Effectiveness of intrathecal nicardipine on cerebral vasospasm in non-traumatic subarachnoid hemorrhage: a systematic review

Preventing Poor Outcomes for Neurosurgical Patients

Ensuring that patients with neurosurgical conditions have the best possible outcome requires early diagnosis, monitoring, and interventions to prevent complications and optimize care. Here, we review several neurosurgical conditions and the measures taken to prevent complications and optimize outcomes. We hope that the practical tips provided herein prove helpful in caring for neurosurgical patients.

RAR-Related Orphan Receptor Gamma T (RoRγt)-Related Cytokines Play a Role in Neutrophil Infiltration of the Central Nervous System After Subarachnoid Hemorrhage

BACKGROUND

How inflammatory cells are recruited into the central nervous system is a topic of interest in a number of neurological injuries. In aneurysmal subarachnoid hemorrhage (SAH), neutrophil accumulation in the central nervous system 3 days after the hemorrhage is a critical step in the development of delayed cerebral injury (DCI). The mechanism by which neutrophils enter the central nervous system is still unclear.

METHODS AND RESULTS

To identify human effectors of neutrophil recruitment, cerebrospinal fluid (CSF) samples were taken from a small, selected sample of SAH patients with external ventricular drainage devices (10 patients). Among a battery of CSF cytokines tested 3 days after SAH, five cytokines were associated with poor 90-day outcome (modified Rankin Score 3-6). A parallel study in a mouse model of mild SAH showed elevation in three cytokines in the CNS compared to sham. IL-17 and IL-2 were increased in both patients and the mouse model. IL-17 was investigated further because of its known role in neutrophil recruitment. Inhibition of RAR-Related Orphan Receptor Gamma T, the master transcription factor of IL-17, with the inverse agonist GSK805 suppressed neutrophils entry into the CNS after SAH compared to control. Using an IL-17 reporter mouse, we investigated the source of IL-17 and found that myeloid cells were a common IL-17-producing cell type in the meninges after SAH, suggesting an autocrine role for neutrophil recruitment.

CONCLUSIONS

Taken together, IL-17 appears to be in important factor in the recruitment of neutrophils into the meninges after SAH and could be an important target for therapies to ameliorate DCI.

Does intrathecal nicardipine for cerebral vasospasm following subarachnoid hemorrhage correlate with reduced delayed cerebral ischemia? A retrospective propensity score-based analysis

OBJECTIVE

Cerebral vasospasm and delayed cerebral ischemia (DCI) contribute to poor outcome following subarachnoid hemorrhage (SAH). With the paucity of effective treatments, the authors describe their experience with intrathecal (IT) nicardipine for this indication.

METHODS

Patients admitted to the Emory University Hospital neuroscience ICU between 2012 and 2017 with nontraumatic SAH, either aneurysmal or idiopathic, were included in the analysis. Using a propensity-score model, this patient cohort was compared to patients in the Subarachnoid Hemorrhage International Trialists (SAHIT) repository who did not receive IT nicardipine. The primary outcome was DCI. Secondary outcomes were long-term functional outcome and adverse events.

RESULTS

The analysis included 1351 patients, 422 of whom were diagnosed with cerebral vasospasm and treated with IT nicardipine. When compared with patients with no vasospasm (n = 859), the treated group was significantly younger (mean age 51.1 ± 12.4 years vs 56.7 ± 14.1 years, p < 0.001), had a higher World Federation of Neurosurgical Societies score and modified Fisher grade, and were more likely to undergo clipping of the ruptured aneurysm as compared to endovascular treatment (30.3% vs 11.3%, p < 0.001). Treatment with IT nicardipine decreased the daily mean transcranial Doppler velocities in 77.3% of the treated patients. When compared to patients not receiving IT nicardipine, treatment was not associated with an increased rate of bacterial ventriculitis (3.1% vs 2.7%, p > 0.1), yet higher rates of ventriculoperitoneal shunting were noted (19.9% vs 8.8%, p < 0.01). In a propensity score comparison to the SAHIT database, the odds ratio (OR) to develop DCI with IT nicardipine treatment was 0.61 (95% confidence interval [CI] 0.44-0.84), and the OR to have a favorable functional outcome (modified Rankin Scale score ≤ 2) was 2.17 (95% CI 1.61-2.91).

