Effect of High-Dose Simvastatin on Cerebral Blood Flow and Static Autoregulation in Subarachnoid Hemorrhage

Effect of Statin Treatment in Patients with Aneurysmal Subarachnoid Hemorrhage: A Network Meta-Analysis

BACKGROUND

There are knowledge gaps regarding the relative efficacy of statins for aneurysmal subarachnoid hemorrhage (aSAH). This study aims to examine the comparative effectiveness and determine the ranking of different statins with network meta‑analysis in patients with aSAH.

METHODS

MEDLINE, Embase, Pubmed, and Cochrane Central Register of Controlled Trials were searched from database inception until December 15, 2022. Outcomes included delayed cerebral ischemia (DCI), functional recovery, and mortality. Relative risk (RRs) ratios and associated 95% confidence intervals (CIs) were estimated. The values derived from surface under the cumulative ranking curve were obtained to rank the treatment hierarchy in the analysis.

RESULTS

We identified 13 trials involving 1,885 patients. Atorvastatin 20 mg (RR 0.68, 95% CI 0.53-0.86), pravastatin 40 mg (RR 0.51, 95% CI 0.31-0.77), and simvastatin 80 mg (RR 0.54, 95% CI 0.40-0.70) were superior to the placebo in preventing DCI. Additionally, simvastatin 80 mg (RR 0.60, 95% CI 0.42-0.84) and pravastatin 40 mg (RR 0.56, 95% CI 0.32-0.93) were associated with a decreased risk of DCI than simvastatin 40 mg. Comparisons across treatment durations suggested that short-term (RR 0.62, 95% CI 0.50-0.76) statin therapy reduced risk of DCI.

CONCLUSIONS

Simvastatin 80 mg might be the most effective intervention in reducing DCI. Additionally, short-term therapy might provide more benefits. Further research with longer follow-up is warranted to validate the current findings in patients with aSAH who are at high risk of DCI.

The Landscape of Randomized Clinical Trial Meta-analyses on Statins for Aneurysmal Subarachnoid Hemorrhage: A Scoping Review

INTRODUCTION

Aneurysmal subarachnoid hemorrhage (aSAH) is a type of non-traumatic SAH that can have detrimental effects on the central nervous system, resulting in severe disability or death.

METHODS

Early nimodipine is currently the only strongly recommended pharmacological treatment that has shown efficacy in improving neurological/functional outcomes in aSAH patients. Whether statin treatment is of benefit to aSAH patients is an issue that has generated considerable interest and debate. In the present scoping review, we mapped and analyzed the available literature on metaanalyses of randomized clinical trials (RCTs) examining the effect of statins on aSAH. Seventeen meta-analyses of RCTs, published between 2008 and 2023, were identified.

RESULTS

Treatments in included meta-analyses were based on various regimens of simvastatin, pravastatin, pitavastatin or atorvastatin for up to 21 days. Eleven of the included reports indicated some beneficial effect of statin treatment, reducing rates of at least one of the following: cerebral vasospasm, delayed cerebral ischemia/delayed ischemic neurologic deficit, mortality or functional/ neurological outcome. In contrast, six meta-analyses, showed no such effects.

CONCLUSION

The limitations reported by several meta-analyses, included low patient numbers or disproportionate representation of patients from certain RCTs, differences in drug treatment, patient diagnostic criteria and outcome evaluation between RCTs, as well as poor data quality or lack of RCTs data. Knowledge of the reported limitations may aid the design of future clinical trials and/or their meta-analyses.

The impact of pre-ictal statin use on vasospasm and outcome in aneurysmal subarachnoid hemorrhage

BACKGROUND

Pleiotropic effects of statins may be beneficial in alleviating cerebral vasospasm (VS) and improving outcome after aneurysmal subarachnoid hemorrhage (aSAH). Initiation of statin treatment at aSAH is not recommended; however, the effect of pre-ictal and continued statin use is not fully investigated.

METHODS

Retrospective study comparing aSAH patients admitted in 2012 to 2021 with pre-ictal statin use versus those not using statins. Patient entry variables, radiological/sonological VS, symptomatic VS, and radiologically documented delayed cerebral ischemia (DCI) were registered. Outcome was scored in terms of mortality, modified Rankin score, Glasgow outcome score extended, and levels of fatigue. Patients were compared on group level and in a case-control design.

RESULTS

We included 961 patients, with 204 (21.2%) statin users. Statin users were older and had more often hypertension. Severe radiological/sonological VS, symptomatic VS, and DCI were less frequent in statin users, and their length of stay was shorter. Mortality, functional outcome, and levels of fatigue were similar in both groups. When analyzing 89 pairs of statin users and non-statin users matched for age, aSAH severity, gender, and hypertension, we confirmed decreased radiological/sonological and symptomatic VS as well as shorter length of stay in statin users. They also had more often a favorable functional outcome and lower levels of fatigue.

CONCLUSIONS

Patients with pre-ictal and continued use of statins have a reduced occurrence of radiological/sonological and symptomatic VS, shorter length of stay, and more often favorable functional outcome, whereas mortality is similar to non-statin users. Even though larger multicenter studies with common, strict protocols for prevention, diagnosis, and treatment of vasospasm are needed to finally establish the value of statins in aSAH, continuation of pre-ictal statin use seems worthwhile.

