(994) Empiric Use of Milrinone in Subarachnoid Hemorrhage to Reduce the Incidence of Cerebral Vasospasm

Introduction: Delayed cerebral ischemia (DCI) in aneurysmal subarachnoid hemorrhage (aSAH) increases the morbidity of this already devastating neurologic crisis and generally occurs 4-14 days after the initial rupture. Cerebral vasospasm (CVS) likely contributes to DCI and worsening clinical outcomes. Milrinone has been reported as an agent that improves clinical outcomes for patients who experience CVS. Therefore, we set out to retrospectively characterize the rate of CVS among a cohort of aSAH patients receiving empiric milrinone therapy. Additionally, we describe the safety and tolerability of this practice.

Methods: Adult patients were included if they had a diagnosis of aSAH and received empiric milrinone infusion. Milrinone administration is protocolized at our institution in patients with a modified Fisher (mF) score of at least 2, is initiated at a rate of 0.5mcg/kg/min on post-bleed day (PBD) 3 and stopped on PBD 14. The rate of CVS was compared to previously published CVS rates according to mF score using a one-sample proportion test. Safety was described according to the categories of hyponatremia, hypotension, and arrhythmias.

Results: From October 2022 through June 2023, a total of 22 patients met eligibility criteria. Female patients accounted for 77.3% of the study population. An irrigating external ventricular drain was used in 31.8% of patients, half of which intrathecal nicardipine was employed as the irrigating solution. Dose and duration demonstrated good compliance with the institutional protocol. The median mF score was 4 which would suggest a CVS rate of 33-40%, however CVS was observed in half of the patients within our cohort. Hyponatremia was the most common adverse effect and occurred in 59.1% of patients

Conclusions: Initial findings of empiric milrinone administration after aSAH did not reveal a reduction in CVS. Adverse effects of milrinone complicated the tolerability of this therapy for most patients. Further study is warranted to delineate if exposure to milrinone before or after CVS improves outcomes.