Systemic administration of simvastatin after the onset of experimental subarachnoid hemorrhage attenuates cerebral vasospasm

Early Brain Injury and Neuroprotective Treatment after Aneurysmal Subarachnoid Hemorrhage: A Literature Review

Early brain injury (EBI) subsequent to subarachnoid hemorrhage (SAH) is strongly associated with delayed cerebral ischemia and poor patient prognosis. Based on investigations into the molecular mechanisms underlying EBI, neurovascular dysfunction resulting from SAH can be attributed to a range of pathological processes, such as microvascular alterations in brain tissue, ionic imbalances, blood-brain barrier disruption, immune-inflammatory responses, oxidative stress, and activation of cell death pathways. Research progress presents a variety of promising therapeutic approaches for the preservation of neurological function following SAH, including calcium channel antagonists, endothelin-1 receptor blockers, antiplatelet agents, anti-inflammatory agents, and anti-oxidative stress agents. EBI can be mitigated following SAH through neuroprotective measures. To enhance our comprehension of the relevant molecular pathways involved in brain injury, including brain ischemia-hypoxic injury, neuroimmune inflammation activation, and the activation of various cell-signaling pathways, following SAH, it is essential to investigate the evolution of these multifaceted pathophysiological processes. Facilitating neural repair following a brain injury is critical for improving patient survival rates and quality of life.

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.

Identifying critical genes associated with aneurysmal subarachnoid hemorrhage by weighted gene co-expression network analysis

Aneurysmal subarachnoid hemorrhage (aSAH) is a life-threatening medical condition with a high mortality and disability rate. aSAH has an unclear pathogenesis, and limited treatment options are available. Here, we aimed to identify critical genes involved in aSAH pathogenesis using peripheral blood gene expression data of 43 patients with aSAH due to ruptured intracranial aneurysms and 18 controls with headache, downloaded from Gene Expression Omnibus. These data were used to construct a co-expression network using weighted gene co-expression network analysis (WGCNA). The biological functions of the hub genes were explored, and critical genes were selected by combining with differentially expressed genes analysis. Fourteen modules were identified by WGCNA. Among those modules, red, blue, brown and cyan modules were closely associated with aSAH. Moreover, 364 hub genes in the significant modules were found to play important roles in aSAH. Biological function analysis suggested that protein biosynthesis-related processes and inflammatory responses-related processes were involved in the pathology of aSAH pathology. Combined with differentially expressed genes analysis and validation in 35 clinical samples, seven gene (CD27, ANXA3, ACSL1, PGLYRP1, ALPL, ARG1, and TPST1) were identified as potential biomarkers for aSAH, and three genes (ANXA3, ALPL, and ARG1) were changed with disease development, that may provide new insights into potential molecular mechanisms for aSAH.

Statins Improve Clinical Outcome After Non-aneurysmal Subarachnoid Hemorrhage: A Translational Insight From a Systematic Review of Experimental Studies

The efficacy of statin-treatment in aneurysmal subarachnoid hemorrhage (SAH) remains controversial. We aimed to investigate the effects of statin-treatment in non-aneurysmal (na)SAH in accordance with animal research data illustrating the pathophysiology of naSAH. We systematically searched PubMed using PRISMA-guidelines and selected experimental studies assessing the statin-effect on SAH. Detecting the accordance of the applied experimental models with the pathophysiology of naSAH, we analyzed our institutional database of naSAH patients between 1999 and 2018, regarding the effect of statin treatment in these patients and creating a translational concept. Patient characteristics such as statin-treatment (simvastatin 40 mg/d), the occurrence of cerebral vasospasm (CVS), delayed infarction (DI), delayed cerebral ischemia (DCI), and clinical outcome were recorded. In our systematic review of experimental studies, we found 13 studies among 18 titles using blood-injection-animal-models to assess the statin-effect in accordance with the pathophysiology of naSAH. All selected studies differ on study-setting concerning drug-administration, evaluation methods, and neurological tests. Patients from the Back to Bedside project, including 293 naSAH-patients and 51 patients with simvastatin-treatment, were recruited for this analysis. Patients under treatment were affected by a significantly lower risk of CVS (p < 0.01; OR 3.7), DI (p < 0.05; OR 2.6), and DCI (p < 0.05; OR 3). Furthermore, there was a significant association between simvastatin-treatment and favorable-outcome (p < 0.05; OR 3). However, dividing patients with statin-treatment in pre-SAH (n = 31) and post-SAH (n = 20) treatment groups, we only detected a tenuously significant higher chance for a favorable outcome (p < 0.05; OR 0.05) in the small group of 20 patients with statin post-SAH treatment. Using a multivariate-analysis, we detected female gender (55%; p < 0.001; OR 4.9), Hunt&Hess ≤III at admission (p < 0.002; OR 4), no anticoagulant-therapy (p < 0.0001; OR 0.16), and statin-treatment (p < 0.0001; OR 24.2) as the main factors improving the clinical outcome. In conclusion, we detected a significantly lower risk for CVS, DCI, and DI in naSAH patients under statin treatment. Additionally, a significant association between statin treatment and favorable outcome 6 months after naSAH onset could be confirmed. Nevertheless, unified animal experiments should be considered to create the basis for developing new therapeutic schemes.