Hemodynamic Management in the Prevention and Treatment of Delayed Cerebral Ischemia After Aneurysmal Subarachnoid Hemorrhage

One of the most serious complications after subarachnoid hemorrhage (SAH) is delayed cerebral ischemia, the cause of which is multifactorial. Delayed cerebral ischemia considerably worsens neurological outcome and increases the risk of death. The targets of hemodynamic management of SAH have widely changed over the past 30 years. Hypovolemia and hypotension were favored prior to the era of early aneurysmal surgery but were subsequently replaced by the use of hypervolemia and hypertension. More recently, the concept of goal-directed therapy targeting euvolemia, with or without hypertension, is gaining preference. Despite the evolving concepts and the vast literature, fundamental questions related to hemodynamic optimization and its effects on cerebral perfusion and patient outcomes remain unanswered. In this review, we explain the rationale underlying the approaches to hemodynamic management and provide guidance on contemporary strategies related to fluid administration and blood pressure and cardiac output manipulation in the management of SAH.

Impacts of Statin Therapy Strategies on Incidence of Ischemic Cerebrovascular Events in Patients With Aneurysmal Subarachnoid Hemorrhage: A Systematic Review and Bayesian Network Meta-Analysis

BACKGROUND

The exacerbation of neurological outcomes often occurs in aneurysmal subarachnoid hemorrhage (aSAH). Statins have been commonly used for aSAH; however, there is lack of evidence of the pharmacological efficacy of different dosages and types of statins.

OBJECTIVE

To apply the Bayesian network meta-analysis to analyze the optimal dosage and type of statins for the amelioration of ischemic cerebrovascular events (ICEs) in patients with aSAH.

METHODS

We developed the Bayesian network meta-analysis and systemic review to analyze the effects of statins on functional prognosis and the impacts of optimal dosage and type of statins on ICEs in patients with aSAH. The outcome variables of the analysis were the incidence of ICEs and functional prognosis.

RESULTS

A total of 2569 patients with aSAH across 14 studies were included. Analysis of 6 randomized controlled trials showed that statin use significantly improved functional prognosis in patients with aSAH (risk ratio [RR], 0.73; 95% CI, 0.55-0.97). Statins significantly reduced the incidence of ICEs (RR, 0.78; 95% CI, 0.67-0.90). Pravastatin (40 mg/d) decreased the incidence ICEs compared with placebo (RR, 0.14; 95% CI, 0.03-0.65) and was ranked the most effective, presenting with a significantly lower rate of the incidence ICEs than the worst-ranked simvastatin (40 mg/d) (RR, 0.13; 95% CI, 0.02-0.79).

CONCLUSION

Statins could significantly diminish the incidence of ICEs and enhance functional prognosis in patients with aSAH. Various types and dosages of statins show distinct efficacies.

Anti-Inflammatory Drug Therapy in Aneurysmal Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis of Prospective Randomized and Placebo-Controlled Trials

Emerging evidence suggests that neuroinflammation may play a potential role in aneurysmal subarachnoid hemorrhage (aSAH). We aim to analyze the influence of anti-inflammatory therapy on survival and outcome in aSAH. Eligible randomized placebo-controlled prospective trials (RCTs) were searched in PubMed until March 2023. After screening the available studies for inclusion and exclusion criteria, we strictly extracted the main outcome measures. Dichotomous data were determined and extracted by odds ratio (OR) with 95% confidence intervals (CIs). Neurological outcome was graded using the modified Rankin Scale (mRS). We created funnel plots to analyze publication bias. From 967 articles identified during the initial screening, we included 14 RCTs in our meta-analysis. Our results illustrate that anti-inflammatory therapy yields an equivalent probability of survival compared to placebo or conventional management (OR: 0.81, 95% CI: 0.55-1.19, p = 0.28). Generally, anti-inflammatory therapy trended to be associated with a better neurologic outcome (mRS ≤ 2) compared to placebo or conventional treatment (OR: 1.48, 95% CI: 0.95-2.32, p = 0.08). Our meta-analysis showed no increased mortality form anti-inflammatory therapy. Anti-inflammatory therapy in aSAH patients tends to improve the neurological outcome. However, multicenter, rigorous, designed, prospective randomized studies are still needed to investigate the effect of fighting inflammation in improving neurological functioning after aSAH.

New Insights of Early Brain Injury after Subarachnoid Hemorrhage: A Focus on the Caspase Family

Spontaneous subarachnoid hemorrhage (SAH), primarily caused by ruptured intracranial aneurysms, remains a prominent clinical challenge with a high rate of mortality and morbidity worldwide. Accumulating clinical trials aiming at the prevention of cerebral vasospasm (CVS) have failed to improve the clinical outcome of patients with SAH. Therefore, a growing number of studies have shifted focus to the pathophysiological changes that occur during the periods of early brain injury (EBI). New pharmacological agents aiming to alleviate EBI have become a promising direction to improve outcomes after SAH. Caspases belong to a family of cysteine proteases with diverse functions involved in maintaining metabolism, autophagy, tissue differentiation, regeneration, and neural development. Increasing evidence shows that caspases play a critical role in brain pathology after SAH. Therefore, caspase regulation could be a potential target for SAH treatment. Herein, we provide an overview pertaining to the current knowledge on the role of caspases in EBI after SAH, and we discuss the promising therapeutic value of caspase-related agents after SAH.

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.

Twitter Journal Club Impact on Engagement Metrics of the Neurocritical Care Journal

BACKGROUND

Twitter journal clubs are a modern way of highlighting articles published in a scientific journal. The Neurocritical Care journal (NCC) initiated a bimonthly, Twitter-based, online journal club in 2015 to increase the outreach of its published articles. We hypothesize that articles included in the Neurocritical Care Society Twitter Journal Club (NCSTJC) had greater engagement than other articles published during the same time period. We also investigated the relationship between number of citations and Altmetric score to assess whether the enhanced online activity resulted in higher citations.

