Long-Term, Continuous Intra-Arterial Nimodipine Treatment of Severe Vasospasm After Aneurysmal Subarachnoid Hemorrhage

Background: Secondary vasospasm and disturbances in cerebrovascular autoregulation are associated with the development of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage. An intra-arterial application of nimodipine has been shown to increase the vessel diameter, although this effect is transient. The feasibility of long-term, continuous, intra-arterial nimodipine treatment and its effects on macrovasospasm, autoregulation parameters, and outcome were evaluated in patients with refractory severe macrovasospasm.

Methods: Ten patients were included with refractory macrovasospasm despite bolus nimodipine application (n = 4) or with primary severe vasospasm (n = 6). The patients were assessed with continuous multimodal neuromonitoring (mean arterial pressure, intraceranial pressure, cerebral perfusion pressure, brain tissue oxygen tension probe), daily transcranial Doppler examinations, and computed tomography angiography/perfusion. Autoregulation indices, the pressure reactivity index, and oxygen reactivity index were calculated. Indwelling microcatheters were placed in the extracranial internal carotid arteries and 0.4 mg nimodipine was continuously infused at 50 mL/hour.

Results: The duration of continuous, intra-arterial nimodipine ranged from 9 to 15 days. During treatment intracranial pressure remained stable, transcranial Doppler flow velocity decreased, and brain tissue oxygen tension improved by 37%. Macrovasospasm, as assessed via computed tomography angiography, had improved (n = 5) or disappeared (n = 5) at the end of treatment. Cerebrovascular autoregulation according to the pressure reactivity index and oxygen reactivity index significantly worsened during treatment. All patients showed a favorable outcome (median Glasgow Outcome Scale 5) at 3 months.

Conclusions: In well-selected patients with prolonged severe macrovasospasm, continuous intra-arterial nimodipine treatment can be applied as a rescue therapy with relative safety for more than 2 weeks to prevent secondary cerebral ischemia. The induced impairment of cerebrovascular autoregulation during treatment seems to have no negative effects.