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.

Simvastatin improves intracerebral hemorrhage through NF-κB-mediated apoptosis via the MyD88/TRIF signaling pathway

The aim was to investigate the neuroprotective effects and potential mechanism mediated by simvastatin in a mouse model of intracerebral hemorrhage. CD-1 mice were subjected to infusion of collagenase type IV into the left striatum in order to induce intracerebral hemorrhage. Western blot analysis, the TUNEL assay and the modified neurological severity score were used in the present study to analyze the efficacy of simvastatin for intracerebral hemorrhage. The results demonstrated that simvastatin treatment improved the cerebral water content and blood-brain barrier disruption in the intracerebral hemorrhage animals. Intracerebral hemorrhage-induced neuronal cell death was downregulated by simvastatin treatment compared with the vehicle-treated model group. In addition, the expression levels of aquaporin-4, matrix metallopeptidase 9 and caspase-3 were downregulated and B-cell lymphoma-2 was upregulated by simvastatin treatment compared with the vehicle-treated model. Simvastatin treatment also significantly reduced the Evans blue leakage into the injured hemispheres and improved motor function. Mechanism analysis further indicated that simvastatin treatment downregulated nuclear factor (NF)-κB expression, and upregulated the myeloid differentiation primary response 88 (MyD88) and TIR domain-containing adaptor protein inducing interferon-β (TRIF) expression levels in neuronal cells in experimental mice. Furthermore, the results revealed that NF-κB overexpression abolished the simvastatin-downregulated MyD88 and TRIF expression levels, as well as the apoptosis of neuronal cells. In conclusion, these results indicated that simvastatin was able to attenuate brain edema and reduce cellular apoptosis by suppressing the NF-κB-mediated MyD88/TRIF signaling pathway subsequent to the induction of intracerebral hemorrhage in mice.

The Role of Circulating Tight Junction Proteins in Evaluating Blood Brain Barrier Disruption following Intracranial Hemorrhage

Brain injury after intracranial hemorrhage (ICH) results in significant morbidity and mortality. Blood brain barrier (BBB) disruption is a hallmark of ICH-induced brain injury; however, data mirroring BBB disruption in human ICH are scarce. The aim of this study was to assess the significance of circulating biomarkers in evaluating BBB disruption after ICH. Twenty-two patients with ICH were recruited in this study. Concentrations of the tight junction proteins (TJs) Claudin-5 (CLDN5), Occludin (OCLN), and zonula occludens 1 (ZO-1) and vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9) were measured by using enzyme-linked immunosorbent assay in serum and cerebrospinal fluid (CSF) samples obtained from patients with ICH. The white blood cell (WBC) count in blood and CSF, albumin (ALB) levels in the CSF (ALBCSF), and the BBB ratio were significantly higher in the ICH than in controls (p < 0.05). Significantly higher levels of CLDN5, OCLN, ZO-1, MMP-9, and VEGF in CSF were observed in the ICH group; these biomarkers were also positively associated with BBB ratio (p < 0.05). Our data revealed that circulating TJs could be considered the potential biomarkers reflecting the integrity of the BBB in ICH.

