Magnesium sulfate therapy after aneurysmal subarachnoid hemorrhage

Outcomes Measures in Subarachnoid Hemorrhage Research

Despite advancements in acute management, morbidity rates for subarachnoid hemorrhage (SAH) remain high. Therefore, it is imperative to utilize standardized outcome scales in SAH research for evaluating new therapies effectively. This review offers a comprehensive overview of prevalent scales and clinical outcomes used in SAH assessment, accompanied by recommendations for their application and prognostic accuracy. Standardized terminology and diagnostic criteria should be employed when reporting pathophysiological outcomes such as symptomatic vasospasm and delayed cerebral ischemia. Furthermore, integrating clinical severity scales like the World Federation of Neurosurgical Societies scale and modified Fisher score into clinical trials is advised to evaluate their prognostic significance, despite their limited correlation with outcomes. The modified Rankin score is widely used for assessing functional outcomes, while the Glasgow outcome scale-extended version is suitable for broader social and behavioral evaluations. Avoiding score dichotomization is crucial to retain valuable information. Cognitive and behavioral outcomes, though frequently affected in patients with favorable neurological outcomes, are often overlooked during follow-up outpatient visits, despite their significant impact on quality of life. Comprehensive neuropsychological evaluations conducted by trained professionals are recommended for characterizing cognitive function, with the Montreal Cognitive Assessment serving as a viable screening tool. Additionally, integrating psychological inventories like the Beck Depression and Anxiety Inventory, along with quality-of-life scales such as the Stroke-Specific Quality of Life Scale, can effectively assess behavioral and quality of life outcomes in SAH studies.

RANDOMIZED EXPERIMENTAL STUDY OF TOPICAL VASODILATORS IN MICROSURGERY WITH COST ANALYSIS

Objective

Throughout microsurgical anastomosis, many surgeons use topical vasodilators in order to reduce pathological vasospasm. It was carried out an experimental study comparing the effectiveness of topical use of Nitroglycerin, Papaverine, Magnesium sulfate over a control group in the femoral artery and vein of rats, in reducing prolonged vasospasm.

Methods

Randomized comparative experimental study in 15 rats, divided into four groups. The external diameter of the vases soaked in the randomized solution was measured. For statistical analysis, it was calculated the percentual increase in the external diameter of the vessels.

Results

A statistically significant increase in arterial dilation was observed after 10 minutes of topical application of 10% magnesium sulfate compared to the control group, with p = 0.044 . No other drug showed a vasodilator effect superior to the control group. Magnesium sulfate at 10% is still not used in microsurgery and costs 15 times less than papaverine, the standard drug for topical vasodilation in clinical cases at our service.

Conclusion

Magnesium sulfate had better vasodilating effects over the control group after 10 minutes of arterial microanastomosis. None of the tested drugs have presented superior vasodilating effects over each other nor the control group after venous microanastomosis. Level of evidence II, Experimental study, Randomized Trial.

Research hotpots and frontier trends of neuroprotective effects of magnesium from 1999 to 2023: A bibliometric analysis

BACKGROUND

The neuroprotective effect of magnesium has been widely discussed, and its effectiveness has been confirmed by animal and clinical trials. However, there are still difficulties in clinical translation in diseases such as cerebral ischemia and subarachnoid hemorrhage. Therefore, it is necessary to analyze the literatures about neuroprotection of magnesium to reveal a more comprehensive knowledge framework, research hotspots and trends in the future.

METHODS

Original articles and reviews related to neuroprotective effects of magnesium from 1999 to 2022 were retrieved from the Web of Science Core Collection (WoSCC). The bibliometrics CiteSpace 6.2.R4 software was used to conduct co-occurrence/co-citation network analysis and plot knowledge visualization maps.

RESULTS

A total of 762 articles from 216 institutions in 64 countries were included in this study. The United States had the largest number of publications, followed by China and Canada. The University of California, UDICE-French Research Universities, and the University of Adelaide were the top three institutions in publication volume. Crowther Caroline A was the most published and cited author. Among the top 10 cited articles, there were seven articles on neuroprotection in preterm infants and three on acute stroke. Keyword cluster analysis obtained 11 clusters, showing that current research hotspots focused on magnesium therapy in neurovascular diseases such as cerebral ischemia, spinal cord injury, subarachnoid hemorrhage, and emerging treatment strategies.

CONCLUSION

The neuroprotective effects of magnesium in preterm infants have been extensively studied and adequately confirmed. The therapeutic effects of magnesium on cerebral ischemia and subarachnoid hemorrhage have been demonstrated in animal models. However, the results of clinical studies were not satisfactory, and exploring new therapeutic strategies may be the solution. Recently, the combination of magnesium and hypothermia had great potential in neuroprotective therapy and may become a development trend and hotspot in the future.

Effect of magnesium sulfate on cerebral vasospasm in the treatment of aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis

Introduction

The use of magnesium sulfate for treating aneurysmal subarachnoid hemorrhage (aSAH) has shown inconsistent results across studies. To assess the impact of magnesium sulfate on outcomes after aSAH, we conducted a systematic review and meta-analysis of relevant randomized controlled trials.

Methods

PubMed, Embase, and the Cochrane Library were searched for relevant literature on magnesium sulfate for aSAH from database inception to March 20, 2023. The primary outcome was cerebral vasospasm (CV), and secondary outcomes included delayed cerebral ischemia (DCI), secondary cerebral infarction, rebleeding, neurological dysfunction, and mortality.

Results

Of the 558 identified studies, 16 comprising 3,503 patients were eligible and included in the analysis. Compared with control groups (saline or standard treatment), significant differences were reported in outcomes of CV [odds ratio (OR) = 0.61, p = 0.04, 95% confidence interval (CI) (0.37-0.99)], DCI [OR = 0.57, p = 0.01, 95% CI (0.37-0.88)], secondary cerebral infarction [OR = 0.49, p = 0.01, 95% CI (0.27-0.87)] and neurological dysfunction [OR = 0.55, p = 0.04, 95% CI (0.32-0.96)] after magnesium sulfate administration, with no significant differences detected in mortality [OR = 0.92, p = 0.47, 95% CI (0.73-1.15)] and rebleeding [OR = 0.68, p = 0.55, 95% CI (0.19-2.40)] between the two groups.

Conclusion

The superiority of magnesium sulfate over standard treatments for CV, DCI, secondary cerebral infarction, and neurological dysfunction in patients with aSAH was demonstrated. Further randomized trials are warranted to validate these findings with increased sample sizes.

Serum concentration-guided intravenous magnesium sulfate administration for neuroprotection in patients with aneurysmal subarachnoid hemorrhage: a retrospective evaluation of a 12-year single-center experience

Delayed cerebral infarction (DCI) is a major cause of morbidity and mortality in patients with aneurysmal subarachnoid hemorrhage (aSAH). The benefits of magnesium sulfate as an alternative treatment are controversial, and most previous studies examined its benefits only as adjunctive treatment to traditional nimodipine. We retrospectively analyzed aSAH patients records with magnesium sulfate between 2010 and 2021. We aimed for a serum magnesium concentration of 2-2.5 mmol/l between post-hemorrhage days 3 and 12. The patients were separated in three groups based on average serum magnesium concentration (magnesium >2 mmol/l, reduced magnesium 1.1-1.9 mmol/l, and no magnesium). Additionally, we assessed delayed cerebral infarction (DCI) and clinical outcome at follow-up, using the modified Rankin Scale (mRS), categorized in favorable (0-3) and unfavorable outcome (4-5). In this analysis, 548 patients were included. Hereof, radiological evidence of DCI could be found in 23.0% (n = 126) of patients. DCI rates were lower if patients' average serum magnesium was higher than 2 mmol/l (magnesium 18.8%, n = 85; reduced magnesium 38.3%, n = 23; no magnesium 51.4%, n = 18; p < 0.001). Also, at the last follow-up, patients in the group with a higher serum magnesium concentration had better outcome (favorable outcome: magnesium 64.7%, n = 293; reduced magnesium 50.0%, n = 30; no magnesium 34.3%, n = 12; p < 0.001). This 12-year study reveals the value of serum concentration-guided magnesium administration in aSAH patients. Our findings demonstrate the safety and efficacy when titrated to a serum concentration of 2-2.5 mmol/l. We observed higher rates of delayed cerebral infarction and unfavorable outcomes in patients with serum concentrations below 2 mmol/l.

