Massachusetts General Hospital Boston, Massachusetts, USA
Introduction: Aneurysmal subarachnoid hemorrhage (aSAH) can be complicated by cerebral vasospasm which can contribute to delayed cerebral ischemia (DCI). IV milrinone, a phosphodiesterase-III inhibitor, has gained popularity as a vasospasm treatment but evidence supporting its use is limited, especially sonographic evidence of vasospasm resolution post-initiation. This study evaluated IV milrinone effectiveness for aSAH-associated vasospasm using transcranial Doppler (TCD) velocities as a proxy for treatment response.
Methods: This was a single-center, retrospective cohort study of adult patients admitted to the neurosciences intensive care unit between 4/2016-7/2023 treated with continuous IV milrinone for aSAH-associated vasospasm. The primary outcome was rates of sonographic treatment success after milrinone initiation, defined as a >20% decrease in TCD peak systolic velocity (PSV) of the spasming vessel (obtained within 24 hours prior to therapy initiation) at 48 hours post-initiation and at therapy discontinuation. Vasospasm improvement was defined as a 10-20% decrease in baseline TCD PSV at the same time points.
Results: The study included 52 patients with a mean age of 55 (±12.7) years and 36 (75%) were female. The median (IQR) Hunt and Hess and modified Fisher grades were 3 (2-4) and 4 (3-4) respectively. Fifty (96.1%) patients had TCD values at baseline and at 48 hours post-initiation of which 17 (34%) experienced treatment success and seven (14%) experienced vasospasm improvement. The overall mean percent decrease (MPD) was 10.9%; TCD PSV declined by 40.6% and 16.6% for those who experienced treatment success or improvement, respectively. After milrinone was stopped, 21 of 37 (56.8%) patients with data available achieved treatment success (MPD 48.9%) and 2 (5.4%) improved (MPD 17.3%). MPD in all patients was 24.42%. Eight (21.6%) patients experienced an increase in TCDs after milrinone discontinuation with a mean percent increase in TCD values of 25.1%.
Conclusions: In 52 patients with aSAH-associated vasospasm, milrinone led to significant improvements in TCD PSV in 34% of patients at 48 hours and 56.8% at the time of discontinuation. TCDs may be an effective tool to assess therapeutic response to IV milrinone, particularly within 48 hours of treatment.