The single and double blood injection rabbit subarachnoid hemorrhage model

Over the past 30 years, the rabbit subarachnoid hemorrhage model (SAH) has been used for investigating the post-hemorrhage pathology, especially with respect to understanding of the mechanisms of cerebral vasospasm. However, the molecular mechanisms of cerebral vasospasm remain to be elucidated. Furthermore, it is not clear whether the rabbit SAH model is suitable for the investigation of pathological conditions other than cerebral vasospasm, such as early brain injury. Therefore, the properties of the rabbit SAH model need to be validated, and the reasons for using the rabbit should be clarified. This review explores the settings and technical issues of establishing a rabbit cisterna magna single and double blood injection SAH model and discusses the characteristics and feasibilities of the models.

Inflammation, vasospasm, and brain injury after subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) can lead to devastating neurological outcomes, and there are few pharmacologic treatments available for treating this condition. Both animal and human studies provide evidence of inflammation being a driving force behind the pathology of SAH, leading to both direct brain injury and vasospasm, which in turn leads to ischemic brain injury. Several inflammatory mediators that are elevated after SAH have been studied in detail. While there is promising data indicating that blocking these factors might benefit patients after SAH, there has been little success in clinical trials. One of the key factors that complicates clinical trials of SAH is the variability of the initial injury and subsequent inflammatory response. It is likely that both genetic and environmental factors contribute to the variability of patients' post-SAH inflammatory response and that this confounds trials of anti-inflammatory therapies. Additionally, systemic inflammation from other conditions that affect patients with SAH could contribute to brain injury and vasospasm after SAH. Continuing work on biomarkers of inflammation after SAH may lead to development of patient-specific anti-inflammatory therapies to improve outcome after SAH.

Cerebral vasospasm after aneurysmal subarachnoid hemorrhage and traumatic brain injury

OPINION STATEMENT

Cerebral vasospasm (cVSP) consists of the vasoconstriction of large and small intracranial vessels which can lead to cerebral hypoperfusion, and in extreme cases, delayed ischemic deficits with stroke. While most commonly observed after aneurysmal subarachnoid hemorrhage (aSAH), cVSP can also occur after traumatic brain injury (TBI) as we have described in detail in this review. For the past decades, the research attention has focused on cVSP because of its association with delayed cerebral ischemia, which is the largest contributor of morbidity and mortality after aSAH. New discoveries in the cVSP pathophysiology involving multifactorial complex cascades and pathways pose new targets for therapeutic interventions in the prevention and treatment of cVSP. The goal of this review is to demonstrate the commonalities and differences in epidemiology and pathophysiology of both aSAH and TBI-associated cVSP, and highlight the more recently discovered pathways of cVSP. Finally, the latest cVSP surveillance methods and treatment options are illustrated.

Nitric oxide in cerebral vasospasm: theories, measurement, and treatment

In recent decades, a large body of research has focused on the role of nitric oxide (NO) in the development of cerebral vasospasm (CV) following subarachnoid hemorrhage (SAH). Literature searches were therefore conducted regarding the role of NO in cerebral vasospasm, specifically focusing on NO donors, reactive nitrogen species, and peroxynitrite in manifestation of vasospasm. Based off the assessment of available evidence, two competing theories are reviewed regarding the role of NO in vasospasm. One school of thought describes a deficiency in NO due to scavenging by hemoglobin in the cisternal space, leading to an NO signaling deficit and vasospastic collapse. A second hypothesis focuses on the dysfunction of nitric oxide synthase, an enzyme that synthesizes NO, and subsequent generation of reactive nitrogen species. Both theories have strong experimental evidence behind them and hold promise for translation into clinical practice. Furthermore, NO donors show definitive promise for preventing vasospasm at the angiographic and clinical level. However, NO augmentation may also cause systemic hypotension and worsen vasospasm due to oxidative distress. Recent evidence indicates that targeting NOS dysfunction, for example, through erythropoietin or statin administration, also shows promise at preventing vasospasm and neurotoxicity. Ultimately, the role of NO in neurovascular disease is complex. Neither of these theories is mutually exclusive, and both should be considered for future research directions and treatment strategies.