Guidelines for the Neurocritical Care Management of Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

The neurointensive care management of patients with aneurysmal subarachnoid hemorrhage (aSAH) is one of the most critical components contributing to short-term and long-term patient outcomes. Previous recommendations for the medical management of aSAH comprehensively summarized the evidence based on consensus conference held in 2011. In this report, we provide updated recommendations based on appraisal of the literature using the Grading of Recommendations Assessment, Development, and Evaluation methodology.

METHODS

The Population/Intervention/Comparator/Outcome (PICO) questions relevant to the medical management of aSAH were prioritized by consensus from the panel members. The panel used a custom-designed survey instrument to prioritize clinically relevant outcomes specific to each PICO question. To be included, the study design qualifying criteria were as follows: prospective randomized controlled trials (RCTs), prospective or retrospective observational studies, case-control studies, case series with a sample larger than 20 patients, meta-analyses, restricted to human study participants. Panel members first screened titles and abstracts, and subsequently full text review of selected reports. Data were abstracted in duplicate from reports meeting inclusion criteria. Panelists used the Grading of Recommendations Assessment, Development, and Evaluation Risk of Bias tool for assessment of RCTs and the "Risk of Bias In Nonrandomized Studies - of Interventions" tool for assessment of observational studies. The summary of the evidence for each PICO was presented to the full panel, and then the panel voted on the recommendations.

RESULTS

The initial search retrieved 15,107 unique publications, and 74 were included for data abstraction. Several RCTs were conducted to test pharmacological interventions, and we found that the quality of evidence for nonpharmacological questions was consistently poor. Five PICO questions were supported by strong recommendations, one PICO question was supported by conditional recommendations, and six PICO questions did not have sufficient evidence to provide a recommendation.

CONCLUSIONS

These guidelines provide recommendations for or against interventions proven to be effective, ineffective, or harmful in the medical management of patients with aSAH based on a rigorous review of the available literature. They also serve to highlight gaps in knowledge that should guide future research priorities. Despite improvements in the outcomes of patients with aSAH over time, many important clinical questions remain unanswered.

Inhibition of Delayed Cerebral Ischemia by Magnesium Is Insufficient for Subarachnoid Hemorrhage Patients: A Network Meta-Analysis

Objective

After subarachnoid hemorrhage, magnesium could reduce the incidence of delayed cerebral ischemia; however, it is still controversial. This study updated the results of recently published magnesium-related studies and conducted an exploratory analysis of the impact of application strategies and intervention factors on the results.

Methods

Public databases were searched from the date of their inception to May 10, 2021. Randomized controlled trials on magnesium agent-related regimens for subarachnoid hemorrhage patients were included.

Results

In total, 28 articles were included in the meta-analysis. For delayed cerebral ischemia, magnesium-related interventions significantly reduced the risk of delayed cerebral ischemia compared with nonmagnesium interventions (odds ratios: 0.40; 95% confidence interval: 0.28–0.56; p < 0.01). For cerebral vasospasm, a random effects model showed that magnesium significantly reduced the risk of cerebral vasospasm (odds ratios: 0.46; 95% confidence interval: 0.33–0.63; p < 0.01). In the subgroup analysis, intracranial magnesium (odds ratios: 6.67; 95% confidence interval: 1.14–38.83; p=0.03) and magnesium plus hydrogen (odds ratios: 10; 95% confidence interval: 1.59–62.73; p=0.01) produced significant results in improving the good recovery rate compared to the control. In the network meta-analysis, magnesium plus nimodipine and simvastatin even showed an effective trend in death/persistent vegetative status improvement.

Conclusion

This study supports the beneficial effect of magnesium in reducing the risk of delayed cerebral ischemia. Based on a single randomized controlled trial, immediate intracranial magnesium therapy with intravenous hydrogen after subarachnoid hemorrhage can increase the good recovery rate. Therefore, more high-quality studies are needed to confirm this finding.

Prophylactic Therapies for Morbidity and Mortality After Aneurysmal Subarachnoid Hemorrhage: A Systematic Review and Network Meta-Analysis of Randomized Trials

BACKGROUND

Aneurysmal subarachnoid hemorrhage (aSAH) is associated with high mortality and morbidity. We aimed to determine the relative benefits of pharmacological prophylactic treatments in patients with aneurysmal subarachnoid hemorrhage by performing a network meta-analysis of randomized trials.

METHODS

We searched Medline, Web of Science, Embase, Scopus, ProQuest, and Cochrane Central to February 2020. Pairs of reviewers independently identified eligible trials, extracted data, and assessed the risk of bias. Eligible trials compared the prophylactic effects of any oral or intravenous medications or intracranial drug-eluting implants to one another or placebo or standard of care in adult hospitalized patients with confirmed aneurysmal subarachnoid hemorrhage. We used the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach to assess the certainty of the evidence.

RESULTS

We included 53 trials enrolling 10 415 patients. Nimodipine likely reduces all-cause mortality compared to placebo (odds ratio [OR],0.73 [95% CI, 0.53-1.00]; moderate certainty; absolute risk reduction (ARR), -3.35%). Nimodipine (OR, 1.46 [95% CI, 1.07-1.99]; high certainty; absolute risk increase, 8.25%) and cilostazol (OR, 3.73 [95% CI, 1.14-12.18]; moderate certainty; absolute risk increase, 23.15%) were the most effective treatments in improving disability at the longest follow-up. Compared to placebo, clazosentan (10 mg/kg; OR, 0.39 [95% CI, 0.22-0.68]; high certainty; ARR, -16.65%), nicardipine (OR, 0.48 [95% CI, 0.24-0.94]; moderate certainty; ARR, -13.70%), fasudil (OR, 0.55 [95% CI, 0.31-0.98]; moderate certainty; ARR, -11.54%), and magnesium (OR, 0.66 [95% CI, 0.46-0.94]; high certainty; ARR, -8.37%) proved most effective in reducing the likelihood of delayed cerebral ischemia.

CONCLUSIONS

Nimodipine and cilostazol are likely the most effective treatments in preventing morbidity and mortality in patients with aneurysmal subarachnoid hemorrhage. Clazosentan, nicardipine, fasudil, and magnesium showed beneficial effects on delayed cerebral ischemia and vasospasm but they were not found to reduce mortality or disability. Future trials are warranted to elaborately investigate the prophylactic effects of medications that may improve mortality and long-term functional outcomes, such as cilostazol and clazosentan.

REGISTRATION

URL: https://www.crd.york.ac.uk/PROSPERO/; Unique identifier: CRD42019122183.

Lessons Learned from Phase II and Phase III Trials Investigating Therapeutic Agents for Cerebral Ischemia Associated with Aneurysmal Subarachnoid Hemorrhage

One of the challenges in bringing new therapeutic agents (since nimodipine) in for the treatment of cerebral ischemia associated with aneurysmal subarachnoid hemorrhage (aSAH) is the incongruence in therapeutic benefit observed between phase II and subsequent phase III clinical trials. Therefore, identifying areas for improvement in the methodology and interpretation of results is necessary to increase the value of phase II trials. We performed a systematic review of phase II trials that continued into phase III trials, evaluating a therapeutic agent for the treatment of cerebral ischemia associated with aSAH. We followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines for systematic reviews, and review was based on a peer-reviewed protocol (International Prospective Register of Systematic Reviews no. 222965). A total of nine phase III trials involving 7,088 patients were performed based on eight phase II trials involving 1558 patients. The following therapeutic agents were evaluated in the selected phase II and phase III trials: intravenous tirilazad, intravenous nicardipine, intravenous clazosentan, intravenous magnesium, oral statins, and intraventricular nimodipine. Shortcomings in several design elements of the phase II aSAH trials were identified that may explain the incongruence between phase II and phase III trial results. We suggest the consideration of the following strategies to improve phase II design: increased focus on the selection of surrogate markers of efficacy, selection of the optimal dose and timing of intervention, adjustment for exaggerated estimate of treatment effect in sample size calculations, use of prespecified go/no-go criteria using futility design, use of multicenter design, enrichment of the study population, use of concurrent control or placebo group, and use of innovative trial designs such as seamless phase II to III design. Modifying the design of phase II trials on the basis of lessons learned from previous phase II and phase III trial combinations is necessary to plan more effective phase III trials.

