Cerebral Vasospasm After Subarachnoid Hemorrhage: Respective Short-Term Effects of Induced Arterial Hypertension and its Combination With IV Milrinone: A Proof-of-Concept Study Using Transcranial Doppler Ultrasound.

OBJECTIVES: It is unclear whether IV milrinone relaxes spasmed cerebral arteries and therefore reduces cerebral blood mean velocity (Vmean). In patients treated for cerebral vasospasm, we aimed to assess and delineate the respective impacts of induced hypertension and its combination with IV milrinone on cerebral hemodynamics as assessed with transcranial Doppler. DESIGN: Observational proof-of-concept prospective study. SETTING: ICU in a French tertiary care center. PATIENTS: Patients with aneurysmal subarachnoid hemorrhage who received induced hypertension (mean arterial blood pressure [MBP] of 100-120 mm Hg) and IV milrinone (0.5 µg/kg/min) for moderate-to-severe cerebral vasospasm. We excluded patients who underwent invasive angioplasty or milrinone discontinuation within 12 hours after the diagnosis of vasospasm. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Vmean was measured at vasospasm diagnosis (TDIAGNOSIS), after the induction of hypertension (THTN), and 1 (THTN+MILRINONE_H1) and 12 hours after the adjunction of IV milrinone (THTN+MILRINONE_H12). Thirteen patients were included. Median Vmean was significantly lower (p < 0.01) at THTN+MILRINONE_H1 (99 [interquartile range (IQR) 89; 134] cm.s-1) and THTN+MILRINONE_H12 (85 [IQR 73-127] cm/s) than at TDIAGNOSIS (136 [IQR 115-164] cm/s) and THTN (148 [IQR 115-183] cm/s), whereas TDIAGNOSIS and THTN did not significantly differ. In all patients but one, Vmean at THTN+MILRINONE_H1 was lower than its value at TDIAGNOSIS (p = 0.0005). Vmean-to-MBP and Vmean-to-cardiac output (CO) ratios (an assessment of Vmean regardless of the level of MBP [n = 13] or CO [n = 7], respectively) were, respectively, similar at TDIAGNOSIS and THTN but were significantly lower after the adjunction of milrinone (p < 0.01). CONCLUSIONS: The induction of arterial hypertension was not associated with a significant decrease in Vmean, whereas the adjunction of IV milrinone was, regardless of the level of MBP or CO. This suggests that IV milrinone may succeed in relaxing spasmed arteries.

Intravenous Milrinone for Cerebral Vasospasm in Subarachnoid Hemorrhage: The MILRISPASM Controlled Before-After Study.

BACKGROUND: Intravenous (IV) milrinone, in combination with induced hypertension, has been proposed as a treatment option for cerebral vasospasm after aneurysmal subarachnoid hemorrhage (aSAH). However, data on its safety and efficacy are scarce. METHODS: This was a controlled observational study conducted in an academic hospital with prospectively and retrospectively collected data. Consecutive patients with cerebral vasospasm following aSAH and treated with both IV milrinone (0.5 µg/kg/min-1, as part of a strict protocol) and induced hypertension were compared with a historical control group receiving hypertension alone. Multivariable analyses aimed at minimizing potential biases. We assessed (1) 6-month functional disability (defined as a score between 2 and 6 on the modified Rankin Scale) and vasospasm-related brain infarction, (2) the rate of first-line or rescue endovascular angioplasty for vasospasm, and (3) immediate tolerance to IV milrinone. RESULTS: Ninety-four patients were included (41 and 53 in the IV milrinone and the control group, respectively). IV milrinone infusion was independently associated with a lower likelihood of 6-month functional disability (adjusted odds ratio [aOR] = 0.28, 95% confidence interval [CI] = 0.10-0.77]) and vasospasm-related brain infarction (aOR = 0.19, 95% CI 0.04-0.94). Endovascular angioplasty was less frequent in the IV milrinone group (6 [15%] vs. 28 [53%] patients, p = 0.0001, aOR = 0.12, 95% CI 0.04-0.38). IV milrinone (median duration of infusion, 5 [2-8] days) was prematurely discontinued owing to poor tolerance in 12 patients, mostly (n = 10) for "non/hardly-attained induced hypertension" (mean arterial blood pressure < 100 mmHg despite 1.5 µg/kg/min-1 of norepinephrine). However, this event was similarly observed in IV milrinone and control patients (n = 10 [24%] vs. n = 11 [21%], respectively, p = 0.68). IV milrinone was associated with a higher incidence of polyuria (IV milrinone patients had creatinine clearance of 191 [153-238] ml/min-1) and hyponatremia or hypokalemia, whereas arrhythmia, myocardial ischemia, and thrombocytopenia were infrequent. CONCLUSIONS: Despite its premature discontinuation in 29% of patients as a result of its poor tolerance, IV milrinone was associated with a lower rate of endovascular angioplasty and a positive impact on long-term neurological and radiological outcomes. These preliminary findings encourage the conduction of confirmatory randomized trials.