METHODS

We gathered data in August 2020 on engagement metrics (number of downloads, Altmetric score, relative citation ratio, and number of citations) of all articles published in NCC between 2015 and 2018. Articles were analyzed into two groups: one featured in NCSTJC and the rest that were not (non-NCSTJC1), and the other comprised those that were not in NCSTJC but published under a similar category of articles as NCSTJC (non-NCSTJC2). Results were analyzed using descriptive statistics, and summary measures were used to report the spread. The groups were compared by using the Wilcoxon rank sum test, given that the data were not normally distributed. Spearman's rank correlation was used to assess correlation between Altmetric score and citations for the articles in the NCSTJC and non-NCSTJC groups. For comparison, the top ten cited articles in NCC were analyzed for similar correlations.

RESULTS

Between 2015 and 2018, NCC published 529 articles, 24 of which were included in the Twitter journal club. A total of 406 articles were published in the same category as the category of articles selected for NCSTJC. The articles discussed as a part of NCSTJC had a statistically significant trend toward a higher number of downloads, Altmetric score, relative citation ratio, and number of citations than rest of the articles published in the journal during the same time period and the rest of the articles published in same categories. Three NCSTJC articles were among the ten most-cited articles published by NCC between 2015 and 2018. We did not find a correlation between Altmetric scores and number of citations in the NCSTJC or non-NCSTJC1 or non-NCSTJC2 group, but there was a strong correlation between these two variables in high performing articles when the top ten cited articles were analyzed.

CONCLUSIONS

Scientific journals are evolving their social media strategies in attempt to increase the outreach of their articles to the medical community. Platforms such as Twitter journal clubs can enhance such engagement. The long-term influence of such strategies on the impact factor of a medical journal and traditional engagement metrics, such as citations, calls for further research.

Optimal Course of Statins for Patients With Aneurysmal Subarachnoid Hemorrhage: Is Longer Treatment Better? A Meta-Analysis of Randomized Controlled Trials

Statins are used in clinical practice to prevent from complications such as cerebral vasospasm (CVS) after aneurysmal subarachnoid hemorrhage (aSAH). However, the efficacy and safety of statins are still controversial due to insufficient evidence from randomized controlled trials and inconsistent results of the existing studies. This meta-analysis aimed to systematically review the latest evidence on the time window and complications of statins in aSAH. The randomized controlled trials in the databases of The Cochrane Library, PubMed, Web of Science, Embase, CNKI, and Wanfang from January 2005 to April 2021 were searched and analyzed systematically. Data analysis was performed using Stata version 16.0. The fixed-effects model (M-H method) with effect size risk ratio (RR) was used for subgroups with homogeneity, and the random-effects model (D-L method) with effect size odds ratio (OR) was used for subgroups with heterogeneity. The primary outcomes were poor neurological prognosis and all-cause mortality, and the secondary outcomes were cerebral vasospasm (CVS) and statin-related complications. This study was registered with PROSPERO (International Prospective Register of Systematic Reviews; CRD42021247376). Nine studies comprising 1,464 patients were included. The Jadad score of the patients was 5–7. Meta-analysis showed that poor neurological prognosis was reduced in patients who took oral statins for 14 days (RR, 0.73 [0.55–0.97]; I² = 0%). Surprisingly, the continuous use of statins for 21 days had no significant effect on neurological prognosis (RR, 1.04 [0.89–1.23]; I² = 17%). Statins reduced CVS (OR, 0.51 [0.36–0.71]; I² = 0%) but increased bacteremia (OR, 1.38 [1.01–1.89]; I² = 0%). In conclusion, a short treatment course of statins over 2 weeks may improve neurological prognosis. Statins were associated with reduced CVS. Based on the pathophysiological characteristics of CVS and the evaluation of prognosis, 2 weeks could be the optimal time window for statin treatment in aSAH, although bacteremia may increase.

Effects of Various Therapeutic Agents on Vasospasm and Functional Outcome After Aneurysmal Subarachnoid Hemorrhage-Results of a Network Meta-Analysis

BACKGROUND

Vasospasm and delayed ischemic neurologic deficits are the leading causes of morbidity and mortality after aneurysmal subarachnoid hemorrhage (aSAH). Several therapeutic agents have been assessed in randomized controlled trials for their efficacy in reducing the incidence of vasospasm and improving functional outcome. The aim of this network meta-analysis is to compare all these therapeutic agents for their effect on functional outcome and other parameters after aSAH.

METHODS

A comprehensive search of different databases was performed to retrieve randomized controlled trials describing the effect of various therapeutic approaches on functional outcome and other parameters after aSAH.

RESULTS

Ninety-two articles were selected for full text review and 57 articles were selected for the final analysis. Nicardipine prolonged-release implants were found to be the best treatment in terms of favorable outcome (odds ratio [OR], 8.55; 95% credible interval [CrI], 1.63-56.71), decreasing mortality (OR, 0.08; 95% CrI, 0-0.82), and preventing angiographic vasospasm (OR, 0.018; 95% CrI, 0.00057-0.16). Cilostazol was found to be the second-best treatment in improving favorable outcomes (OR, 3.58; 95% CrI, 1.97-6.57) and decreasing mortality (OR, 0.41; 95% CrI, 0.12-1.15). Fasudil (OR, 0.16; 95% CrI, 0.03-0.78) was found to be the best treatment in decreasing increased vessel velocity and enoxaparin (OR, 0.25; 95% CrI, 0.057-1.0) in preventing delayed ischemic neurologic deficits.