Deep Learning-Based Detection and Diagnosis of Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is one of the critical and severe neurological diseases with high morbidity and mortality. Head computed tomography (CT) is among the preferred methods for the diagnosis of SAH, which is confirmed by CT showing high-density shadow in the subarachnoid space. Analysis of these images through a deep learning-based subarachnoid hemorrhage will reduce the approximate rate of misdiagnosis in general and missed diagnosis by clinicians in particular. Deep learning-based detection of subarachnoid hemorrhage mainly includes two tasks, i.e., subarachnoid hemorrhage classification and subarachnoid hemorrhage region segmentation. However, it is difficult to effectively judge reliability of the model and classify bleeding which is based on limited predictive probability of convolutional neural network output. Moreover, deep learning-based bleeding area segmentation requires a large amount of training data to be marked in advance and the large number of network parameters makes the model training unable to reach the optimal. To resolve these problems associated with existing models, Bayesian deep learning and neural network-based hybrid model is presented in this paper to estimate uncertainty and efficiently classify subarachnoid hemorrhage. Uncertainty estimation of the proposed model helps in judging whether the model's prediction is reliable or not. Additionally, it is used to guide clinicians to find the neglected subarachnoid hemorrhage area. In addition, a teacher-student mechanism deep learning model was designed to introduce observational uncertainty estimation for semisupervised learning of subarachnoid hemorrhage. Observation uncertainty estimation detects the uncertain bleeding areas in CT images and then selects areas with high reliability. Finally, it uses these unlabeled data for model training purposes as well.

Effectiveness comparisons of drug therapies for postoperative aneurysmal subarachnoid hemorrhage patients: network meta‑analysis and systematic review

Objective

To compare the effectiveness of various drug interventions in improving the clinical outcome of postoperative patients after aneurysmal subarachnoid hemorrhage (aSAH) and assist in determining the drugs of definite curative effect in improving clinical prognosis.

Methods

Eligible Randomized Controlled Trials (RCTs) were searched in databases of PubMed, EMBASE, and Cochrane Library (inception to Sep 2020). Glasgow Outcome Scale (GOS) score, Extended Glasgow Outcome Scale (GOSE) score or modified Rankin Scale (mRS) score was used as the main outcome measurements to evaluate the efficacy of various drugs in improving the clinical outcomes of postoperative patients with aSAH. The network meta-analysis (NMA) was conducted based on a random-effects model, dichotomous variables were determined by using odds ratio (OR) with 95% confidence interval (CI), and a surface under the cumulative ranking curve (SUCRA) was generated to estimate the ranking probability of comparative effectiveness among different drug therapies.

Results

From the 493 of initial citation screening, forty-four RCTs (n = 10,626 participants) were eventually included in our analysis. Our NMA results showed that cilostazol (OR = 3.35,95%CI = 1.50,7.51) was the best intervention to improve the clinical outcome of patients (SUCRA = 87.29%, 95%CrI 0.07–0.46). Compared with the placebo group, only two drug interventions [nimodipine (OR = 1.61, 95%CI 1.01,2.57) and cilostazol (OR = 3.35, 95%CI 1.50, 7.51)] achieved significant statistical significance in improving the clinical outcome of patients.

Conclusions

Both nimodipine and cilostazol have exact curative effect to improve the outcome of postoperative patients with aSAH, and cilostazol may be the best drug to improve the outcome of patients after aSAH operation. Our study provides implications for future studies that, the combination of two or more drugs with relative safety and potential benefits (e.g., nimodipine and cilostazol) may improve the clinical outcome of patients more effectively.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02303-8.

An overview of pharmacotherapy for cerebral vasospasm and delayed cerebral ischemia after subarachnoid hemorrhage

Introduction: Survival from aneurysmal subarachnoid hemorrhage has increased in the past few decades. However, functional outcome after subarachnoid hemorrhage is still suboptimal. Delayed cerebral ischemia (DCI) is one of the major causes of morbidity.Areas covered: Mechanisms underlying vasospasm and DCI after aneurysmal subarachnoid hemorrhage and pharmacological treatment are summarized in this review.Expert opinion: Oral nimodine, an L-type dihydropyridine calcium channel blocker, is the only FDA-approved drug for the prevention and treatment of neurological deficits after aneurysmal subarachnoid hemorrhage. Fasudil, a potent Rho-kinase inhibitor, has also been shown to improve the clinical outcome and has been approved in some countries for use in patients with aneurysmal subarachnoid hemorrhage. Although other drugs, including nicardipine, cilostazol, statins, clazosentan, magnesium and heparin, have been expected to have beneficial effects on DCI, there has been no convincing evidence supporting the routine use of those drugs in patients with aneurysmal subarachnoid hemorrhage in clinical practice. Further elucidation of the mechanisms underlying DCI and the development of effective therapeutic strategies for DCI, including combination therapy, are necessary to further improve the functional outcome and mortality after subarachnoid hemorrhage.

Mechanically Induced Vasospasm-Evaluation of Spasmolytic Efficacy of 10 Pharmaceutical Agents Using Laser Speckle Contrast Imaging

BACKGROUND AND OBJECTIVES

Vasospasm is a thorny problem often encountered in microvascular surgery that seriously threatens the survival of vascularized tissue transfers. This investigation is dedicated to establishing a model of vasospasm and to evaluating the antispasmodic efficacy of 10 pharmacologic agents.

STUDY DESIGN/MATERIALS AND METHODS

Eighty Sprague-Dawley rats were used. After anesthesia and depilation, the femoral neurovascular bundle was exposed, and a pair of microsurgical forceps were used to trigger vasospasm of the femoral vessels by blunt dissection. Then, 10 pharmacological agents, namely, prostaglandin E1, sodium nitroprusside, magnesium sulfate, papaverine, normal saline, phentolamine, verapamil, 2% lidocaine hydrochloride, amrinone, and 12% lidocaine hydrochloride, were dripped to the femoral vessels, after which laser speckle contrast imaging was used to collect perfusion images, acquiring the perfusion and the inner caliber of the femoral vessels at multiple timepoints. Furthermore, blood perfusion and the time consumed to escape vasospasm and reach hyperperfusion in each group were calculated. The difference of spasmolytic efficacy among the agents was statistically analyzed by one-way analysis of variance.

RESULTS

There was a significant difference in antispasmodic ability among the 10 agents (P < 0.001). 10% magnesium sulfate and 12% lidocaine were distinguished among the 10 agents in resolving the vasospasm. 10% magnesium sulfate demonstrated the best antispasmodic potency, which enabled the shortest time consumed for vessels to escape spasm and reach hyperperfusion. 12% lidocaine ranked second in efficacy, demonstrating a similar effect except that it could not propel the femoral vein to a state of hyperperfusion. For the remaining agents, the time consumed for the artery to escape spasm was all significantly shortened when compared with normal saline (P < 0.001). For the venous spasm, all agents except prostaglandin E1 could significantly shorten the time consumed for the vein to escape spasm (P < 0.001).

CONCLUSIONS

In terms of resolving mechanically induced vasospasm, 10% magnesium sulfate is the best antispasmodic, followed by 12% lidocaine. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

The role of nimodipine and magnesium sulfate in the prevention and treatment of vascular spasm in patients in the acute rupture of cerebral aneurysms

Vascular spasm in patients with hemorrhage from rupture of cerebral aneurysms is the main cause of adverse outcomes of the disease. One way to treat persistent contraction of cerebral arteries is to use nimodipine and magnesium sulfate. This literature review presents studies on the use of nimodipine and magnesium sulfate in the treatment of vascular spasm, and highlights the main links of pathogenesis and drug action mechanisms.

Outcome of Oral and Intra-arterial Nimodipine Administration After Aneurysmal Subarachnoid Haemorrhage - A Single-centre Study

BACKGROUND

Oral nimodipine is administered to improve clinical outcome in patients with aneurysmal subarachnoid hemorrhage (aSAH). In this study, clinical outcome in patients with and without oral nimodipine administration was assessed.

MATERIALS AND METHODS

A total of 105 patients did not receive oral nimodipine but did receive intra-arterial nimodipine in the occurrence of hemodynamically relevant vasospasm after aSAH, whereas 74 patients received applications of both. Demographic/radiological details and clinical presentation were abstracted from the case records.