Statins and anti-inflammatory therapies for subarachnoid hemorrhage

OPINION STATEMENT

Aneurysmal subarachnoid hemorrhage (SAH) induces a potent inflammatory cascade that contributes to endothelial dysfunction, imbalance of vasoactive substances (excess endothelin, depletion of nitric oxide), and arterial vasospasm. This process results in delayed cerebral ischemia, a major cause of neurologic disability in those surviving the initial hemorrhage. The only therapy shown to be effective in improving neurologic outcomes after SAH is a calcium-channel antagonist, nimodipine (although it achieved this result without reducing vasospasm). A number of novel therapies have been explored to inhibit the development of vasospasm and reduce the burden of ischemia and cerebral infarction. Statins are promising candidates, as they block multiple aspects of the inflammatory pathway that contributes to ischemic brain injury. Early clinical trials have produced conflicting results, however, and the adoption of statins in clinical practice should await the results of larger, more definitive studies. Though endothelin-receptor antagonists showed promise in significantly reducing vasospasm in preliminary trials, their failure to improve clinical outcomes in phase 3 studies has been disappointing, highlighting the complex link between vasospasm and ischemia. Future directions in the quest to improve outcomes of patients with SAH may need to approach ischemia as a multifactorial process with inflammatory, vasoactive, and ionic/metabolic components.

Pharmacologic reduction of angiographic vasospasm in experimental subarachnoid hemorrhage: systematic review and meta-analysis

Animal models have been developed to simulate angiographic vasospasm secondary to subarachnoid hemorrhage (SAH) and to test pharmacologic treatments. Our aim was to evaluate the effect of pharmacologic treatments that have been tested in humans and in preclinical studies to determine if animal models inform results reported in humans. A systematic review and meta-analysis of SAH studies was performed. We investigated predictors of translation from animals to humans with multivariate logistic regression. Pharmacologic reduction of vasospasm was effective in mice, rats, rabbits, dogs, nonhuman primates (standard mean difference of -1.74; 95% confidence interval -2.04 to -1.44) and humans. Animal studies were generally of poor methodologic quality and there was evidence of publication bias. Subgroup analysis by drug and species showed that statins, tissue plasminogen activator, erythropoietin, endothelin receptor antagonists, calcium channel antagonists, fasudil, and tirilazad were effective whereas magnesium was not. Only evaluation of vasospasm >3 days after SAH was independently associated with successful translation. We conclude that reduction of vasospasm is effective in animals and humans and that evaluation of vasospasm >3 days after SAH may be preferable for preclinical models.

Statins in the management of aneurysmal subarachnoid hemorrhage: an overview of animal research, observational studies, randomized controlled trials and meta-analyses

BACKGROUND

the pathophysiology of delayed neurological deficits (DNDs) following aneurysmal subarachnoid hemorrhage (SAH) is complex, and is not limited to arterial narrowing (vasospasm) and classical ischemia. Thus, combined drug approaches, or therapies with multiple effects, may have the greatest potential for benefit. Statins are known to have pleiotropic vascular effects, some of which may interrupt the pathogenesis of DNDs. Based on promising preliminary reports, many clinicians routinely administer statins to prevent DNDs.

METHODS

a systematic review was performed to identify and summarize all animal research, observational studies, randomized controlled trials (RCTs) and meta-analyses which have evaluated the use of statins in the management of SAH.

RESULTS

nine animal studies, nine observational (cohort and case-control) studies, six RCTs and three meta-analyses were identified. Animal studies have generally administered statin doses that, when adjusted for body weight, are 10-80 times larger than what is used in humans. Nevertheless, these models have consistently reported statins to reduce vasospasm and to demonstrate additional neuroprotective effects. However, observational studies have not revealed an association between statin-use and reduced DNDs or improved neurological outcomes. Results of RCTs have been inconsistent and limited by small sample size, but together suggest that statins may reduce DNDs, with no clear impact on mortality or neurological recovery. Optimal drug administration strategies (timing of initiation, most effective dose and duration) have not been clarified.

CONCLUSIONS

the role of statins in the management of patients with SAH remains unclear. Although promising, statins should not, at this time, be considered standard care.

Mechanisms of statin treatment in cerebral vasospasm

3-Hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors, commonly known as statins, are widely used clinically for their lipid lowering properties. Recent experimental evidence shows that statins are also effective in ameliorating cerebral vasospasm, which occurs as sequelae of subarachnoid hemorrhage. This literature review focuses on the literature-based putative mechanisms involved in statin mediated attenuation of cerebral vasospasm, such as eNOS, vascular inflammation, apoptosis, especially the phosphatidylinositol 3-kinase/Akt (PI3K/Akt) pathway from our experimental study.