CONCLUSIONS

Our analysis showed that nicardipine prolonged-release implants and cilostazol were associated with the best chance of improving favorable outcome and mortality in patients with aSAH. However, larger multicentric studies from other parts of the world are required to confirm these findings.

Cerebral Autoregulation in Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is a devastating stroke subtype with a high rate of mortality and morbidity. The poor clinical outcome can be attributed to the biphasic course of the disease: even if the patient survives the initial bleeding emergency, delayed cerebral ischemia (DCI) frequently follows within 2 weeks time and levies additional serious brain injury. Current therapeutic interventions do not specifically target the microvascular dysfunction underlying the ischemic event and as a consequence, provide only modest improvement in clinical outcome. SAH perturbs an extensive number of microvascular processes, including the “automated” control of cerebral perfusion, termed “cerebral autoregulation.” Recent evidence suggests that disrupted cerebral autoregulation is an important aspect of SAH-induced brain injury. This review presents the key clinical aspects of cerebral autoregulation and its disruption in SAH: it provides a mechanistic overview of cerebral autoregulation, describes current clinical methods for measuring autoregulation in SAH patients and reviews current and emerging therapeutic options for SAH patients. Recent advancements should fuel optimism that microvascular dysfunction and cerebral autoregulation can be rectified in SAH patients.

Effect of statins on functional outcome and mortality following aneurysmal subarachnoid hemorrhage - Results of a meta-analysis, metaregression and trial sequential analysis

OBJECTIVE

Cerebral vasospasm (CVS) and delayed ischemic neurological deficits (DIND) are a common cause of morbidity following aneurysmal subarachnoid hemorrhage (SAH). Statins have been shown to decrease CVS. The objective of this article was to ascertain the effect of statins on functional outcome and mortality following aneurysmal SAH by performing meta-analysis.

METHODS

A comprehensive search of different databases was performed to retrieve randomized controlled trials. Meta-analysis with subgroup analysis and metaregression was done. Trial sequential analysis (TSA) was performed to determine if the cumulative sample size was appropriately powered for the obtained pooled effect values and to avoid random error.

RESULTS

Twelve articles were selected for meta-analysis. Pooled OR for the change in favorable outcome, mortality, CVS, DIND and elevated transaminases was 1.07 (p = 0.55), 0.78 (p = 0.17), 0.58 (p = 0.0004), 0.54 (p = 0.0293) and 0.68 (p = 0.1774) respectively. Further, subgroup analysis and metaregression showed that the use of different statin or dose did not result in significant variation in results in the parameters studied. TSA showed that more trials and patients are required to reach to a definitive conclusion regarding any effect on statins on functional outcome and mortality as the current studies neither reached the level of confidence nor crossed the futility boundary.

CONCLUSION

Use of statins in patients with aneurysmal SAH resulted in marginal but non-significant favorable impact on functional outcome and mortality. TSA showed that more studies are required to get conclusive evidence in this regard.

Identification of upregulated NF-κB inhibitor alpha and IRAK3 targeting lncRNA following intracranial aneurysm rupture-induced subarachnoid hemorrhage

Background

This study was performed to identify genes and lncRNAs involved in the pathogenesis of subarachnoid hemorrhage (SAH) from ruptured intracranial aneurysm (RIA).

Methods

Microarray GSE36791 was downloaded from Gene Expression Omnibus (GEO) database followed by the identification of significantly different expressed RNAs (DERs, including lncRNA and mRNA) between patients with SAH and healthy individuals. Then, the functional analyses of DEmRNAs were conducted and weighted gene co-expression network analysis (WGCNA) was also performed to extract the modules associated with SAH. Following, the lncRNA-mRNA co-expression network was constructed and the gene set enrichment analysis (GSEA) was performed to screen key RNA biomarkers involved in the pathogenesis of SAH from RIA. We also verified the results in a bigger dataset GSE7337.

Results

Totally, 561 DERs, including 25 DElncRNAs and 536 DEmRNAs, were identified. Functional analysis revealed that the DEmRNAs were mainly associated with immune response-associated GO-BP terms and KEGG pathways. Moreover, there were 6 modules significantly positive-correlated with SAH. The lncRNA-mRNA co-expression network contained 2 lncRNAs (LINC00265 and LINC00937) and 169 mRNAs. The GSEA analysis showed that these two lncRNAs were associated with three pathways (cytokine-cytokine receptor interaction, neurotrophin signaling pathway, and apoptosis). Additionally, IRAK3 and NFKBIA involved in the neurotrophin signaling pathway and apoptosis while IL1R2, IL18RAP and IL18R1 was associated with cytokine-cytokine receptor interaction pathway. The expression levels of these genes have the same trend in GSE36791 and GSE7337.

Conclusion

LINC00265 and LINC00937 may be implicated with the pathogenesis of SAH from RIA. They were involved in three important regulatory pathways. 5 mRNAs played important roles in the three pathways.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02156-1.