RESULTS

Patient baseline characteristics were comparable, a predominance of endovascular coiling was shown in cohort 2 (p=0.0135). Severity of initial aSAH and clinical status at admission (Hunt and Hess) was significantly higher in those receiving oral nimodipine. Incidence of angiographic vasospasm was significantly higher in patients not treated with oral nimodipine (p=0.0305); a significantly better outcome measured by the National Institute of Health Stroke Scale (p=0.0213), was noted in those receiving oral nimodipine.

CONCLUSION

Oral nimodipine administration improved clinical outcome of patients after aSAH and should be administered routinely for such patients.

Clinical and experimental aspects of aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) continues to be associated with significant morbidity and mortality despite advances in care and aneurysm treatment strategies. Cerebral vasospasm continues to be a major source of clinical worsening in patients. We intended to review the clinical and experimental aspects of aSAH and identify strategies that are being evaluated for the treatment of vasospasm. A literature review on aSAH and cerebral vasospasm was performed. Available treatments for aSAH continue to expand as research continues to identify new therapeutic targets. Oral nimodipine is the primary medication used in practice given its neuroprotective properties. Transluminal balloon angioplasty is widely utilized in patients with symptomatic vasospasm and ischemia. Prophylactic "triple-H" therapy, clazosentan, and intraarterial papaverine have fallen out of practice. Trials have not shown strong evidence supporting magnesium or statins. Other calcium channel blockers, milrinone, tirilazad, fasudil, cilostazol, albumin, eicosapentaenoic acid, erythropoietin, corticosteroids, minocycline, deferoxamine, intrathecal thrombolytics, need to be further investigated. Many of the current experimental drugs may have significant roles in the treatment algorithm, and further clinical trials are needed. There is growing evidence supporting that early brain injury in aSAH may lead to significant morbidity and mortality, and this needs to be explored further.

Transcranial Doppler in the Diagnosis of Cerebral Vasospasm: An Updated Meta-Analysis

OBJECTIVES

To evaluate the performance of transcranial Doppler and transcranial color-coded duplex Doppler in patients with cerebral vasospasm due to aneurysm rupture. Angiography was considered as the gold standard comparator.

DATA SOURCES

Search in MEDLINE, Embase, and Central from January 2001 to October 2017, without language restriction. Bibliographies of retrieved articles were screened for additional studies.

STUDY SELECTION

Randomized studies comparing transcranial Doppler or transcranial color-coded duplex Doppler with angiography in adults.

DATA EXTRACTION

Data were extracted independently by several investigators. Sensitivity and specificity were combined across studies using a bivariate model. Preferred Reporting Items for Systematic Reviews and Meta-Analyses was used for reporting and Quality Assessment of Diagnostic Accuracy Studies-2 for quality assessment.

DATA SYNTHESIS

We included 18 studies. Fifteen tested transcranial Doppler. For the middle cerebral artery (10 studies, 1,408 tests), the pooled sensitivity was 66.7% (95% CI, 55.9-75.9) and specificity was 89.5% (80.3-94.7). Three studies (278 tests) tested transcranial color-coded duplex Doppler for the middle cerebral artery. The pooled sensitivity was 81.5% (66.0-90.0), and specificity was 96.6% (93.0-98.0). For an arbitrarily chosen prevalence of vasospasm of 70%, positive and negative predictive values were 93.7% (88.9-96.6) and 53.4% (46.7-60.9) for transcranial Doppler and 98.2% (96.4-99.1) and 69.1% (56.1-80.9) for transcranial color-coded duplex Doppler.

CONCLUSIONS

Assuming a high prevalence of vasospasm of the middle cerebral artery, both transcranial Doppler and transcranial color-coded duplex Doppler are likely to detect it, but neither is useful to exclude it. There is no convincing evidence that the accuracy of transcranial color-coded duplex Doppler is any better than that of transcranial Doppler. For arteries other than middle cerebral artery, there is a lack of evidence of the usefulness of transcranial Doppler.

Neuroprotective Agents in the Intensive Care Unit: -Neuroprotective Agents in ICU

Neuroprotection or prevention of neuronal loss is a complicated molecular process that is mediated by various cellular pathways. Use of different pharmacological agents as neuroprotectants has been reported especially in the last decades. These neuroprotective agents act through inhibition of inflammatory processes and apoptosis, attenuation of oxidative stress and reduction of free radicals. Control of this injurious molecular process is essential to the reduction of neuronal injuries and is associated with improved functional outcomes and recovery of the patients admitted to the intensive care unit. This study reviews neuroprotective agents and their mechanisms of action against central nervous system damages.

Magnesium Protects in Episodes of Critical Perfusion after Aneurysmal SAH

BACKGROUND

To analyze whether magnesium has a neuroprotective effect during episodes that indicate a critical brain perfusion after aneurysmal subarachnoid hemorrhage (SAH).

METHODS

107 patients with aSAH were randomized to continuously receive intravenous magnesium sulfate with target serum levels of 2.0 - 2.5 mmol/l (n = 54) or isotonic saline (n = 53). Neurological examination and transcranial Doppler sonography (TCD) were performed daily, Perfusion-CT (PCT) was acquired in 3-day intervals, angiography in case of suspected vasospasm. The primary endpoint was the development of secondary infarction following episodes of delayed ischemic neurological deficit (DIND), elevated mean flow velocity (MFV) in TCD or pathological findings in PCT.

RESULTS

In the magnesium group, 9 episodes of DIND were registered, none was followed by secondary infarction. In the control group, 23 episodes of DIND were registered, 9 were followed by secondary infarction (p < 0.05). In the magnesium group, 114 TCD-measurements showed an elevated MFV(> 140 cm/s). 7 were followed by new infarction. In control patients, 135 measurements showed elevated MFV, 32 were followed by new infarction (p < 0.05). 10 of 117 abnormal PCT-findings were followed by new infarction, compared to 30 of 122 in the control-group (p < 0.05).

CONCLUSION

DIND, elevated MFV in TCD and abnormal PCT are findings which are associated with an increased risk to develop delayed secondary infarction. The results of this analysis suggest that magnesium-treatment may reduce the risk to develop infarction in a state of critical brain perfusion.

Magnesium sulfate in combination with nimodipine for the treatment of subarachnoid hemorrhage: a randomized controlled clinical study

Objective Cerebral vasospasm(CVS) after Subarachnoid hemorrhage (SAH) can cause delayed cerebral ischemia,secondary cerebral infarction, and rehemorrhage, which are the leading causes of mutilation and death. Nimodipine has been shown to prevent CVS. Magnesium ion (Mg²⁺) can competitively inhibit the influx of calcium (Ca²⁺) and prevent vasospasm. There is evidence that magnesium sulfate can prevent CVS and reduce infarct volume after SAH. In this study, we evaluated the efficacy and safety of intravenous magnesium sulfate combined with oral nimodipine on CVS, delayed cerebral ischemia, secondary cerebral infarction, and rehemorrhage after SAH. Methods This is a prospective randomized, double-blind trial of 120 patients with SAH who were recruited between January 2003 and January 2009. These patients were assigned to two groups and received the same basic treatment and symptomatic treatment. In group A, patients received 14 days of intravenous administration of 1400 mL 0.9% normal saline + 40 mL 25% magnesium sulfate, 1 mL/min, once per day, followed 7 days of intravenous administration of 500 mL 0.9% normal saline + 15 mL 25% magnesium sulfate, 1 mL/min, once per day and oral nimodipine, 20 mg once, four times a day, for 21 days. Patients in group B received identical treatment to that in group A, except that 25% magnesium sulfate was replaced by placebo. On day 22 of treatment, incidences of intracranial CVS, delayed cerebral ischemia, secondary cerebral infarction, rehemorrhage, neurologic deficits, and death were assessed and adverse events were monitored. Results CVS occurred in 4, 12 patients, lasting for 11.09 ± 5.38, 13.73 ± 6.24 hours, mean velocity (Vm) of 143.2 ± 12.7, 149.6 ± 18.9 cm/s in group A, B; Delayed cerebral ischemia occurred in 3, 10 patients, lasting for 13.16 ± 4.82, 15.57 ± 5.35 hours in group A, B; Secondary cerebral infarction occurred in 2 and 8 patients in groups A and B; Neurologic deficits occurred in3 and 11 patients in groups A and B, All P < 0.05; Rehemorrhage occurred in 4 and 5 patients; Death occurred in 5 and 8 patients in groups A and B, respectively, P >0.05. No obvious adverse events were found in both groups. Conclusion Intravenous magnesium sulfate in combination with oral nimodipine for the treatment of SAH can help reduce the incidences of CVS, delayed cerebral ischemia, secondary cerebral infarction, and neurologic deficits with good safety, but it does not reduce the incidences of rehemorrhage and death.

