Novel index for predicting mortality during the first 24 hours after traumatic brain injury

Cerebrovascular Pressure Reactivity According to Long-Pressure Reactivity Index During Spreading Depolarizations in Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Spreading depolarization (SD) has been linked to the impairment of neurovascular coupling. However, the association between SD occurrence and cerebrovascular pressure reactivity as a surrogate of cerebral autoregulation (CA) remains unclear. Therefore, we analyzed CA using the long-pressure reactivity index (L-PRx) during SDs in patients with aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

A retrospective study of patients with aSAH who were recruited at two centers, Heidelberg (HD) and Berlin (BE), was performed. Continuous monitoring of mean arterial pressure (MAP) and intracranial pressure (ICP) was recorded. ICP was measured using an intraparenchymal probe in HD patients and was measure in BE patients through external ventricular drainage. Electrocorticographic (ECoG) activity was continuously recorded between 3 and 13 days after hemorrhage. Autoregulation according to L-PRx was calculated as a moving linear Pearson's correlation of 20-min averages of MAP and ICP. For every identified SD, 60-min intervals of L-PRx were averaged, plotted, and analyzed depending on SD occurrence. Random L-PRx recording periods without SDs served as the control.

RESULTS

A total of 19 patients (HD n = 14, BE n = 5, mean age 50.4 years, 9 female patients) were monitored for a mean duration of 230.4 h (range 96-360, STD ± 69.6 h), during which ECoG recordings revealed a total number of 277 SDs. Of these, 184 represented a single SD, and 93 SDs presented in clusters. In HD patients, mean L-PRx values were 0.12 (95% confidence interval [CI] 0.11-0.13) during SDs and 0.07 (95% CI 0.06-0.08) during control periods (p < 0.001). Similarly, in BE patients, a higher L-PRx value of 0.11 (95% CI 0.11-0.12) was detected during SDs than that during control periods (0.08, 95% CI 0.07-0.09; p < 0.001). In a more detailed analysis, CA changes registered through an intraparenchymal probe (HD patients) revealed that clustered SD periods were characterized by signs of more severely impaired CA (L-PRx during SD in clusters: 0.23 [95% CI 0.20-0.25]; single SD: 0.09 [95% CI 0.08-0.10]; control periods: 0.07 [95% CI 0.06-0.08]; p < 0.001). This group also showed significant increases in ICP during SDs in clusters compared with single SD and control periods.

CONCLUSIONS

Neuromonitoring for simultaneous assessment of cerebrovascular pressure reactivity using 20-min averages of MAP and ICP measured by L-PRx during SD events is feasible. SD occurrence was associated with significant increases in L-PRx values indicative of CA disturbances. An impaired CA was found during SD in clusters when using an intraparenchymal probe. This preliminary study validates the use of cerebrovascular reactivity indices to evaluate CA disturbances during SDs. Our results warrant further investigation in larger prospective patient cohorts.

Single session versus multisession stereotactic radiosurgery for the management of intracranial meningiomas: a systematic review and meta-analysis

PURPOSE

To compare the efficacy, outcomes, and complications of single session (SS-SRS) and multisession (MS-SRS) stereotactic radiosurgery in the treatment of intracranial meningiomas.

METHODS

Relevant articles were retrieved from PubMed, Scopus, Web of Science, and Cochrane. A systematic review and meta-analysis of treatment protocols and outcomes were conducted. After the selection process, 20 articles describing 1483 cases were included.

RESULTS

A total of 1303 patients who underwent SS-SRS and 180 patients who underwent MS-SRS for the management of their intracranial meningioma were reported in the included studies. SS-SRS and MS-SRS had comparable one-year (SS-SRS: 98% vs. MS-SRS: 100%, p > 0.99) and five-year (SS-SRS: 94% vs. MS-SRS: 93%, p = 0.71) tumor control rates. The groups also had comparable tumor volume reduction/tumor regression rates (SS-SRS: 44% vs. MS-SRS: 25%, p = 0.25), tumor volume stability rates (SS-SRS: 51% vs. MS-SRS: 75%, p = 0.12), and tumor progression rates (SS-SRS: 4% vs. MS-SRS: 4%, p = 0.89). SS-SRS and MS-SRS yielded similar complication rates (10.4% vs. 11.4%, p = 0.68) and comparable functional improvement rates (MS-SRS: 44% vs. SS-SRS: 36%, p = 0.57). However, MS-SRS was used for significantly larger tumor volumes (MS-SRS: 23.8 cm³ vs. SS-SRS: 6.1 cm³, p = 0.02).

CONCLUSION

SS-SRS and MS-SRS resulted in comparable tumor control, tumor volumetric change, and functional outcomes despite significant biases in selecting patients for SS- or MS-SRS.

Initial neurocritical care of severe traumatic brain injury: New paradigms and old challenges

Background:

Early neurocritical care aims to ameliorate secondary traumatic brain injury (TBI) and improve neural salvage. Increased engagement of neurosurgeons in neurocritical care is warranted as daily briefings between the intensivist and the neurosurgeon are considered a quality indicator for TBI care. Hence, neurosurgeons should be aware of the latest evidence in the neurocritical care of severe TBI (sTBI).

