Intrathecal Nicardipine After Aneurysmal Subarachnoid Hemorrhage: A Scoping Review

Intrathecal nicardipine (ITN) is an investigational therapy for cerebral vasospasm (CVS) and delayed cerebral ischemia (DCI) in patients with aneurysmal subarachnoid hemorrhage (aSAH). The objective of this scoping review was to characterize the current state of the literature and map the current available evidence, examine research methodology, clarify key concepts and definitions in the literature, report procedural characteristics, identify and analyze knowledge gaps, and serve as a precursor for future systematic reviews, meta-analyses, and randomized controlled trials. An electronic search for studies on ITN for the treatment of CVS and DCI in patients with aSAH was conducted in accordance with published standards. A total of 390 studies were identified by the search. After inclusion criteria were applied, 20 studies were identified for analysis. The identified studies included a total of 976 patients with aSAH who received ITN for the treatment of CVS and DCI. One randomized controlled trial, two prospective observational studies, nine retrospective observational studies, seven retrospective case series, and one case report met inclusion criteria. Study designs, drug administration, dosing regimens, drug concentrations, pharmacokinetics, patient selection, duration of therapy, outcome measures, adverse event monitoring, and definitions of CVS and DCI used are synthesized and discussed. Despite advances in the care of patients with aSAH, CVS and DCI remain leading causes of morbidity and mortality, and ITN represents a potential therapy to help prevent and treat this disease process. With one published randomized controlled trial on one method of administration, one trial underway on a second method of administration, and numerous heterogeneous and primarily retrospective studies published to date, future study with an emphasis on homogenizing study design and outcomes measured is needed to better understand this potential therapy.