The Role of Magnesium in Neurological Disorders

Magnesium is well known for its diverse actions within the human body. From a neurological standpoint, magnesium plays an essential role in nerve transmission and neuromuscular conduction. It also functions in a protective role against excessive excitation that can lead to neuronal cell death (excitotoxicity), and has been implicated in multiple neurological disorders. Due to these important functions within the nervous system, magnesium is a mineral of intense interest for the potential prevention and treatment of neurological disorders. Current literature is reviewed for migraine, chronic pain, epilepsy, Alzheimer’s, Parkinson’s, and stroke, as well as the commonly comorbid conditions of anxiety and depression. Previous reviews and meta-analyses are used to set the scene for magnesium research across neurological conditions, while current research is reviewed in greater detail to update the literature and demonstrate the progress (or lack thereof) in the field. There is strong data to suggest a role for magnesium in migraine and depression, and emerging data to suggest a protective effect of magnesium for chronic pain, anxiety, and stroke. More research is needed on magnesium as an adjunct treatment in epilepsy, and to further clarify its role in Alzheimer’s and Parkinson’s. Overall, the mechanistic attributes of magnesium in neurological diseases connote the macromineral as a potential target for neurological disease prevention and treatment.

Endovascular Treatment of Symptomatic Vasospasm after Aneurysmal Subarachnoid Hemorrhage: A Three-year Experience

Objective

The cause of severe clinical vasospasm after aneurysmal subarachnoid hemorrhage remains unknown, despite extensive research over the past 30 years. However, the intra-arterial administration of vasodilating agents and balloon angioplasty have been successfully used in severe refractory cerebral vasospasm.

Materials and Methods

We retrospectively analyzed the data of 233 patients admitted to our institute with aneurysmal subarachnoid hemorrhage (SAH) over the past 3 years.

Results

Of these, 27 (10.6%) developed severe symptomatic vasospasm, requiring endovascular therapy. Vasospasm occurred at an average of 5.3 days after SAH. A total of 46 endovascular procedures were performed in 27 patients. Endovascular therapy was performed once in 18 (66.7%) patients, 2 times in 4 (14.8%) patients, 3 or more times in 5 (18.5%) patients. Intra-arterial vasodilating agents were used in 44 procedures (27 with nimodipine infusion, 17 with nicardipine infusion). Balloon angioplasty was performed in only 2 (7.4%) patients. The Average nimodipine infusion volume was 2.47 mg, and nicardipine was 3.78 mg. Most patients recovered after the initial emergency room visit. Two patients (7.4%) worsened, but there were no deaths.

Conclusion

With advances in endovascular techniques, administration of vasodilating agents and balloon angioplasty reduces the morbidity and mortality of vasospasm after aneurysmal SAH.

The role of magnesium sulfate in the intensive care unit

Magnesium (Mg) has been developed as a drug with various clinical uses. Mg is a key cation in physiological processes, and the homeostasis of this cation is crucial for the normal function of body organs. Magnesium sulfate (MgSO4) is a mineral pharmaceutical preparation of magnesium that is used as a neuroprotective agent. One rationale for the frequent use of MgSO4 in critical care is the high incidence of hypomagnesaemia in intensive care unit (ICU) patients. Correction of hypomagnesaemia along with the neuroprotective properties of MgSO4 has generated a wide application for MgSO4 in ICU.

Management of aneurysmal subarachnoid hemorrhage: State of the art and future perspectives

Background:

Aneurysmal subarachnoid hemorrhage (SAH) accounts for 5% of strokes and carries a poor prognosis. It affects around 6 cases per 100,000 patient years occurring at a relatively young age.

Methods:

Common risk factors are the same as for stroke, and only in a minority of the cases, genetic factors can be found. The overall mortality ranges from 32% to 67%, with 10–20% of patients with long-term dependence due to brain damage. An explosive headache is the most common reported symptom, although a wide spectrum of clinical disturbances can be the presenting symptoms. Brain computed tomography (CT) allow the diagnosis of SAH. The subsequent CT angiography (CTA) or digital subtraction angiography (DSA) can detect vascular malformations such as aneurysms. Non-aneurysmal SAH is observed in 10% of the cases. In patients surviving the initial aneurysmal bleeding, re-hemorrhage and acute hydrocephalus can affect the prognosis.

Results:

Although occlusion of an aneurysm by surgical clipping or endovascular procedure effectively prevents rebleeding, cerebral vasospasm and the resulting cerebral ischemia occurring after SAH are still responsible for the considerable morbidity and mortality related to such a pathology. A significant amount of experimental and clinical research has been conducted to find ways in preventing these complications without sound results.

Conclusions:

Even though no single pharmacological agent or treatment protocol has been identified, the main therapeutic interventions remain ineffective and limited to the manipulation of systemic blood pressure, alteration of blood volume or viscosity, and control of arterial dioxide tension.

Considerations in Fluids and Electrolytes After Traumatic Brain Injury

Appropriate fluid management of patients with traumatic brain injury (TBI) presents a challenge for many clinicians. Many of these patients may receive osmotic diuretics for the treatment of increased intracranial pressure or develop sodium disturbances, which act to alter fluid balance. However, establishment of fluid balance is extremely important for improving patient outcomes after neurologic injury. The use of hyperosmolar fluids, such as hypertonic saline, has gained significant interest because they are devoid of dehydrating properties and may have other beneficial properties for patients with TBI. Electrolyte derangements are also common after neurologic injury, with many having neurologic manifestations. In addition, the role of electrolyte abnormalities in the secondary neurologic injury cascade is being delineated and may offer a potential future therapeutic intervention.

Cerebral vasospasm and wernicke encephalopathy secondary to adult cyclic vomiting syndrome: the role of magnesium

Background

Magnesium has a regulatory role in the excitability of cell membranes, and is also a cofactor in the phosphorylation of thiamine. Hypomagnesemia has been associated with coronary vasospasm, but its role in cerebrovascular pathology is controversial, and cerebral vasospasm exclusively attributable to hypomagnesemia has not been reported in humans.

Case presentation

We report the case of a 51-year-old man in whom uncontrollable vomiting, treatment with omeprazole and thiazide, and renal impairment lead to a severe hypomagnesemia (magnesium below the level of detection in blood tests), which secondarily caused Wernicke’s encephalopathy and vasospasm in multiple cerebral arteries (seen with cerebral angiography and CT angiography) that presented with a complete right hemisphere neurological deficit. These disturbances completely resolved when magnesium levels were normalized and subsequent neuroimaging tests confirmed the resolution of angiographic changes.

Conclusion

Our case suggests that hypomagnesemia should be considered in the differential diagnosis of patients with neurological symptoms and predisposing causes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12883-016-0660-x) contains supplementary material, which is available to authorized users.

Pharmacological agents in aneurysmal subarachnoid hemorrhage: successes and failures

BACKGROUND

Aneurysmal subarachnoid hemorrhage (aSAH) is a devastating condition with high mortality. Proper management of this complex disease requires early surgical intervention followed by medical therapy. Pharmacological agents that unequivocally improve outcomes in aSAH are scarce.

METHODS

The authors performed an exhaustive query of several databases including MEDLINE, the CENTRAL Register of Controlled Trials, and the Cochrane Database of Systematic Reviews for specific evidence on key medications that have been used in the treatment of aSAH.

RESULTS

The bulk of the data available pertained to the following medications: calcium channel blockers, magnesium, statins, antifibrinolytics, aspirin, glucocorticoids, clazosentan, and tirilazad. Except for calcium channel blockers, the authors could not find any hard evidence that any of these agents affected outcome to a tangible degree. Aspirin may have some promise in prevention of aneurysm rupture and incidence of aSAH, but more substantive data are needed to conclusively corroborate this.