Methods:

We conducted a narrative literature review of bibliographic databases (PubMed and Scopus) to examine recent research of sTBI.

Results:

This review has several take-away messages. The concept of critical neuroworsening and its possible causes is discussed. Static thresholds of intracranial pressure (ICP) and cerebral perfusion pressure may not be optimal for all patients. The use of dynamic cerebrovascular reactivity indices such as the pressure reactivity index can facilitate individualized treatment decisions. The use of ICP monitoring to tailor treatment of intracranial hypertension (IHT) is not routinely feasible. Different guidelines have been formulated for different scenarios. Accordingly, we propose an integrated algorithm for ICP management in sTBI patients in different resource settings. Although hyperosmolar therapy and decompressive craniectomy are standard treatments for IHT, there is a lack high-quality evidence on how to use them. A discussion of the advantages and disadvantages of invasive ICP monitoring is included in the study. Addition of beta-blocker, anti-seizure, and anticoagulant medications to standardized management protocols (SMPs) should be considered with careful patient selection.

Conclusion:

Despite consolidated research efforts in the refinement of SMPs, there are still many unanswered questions and novel research opportunities for sTBI care.

Brain-Derived Extracellular Vesicles Induce Vasoconstriction and Reduce Cerebral Blood Flow in Mice

Traumatic brain injury (TBI) impairs cerebrovascular autoregulation and reduces cerebral blood flow (CBF), leading to ischemic secondary injuries. We have shown that injured brains release brain-derived extracellular vesicles (BDEVs) into circulation, where they cause a systemic hypercoagulable state that rapidly turns into consumptive coagulopathy. BDEVs induce endothelial injury and permeability, leading to the hypothesis that they contribute to TBI-induced cerebrovascular dysregulation. In a study designed to test this hypothesis, we detected circulating BDEVs in C57BL/6J mice subjected to severe TBI, reaching peak levels of 3x104/µl at 3 hours post injury (71.2±21.5% of total annexin V-binding EVs). We further showed in an adaptive transfer model that 41.7±5.8% of non-injured mice died within 6 hours after being infused with 3x104/µl of BDEVs. BDEVs transmigrated through the vessel walls, induced rapid vasoconstriction by inducing calcium influx in vascular smooth muscle cells, and reduced CBF by 93.8±5.6% within 30 minutes after infusion. The CBF suppression was persistent in mice that eventually died but it recovered quickly in surviving mice. It was prevented by the calcium channel blocker nimodipine. When being separated, neither protein nor phospholipid components from the lethal number of BDEVs induced vasoconstriction, reduced CBF, and caused death. These results demonstrate a novel vasoconstrictive activity of BDEVs that depends on the structure of BDEVs and contributes to TBI-induced disseminated cerebral ischemia and sudden death.

Management of non-vestibular schwannomas in adult patients: a systematic review and consensus statement on behalf of the EANS skull base section. Part I: oculomotor and other rare non-vestibular schwannomas (I, II, III, IV, VI)

BACKGROUND

Non-vestibular schwannomas are relatively rare, with trigeminal and jugular foramen schwannomas being the most common. This is a heterogeneous group which requires detailed investigation and careful consideration to management strategy. The optimal management for these tumours remains unclear, and there are several controversies. The aim of this paper is to provide insight into the main principles defining management and surgical strategy, in order to formulate a series of recommendations.

METHODS

A task force was created by the EANS skull base section along with its members and other renowned experts in the field to generate recommendations for the surgical management of these tumours on a European perspective. To achieve this, the task force performed an extensive systematic review in this field and had discussions within the group. This article is the first of a three-part series describing non-vestibular schwannomas (I, II, III, IV, VI).

RESULTS

A summary of literature evidence was proposed after discussion within the EANS skull base section. The constituted task force dealt with the practice patterns that exist with respect to pre-operative radiological investigations, ophthalmological assessments, optimal surgical and radiotherapy strategies and follow-up management.

CONCLUSION

This article represents the consensually derived opinion of the task force with respect to the treatment of non-vestibular schwannomas. For each of these tumours, the management of these patients is complex, and for those which are symptomatic tumours, the paradigm is shifting towards the compromise between function preservation and progression-free survival.

Management of tandem occlusions in patients who receive rtPA

BACKGROUND

Tandem occlusions exist in 17-32% of large vessel occlusion (LVO) strokes. A significant concern is bleeding when carotid stenting is performed in tandem with thrombectomy due the administration of antiplatelet agents such as glycoprotein IIb/IIIa inhibitors (GP2b3aI) after receiving rtPA, but data are limited in this setting.

METHODS

A mutlicenter, retrospective chart review was conducted at two comprehensive stroke centers to assess the safety and efficacy of using GP2b3aI to facilitate carotid stent placement simultaneously with endovascular thrombectomy in patients who have received rtPA.

