Location‐Specific Hematoma Volume Tolerance for Spontaneous Intracerebral Hemorrhage: A Pooled Analysis of INTERACT2 and ATACH II

BACKGROUND: Location-specific hematoma-volume thresholds are potentially important for prognostication and surgical decisions in acute intracerebral hemorrhage. We aimed to define this metric in relation to poor functional outcome in a pooled individual patient-level data analysis of 2 large intracerebral hemorrhage clinical trials: ATACH II (Antihypertensive Treatment of Acute Cerebral Hemorrhage) and INTERACT2 (Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial). METHODS: Final hematoma volumes were measured using planimetric analysis of 24-hour computed tomography in relation to hematoma location stratified by basal ganglia, thalamus, and lobar regions. Volume thresholds in 5-mL increments to >50 mL and Youden's index were used to identify optimal thresholds associated with poor outcome (modified Rankin Scale scores, 4-6) and death at 3 months. Multivariable logistic regression was used to estimate adjusted odds ratio models within each location. RESULTS: There were 1691 patients included in these analyses, with 919 (54.3%), 551 (32.6%), and 221 (13.1%) located in the basal ganglia, thalamus, and lobar regions, respectively. Using Youden's index, location-specific hematoma volume thresholds (mL) that were most predictive of poor outcome were: 22.24 for basal ganglia (sensitivity, 0.57; specificity, 0.84; adjusted odds ratio, 4.82 [95% CI, 3.19-7.27]), 8.13 for thalamus (sensitivity, 0.68; specificity, 0.75; adjusted odds ratio, 2.73 [95% CI, 1.62-4.59]), and 21.99 for lobar (sensitivity, 0.82; specificity, 0.64; adjusted odds ratio, 6.31 [95% CI, 2.53-15.74]). Hematoma volume thresholds predictive of death were 19.72 for basal ganglia, 10.06 for thalamic, and 51.94 for lobar intracerebral hemorrhage. CONCLUSIONS: Hematoma volumes associated with poor outcomes and death vary by anatomic location, indicating that each brain region has a distinct volume tolerance. Location-specific volume thresholds may guide surgical intervention to reduce hematoma burden.