Effect of intraarterial papaverine or nimodipine on vessel diameter in patients with cerebral vasospasm after subarachnoid hemorrhage

Introduction. Papaverine (P) and nimodipine (N) are the most widely used vasodilators when angiographic and symptomatic vasospasm is present after subarachnoid aneurysmatic hemorrhage (SAH). Their effect is only short-lived and no direct comparisons have been undertaken to evaluate the action of both substances directly. We retrospectively assessed the effect of either P or N on angiographic diameter reduction and capillary blood flow. Methods. Fifteen SAH patients with secured aneurysms and cerebral vasospasm received intraarterial P, fifteen similar patients received N. As the primary endpoint, pre- and post-infusion arterial diameters and capillary blood flow were rated retrospectively on angiographies and compared by RM-ANOVA. Secondary endpoints were the difference in the modified Rankin Scale between the two groups on admission and at discharge, the occurrence of delayed cerebral ischemia, the separate effects on angiographic diameter and capillary blood flow and the overall response rate to the vasodilator infusion. Results. Angiographic resolution of diameter reduction and angiographically assessed capillary blood flow together differed not significantly between both groups. P infusion dilated all angiographic demonstrable vessels while N infusion was ineffective in 16% of the patients. Capillary flow on pre- and post-infusion angiographies was not different between the two groups. Conclusion. P and N seem to differ in the effect on cerebral diameter reduction in patients with vasospasm after SAH. The clinical implications remain to be established. A multimodal approach, perhaps combining different agents for intraarterial infusion in such patients, needs to be evaluated.