The Updated Role of the Blood Brain Barrier in Subarachnoid Hemorrhage: From Basic and Clinical Studies

Subarachnoid hemorrhage (SAH) is a type of hemorrhagic stroke associated with high mortality and morbidity. The blood-brain-barrier (BBB) is a structure consisting primarily of cerebral microvascular endothelial cells, end feet of astrocytes, extracellular matrix, and pericytes. Post-SAH pathophysiology included early brain injury and delayed cerebral ischemia. BBB disruption was a critical mechanism of early brain injury and was associated with other pathophysiological events. These pathophysiological events may propel the development of secondary brain injury, known as delayed cerebral ischemia. Imaging advancements to measure BBB after SAH primarily focused on exploring innovative methods to predict clinical outcome, delayed cerebral ischemia, and delayed infarction related to delayed cerebral ischemia in acute periods. These predictions are based on detecting abnormal changes in BBB permeability. The parameters of BBB permeability are described by changes in computed tomography (CT) perfusion and magnetic resonance imaging (MRI). K_ep seems to be a stable and sensitive indicator in CT perfusion, whereas K^trans is a reliable parameter for dynamic contrast-enhanced MRI. Future prediction models that utilize both the volume of BBB disruption and stable parameters of BBB may be a promising direction to develop practical clinical tools. These tools could provide greater accuracy in predicting clinical outcome and risk of deterioration. Therapeutic interventional exploration targeting BBB disruption is also promising, considering the extended duration of post-SAH BBB disruption.

Cerebral autoregulation after aneurysmal subarachnoid haemorrhage. A preliminary study comparing dexmedetomidine to propofol and/or midazolam

BACKGROUND

Cerebral autoregulation is often impaired after aneurysmal subarachnoid haemorrhage (aSAH). Dexmedetomidine is being increasingly used, but its effects on cerebral autoregulation in patients with aSAH have not been studied before. Dexmedetomidine could be a useful sedative in patients with aSAH as it enables neurological assessment during the infusion. The aim of this preliminary study was to compare the effects of dexmedetomidine on dynamic and static cerebral autoregulation with propofol and/or midazolam in patients with aSAH.

METHODS

Ten patients were recruited. Dynamic and static cerebral autoregulation were assessed using transcranial Doppler ultrasound during propofol and/or midazolam infusion and then during three increasing doses of dexmedetomidine infusion (0.7, 1.0 and 1.4 μg/kg/h). Transient hyperaemic response ratio (THRR) and strength of autoregulation (SA) were calculated to assess dynamic cerebral autoregulation. Static rate of autoregulation (sRoR)% was calculated by using noradrenaline infusion to increase the mean arterial pressure 20 mm Hg above the baseline.

RESULTS

Data from nine patients were analysed. Compared to baseline, we found no statistically significant changes in THRR or sROR%. THRR was (mean ± SD) 1.20 ± 0.14, 1.17 ± 0.13 (P = .93), 1.14 ± 0.09 (P = .72) and 1.19 ± 0.18 (P = 1.0) and sROR% was 150.89 ± 84.37, 75.22 ± 27.75 (P = .08), 128.25 ± 58.35 (P = .84) and 104.82 ± 36.92 (P = .42) at baseline and during 0.7, 1.0 and 1.4 μg/kg/h dexmedetomidine infusion, respectively. Dynamic SA was significantly reduced after 1.0 μg/kg/h dexmedetomidine (P = .02).

CONCLUSIONS

Compared to propofol and/or midazolam, dexmedetomidine did not alter static cerebral autoregulation in aSAH patients, whereas a significant change was observed in dynamic SA. Further and larger studies with dexmedetomidine in aSAH patients are warranted.

Low total cholesterol and high density lipoprotein are independent predictors of poor outcomes following aneurysmal subarachnoid hemorrhage: A preliminary report

INTRODUCTION

Aneurysmal subarachnoid hemorrhage (aSAH) is devastating, with delayed cerebral ischemia (DCI) significantly contributing to the high morbidity and mortality rates. Cholesterol has been studied as a measure of nutritional status in other neurological pathologies, but reports examining cholesterol's effects on aSAH outcomes are sparse. This study aimed to elucidate the effect of low total cholesterol (TC) and high density lipoprotein (HDL) on mortality and DCI following aSAH.

METHODS

We performed a retrospective cohort study at a quaternary academic medical center between June 2014 and July 2018. All patients had aSAH confirmed by digital subtraction angiography and had TC measured on admission. Primary outcomes were mortality and DCI. Secondary outcome was radiographic vasospasm. Univariate and multivariate logistic regressions were performed.

RESULTS

There were 75 aSAH patients, with an average age of 58.7 ± 1.7 (range: 14-89) and Hunt & Hess score of 2.8 ± 0.1, included for analysis. Those with a low TC < 160 mg/dL had 3 times increased odds of DCI (OR = 3.4; 95 %CI: 1.3-9.0; p = 0.0175) and a nearly 5 times increased odds of death (OR = 4.9; 95 %CI: 1.1-18.3; p = 0.0339). Low HDL < 40 mg/dL was associated with 12 times increased odds of DCI (OR = 12.3; 95 %CI: 2.7-56.4; p = 0.0003) but no significant differences in death (p = 0.2205). In multivariate analysis, low TC was an independent risk factor for increased mortality (OR = 5.6; 95 %CI: 1.2-27.6; p = 0.0335) while low HDL was associated with increased risk for DCI (OR = 17.9; 95 %CI: 3.1-104.4; p = 0.0013). There was no effect of TC or HDL on radiographic vasospasm.

CONCLUSIONS

Low TC and HDL are independent predictors of increased mortality and DCI, respectively, following aSAH. Low TC and HDL may be markers of poor overall health, in addition to having some pathophysiological effect on cerebral vasculature. These results may have practical implications for the improvement of aSAH prognostication and management.

