Comparative study of vasodilatation after intra-arterial nicardipine or dantrolene infusion in animal model of cerebral vasospasm
Abstract Intra-arterial (IA) infusions of calcium channel blockers (CCBs) have been widely applied in treating medically refractory vasospasm. However, surprisingly little is known regarding their vasodilatory duration. This study was undertaken to compare attributes of nicardipine and dantrolene, focusing on efficacy and capacity for sustained vasodilation. In New Zealand white rabbits (N=22), vasospasm was individually provoked through experimentally induced subarachnoid hemorrhage and confirmed via conventional angiography, grouping animals by IA-infused drug (nicardipine vs dantrolene). Controls received normal saline. After chemoangioplasty, follow-up angiography was performed at intervals of 1-3 hours for 6 hours to compare vasospastic and dilated (ie, treated) arterial diameters. Drug efficacy, duration of action, and changes in mean arterial pressure (relative to baseline) were analyzed by group. Compared with controls, effective vasodilation was evident in both nicardipine and dantrolene test groups after IA infusion. Vasodilatory effects of nicardipine peaked at 1 hour, returning to former vasospastic states at 3 hours. In dantrolene recipients, vasodilation endured longer, lasting >6 hours. This outcome suggests that IA dantrolene infused alone or together with a conventional CCB infusion may be a new means of prolonging vasodilatory effect. Further research is needed to assess durations of IA-infused vasodilatory drug based on perfusion status.