Relative Edema Volume Is a Predictor of Outcome in Patients With Hyperacute Spontaneous Intracerebral Hemorrhage

BACKGROUND AND PURPOSE: Little is known about the relationship between perihematomal edema in spontaneous intracerebral hemorrhage (ICH) and outcome. The purpose of this study was to determine whether absolute or relative edema volume (edema volume divided by hematoma volume) predicts mortality or functional outcome in patients with hyperacute spontaneous ICH. We hypothesized that increasing baseline relative edema volume is associated with greater probability of poor functional outcome. METHODS: This was a secondary analysis of a prospective, population-based study of hematoma growth in 142 patients with spontaneous ICH. Patients were imaged within 3 hours of onset, then 1 and 20 hours later. Our primary analysis excluded patients with anticoagulant use (n=7), underlying aneurysm/vascular malformation (n=9), trauma (n=1), incomplete data (n=20), infratentorial ICH (n=17), intraventricular extension (n=38), and no consent (n=2). We analyzed whether associations existed between baseline edema volumes or other clinical/radiological variables and either 12-week modified Rankin Scale score >2 or 30-day mortality. Secondary analyses used 20-hour CT scan data, all patients with supratentorial ICH, and 12-week Barthel Index score <85. RESULTS: By multivariable logistic regression analysis, baseline relative edema was the strongest independent predictor of functional outcome and was associated with lesser odds of poor 3-month functional outcome (odds ratio, 0.09 per 1.0-unit 100% increase; 95% CI, 0.01 to 0.64; P=0.016) and 12-week Barthel Index score <85 (odds ratio, 0.12; 95% CI, 0.02 to 0.91; P=0.039) but did not predict mortality. Secondary analyses confirmed this result. Absolute edema volume predicted neither mortality nor functional outcome. CONCLUSIONS: Relative edema is strongly predictive of functional outcome in patients with hyperacute supratentorial spontaneous ICH without intraventricular extension.