Vasospasm: my first 25 years-what worked? what didn't? what next?

A Double-Blind, Randomized, Placebo-Controlled Trial of Soluble Epoxide Hydrolase Inhibition in Patients with Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Epoxyeicosatrienoates (EETs) are endogenous regulators of neuroinflammation and cerebral blood flow. Their metabolism to dihydroxyeicosatrienoates (DHETs) is catalyzed by soluble epoxide hydrolase (sEH). After subarachnoid hemorrhage (SAH), EETs' pathway amplification may be a therapeutic target for the prevention of delayed cerebral ischemia (DCI). We conducted a double-blind, placebo-controlled, phase Ib randomized trial of GSK2256294, a pharmacologic inhibitor of sEH, to evaluate the safety profile and to assess biomarkers of neurovascular inflammation in patients with aneurysmal SAH.

METHODS

Patients were randomly assigned to receive 10 mg of GSK2256294 or a placebo treatment once daily for 10 days, beginning within 72 hours after aneurysm rupture. The primary study end point was safety. Secondary end points included serum and cerebrospinal fluid (CSF) EETs-to-DHETs ratio, cytokine levels, and serum endothelial injury biomarkers, measured at day 7 and day 10 after SAH. Tertiary end points included neurologic status, disposition, length of stay, incidence of DCI, and mortality; these were assessed at hospital discharge and at 90 days.

RESULTS

Ten patients received GSK2256294 and nine patients received a placebo. There were no adverse events related to the study drug. GSK2256294 administration resulted in a significant increase in the EET/DHET ratio at day 7 and day 10 in serum, but not in the CSF. There was a trend for decreased CSF inflammatory cytokines following GSK2256294 administration, but this did not reach statistical significance.

CONCLUSIONS

GSK2256294 administration was safe and well tolerated in critically ill patients with SAH, producing an increase in serum EETs and the EET-to-DHET ratio. Our findings support future studies in a larger population to evaluate the role of sEH inhibition in the prevention of DCI after SAH and other forms of brain injury and inflammatory conditions.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT03318783.

Vasopressor Infusion After Subarachnoid Hemorrhage Does Not Increase Regional Cerebral Tissue Oxygenation

INTRODUCTION

Vasopressors are commonly used after aneurysmal subarachnoid hemorrhage (aSAH) to sustain cerebral pressure gradients. Yet, the relationship between vasopressors and the degree of cerebral microcirculatory support achieved remains unclear. This study aimed to explore the changes in cerebral and peripheral regional tissue oxygen saturation (rSO2) as well as blood pressure (BP) before and after vasopressor infusion in patients with aSAH.

METHODS

Continuous noninvasive cerebral and peripheral rSO2 was obtained using near-infrared spectroscopy for up to 14 days after aSAH. Within-subject differences in rSO2 before and after the commencement of vasopressor infusion were analyzed controlling for Hunt and Hess grade and vasospasm.

RESULTS

Of 45 patients with continuous rSO2 monitoring, 19 (42%) received vasopressor infusion (all 19 on norepinephrine, plus epinephrine in 2 patients, phenylephrine in 4 patients, and vasopressin in 2 patients). In these 19 patients, their vasopressor infusion times were associated with higher BP (systolic [b = 15.1], diastolic [b = 7.3], and mean [b = 10.1]; P = .001) but lower cerebral rSO2 (left cerebral rSO2 decreased by 4.4% [b = -4.4, P < .0001]; right cerebral rSO2 decreased by 5.5% [b = -5.5, P = .0002]).

CONCLUSIONS

Despite elevation in systemic BP during vasopressor infusion times, cerebral rSO2 was concurrently diminished. These findings warrant further investigation for the effect of induced hypertension on cerebral microcirculation.

Neurobehavioral testing in subarachnoid hemorrhage: A review of methods and current findings in rodents

The most important aspect of a preclinical study seeking to develop a novel therapy for neurological diseases is whether the therapy produces any clinically relevant functional recovery. For this purpose, neurobehavioral tests are commonly used to evaluate the neuroprotective efficacy of treatments in a wide array of cerebrovascular diseases and neurotrauma. Their use, however, has been limited in experimental subarachnoid hemorrhage studies. After several randomized, double-blinded, controlled clinical trials repeatedly failed to produce a benefit in functional outcome despite some improvement in angiographic vasospasm, more rigorous methods of neurobehavioral testing became critical to provide a more comprehensive evaluation of the functional efficacy of proposed treatments. While several subarachnoid hemorrhage studies have incorporated an array of neurobehavioral assays, a standardized methodology has not been agreed upon. Here, we review neurobehavioral tests for rodents and their potential application to subarachnoid hemorrhage studies. Developing a standardized neurobehavioral testing regimen in rodent studies of subarachnoid hemorrhage would allow for better comparison of results between laboratories and a better prediction of what interventions would produce functional benefits in humans.

Treatment of cerebral vasospasm following aneurysmal subarachnoid haemorrhage: a systematic review and meta-analysis

OBJECTIVES

To examine the clinical outcome of aneurysmal subarachnoid haemorrhage (aSAH) patients exposed to cerebral vasospasm (CVS)-targeted treatments in a meta-analysis and to evaluate the efficacy of intra-arterial (IA) approaches in patients with severe/refractory vasospasm.

METHODS

Randomised controlled trials, prospective and retrospective observational studies reporting clinical outcomes of aSAH patients exposed to CVS targeted treatments, published between 2006-2016 were searched using PubMed, EMBASE and the Cochrane Library. The main endpoint was the proportion of unfavourable outcomes, defined as a modified Rankin score of 3-6 at last follow-up.

RESULTS

Sixty-two studies, including 26 randomised controlled trials, were included (8,976 patients). At last follow-up 2,490 of the 8,976 patients had an unfavourable outcome, including death (random-effect weighted-average, 33.7%; 99% confidence interval [CI], 28.1-39.7%; Q value, 806.0; I ² = 92.7%). The RR of unfavourable outcome was lower in patients treated with Cilostazol (RR = 0.46; 95% CI, 0.25-0.85; P = 0.001; Q value, 1.5; I ² = 0); and in refractory CVS patients treated by IA intervention (RR = 0.68; 95% CI, 0.57-0.80; P < 0.0001; number needed to treat with IA intervention, 6.2; 95% CI, 4.3-11.2) when compared with the best available medical treatment.

CONCLUSIONS

Endovascular treatment may improve the outcome of patients with severe-refractory vasospasm. Further studies are needed to confirm this result.

KEY POINTS

• 33.7% of patients with cerebral Vasospasm following aneurysmal subarachnoid-hemorrhage have an unfavorable outcome. • Refractory vasospasm patients treated using endovascular interventions have lower relative risk of unfavourable outcome. • Subarachnoid haemorrhage patients with severe vasospasm may benefit from endovascular interventions. • The relative risk of unfavourable outcome is lower in patients treated with Cilostazol.