Endovascular rescue treatment for delayed cerebral ischemia after subarachnoid hemorrhage is safe and effective

Aneurysmal subarachnoid hemorrhage (aSAH) is a subtype of hemorrhagic stroke with consistently poor prognosis despite considerable research efforts over the past decades. Early brain injury and delayed, ischemic complications frequently lead to oftentimes devastating clinical outcomes. A key issue in aSAH remains our incomplete pathophysiological understanding of later complications such as delayed cerebral ischemia (DCI), including its timely diagnosis and possible treatment approaches. As a consequence, worldwide treatment of DCI is highly variable, and in lack of sufficient clinical data personal belief and experience are dominating local practice.Cerebral vasospasm has historically been at the center of treatment efforts. However, prevention is limited to a single drug (nimodipine), but treatment may require escalation including vasodilating drugs applied parenterally or intrathecally, or mechanical vasodilation. However, many centers are hesitant to adopt more aggressive treatment approaches for the lack of supporting data and the inherent risk profile. At our institution, the Departments of Neurosurgery, Operative Intensive Care Medicine and Neuroradiology together have implemented a standardized treatment approach, where treatment escalation includes the use balloon angioplasty and continuous intraarterial nimodipine application to treat DCI after conservative treatment has failed. In this prospective, observational study from 01/2014 to 08/2018, safety and efficacy criteria were assessed in the so far largest published cohort of 33 patients with a total of 54 interventions. The indication of treatment (neurological or function deterioration) and later treatment efficacy were monitored by invasive neuromonitoring probes assessing intracerebral oxygenation and metabolism. Additionally, criteria determining success and failure necessitating more than one treatment session were investigated in a binary logistic regression analysis. While we determined no serious complications of treatment for both treatment modalities, the results displayed an inherent challenge: to maintain an elevated blood pressure during continuous vasodilator application. Based on the current work, prioritization of pressure maintenance may be abandoned in favor of nimodipine application in the future. It could be shown that both treatment modalities (balloon angioplasty and intraarterial nimodipine) were associated with reversal of neurological and functional deterioration, and with improvement of transcranial doppler values, CT-graphic hypoperfusion and angiographic vasospasm in the majority of patients. However, it was determined that patients with severe local hypoxia required retreatment more often, emphasizing the need for continuous monitoring and swift reaction in case of functional deterioration. Retreatment was also shown to be required less often with intraarterial nimodipine than after balloon angioplasty. Furthermore, we identified a critical time threshold of 3 days treatment duration as, according to the present data, retreatment was most often required when treatment was prematurely stopped. Taking also into account the larger area of territories covered and the option of adjustment of treatment (by varying the dosage), it was concluded that continuous intraarterial nimodipine may serve the profile of DCI most appropriately, provided that early treatment interruptions are prevented as far as possible. The present work comprises the largest, prospective cohort up to date investigating endovascular rescue strategies in the context of functional monitoring. Though still lacking an appropriate control cohort but provided the respective local expertise and a comparably low complication profile, we believe that continuous can serve as a relatively safe and effective treatment option to improve outcome when conservative measures have failed