To evaluate the safety and feasibility of early intravenous (IV) milrinone therapy for delayed cerebral ischemia (DCI) and vasospasm after aneurysmal subarachnoid hemorrhage (aSAH) and to develop a standardized clinical protocol for its implementation in neurocritical care practice. 

Intravenous milrinone, a phosphodiesterase-3 inhibitor with inotropic and vasodilatory properties, shows promise for DCI and vasospasm management; however, a standardized protocol remains lacking.

This retrospective pilot study at Staten Island University Hospital involved consecutive patients with non-traumatic SAH admitted from January 2023 to January 2025, who developed DCI or vasospasm and received early IV milrinone treatment. We established patient selection criteria, a dosing chart, monitoring parameters, and criteria for escalation or discontinuation. Outcomes assessed included milrinone side effects, vasospasm-related ischemic stroke, and rescue endovascular angioplasty rates. Descriptive statistics summarized clinical characteristics and outcomes.

Seven patients received IV milrinone upon clinical or radiographic DCI or vasospasm onset. Median age was 58.5 years; 50% were female. Most (87.5%) had Hunt-Hess grades ≥3; five had modified Fisher scale (mFS) scores of 4, two had mFS of 3. Modified Rankin Scale scores at discharge ranged from 0 (no symptoms) to 5 (severe disability). The standardized protocol parameters were:

Median starting dose: 0.125 µg/kg/min

Median maximum dose: 0.375 µg/kg/min

Median treatment duration: 8 days

No milrinone-related side effects (hypotension, arrhythmias, worsening kidney function, or electrolyte disturbances) were observed. Triggers for milrinone were predominantly new focal neurological deficits or radiographic vasospasm. Clinical and/or radiographic improvement occurred in most patients, and importantly, none required rescue intra-arterial angioplasty. These findings informed our standardized protocol, encompassing patient selection, dosing, monitoring, escalation, and discontinuation guidelines.

IV milrinone appears safe and potentially effective in managing DCI and vasospasm symptoms. These promising preliminary results support implementing our standardized clinical protocol and justify further prospective randomized controlled studies.