Nitric oxide in early brain injury after subarachnoid hemorrhage

Nitric Oxide (NO) is the major regulator of cerebral blood flow. In addition, it inhibits platelet adherence and aggregation, reduces adherence of leukocytes to the endothelium, and suppresses vessel injury. NO is produced on demand by nitric oxide synthase and has a very short half life. Hence maintenance of its cerebral level is crucial for normal vascular physiology. Time dependent alterations in cerebral NO level and the enzymes responsible for its synthesis are found after subarachnoid hemorrhage (SAH). Cerebral NO level decreases, recovers and increases within the first 24 h after SAH. Each change in cerebral NO level elicits a different pathological response form already compromised brain. These response range from constriction, platelet aggregation and vascular injury that occurs during the early hours and delayed occurring vasospasm, neuronal and axonal damage. This review summarizes the underlying mechanism and the consequence of alteration in cerebral NO level on brain during the first 72 h after SAH.

Simvastatin re-couples dysfunctional endothelial nitric oxide synthase in experimental subarachnoid hemorrhage

Reduced endothelial nitric oxide synthase (eNOS) function has been linked to secondary complications of subarachnoid hemorrhage (SAH). We previously found that there is increased eNOS function after SAH but that it is uncoupled, leading to secondary complications such as vasospasm, microthromboembolism and neuronal apoptosis. Here we test the hypothesis that recoupling eNOS with simvastatin can prevent these complications. SAH was created in mice that were treated with vehicle or simvastatin starting 2 weeks before or 30 minutes after SAH. SAH increased phosphorylated eNOS which was prevented by pre- or post-treatment with simvastatin. Simvastatin pre-treatment also prevented the increase in eNOS monomer formation that was associated with SAH, decreased superoxide anion radical production and increased NO. These changes were associated with decreased vasospasm, microthromboemboli and neuronal injury. The data suggest that simvastatin re-couples eNOS after SAH, leading to decreased secondary complications such as vasospasm, microthromboemboli and neuronal injury.

Clinicoradiological profile and serum lipid levels of intracerebral hemorrhage in prior statin users

OBJECTIVE

We aimed to evaluate whether serum lipid levels can influence the clinicoradiological recovery of intracerebral hemorrhage (ICH) in prior statin users.

PATIENTS AND METHODS

Medical records were reviewed retrospectively in 381 ICH patients (253 men and 128 women). Cardiovascular disease (CVD) risk factors, blood pressure at admission and the first in-hospital day, admission and 30-day scores of National Institute Health Stroke Scale (NIHSS) and modified Rankin scale (mRS), hematoma volume (HV), serum lipid levels were compared between prior statin users and non-users.

RESULTS

Statins were pretreated in 56 patients (31 men and 25 women). Statin users were older age, and had higher frequencies of dyslipidemia, diabetes mellitus, atrial fibrillation, prior stroke history and large HV compared to non-users. Serum levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were significantly decreased in the statin group compared to the non-statin group. There were no statistical differences in the other CVD risk factors, functional scores and other serum lipid levels between the two groups. HV was correlated inversely with serum levels of TC and LDL-C in both groups. Multiple logistic regression analysis showed that serum TC levels ≤150 mg/dL were associated with statin use [Odds ratio (OR)=5.5, 95% confidence interval (CI)=1.55-19.58], worsening of NIHSS score (OR=1.4, 95% CI=1.21-1.63) and HV (OR=1.1, 95% CI=1.07-1.13) in ICH patients. A significant association was found between worsening of NIHSS score (OR=2.0, 95% CI=1.32-3.12) and worsening of mRS score (OR=3.3, 95% CI=1.33-8.00), HV (OR=1.3, 95% CI=1.01-1.76), and serum TC levels ≤150 mg/dL in statin users.

CONCLUSION

Prior statin users with serum TC levels ≤150 mg/dL had worsening of outcome and HV. Excessive lowering of serum TC levels due to statin pretreatment may cause unfavorable clinicoradiological recovery of ICH. Physicians should monitor serum lipid levels carefully in statin users.

