215 Reexamining Nimodipine's Effect on Neurological Outcomes After Aneurysmal Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis

INTRODUCTION: Nimodipine therapy is a guideline-directed treatment to improve neurological outcomes after ruptured aneurysmal subarachnoid hemorrhage (aSAH). METHODS: We performed a systematic review and meta-analysis of ruptured aSAH trials reporting ‘good’ neurological outcomes, defined as Modified Rankin Scale 0-2 or the study’s own criteria. ‘Pre-nimodipine’ studies included those prior to the use of nimodipine. ‘Nimodipine’ studies gave nimodipine as an investigational drug, leading to its widespread acceptance. ‘Post-nimodipine’ studies gave nimodipine as standard-of-care to controls. 172 studies were screened, 122 were evaluated in full for eligibility, and 52 were included. Rates of ‘good’ outcomes were aggregated and compared with respect to era and nimodipine status. RESULTS: ‘Nimodipine’ era nimodipine recipients had exceptionally high rates of ‘good’ neurological outcome at 81% (95% CI 68-92%). ‘Post-nimodipine’ era nimodipine recipients had a 67% (95% CI 64-70%) rate of ‘good’ neurological outcome. When subcategorized by decade, this was stable at 68% (95% CI 62-73%), 64% (95% CI 58-69%), and 70% (95% CI 64-73%). Those not receiving nimodipine in the ‘pre-nimodipine’ and ‘nimodipine’ eras also had a similar chance of ‘good’ neurological outcome at 60% (95% CI 49-71%) and 69% (95% CI 55-82%) respectively. ‘Nimodipine’ era studies were too heterogeneous to be statistically different, however 5 of the 7 are outside 95% confidence intervals when compared to any other group. CONCLUSIONS: Approximately 60-70% of patients in randomized studies of ruptured aSAH have ‘good’ neurologic outcomes regardless of nimodipine status or era of treatment. The studies that examined nimodipine as an intervention, leading to its acceptance as the standard of care, are historical outliers. This raises concerns about nimodipine’s overall efficacy in treating aSAH, and the validity of its recommendation in the ruptured aSAH management guidelines.