Intra-arterial nimodipine and outcomes in delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

Introduction: Vasospasm after aneurysmal subarachnoid hemorrhage (aSAH) may cause delayed cerebral ischemia (DCI). Intra-arterial nimodipine (IAN) is used in vasospasms resistant to standard hemodynamic therapy. The effect of IAN on long-term outcomes remains uncertain, particularly in patients requiring repeated infusions. Research question: What are the outcomes of aSAH patients treated with IAN, especially compared to the characteristics of patients undergoing repeated versus single IAN infusions. Material and methods: We retrospectively reviewed all aSAH patients with DCI treated with IAN at a tertiary referral center between 2017 and 2024. Logistic regression was used to identify predictors of unfavorable outcome (modified Rankin Scale scores >2) at 3-6 months. Results: Fifty-two patients (mean age 53 years, 65% female) were included. At 3-6 months, 28 patients (54%) had unfavorable outcomes. After propensity score matching for baseline severity of SAH, repeated IAN was associated with unfavorable outcome compared to single IAN (OR 5.13, 95% CI 1.53-19.35) using Firth's penalized logistic regression. Seven patients (13%) died during the six-month follow-up. Mortality did not differ significantly between single and repeated IAN infusion groups (OR 0.74, 95% CI 0.15-3.44). Discussion and conclusions: In this cohort of aSAH patients with vasospasm-related DCI treated with IAN, repeated IAN was associated with unfavorable outcomes. However, mortality did not differ significantly between single and repeated IAN groups. Earlier treatment was not associated with improved outcomes.