Effect of a free radical scavenger, edaravone, on free radical reactions: related signal transduction and cerebral vasospasm in the rabbit subarachnoid hemorrhage model

OBJECTIVE

it is hypothesized that free radical reactions evoked by oxyhemoglobin (oxyHb) cause cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH), even though the detailed mechanisms have not yet been fully established. The aims of this study were thus to investigate, through the use of the double-hemorrhage rabbit model, the possibility that free radical reactions play a role in cerebral vasospasm and to delineate the mechanism of signal transduction that causes cerebral vasospasm.

METHODS

in the SAH group, SAH was simulated using the double-hemorrhage rabbit model. In the treatment group, edaravone (0.6 mg/kg), a potent free radical scavenger, was injected into the central ear vein twice a day. Four days after SAH, the basilar artery was excised. The degree of cerebral vasospasm was evaluated by measuring the diameter of each basilar artery, and the expression of Rho-kinase in the vascular wall was examined by western blotting.

RESULTS

the diameter of the basilar artery in the edaravone-treated group was 0.64 ± 0.06 mm, which was statistically significantly larger than that in the nontreated SAH group (0.50 ± 0.03 mm; p < 0.01). The expression of Rho-kinase in the edaravone-treated group was statistically significantly reduced in comparison to that of the nontreated SAH group.

CONCLUSION

results from this study have indicated for the first time that free radical reactions mediated by oxyHb may play an important role in the pathogenesis of cerebral vasospasm through the expression of Rho-kinase.

Advances in experimental subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) remains to be a devastating disease with high mortality and morbidity. Two major areas are becoming the focus of the research interest of SAH: these are cerebral vasospasm (CVS) and early brain injury (EBI). This mini review will provide a broad summary of the major advances in experimental SAH during the last 3 years. Treatments interfering with nitric oxide (NO)- or endothelin-pathways continue to show antispasmotic effects in experimental SAH. HIF 1 may play both a detrimental and beneficial role in the setting of SAH, depending on its activation stage. Inflammation and oxidative stress contribute to the pathophysiology of both CVS and EBI. Apoptosis, a major component of EBI after SAH, also underlie the etiology of CVS. Since we recognize now that CVS and EBI are the two major contributors to the significant mortality and morbidity associated with SAH, ongoing research will continue to elucidate the underlying pathophysiological pathways and treatment strategies targeting both CVS and EBI may be more successful and improve outcome of patients with SAH.

Uncoupling of endothelial nitric oxide synthase after experimental subarachnoid hemorrhage

We studied whether endothelial nitric oxide synthase (eNOS) is upregulated and uncoupled in large cerebral arteries after subarachnoid hemorrhage (SAH) and also whether this causes cerebral vasospasm in a mouse model of anterior circulation SAH. Control animals underwent injection of saline instead of blood (n=16 SAH and n=16 controls). There was significant vasospasm of the middle cerebral artery 2 days after SAH (lumen radius/wall thickness ratio 4.3 ± 1.3 for SAH, 23.2 ± 2.1 for saline, P<0.001). Subarachnoid hemorrhage was associated with terminal deoxynucleotidyl transferase dUTP nick-end labeling, cleaved caspase-3, and Fluoro-Jade-positive neurons in the cortex and with CA1 and dentate regions in the hippocampus. There were multiple fibrinogen-positive microthromboemboli in the cortex and hippocampus after SAH. Transgenic mice expressing lacZ under control of the eNOS promoter had increased X-gal staining in large arteries after SAH, and this was confirmed by the increased eNOS protein on western blotting. Evidence that eNOS was uncoupled was found in that nitric oxide availability was decreased, and superoxide and peroxynitrite concentrations were increased in the brains of mice with SAH. This study suggests that artery constriction by SAH upregulates eNOS but that it is uncoupled and produces peroxynitrite that may generate microemboli that travel distally and contribute to brain injury.

Metamorphosis of subarachnoid hemorrhage research: from delayed vasospasm to early brain injury

Delayed vasospasm that develops 3–7 days after aneurysmal subarachnoid hemorrhage (SAH) has traditionally been considered the most important determinant of delayed ischemic injury and poor outcome. Consequently, most therapies against delayed ischemic injury are directed towards reducing the incidence of vasospasm. The clinical trials based on this strategy, however, have so far claimed limited success; the incidence of vasospasm is reduced without reduction in delayed ischemic injury or improvement in the long-term outcome. This fact has shifted research interest to the early brain injury (first 72 h) evoked by SAH. In recent years, several pathological mechanisms that activate within minutes after the initial bleed and lead to early brain injury are identified. In addition, it is found that many of these mechanisms evolve with time and participate in the pathogenesis of delayed ischemic injury and poor outcome. Therefore, a therapy or therapies focused on these early mechanisms may not only prevent the early brain injury but may also help reduce the intensity of later developing neurological complications. This manuscript reviews the pathological mechanisms of early brain injury after SAH and summarizes the status of current therapies.

