Abstract WP117: Effectiveness Of Minimally Invasive Surgery With Thrombolysis For Evacuation Of Intracerebral Hemorrhage: Post Hoc Bayesian Analysis Of A Phase 3 Randomized Controlled Trial

Abstract

Introduction: Bayesian analyses provide meaningful interpretations of clinical trial data in terms of probabilities of treatment effect. This extends the value of results beyond that obtained from traditional binary cut offs. Such interpretations provide actionable information for conditions with high mortality and no proven treatments, such as intracerebral hemorrhage (ICH). Methods: The minimally invasive surgery with thrombolysis in ICH evacuation (MISTIE 3) trial randomized 506 adults with spontaneous, supratentorial ICH of ≥ 30mL to receive either MISTIE intervention or standard medical care. Using reference priors (minimally informative, enthusiastic, skeptical) and a MISTIE 2-derived prior, we estimated probabilities that the effect of MISTIE intervention exceeds pre-specified thresholds of relative risks (RR) for achieving a 365-day Modified Rankin Scale (mRS) score of 0-3. We also computed the effects of MISTIE intervention on 180 and 30-day mRS and 365, 180 and 30-day mortality. Results: Using a minimally informative prior, the posterior probability of MISTIE intervention having any beneficial effect (RR > 1) on 365-day mRS was 70%. The probabilities of observing RR > 1.02 and > 1.10 were 63% and 34%, respectively. The probabilities of observing RR > 1, 1.02 and 1.10, with other priors are: 87%, 82% and 55% (enthusiastic); 68%, 60% and 30% (skeptical); and 73%, 66% and 38% (MISTIE 2-derived). The probabilities that MISTIE intervention has any beneficial effect on 180 and 30-day mRS, and 365, 180, and 30-day mortality are 65%,80%, 93%, 98% and 99%, respectively. RR, 95% credible intervals across various priors are shown in Figure. Conclusions: The probability that the MISTIE intervention has a favorable functional outcome at 365-days among ICH patients is 68 to 87%. Bayesian-derived probabilities of treatment effect may facilitate shared decision making in ICH management, above and beyond p-value-based frequentist interpretation of trial results.