Abstract 216: Minimally Invasive Surgery plus Tissue Plasminogen Activator for Intracerebral Hemorrhage Evacuation (MISTIE) Leads to a Reduction in Perihematomal Edema

Background: Intracerebral hemorrhage (ICH) remains the most devastating form of stroke without treatment. Secondary damage such as perihematomal edema (PHE) can negatively impact long-term outcome. Several reports suggest that blood and its degradation products lead to PHE. Treatments aimed at blood removal and edema prevention have a potential to improve outcome in these stroke patients. We hypothesized that successful hematoma evacuation would reduce PHE volume. Methods: MISTIE is a multi-center, prospective, randomized trial testing the safety and efficacy of hematoma evacuation after spontaneous ICH compared to medical management. Study interventions were consistently applied in a protocol-based manner across study sites. We conducted a semi-automated, computerized volumetric analysis on CT imaging to assess the effect of hematoma removal on PHE. Both arms of the study were assessed for ICH and PHE volumes at two time points: T1, pre-enrollment, and T2, end of treatment. Results: Of 123 patients enrolled, 79 surgical and 39 medical patients were analyzed. There was no significant difference between the treatment cohorts in age, enrollment GCS, intraventricular involvement, baseline ICH volume, or baseline PHE volume. Mean hematoma volume at T2 was 19.64±14.5 cc for the surgical cohort and 40.74±13.9 cc for the medical cohort (p&lt0.001). Mean edema volume at T2 was 27.67±13.3 cc for the surgical cohort while medical patients had 41.69±14.6 cc (p&lt0.001). When patients within each treatment arm were subdivided into groups of &gt65%, 20-65%, and &lt20% ICH removal, surgical patients were 32, 39, and 8 respectively, whereas all medical patients experienced &lt20% clot removal. A significant difference in edema volume was seen among the three groups (ANOVA p&lt0.001). On further analysis, there was a positive correlation between edema reduction and percent of ICH removed: the more ICH removed, the greater the reduction in edema (Spearman R=0.645; p&lt0.001). Conclusion: Safe, early, and effective hematoma evacuation of parenchymal blood in ICH is associated with significant reduction in perihematomal edema, especially when a high percentage of blood is removed.