RESULTS

Overall, 32 patients were included in this study, with average age of 66.3 ± 10.4 years and predominantly male (87.5%). The cause of stroke was mostly large artery atherosclerosis (59.4%) and the thrombectomy target vessels were typically first- or second segment middle cerebral artery (37.5% and 31.3%). Time from symptom onset to rtPA bolus was 1.8 h [interquartile range (IQR) 1.5-2.7], rtPA bolus to first pass was 2 h [IQR 1.5-3.1], rtPA bolus to GP2b3aI bolus was 2 h [IQR 1.6-3.5], and rtPA bolus to aspirin and clopidogrel administration was 4.3 h [IQR 2.6-8.9] and 6.6 h [IQR 4.5-11.6] respectively. No patients had acute in-stent thrombosis or post-op bleeding from the access site. Two patients (6.3%) had significant hemorrhagic conversion.

CONCLUSION

The use of GP2b3aI in the setting of tandem occlusions that required emergent stent placement post-rtPA appears safe and effective. Given the small sample size, these findings should be interpreted cautiously, and need to be confirmed in a larger patient population.

The effect of xylazine on intracranial pressure in anesthetized and standing horses

OBJECTIVE

To determine the effect of xylazine on intracranial pressure (ICP) in standing compared to isoflurane-anesthetized horses.

DESIGN

Prospective, crossover study design.

SETTING

University Teaching Hospital.

ANIMALS

Six adult horses donated to the University. Horses were determined to be healthy via physical examination, complete blood count, and neurological evaluation.

INTERVENTIONS

Horses were anesthetized, maintained on isoflurane in oxygen in left lateral recumbency, and ventilated to normocapnia. Horses were instrumented for intraparenchymal measurement of ICP, invasive blood pressure, pulse oximetry, and end tidal gas analyzer. Xylazine 1 mg/kg was administered IV and ICP, systolic arterial pressure, mean arterial pressure (MAP), diastolic arterial pressure, and heart rate were recorded and cerebral perfusion pressure (CPP) was calculated for the following 15 minutes. Twenty-four to 36 hours following anesthetic recovery, xylazine 1 mg/kg was administered IV and ICP, heart rate, and Doppler blood pressure (BPdop) on the tail were monitored for 15 minutes.

MEASUREMENTS AND MAIN RESULTS

There was a decrease in ICP following administration of xylazine in anesthetized horses (P < 0.003) but not standing horses (P = 0.227). There was an increase in systolic arterial pressure, MAP, diastolic arterial pressure (P < 0.001), and BPdop (P = 0.001) following administration of xylazine. As a result, CPP increased in anesthetized horses (P < 0.03). There was a negative association between ICP and MAP in anesthetized horses (P = 0.007) but not ICP and BPdop conscious horses (P = 0.379).

CONCLUSIONS

Administration of xylazine to anesthetized horses resulted in an increased CPP due to decreased ICP with concurrent increased MAP. Administration of xylazine to standing horses did not result in a change in ICP. However, with the increase in BPdop found in awake horses, it is likely that CPP would also increase in awake horses following xylazine administration.

Hypoperfusion assessed by pressure reactivity index is associated with delayed cerebral ischemia after subarachnoid hemorrhage: an observational study

Background

Dysfunction of cerebral autoregulation is one of the pathophysiological mechanisms that causes delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH). Pressure reactivity index (PRx) have been confirmed to reflect the level of cerebral autoregulation and used to derive optimal cerebral perfusion pressure (CPPopt). The goal of this study is to explore the associations between autoregulation, CPPopt, PRx, and DCI.

Methods

Continuous intracranial pressure (ICP), arterial blood pressure (ABP), and cerebral perfusion pressure (CPP) signals acquired from 61 aSAH patients were retrospectively analyzed. PRx was calculated and collected by Pneumatic computer system. The CPP at the lowest PRx was determined as the CPPopt. The duration of a hypoperfusion event (dHP) was defined as the cumulative time that the PRx was > 0.3 and the CPP was <CPPopt. The duration of CPP more than 10 mmHg below CPPopt (ΔCPPopt < − 10 mmHg) was also used to assess hypoperfusion. The percent of the time of hypoperfusion by dHP and ΔCPPopt < − 10 mmHg (%dHP and %ΔCPPopt) were compared between DCI group and control group, utilizing univariate and multivariable logistic regression. It was the clinical prognosis at 3 months after hemorrhage that was assessed with the modified Rankin Scale, and logistic regression and ROC analysis were used for predictive power for unfavorable outcomes (mRs 3–5).

Results

Data from 52 patients were included in the final analysis of 61 patients. The mean %dHP in DCI was 29.23% and 10.66% in control. The mean %ΔCPPopt < − 10 mmHg was 22.28%, and 5.90% in control. The %dHP (p < 0.001) and the %ΔCPPopt < − 10mmHg (p < 0.001) was significantly longer in the DCI group. In multivariate logistic regression model, %ΔCPPopt <− 10 mmHg (p < 0.001) and %dHP (p < 0.001) were independent risk factor for predicting DCI, and %ΔCPPopt <− 10 mmHg (p = 0.010) and %dHP (p = 0.026) were independent risk factor for predicting unfavorable outcomes.

Conclusions

The increase of duration of hypoperfusion events and duration of CPP below CPPopt over 10 mmHg, evaluated as time of lowered CPP, is highly indicative of DCI and unfavorable outcomes.