Burden of cerebral hypoperfusion in patients with delayed cerebral ischemia after subarachnoid hemorrhage

OBJECTIVE

Delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH) may result in focal neurological deficits and cerebral infarction, believed to result from critical regional rather than global impairments in cerebral blood flow (CBF). However, the burden of such regional hypoperfusion has not been evaluated by gold-standard voxel-by-voxel CBF measurements. Specifically, the authors sought to determine whether the proportion of brain affected by hypoperfusion was greater in patients with DCI than in SAH controls without DCI and whether the symptomatic hemisphere (in those with lateralizing deficits) exhibited a greater cerebral hypoperfusion burden.

METHODS

Sixty-one patients with aneurysmal SAH underwent 15O PET to measure regional CBF during the period of risk for DCI (median 8 days after SAH, IQR 7-10 days). Regions of visibly abnormal brain on head CT studies, including areas of hemorrhage and infarction, were excluded. Burden of hypoperfusion was defined as the proportion of PET voxels in normal-appearing brain with CBF < 25 ml/100 g/min. Global CBF and hypoperfusion burden were compared between patients with and those without DCI at the time of PET. For patients with focal impairments from DCI, the authors also compared average CBF and hypoperfusion burden in symptomatic versus asymptomatic hemispheres.

RESULTS

Twenty-three patients (38%) had clinical DCI at the time of PET. Those with DCI had higher mean arterial pressure (MAP; 126 ± 14 vs 106 ± 12 mm Hg, p < 0.001) and 18 (78%) were on vasopressor therapy at the time of PET study. While global CBF was not significantly lower in patients with DCI (mean 39.4 ± 11.2 vs 43.0 ± 8.3 ml/100 g/min, p = 0.16), the burden of hypoperfusion was greater (20%, IQR 12%-23%, vs 12%, 9%-16%, p = 0.006). Burden of hypoperfusion performed better than global CBF as a predictor of DCI (area under the curve 0.71 vs 0.65, p = 0.044). Neither global CBF nor hypoperfusion burden differed in patients who responded to therapy compared to those who had not improved by the time of PET. Although hemispheric CBF was not lower in the symptomatic versus contralateral hemisphere in the 13 patients with focal deficits, there was a trend toward greater burden of hypoperfusion in the symptomatic hemisphere (21% vs 18%, p = 0.049).

CONCLUSIONS

The burden of hypoperfusion was greater in patients with DCI, despite hemodynamic therapies, higher MAP, and equivalent global CBF. Similarly, hypoperfusion burden was greater in the symptomatic hemisphere of DCI patients with focal deficits even though the average CBF was similar to that in the contralateral hemisphere. Evaluating the proportion of the brain with critical hypoperfusion after SAH may better capture the extent of DCI than averaging CBF across heterogenous brain regions.

Atorvastatin reduces cerebral vasospasm and infarction after aneurysmal subarachnoid hemorrhage in elderly Chinese adults

We explored whether acute atorvastatin treatment would improve clinical outcomes and reduce the incidence of cerebral vasospasm after aneurysmal subarachnoid hemorrhage in elderly Chinese adults. Patients (60 to 90 years old) were admitted to intensive care units after surgery to clip or embolize their aneurysms. We assessed 592 patients and assigned 159 to receive atorvastatin (20 mg/day) and 158 to receive placebo once daily for up to 14 days. The primary outcome was the Glasgow outcome scale at 6 months, and secondary outcomes were cerebral vasospasm, 30-days all-cause mortality, cerebral infarction, and delayed ischemic neurological deficit. The incidence of postoperative cerebral vasospasm (39.3% vs 56%, P =0.004) and cerebral infarction (18.7% vs 27.3%, P=0.027) were significantly lower in the atorvastatin group. The study did not detect benefits in the use of atorvastatin for 6 months clinical outcome or 30-day all-cause mortality, but it suggests that atorvastatin together with nimodipine can reduce cerebral vasospasm and cerebral infarction after subarachnoid hemorrhage.

Posterior Reversible Encephalopathy Syndrome as a Complication of Induced Hypertension in Subarachnoid Hemorrhage: A Case-Control Study

BACKGROUND

Induced hypertension (IH) remains the mainstay of medical management for delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH). However, raising blood pressure above normal levels may be associated with systemic and neurological complications, of which posterior reversible encephalopathy syndrome (PRES) has been increasingly recognized.

OBJECTIVE

To ascertain the frequency and predisposing factors for PRES during IH therapy.

METHODS

We identified 68 patients treated with IH from 345 SAH patients over a 3-yr period. PRES was diagnosed based on clinical suspicion, confirmed by imaging. We extracted additional data on IH, including baseline and highest target mean arterial pressure (MAP), comparing PRES to IH-treated controls.

RESULTS

Five patients were diagnosed with PRES at median 6.6 d (range 1-8 d) from vasopressor initiation. All presented with lethargy, 3 had new focal deficits, and 1 had a seizure. Although baseline MAP (prior to DCI) did not differ between cases and controls, both MAP immediately prior to IH (112 vs 90) and highest MAP targeted were greater (140 vs 120 mm Hg, both P < .01). Magnitude of MAP elevation was greater (54 vs 34 above baseline, P = .004) while degree of IH was not (37 vs 38 above pre-IH MAP). All 4 surviving PRES patients had complete resolution with IH discontinuation.

CONCLUSION

PRES was diagnosed in 7% of SAH patients undergoing IH therapy, most often when MAP was raised well above baseline to levels that exceed traditional autoregulatory thresholds. High suspicion for this reversible disorder appears warranted in the face of unexplained neurological deterioration during aggressive IH.