CONCLUSIONS

Investigational efforts to attain outcome-modifying agents have had dubious results, but the inquest for discovery should not discontinue.

Mechanisms of magnesium-induced vasodilation in cerebral penetrating arterioles

We investigated in cerebral penetrating arterioles the signaling mechanisms and dose-dependency of extracellular magnesium-induced vasodilation and also its vasodilatory effects in vessels preconstricted with agonists associated with delayed cerebral vasospasm following SAH. Male rat penetrating arterioles were cannulated. Their internal diameters were monitored. To investigate mechanisms of magnesium-induced vasodilation, inhibitors of endothelial function, potassium channels and endothelial impairment were tested. To simulate cerebral vasospasm we applied several spasmogenic agonists. Increased extracellular magnesium concentration produced concentration-dependent vasodilation, which was partially attenuated by non-specific calcium-sensitive potassium channel inhibitor tetraethylammonium, but not by other potassium channel inhibitors. Neither the nitric oxide synthase inhibitor L-NNA nor endothelial impairment induced by air embolism reduced the dilation. Although the magnesium-induced vasodilation was slightly attenuated by the spasmogen ET-1, neither application of PF2α nor TXA2 analog effect the vasodilation. Magnesium induced a concentration- and smooth muscle cell-dependent dilation in cerebral penetrating arterioles. Calcium-sensitive potassium channels of smooth muscle cells may play a key role in magnesium-induced vasodilation. Magnesium also dilated endothelium-impaired vessels as well as vessels preconstricted with spasmogenic agonists. These results provide a fundamental background for the clinical use of magnesium, especially in treatment against delayed cerebral ischemia or vasospasm following SAH.

Impact of Comorbidity on Early Outcome of Patients with Subarachnoid Hemorrhage Caused by Cerebral Aneurysm Rupture

BACKGROUND

One of the complications aneurysms subarachnoid hemorrhage is the development of vasospasm, which is the leading cause of disability and death from ruptured cerebral aneurysm.

AIM

To evaluate the significance of previous comorbidities on early outcome of patients with subarachnoid hemorrhage caused by rupture of a cerebral aneurysm in the prevention of vasospasm.

PATIENTS AND METHODS

The study had prospective character in which included 50 patients, whose diagnosed with SAH caused by the rupture of a brain aneurysm in the period from 2011to 2013. Two groups of patients were formed. Group I: patients in addition to the standard initial treatment and "3H therapy" administered nimodipine at a dose of 15-30 mg / kg bw / h (3-10 ml) for the duration of the initial treatment. Group II: patients in addition to the standard initial treatment and "3H therapy" administered with MgSO4 at a dose of 12 grams in 500 ml of 0.9% NaCl / 24 h during the initial treatment.

RESULTS

Two-thirds of the patients (68%) from both groups had a good outcome measured with values according to GOS scales, GOS IV and V. The poorer outcome, GOS III had 20% patients, the GOS II was at 2% and GOS I within 10% of patients. If we analyze the impact of comorbidity on the outcome, it shows that there is a significant relationship between the presence of comorbidity and outcomes. The patients without comorbidity (83.30%) had a good outcome (GOS IV and V), the same outcome was observed (59.4%) with comorbidities, which has a statistically significant difference (p = 0.04). Patients without diabetes (32%) had a good outcome (GOS IV and V), while the percentage of patients with diabetes less frequent (2%) with a good outcome, a statistically significant difference (p = 0.009).

CONCLUSION

The outcome of treatment 30 days after the subarachnoid hemorrhage analyzed values WFNS and GOS, is not dependent on the method of prevention and treatment of vasospasm. Most concomitant diseases in patients with SAH which, requiring additional treatment measures are arterial hypertension and diabetes mellitus. The best predictors in the initial treatment of patients with subarachnoid hemorrhage caused by rupture of a cerebral aneurysm has the presence of comorbidity, which has statistical significance.

Cerebral Vasospasm: A Review

Cerebral vasospasm is a prolonged but reversible narrowing of cerebral arteries beginning days after subarachnoid hemorrhage. Progression to cerebral ischemia is tied mostly to vasospasm severity, and its pathogenesis lies in artery encasement by blood clot, although the complex interactions between hematoma and surrounding structures are not fully understood. The delayed onset of vasospasm provides a potential opportunity for its prevention. It is disappointing that recent randomized, controlled trials did not demonstrate that the endothelin antagonist clazosentan, the cholesterol-lowering agent simvastatin, and the vasodilator magnesium sulfate improve patient outcome. Minimizing ischemia by avoiding inadequate blood volume and pressure, administering the calcium antagonist nimodipine, and intervention with balloon angioplasty, when necessary, constitutes current best management. Over the past two decades, our ability to manage vasospasm has led to a significant decline in patient morbidity and mortality from vasospasm, yet it still remains an important determinant of outcome after aneurysm rupture.

Prophylactic magnesium sulfate for aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis

Delayed cerebral ischemia following aneurysmal subarachnoid hemorrhage is a cause of considerable morbidity and mortality. Magnesium sulfate has been proposed as a prophylactic intervention for angiographic vasospasm and to improve clinical outcomes. A systematic review was conducted to determine the evidence for the prophylactic use of magnesium sulfate in aneurysmal subarachnoid hemorrhage. Medline, Embase, Cochrane library, clinicaltrials.gov, and controlled-trials.com were searched with a comprehensive search strategy. 2,035 records were identified in the initial search and 1,574 remained after removal of duplicates. Randomized, parallel group, controlled trials of magnesium sulfate in patients with aneurysmal subarachnoid hemorrhage were included. A total of ten studies were included. Review Manager and GRADE software were used to synthesize the results. The summary effect for Glasgow outcome scale and the modified Rankin scale is a risk ratio (RR) of 0.93 [95 % confidence interval (CI) 0.82-1.06]. The RR for mortality is 0.95 [95 % CI 0.76-1.17]. Delayed cerebral ischemia has a RR of 0.54 [95 % CI 0.38-0.75], which is the only outcome with a statistically significant summary effect measure favoring magnesium treatment. Delayed ischemic neurological deficit has a RR of 0.93 [95 % CI 0.62-1.39]. Transcranial doppler vasospasm has a RR of 0.72 [95 % CI 0.51-1.03]. Current evidence does not support the prophylactic use of magnesium sulfate in aneurysmal subarachnoid hemorrhage.

Aneurysmal subarachnoid hemorrhage: pathobiology, current treatment and future directions

Aneurysmal subarachnoid hemorrhage is the most devastating form of stroke. Many pathological mechanisms ensue after cerebral aneurysm rupture, including hydrocephalus, apoptosis of endothelial cells and neurons, cerebral edema, loss of blood-brain barrier, abnormal cerebral autoregulation, microthrombosis, cortical spreading depolarization and macrovascular vasospasm. Although studied extensively through experimental and clinical trials, current treatment guidelines to prevent delayed cerebral ischemia is limited to oral nimodipine, maintenance of euvolemia, induction of hypertension if ischemic signs occur and endovascular therapy for patients with continued ischemia after induced hypertension. Future investigations will involve agents targeting vasodilation, anticoagulation, inhibition of apoptosis pathways, free radical neutralization, suppression of cortical spreading depolarization and attenuation of inflammation.

Cerebral Vasospasm in Critically III Patients with Aneurysmal Subarachnoid Hemorrhage: Does the Evidence Support the Ever-Growing List of Potential Pharmacotherapy Interventions?

The occurrence of cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) is a significant event resulting in decreased cerebral blood flow and oxygen delivery. Prevention and treatment of cerebral vasospasm is vital to avert neurological damage and reduced functional outcomes. A variety of pharmacotherapy interventions for the prevention and treatment of cerebral vasospasm have been evaluated. Unfortunately, very few large randomized trials exist to date, making it difficult to make clear recommendations regarding the efficacy and safety of most pharmacologic interventions. Considerable debate exists regarding the efficacy and safety of hypervolemia, hemodilution, and hypertension (triple-H therapy), and the implementation of each component varies substantially amongst institutions. There is a new focus on euvolemic-induced hypertension as a potentially preferred mechanism of hemodynamic augmentation. Nimodipine is the one pharmacologic intervention that has demonstrated favorable effects on patient outcomes and should be routinely administered unless contraindications are present. Intravenous nicardipine may offer an alternative to oral nimodipine. The addition of high-dose magnesium or statin therapy has shown promise, but results of ongoing large prospective studies are needed before they can be routinely recommended. Tirilazad and clazosentan offer new pharmacologic mechanisms, but clinical outcome results from prospective randomized studies have largely been unfavorable. Locally administered pharmacotherapy provides a targeted approach to the treatment of cerebral vasospasm. However, the paucity of data makes it challenging to determine the most appropriate therapy and implementation strategy. Further studies are needed for most pharmacologic therapies to determine whether meaningful efficacy exists.