CONCLUSIONS

IT nicardipine was associated with improved outcome and reduced DCI compared with propensity-matched controls. There was an increased need for permanent CSF diversion but no other safety issues. These data should be considered when selecting medications and treatments to study in future randomized controlled clinical trials for SAH.

Novel Treatment of Cerebral Vasospasm Using Solitaire Stent Retriever-Assisted Angioplasty: Case Series

BACKGROUND

Endovascular procedures such as intraarterial (IA) vasodilator injection and balloon angioplasty are used to treat medically refractory cerebral vasospasm. The effects of IA therapy may be short lived and thus require multiple treatments. Balloon angioplasty also has limitations including transient occlusion of the spastic blood vessel, possible endothelial injury, and limited access to proximal vessels. We aim to demonstrate a novel technique using a stent retriever for the management of medically refractory vasospasm, especially in distal vessels. Compared with balloon angioplasty, stent retrievers provide a passive, self-limiting expansion of blood vessels. Other benefits over balloon angioplasty include 1) ability to simultaneously inject IA vasodilators, 2) limited contact and damage to vessel wall, 3) nonocclusive expansion, and 4) technical ease.

METHODS

Fourteen blood vessels from 6 patients with symptomatic vasospasm after subarachnoid hemorrhage were identified. We injected 5 mg of IA vasodilator medication into the vasospastic segments without radiographic improvement in vessel diameter and blood flow. The stent retriever was deployed for 2-5 minutes in each vasospastic segment.

RESULTS

Distal anterior and posterior circulation segments were easily accessible with the stent retriever system. It resulted in improved vessel diameter and blood flow with subsequent improvement in neurologic examination. All patients demonstrated radiographic resolution of vasospasm. No procedural-related complications were noted.

CONCLUSIONS

We demonstrate the safety and efficacy of a novel technique for the treatment of medically refractory cerebral vasospasm using stent retriever angioplasty in distal vessels. Stent angioplasty can be used as an additional tool in the management of subarachnoid hemorrhage-induced cerebral vasospasm.

Perfusion fixation in brain banking: a systematic review

Background

Perfusing fixatives through the cerebrovascular system is the gold standard approach in animals to prepare brain tissue for spatial biomolecular profiling, circuit tracing, and ultrastructural studies such as connectomics. Translating these discoveries to humans requires examination of postmortem autopsy brain tissue. Yet banked brain tissue is routinely prepared using immersion fixation, which is a significant barrier to optimal preservation of tissue architecture. The challenges involved in adopting perfusion fixation in brain banks and the extent to which it improves histology quality are not well defined.

Methodology

We searched four databases to identify studies that have performed perfusion fixation in human brain tissue and screened the references of the eligible studies to identify further studies. From the included studies, we extracted data about the methods that they used, as well as any data comparing perfusion fixation to immersion fixation. The protocol was preregistered at the Open Science Framework: https://osf.io/cv3ys/.

Results

We screened 4489 abstracts, 214 full-text publications, and identified 35 studies that met our inclusion criteria, which collectively reported on the perfusion fixation of 558 human brains. We identified a wide variety of approaches to perfusion fixation, including perfusion fixation of the brain in situ and ex situ, perfusion fixation through different sets of blood vessels, and perfusion fixation with different washout solutions, fixatives, perfusion pressures, and postfixation tissue processing methods. Through a qualitative synthesis of data comparing the outcomes of perfusion and immersion fixation, we found moderate confidence evidence showing that perfusion fixation results in equal or greater subjective histology quality compared to immersion fixation of relatively large volumes of brain tissue, in an equal or shorter amount of time.

Conclusions

This manuscript serves as a resource for investigators interested in building upon the methods and results of previous research in designing their own perfusion fixation studies in human brains or other large animal brains. We also suggest several future research directions, such as comparing the in situ and ex situ approaches to perfusion fixation, studying the efficacy of different washout solutions, and elucidating the types of brain donors in which perfusion fixation is likely to result in higher fixation quality than immersion fixation.

Electronic supplementary material

The online version of this article (10.1186/s40478-019-0799-y) contains supplementary material, which is available to authorized users.