Current and future treatment considerations in the management of aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a type of hemorrhagic stroke that can cause significant morbidity and mortality. Although guidelines have been published to help direct the care of these patients, there is insufficient quality literature regarding the medical and pharmacological management of patients with aSAH. Treatment is divided into 3 categories: supportive therapy, prevention of complications, and treatment of complications. There are numerous pharmacological therapies that are targeted at prevention and treatment of the neurological and medical complications that may arise. Rebleeding, hydrocephalus, cerebral vasospasm, and seizures are the most common neurological complications while the most common medical complications include hyponatremia, pulmonary edema, cardiac arrhythmias, neurogenic stunned myocardium, fever, anemia, infection, hyperglycemia, and venous thromboembolism. Risk factors, clinical presentation, diagnosis, pathophysiology, as well as initial management, prevention, and treatment of complications will be the focus of this discussion.

Atorvastatin preconditioning attenuates the production of endothelin-1 and prevents experimental vasospasm in rats

OBJECTIVE

Induced endothelin-1 (ET-1) production and decreased nitric oxide synthase (NOS) bioavailability have been found in aneurysmal subarachnoid hemorrhage (SAH). Atorvastatin is recognized to have pleiotropic effects including increasing NOS bioavailability as well as reducing inflammation and oxidative damage other than reducing dyslipidemia. This study is of interest to examine the effect of atorvastatin on ET-1/endothelial nitric oxide synthase (eNOS) in experimental SAH.

METHODS

A rodent double-hemorrhage SAH model was employed. Animals were randomly assigned as sham-operated, SAH, vehicle plus SAH, 5 mg/day atorvastatin treatment plus SAH and 5 mg/day atorvastatin precondition plus SAH groups. Administration with atorvastatin (5 mg/day) was initiated 1 week before (precondition) and 24 hr later (treatment). Cerebrospinal fluid samples were collected at 72 hr after second SAH. ET-1 (ELISA) was measured. The basilar arteries (BAs) were harvested and sliced, and their cross-sectional areas were measured. Radiolabeled NOS assay kit was used to detect eNOS.

RESULTS

Morphologically, convoluted internal elastic lamina, distorted endothelial cells and myonecrosis of the smooth muscle were predominantly observed in the BA of SAH and vehicle-treated SAH groups, which was not detected in the atorvastatin-preconditioned SAH group or the healthy controls. Significant vasospasm was noted in the vehicle group (lumen potency 64.5%, compared with the sham group, p </= 0.01) and less prominent in the atorvastatin treatment group (lumen potency, 76.6%, p < 0.05). In addition, increased ET-1 levels were found in all the animals subject to SAH (SAH only, SAH plus vehicle and SAH plus atorvastatin reversal) except in the atorvastatin precognition group when compared with the healthy controls (no SAH). Likewise, the levels of expressed NOS in BAs is induced in the atorvastatin groups (both atorvastatin treatment and precondition) when compared with that in the SAH group (p < 0.01).

CONCLUSION

This study offers first evidence that atorvastatin in the preconditioning status reduces the level of ET-1, which corresponds to its antivasospastic effect in the condition of chronic vasospasm. Although there is increased expression of NOS in both atorvastatin precondition and reversal groups, BA's lumen potency is significantly increased in the atorvastatin precondition group when compared with the SAH group (p < 0.01).

[Effect of the administration of statins in non-cardiac critical disease]

Administration of statins has been shown to be effective in reducing cardiovascular mortality. Their benefit could expand towards other areas of intensive medicine, it being possible to decrease mortality of the critically ill patient. There are several studies, although without a high level of evidence, that have detected a possible benefit when they are administered as well as clinical deterioration when they are discontinued, compared to those patients who had previously taken them. Even though most of the patients who had previously taken statins did so as primary or secondary prevention, thus having greater comorbidity, overall, a decrease is detected in the mortality of these subgroups. This benefit could be generalized to all the critical conditions, although studies with a higher level of evidence are needed for their adequate comparison.