Magnesium physiology and clinical therapy in veterinary critical care

OBJECTIVE

To review magnesium physiology including absorption, excretion, and function within the body, causes of magnesium abnormalities, and the current applications of magnesium monitoring and therapy in people and animals.

ETIOLOGY

Magnesium plays a pivotal role in energy production and specific functions in every cell in the body. Disorders of magnesium can be correlated with severity of disease, length of hospital stay, and recovery of the septic patient. Hypermagnesemia is seen infrequently in people and animals with significant consequences reported. Hypomagnesemia is more common in critically ill people and animals, and can be associated with platelet, immune system, neurological, and cardiovascular dysfunction as well as alterations in insulin responsiveness and electrolyte imbalance.

DIAGNOSIS

Measurement of serum ionized magnesium in critically or chronically ill veterinary patients is practical and provides information necessary for stabilization and treatment. Tissue magnesium concentrations may be assessed using nuclear magnetic resonance spectroscopy as well as through the application of fluorescent dye techniques.

THERAPY

Magnesium infusions may play a therapeutic role in reperfusion injury, myocardial ischemia, cerebral infarcts, systemic inflammatory response syndromes, tetanus, digitalis toxicity, bronchospasms, hypercoagulable states, and as an adjunct to specific anesthetic or analgesic protocols. Further veterinary studies are needed to establish the frequency and importance of magnesium disorders in animals and the potential benefit of magnesium infusions as a therapeutic adjunct to specific diseases.

PROGNOSIS

The prognosis for most patients with magnesium disorders is variable and largely dependent on the underlying cause of the disorder.

Effects of intravenous infusion of hydrogen-rich fluid combined with intra-cisternal infusion of magnesium sulfate in severe aneurysmal subarachnoid hemorrhage: study protocol for a randomized controlled trial

Background

The failures of recent studies intended to prevent cerebral vasospasm have moved the focus of research into delayed cerebral ischemia away from cerebral artery constriction towards other mechanisms. Recent accumulating evidence has suggested that early brain injury is also involved in the development of delayed cerebral ischemia, and that hydrogen can prevent early brain injury. Therefore, we have established a combination therapy of intravenous hydrogen infusion and intra-cisternal magnesium sulfate infusion for the treatment of both early brain injury and cerebral vasospasm. The present randomized controlled clinical trial is designed to investigate the effects of this novel therapeutic strategy on the occurrence of cerebral vasospasm, delayed cerebral ischemia, and clinical outcomes after high-grade subarachnoid hemorrhage.

Methods

This study is a randomized, double-blind, placebo-controlled design to be conducted in two hospitals. A total of 450 patients with high-grade subarachnoid hemorrhage will be randomized to one of three arms: (i) Mg + H₂ group, (ii) Mg group, and (iii) control group. Patients who are assigned to the Mg + H₂ group will receive intra-cisternal magnesium sulfate infusion (2.5 mmol/L) at 20 mL/h for 14 days and intravenous hydrogen-rich fluid infusion (200 mL) twice a day for 14 days. Patients who are assigned to the Mg group will receive intra-cisternal magnesium sulfate infusion (2.5 mmol/L) at 20 mL/h for 14 days and intravenous normal glucose-electrolyte solution (200 mL) without added hydrogen twice a day for 14 days. Patients who are assigned to the control group will receive intra-cisternal Ringer solution without magnesium sulfate at 20 mL/h for 14 days and intravenous normal glucose-electrolyte solution (200 mL) without added hydrogen twice a day for 14 days. Primary outcome measures will be occurrence of delayed cerebral ischemia and cerebral vasospasm. Secondary outcome measures will be modified Rankin scale score at 3, 6, and 12 months and biochemical markers.

Discussion

The present protocol for a randomized, placebo-controlled study of intravenous hydrogen therapy with intra-cisternal magnesium infusion is expected to establish the efficacy and safety of this therapeutic strategy.

Trial registration

UMIN-CTR: UMIN000014696

To look beyond vasospasm in aneurysmal subarachnoid haemorrhage

Delayed cerebral vasospasm has classically been considered the most important and treatable cause of mortality and morbidity in patients with aneurysmal subarachnoid hemorrhage (aSAH). Secondary ischemia (or delayed ischemic neurological deficit, DIND) has been shown to be the leading determinant of poor clinical outcome in patients with aSAH surviving the early phase and cerebral vasospasm has been attributed to being primarily responsible. Recently, various clinical trials aimed at treating vasospasm have produced disappointing results. DIND seems to have a multifactorial etiology and vasospasm may simply represent one contributing factor and not the major determinant. Increasing evidence shows that a series of early secondary cerebral insults may occur following aneurysm rupture (the so-called early brain injury). This further aggravates the initial insult and actually determines the functional outcome. A better understanding of these mechanisms and their prevention in the very early phase is needed to improve the prognosis. The aim of this review is to summarize the existing literature on this topic and so to illustrate how the presence of cerebral vasospasm may not necessarily be a prerequisite for DIND development. The various factors determining DIND that worsen functional outcome and prognosis are then discussed.

Magnesium: potential roles in neurovascular disease

OBJECTIVE

Magnesium therapy has been studied extensively in pre-clinical and clinical trials in multiple organ systems. Cerebrovascular diseases may benefit from its neuroprotective properties. This review summarizes current studies of magnesium in a wide range of neurovascular diseases.

METHODS

We searched relevant terms in the National Library of Medicine PubMed database and selected research including basic science, translational reports, meta-analyses, and clinical studies.

RESULTS

Studies examining magnesium administration in ischemic stroke have failed to show any benefit in clinical outcome. Data on magnesium for intracerebral hemorrhage (ICH) are limited. Preliminary investigations in subarachnoid hemorrhage (SAH) were promising, but definitive studies did not reveal differences in clinical outcome between magnesium and placebo-treated groups. Studies examining magnesium administration in global ischemia following cardiac arrest suggest a trend toward improved clinical outcome. The strongest evidence for clinically relevant neuroprotection following magnesium administration derives from studies of pre-term infants and patients undergoing cardiac bypass and carotid endarterectomy procedures. Magnesium was found to have an excellent safety profile across all investigations.

CONCLUSION

Magnesium is easy to administer and possesses a favorable safety profile. Its utility as a neuroprotectant in cardiac surgery, carotid endarterectomy, and pre-term infant hypoxia remain promising. Value as a therapeutic agent in ischemic stroke, ICH, and SAH is unclear and appears to be limited by late administration. Ongoing clinical trials assessing magnesium administration in the first hours following symptom onset may help clarify the role of magnesium therapy in these disease processes.

Magnesium sulfate treatment improves outcome in patients with subarachnoid hemorrhage: a meta-analysis study

OBJECTIVE

To elucidate the role of magnesium sulfate in patients with subarachnoid hemorrhagic (SAH) brain injury

METHOD

Studies for the meta-analysis were identified from PubMed (1966 to 2009), Embase (1980 to 2009), and two Chinese journals (1989 to 2009). Paper selection was based on randomized controlled trials comparing magnesium sulfate to placebo treatment in patients with SAH. Two independent review authors extracted the data and assessed trial quality. Meta-analysis was performed using the Cochrane Review Manger software.

RESULTS

Five trials involving 482 patients were included in the review. Magnesium sulfate reduced the risk of poor outcome and reduced the occurrence of delayed cerebral ischemia. In the treatment groups, relative risk for poor outcome was 0.73 (CI 0.57-0.93) and 0.66 (CI 0.47-0.92) for delayed cerebral ischemia. Case fatality assessment at three to six months did not show statistically significant data (RR 0.88; CI 0.61-1.29).