Dose-Dependent Effects of Statins for Patients with Aneurysmal Subarachnoid Hemorrhage: Meta-Regression Analysis

OBJECTIVE

The study uses meta-regression analysis to quantify the dose-dependent effects of statin pharmacotherapy on vasospasm, delayed ischemic neurologic deficits (DIND), and mortality in aneurysmal subarachnoid hemorrhage.

METHODS

Prospective, retrospective observational studies, and randomized controlled trials (RCTs) were retrieved by a systematic database search. Summary estimates were expressed as absolute risk (AR) for a given statin dose or control (placebo). Meta-regression using inverse variance weighting and robust variance estimation was performed to assess the effect of statin dose on transformed AR in a random effects model. Dose-dependence of predicted AR with 95% confidence interval (CI) was recovered by using Miller's Freeman-Tukey inverse.

RESULTS

The database search and study selection criteria yielded 18 studies (2594 patients) for analysis. These included 12 RCTs, 4 retrospective observational studies, and 2 prospective observational studies. Twelve studies investigated simvastatin, whereas the remaining studies investigated atorvastatin, pravastatin, or pitavastatin, with simvastatin-equivalent doses ranging from 20 to 80 mg. Meta-regression revealed dose-dependent reductions in Freeman-Tukey-transformed AR of vasospasm (slope coefficient -0.00404, 95% CI -0.00720 to -0.00087; P = 0.0321), DIND (slope coefficient -0.00316, 95% CI -0.00586 to -0.00047; P = 0.0392), and mortality (slope coefficient -0.00345, 95% CI -0.00623 to -0.00067; P = 0.0352).

CONCLUSIONS

The present meta-regression provides weak evidence for dose-dependent reductions in vasospasm, DIND and mortality associated with acute statin use after aneurysmal subarachnoid hemorrhage. However, the analysis was limited by substantial heterogeneity among individual studies. Greater dosing strategies are a potential consideration for future RCTs.

Alendronate promotes osteoblast differentiation and bone formation in ovariectomy-induced osteoporosis through interferon-β/signal transducer and activator of transcription 1 pathway

Alendronate is commonly used for the treatment of postmenopausal osteoporosis; however, the underlying pathological molecular mechanisms of its action remain unclear. In the present study, the alendronate-treated signaling pathway in bone metabolism in rats with ovariectomy induced by osteoporosis was investigated. Rats with osteoporosis were orally administered alendronate or phosphate-buffered saline (control). In addition, the interferon-β (IFN-β)/signal transducer and activator of transcription 1 (STAT1) signaling pathway was investigated in osteoblasts following treatment with alendronate in vitro and in vivo. During the differentiation period, IFN-β (100 ng/ml) was used to treat the osteoblast cells, and the activity, viability and bone metabolism-associated gene expression levels (STAT1, p-STAT1, Fra1, TRAF6 and SOCS1) were analyzed in osteoblast cells. Histopathological changes were used to evaluate osteoblasts, osteoclasts, inflammatory phase of bone healing and osteonecrotic areas. The results demonstrated that alendronate significantly inhibited the activity of osteoporotic osteoclasts by stimulating expression of IFN-β, as well as markedly improved the viability and activity of osteoblasts compared with the control group. In addition, alendronate increased the expression and phosphorylation levels of STAT1 in osteoclasts, enhanced osteoblast differentiation, upregulated the expression levels of alkaline phosphatase and osteocalcin, and increased the expression of osteoblast differentiation-associated genes (osteocalcin, osterix and Runx2). Inhibition of IFN-β expression canceled the benefits of alendronate-mediated osteoblast differentiation. Notably, alendronate enhanced bone formation in rats with osteoporosis induced by ovariectomy. In conclusion, these findings suggest that alendronate can regulate osteoblast differentiation and bone formation in rats with osteoporosis induced by ovariectomy through upregulation of IFN-β/STAT1 signaling pathway.

Anti-inflammatory effects of Simvastatin in patients with acute intracerebral hemorrhage in an intensive care unit

Intracerebral hemorrhage is one of the most common types of cerebrovascular disease in humans and often causes paralysis, a vegetative state and even death. Patients with acute intracerebral hemorrhage are frequently monitored in intensive care units (ICUs). Spontaneous intracerebral hemorrhage is associated with a higher rate of mortality and morbidity than other intracephalic diseases. The expression levels of inflammatory factors have important roles in inflammatory responses indicative of changes in a patient's condition and are therefore important in the monitoring and treatment of affected patients at the ICU as well as the development of therapeutic strategies for acute cerebral hemorrhage. The present study investigated the anti-inflammatory effects of Simvastatin in patients with acute intracerebral hemorrhage at an ICU, and inflammatory factors and cellular changes were systematically analyzed. The plasma concentrations of inflammatory factors, including interleukin (IL)-4, IL-6, IL-8 and IL-10, were evaluated by ELISAs. The plasma concentrations of inflammatory cellular changes were detected by using flow cytometry. The results demonstrated that after Simvastatin treatment of patients with acute cerebral hemorrhage at the ICU, the plasma concentrations of IL-4, IL-6, IL-8 and IL-10 were downregulated compared with those in placebo-treated controls. In addition, Simvastatin treatment at the ICU decreased lymphocytes, granulocytes and mononuclear cells in patients with acute cerebral hemorrhage. The levels of inflammatory factors were associated with brain edema in patients with acute cerebral hemorrhage treated at the ICU. In addition, the amount of bleeding was reduced in parallel with the inflammatory cell plasma concentration of lymphocytes, granulocytes and mononuclear cells. Importantly, Simvastatin treatment produced beneficial outcomes by improving brain edema and reducing the amount of bleeding. In conclusion, the present study demonstrated the efficacy of Simvastatin in treating acute intracerebral hemorrhage and evidenced the association between inflammatory responses and the progress of affected patients at the ICU, thereby providing insight for applying effective therapies for patients with acute intracerebral hemorrhage.

