Dose-response and infusion duration of intra-arterial nimodipine in cerebral vasospasm after aneurysmal subarachnoid hemorrhage: a single-center case series

Background: This single-center case series evaluates the effects on arterial diameter, perfusion imaging, and safety of intra-arterial (IA) nimodipine administration for CV following aSAH. Methods: In this prospective single-center observational study (SAVEBRAIN PWI; NCT05276934), 14 patients with CV refractory to medical treatment were treated with IA nimodipine. We assessed changes in vessel diameter and perfusion parameters pre- and post-treatment. Associations between nimodipine dose, infusion duration, and outcomes were analyzed using regression models. Results: The median age of patients was 48 years; 50% were male. The median nimodipine dose was 2.00 mg with a median infusion duration of 10 minutes. Post-treatment, the median artery diameter increased from 1.50 mm to 1.90 mm (25% change), TMAX decreased from 2.58 to 2.11 seconds, and TTD decreased from 4.58 to 4.09 seconds. Higher nimodipine doses (> 2 mg) were associated with increased odds of hypotension requiring injection breaks (OR 3.6, 95% CI 2.1 to 5.6, p < 0.001). Retreatment was necessary in 69% of cases, with a median time to retreatment of 2 days. Conclusions: IA nimodipine administration appears to improve vascular diameters and perfusion parameters in CV following aSAH but carries a significant risk of hypotension, especially at doses > 2 mg. Longer infusion durations may reduce hypotension risk. These findings emphasize the need for careful dose management and further research to standardize treatment protocols.