CONCLUSION

Magnesium sulfate appears to be an effective treatment option in the management of SAH. Further clinical trials are needed before magnesium sulfate can become a routine treatment for SAH.

Current controversies in the prediction, diagnosis, and management of cerebral vasospasm: where do we stand?

Aneurysmal subarachnoid hemorrhage occurs in approximately 30,000 persons in the United States each year. Around 30 percent of patients with aneurysmal subarachnoid hemorrhage suffer from cerebral ischemia and infarction due to cerebral vasospasm, a leading cause of treatable death and disability following aneurysmal subarachnoid hemorrhage. Methods used to predict, diagnose, and manage vasospasm are the topic of recent active research. This paper utilizes a comprehensive review of the recent literature to address controversies surrounding these topics. Evidence regarding the effect of age, smoking, and cocaine use on the incidence and outcome of vasospasm is reviewed. The abilities of different computed tomography grading schemes to predict vasospasm in the aftermath of subarachnoid hemorrhage are presented. Additionally, the utility of different diagnostic methods for the detection and visualization of vasospasm, including transcranial Doppler ultrasonography, CT angiography, digital subtraction angiography, and CT perfusion imaging is discussed. Finally, the recent literature regarding interventions for the prophylaxis and treatment of vasospasm, including hyperdynamic therapy, albumin, calcium channel agonists, statins, magnesium sulfate, and endothelin antagonists is summarized. Recent studies regarding each topic were reviewed for consensus recommendations from the literature, which were then presented.

Nitric oxide suppresses L-type calcium currents in basilar artery smooth muscle cells in rabbits

OBJECTIVES

Nitric oxide (NO) is well known to be a vasodilator, and NO donor compounds are currently used for treating vasospasm following subarachnoid hemorrhage. However, the action mechanism of cerebral vascular relaxation is not yet clear. L-type calcium channels have been determined to play an essential role in smooth muscle contraction. To investigate the role of L-type calcium channels in NO-induced relaxation of basilar smooth muscle cells, we examined the effect of the NO donor, sodium nitroprusside (SNP) on calcium (Ca2+) currents using smooth muscle cells isolated from a rabbit basilar artery.

METHOD

The smooth muscle cells were isolated from rabbit basilar artery by enzyme treatment. To identify L-type Ca2+ currents, we used cesium chloride, a potassium channel blocker and Bay K8644, an activator of L-type Ca2+ channel.

RESULTS

The L-type calcium currents (91±13.0 pA; n = 11) were significantly reduced by SNP (32±5 pA; n = 11; P<0.05). 1H-[1,2,4] Oxadiazolo [4,3-a] quinoxalin-1-one, a 3',5'-cyclic guanosine monophosphate inhibitor, blocked the effect of SNP on L-type Ca2+ currents, and similar results were obtained after the application of 7-nitroindazole, a specific NO synthase inhibitor. Furthermore, inward currents were enhanced by Bay K8644 (170±22 pA; n = 5) and were suppressed by SNP (54±13 pA; n = 5; P<0.05).

DISCUSSION

These results demonstrate that NO suppresses the L-type Ca2+ currents in rabbit basilar smooth muscle cells, and suggest that L-type Ca2+ channels may play a pivotal role in NO-induced vascular relaxation.

Magnesium therapy within 48 hours of an aneurysmal subarachnoid hemorrhage: neuro-panacea

Whereas advances in neurosurgical treatment and intensive care management improve the results from many of the devastating complications associated with aneurysmal subarachnoid hemorrhage, cerebral vasospasm remains a major cause of neurological morbidity and mortality. Experimental studies suggested that MgSO(4) inhibits excitatory amino acid release, blocks N-methyl-D-aspartate (NMDA) receptors and prevents calcium entry into the cell. Magnesium also increases red blood cell deformability. These changes may reduce the occurrence of cerebral vasospasm and minimize neuronal injury during episodes of cerebral vasospasm. Our group is currently hosting the intravenous magnesium sulfate to improve outcome after aneurysmal subarachnoid hemorrhage (IMASH) trial, which is a randomized, placebo-controlled, double-blinded, multicentered trial to evaluate the effect of magnesium sulfate infusion on the clinical outcome of patients with aneurysmal subarachnoid hemorrhage since 2002. The pilot result showed a trend towards decreased clinical vasospasm and better patient outcome. Magnesium sulfate infusion may prove to be an effective and inexpensive way to reduce the morbidity and mortality associated with aneurysmal subarachnoid hemorrhage, which is a major breakthrough in the current management.

The role of magnesium in the management of cerebral vasospasm

Subarachnoid hemorrhage (SAH) is characterized by bleeding into the subarachnoid space, often caused by ruptured aneurysm. Aneurysmal rupture occurs in 700,000 individuals per year worldwide, with 40,000 cases taking place in the United States. Beyond the high mortality associated with SAH alone, morbidity and mortality are further increased with the occurrence of cerebral vasospasm, a pathologic constriction of blood vessels that can lead to delayed ischemic neurologic deficits (DIND). Treatment of cerebral vasospasm is a source of contention. One extensively studied therapy is Magnesium (Mg) as both a competitive antagonist of calcium at the N-methyl D-aspartate (NMDA) receptor, and a noncompetitive antagonist of both IP3 and voltage-gated calcium channels, leading to smooth muscle relaxation. In our literature review, several animal and human studies are summarized in addition to two Phase III trials assessing the use of intravenous Mg in the treatment of SAH (IMASH and MASH-2). Though many studies have shown promise for the use of Mg in SAH, there has been inconsistency in study design and outcomes. Furthermore, the results of the recently completed clinical trials have shown no significant benefit from using intravenous Mg as adjuvant therapy in the treatment of cerebral vasospasm.

Magnesium treatment for neuroprotection in ischemic diseases of the brain

This article reviews experimental and clinical data on the use of magnesium as a neuroprotective agent in various conditions of cerebral ischemia. Whereas magnesium has shown neuroprotective properties in animal models of global and focal cerebral ischemia, this effect could not be reproduced in a large human stroke trial. These conflicting results may be explained by the timing of treatment. While treatment can be started before or early after ischemia in experimental studies, there is an inevitable delay of treatment in human stroke. Magnesium administration to women at risk for preterm birth has been investigated in several randomized controlled trials and was found to reduce the risk of neurological deficits for the premature infant. Postnatal administration of magnesium to babies after perinatal asphyxia has been studied in a number of controlled clinical trials. The results are promising but the trials have, so far, been underpowered. In aneurysmal subarachnoid hemorrhage (SAH), cerebral ischemia arises with the onset of delayed cerebral vasospasm several days after aneurysm rupture. Similar to perinatal asphyxia in impending preterm delivery, treatment can be started prior to ischemia. The results of clinical trials are conflicting. Several clinical trials did not show an additive effect of magnesium with nimodipine, another calcium antagonist which is routinely administered to SAH patients in many centers. Other trials found a protective effect after magnesium therapy. Thus, it may still be a promising substance in the treatment of secondary cerebral ischemia after aneurysmal SAH. Future prospects of magnesium therapy are discussed.

Medical Management of Cerebral Vasospasm following Aneurysmal Subarachnoid Hemorrhage: A Review of Current and Emerging Therapeutic Interventions

Cerebral vasospasm is a major source of morbidity and mortality in patients with aneurysmal subarachnoid hemorrhage (aSAH). Evidence suggests a multifactorial etiology and this concept remains supported by the assortment of therapeutic modalities under investigation. The authors provide an updated review of the literature for previous and recent clinical trials evaluating medical treatments in patients with cerebral vasospasm secondary to aSAH. Currently, the strongest evidence supports use of prophylactic oral nimodipine and initiation of triple-H therapy for patients in cerebral vasospasm. Other agents presented in this report include magnesium, statins, endothelin receptor antagonists, nitric oxide promoters, free radical scavengers, thromboxane inhibitors, thrombolysis, anti-inflammatory agents and neuroprotectants. Although promising data is beginning to emerge for several treatments, few prospective randomized clinical trials are presently available. Additionally, future investigational efforts will need to resolve discrepant definitions and outcome measures for cerebral vasospasm in order to permit adequate study comparisons. Until then, definitive recommendations cannot be made regarding the safety and efficacy for each of these therapeutic strategies and medical management practices will continue to be implemented in a wide-ranging manner.