBP) during 3 time periods post randomization (15-60 minutes, 1-24 hours, and 2-7 days) on poor outcome (death or major disability) at 90 days were analyzed in multivariable logistic regression models with odds ratios and 95% confidence intervals. Larger SBP reductions within the first hour after randomization were associated with lower risks of poor outcome: compared with minimal reduction (<10 mm Hg), odds ratios were 0.80 (95% confidence interval, 0.63-1.02) for moderate (10-20 mm Hg) and 0.65 (0.52-0.82) for large (≥20 mm Hg) reductions (P trend <0.01). Similar associations were also observed for SBP reductions during 1 to 24 hours (P<0.01) and 2 to 7 days (P 0.02). No heterogeneity in associations for patients above or below baseline SBP 180 mm Hg was reported (P>0.30). Optimal recovery from intracerebral hemorrhage was observed in hypertensive patients who achieved the greatest SBP reductions (=20 mm Hg) in the first hour and maintained for 7 days. [ABSTRACT FROM AUTHOR]

The pilot phase of the Intensive Blood Pressure Reduction in Acute Cerebral Haemorrhage Trial (INTERACT) showed that rapid blood pressure (BP) lowering can attenuate hematoma growth in acute intracerebral hemorrhage. We sought to define the systolic BP level associated with greatest attenuation of hematoma growth. INTERACT included 404 patients with computed tomographic-confirmed intracerebral hemorrhage, elevated systolic BP (150 to 220 mm Hg), and capacity to commence BP lowering treatment within 6 hours of onset. Computed tomography was done at baseline and at 24 hours using standardized techniques, with digital images analyzed centrally, blinded to clinical data. Associations of baseline and achieved on-treatment (mean during the first 24 hours) systolic BP levels with the primary outcome of increase in hematoma volume were explored. There were 346 patients with duplicate computed tomographic scans. There was no significant association between baseline systolic BP levels and either the absolute or proportional growth in hematoma volume (P trend=0.26 and 0.12, respectively). By contrast, achieved on-treatment systolic BP levels in the first 24 hours were clearly associated with both absolute and proportional hematoma growth (both P trend=0.03). Maximum reduction in hematoma growth occurred in the one third of participants with the lowest on-treatment systolic BP levels (median: 135 mm Hg). Intensive BP reduction to systolic levels between 130 and 140 mm Hg is likely to provide the maximum protection against hematoma growth after intracerebral hemorrhage. [ABSTRACT FROM AUTHOR]