The Efficacy and Safety of 3 Types of Interventions for Stroke Prevention in Patients With Cardiovascular and Cerebrovascular Diseases: A Network Meta-analysis

PURPOSE

The goal of this study was to compare the relative efficacy and safety of different types of interventions for stroke prevention in patients with cardiovascular and cerebrovascular diseases.

METHODS

This network meta-analysis (NMA) was conducted with a random effects model of Bayesian framework using Stata version 12.0. Odds ratios (ORs) and their credible intervals (CrIs) were applied for the efficacy and safety evaluation of various medical interventions, including aspirin, dipyridamole, ticlopidine, warfarin, and apixaban. In addition, the ranking of probability of every clinical outcome was estimated by comparing the surface under the cumulative ranking curve.

FINDINGS

Compared with dabigatran, both edoxaban and aspirin + warfarin exhibited a higher rate of all-cause stroke (OR, 2.84 [95% CrI, 1.17-6.97]; OR, 3.42 [95% CrI, 1.20-9.84]). With respect to intracranial hemorrhage, aspirin + clopidogrel yielded worse outcomes than 7 treatments, including placebo, apixaban, aspirin, aspirin + dipyridamole, cilostazol, clopidogrel, and dabigatran (OR, 2.21 [95% CrI, 1.45-3.40]; OR, 2.11 [95% CrI, 1.05-4.17]; OR, 1.53 [95% CrI, 1.11-2.15]; OR, 1.78 [95% CrI, 1.01-3.03]; OR, 4.17 [95% CrI, 1.37-14.28]; OR, 1.85 [95% CrI, 1.22-2.86]; and OR, 2.56 [95% CrI, 1.37-4.76]). In terms of ischemic stroke, dabigatran provided better efficacy than placebo, aspirin, and aspirin + dipyridamole (OR, 0.36 [95% CrI, 0.18-0.72]; OR, 0.43 [95% CrI, 0.21-0.84]; and OR, 0.41 [95% CrI, 0.17-0.94]). As for mortality, dabigatran resulted in a lower mortality compared with aspirin, aspirin + clopidogrel, edoxaban, and warfarin (OR, 0.48 [95% CrI, 0.23-0.97]; OR, 0.40 [95% CrI, 0.17-0.92]; OR, 0.27 [95% CrI, 0.10-0.72]; and OR, 0.52 [95% CrI, 0.28-0.92]).

IMPLICATIONS

There are still some limitations to our NMA research. For instance, the lack of direct evidence for some therapies resulted in inconsistencies, particularly for warfarin compared with placebo and clopidogrel under different end points. Moreover, the included randomized controlled trials for patients with cardiovascular and cerebrovascular diseases are relatively broad, involving atrial fibrillation, myocardial infarction, and large-artery atherosclerosis stroke. Although further research is needed, dabigatran is highly recommended based on the present NAM for the treatment of cardiovascular and cerebrovascular diseases due to the drug's efficacy and safety.

RBC Transfusion Improves Cerebral Oxygen Delivery in Subarachnoid Hemorrhage

OBJECTIVES

Impaired oxygen delivery due to reduced cerebral blood flow is the hallmark of delayed cerebral ischemia following subarachnoid hemorrhage. Since anemia reduces arterial oxygen content, it further threatens oxygen delivery increasing the risk of cerebral infarction. Thus, subarachnoid hemorrhage may constitute an important exception to current restrictive transfusion practices, wherein raising hemoglobin could reduce the risk of ischemia in a critically hypoperfused organ. In this physiologic proof-of-principle study, we determined whether transfusion could augment cerebral oxygen delivery, particularly in vulnerable brain regions, across a broad range of hemoglobin values.

DESIGN

Prospective study measuring cerebral blood flow and oxygen extraction fraction using O-PET. Vulnerable brain regions were defined as those with baseline oxygen delivery less than 4.5 mL/100 g/min.

SETTING

PET facility located within the Neurology/Neurosurgery ICU.

PATIENTS

Fifty-two patients at risk for delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage with hemoglobin 7-13 g/dL.

INTERVENTIONS

Transfusion of one unit of RBCs over 1 hour.

MEASUREMENTS AND MAIN RESULTS

Baseline hemoglobin was 9.7 g/dL (range, 6.9-12.9), and cerebral blood flow was 43 ± 11 mL/100 g/min. After transfusion, hemoglobin rose from 9.6 ± 1.4 to 10.8 ± 1.4 g/dL (12%; p < 0.001) and oxygen delivery from 5.0 (interquartile range, 4.4-6.6) to 5.5 mL/100 g/min (interquartile range, 4.8-7.0) (10%; p = 0.001); the response was comparable across the range of hemoglobin values. In vulnerable brain regions, transfusion resulted in a greater (16%) rise in oxygen delivery associated with reduction in oxygen extraction fraction, independent of Hgb level (p = 0.002 vs normal regions).

CONCLUSIONS

This study demonstrates that RBC transfusion improves cerebral oxygen delivery globally and particularly to vulnerable regions in subarachnoid hemorrhage patients at risk for delayed cerebral ischemia across a wide range of hemoglobin values and suggests that restrictive transfusion practices may not be appropriate in this population. Large prospective trials are necessary to determine if these physiologic benefits translate into clinical improvement and outweigh the risk of transfusion.