Hemodynamic response and clinical outcome following intravenous milrinone plus norepinephrine–based hyperdynamic hypertensive therapy in patients suffering secondary cerebral ischemia after aneurysmal subarachnoid hemorrhage

PURPOSE: Intravenous and intra-arterial milrinone as a rescue measure for delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH) has been adopted by several groups, but so far, evidence for the clinical benefit is unclear and effect on brain perfusion is unknown. The aim of the actual analysis was to define cerebral hemodynamic effects and outcome of intravenous milrinone plus norepinephrine supplemented by intra-arterial nimodipine as a rescue strategy for DCI following aneurysmal SAH. METHODS: Of 176 patients with aneurysmal SAH treated at our neurosurgical department between April 2016 and March 2021, 98 suffered from DCI and were submitted to rescue therapy. For the current analysis, characteristics of these patients and clinical response to rescue therapy were correlated with hemodynamic parameters, as assessed by CT angiography (CTA) and perfusion CT. Time to peak (TTP) delay in the ischemic focus and the volume with a TTP delay of more than 4 s (T4 volume) were used as hemodynamic parameters. RESULTS: The median delay to neurological deterioration following SAH was 5 days. Perfusion CT at that time showed median T4 volumes of 40 cc and mean focal TTP delays of 2.5 ± 2.1 s in these patients. Following rescue therapy, median T4 volume decreased to 10 cc and mean focal TTP delay to 1.7 ± 1.9 s. Seventeen patients (17% of patients with DCI) underwent additional intra-arterial spasmolysis using nimodipine. Visible resolution of macroscopic vasospasm on CTA was observed in 43% patients with DCI and verified vasospasm on CTA, including those managed with additional intra-arterial spasmolysis. Initial WFNS grade, occurrence of secondary infarction, ischemic volumes and TTP delays at the time of decline, the time to clinical decline, and the necessity for additional intra-arterial spasmolysis were identified as the most important features determining neurological outcome at 6 months. CONCLUSION: The current analysis shows that cerebral perfusion in the setting of secondary cerebral ischemia following SAH is measurably improved by milrinone and norepinephrine–based hyperdynamic therapy. A long-term clinical benefit by the addition of milrinone appears likely. Separation of the direct effect of milrinone from the effect of induced hypertension is not possible based on the present dataset.