Statins in traumatic brain injury

Traumatic brain injury (TBI) is a common cause of long-term neurological morbidity, with devastating personal and societal consequences. At present, no pharmacological intervention clearly improves outcomes, and therefore a compelling unmet clinical need remains. 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, or "statins," offer a potential novel therapeutic strategy for TBI. Statins are well tolerated, easy to administer, and have a long clinical track record in critically ill patients. Their side effects are well defined and easily monitored. Preclinical studies have shown significant benefit of statins in models of TBI and related disease processes, including cerebral ischemia, intracerebral hemorrhage, and subarachnoid hemorrhage. In fact, multiple mechanisms have been defined by which statins may exert benefit after acute brain injury. Statins are currently positioned to be translated into clinical trials in acute brain injury and have the potential to improve outcomes after TBI.

Simvastatin activates Akt/glycogen synthase kinase-3beta signal and inhibits caspase-3 activation after experimental subarachnoid hemorrhage

This study was designed to explore the role of simvastatin and its effects on the Akt/GSK3beta survival signal and apoptosis pathway after experimental subarachnoid hemorrhage (SAH). SAH was induced by blood injection into the cisterna magna in New Zealand white rabbits. Increased expression of phospho-Akt and phospho-GSK3beta was observed in brain tissue after SAH. Apoptosis and related proteins, including P53, apoptosis-inducing factor (AIF), cytochrome C, and cleaved caspase-3, were also activated. Simvastatin, at both low dose (10 mg/kg) and high dose (40 mg/kg), further increased expression of phospho-Akt and phospho-GSK3beta, decreased activation of caspase-3, and inhibited apoptosis. Preserved blood-brain barrier and attenuated brain edema were observed following simvastatin treatment. In addition, the neuroprotective effects of simvastatin were blocked by wortmannin (2.5 microg/kg/min), an irreversible PIK3 inhibitor. P53, AIF, and cytochrome C were not affected by simvastatin treatment. Findings from the present study suggest that simvastatin ameliorates acute brain injury after SAH. The potential mechanisms of action include activation of the Akt/GSK3beta survival signal and inhibition of caspase-dependent apoptosis pathway.

Statins and ischemic stroke severity: cytoprotection

Cytoprotective or neuroprotective interventions would be of value if they could block the processes leading to delayed neuronal death or if they could delay the period between the onset of ischemia and irreversible necrotic injury, thereby lengthening the period for effective reperfusion therapy. Experimental studies in cell culture systems and laboratory animals show that statins have several potential cytoprotective actions, including promotion of angiogenesis, reduction of clot formation and facilitation of clot lysis, upregulation of endothelial nitric oxide synthase, downregulation of inducible nitric oxide synthase, reduction of excitotoxicity, and modulation of the inflammatory response. Clinically, statins appear to protect against vasospasm-related ischemic injury after subarachnoid hemorrhage. There have been no prospective randomized trials aimed at determining whether statins reduce acute stroke severity, and observational studies have had inconsistent results. Although a prospective, randomized trial assessing the effect of pre- or poststroke statin treatment on initial stroke severity would be the most appropriate study design to test for this type of effect, it is unlikely that such a trial will be conducted given the benefits of these drugs in reducing the risk of cardiovascular events and stroke in high-risk populations.

Factors associated with the development of anemia after subarachnoid hemorrhage

INTRODUCTION

Anemia is common after subarachnoid hemorrhage (SAH) and may exacerbate the reduction in oxygen delivery that underlies delayed cerebral ischemia. Fall in hemoglobin may relate to blood loss as well as inflammatory suppression of erythropoiesis. Identifying factors associated with anemia may facilitate targeted interventions, such as the use of erythropoiesis-stimulating agents, which could minimize the burden of anemia and reduce red blood cell (RBC) transfusion requirements.

METHODS

We analyzed a cohort of patients with spontaneous SAH admitted over a 3-year period who survived at least 4 days. All patients had daily hematocrit values drawn while in the ICU. Multivariate regression was performed to determine baseline and early post-admission variables associated with development of anemia (defined as hematocrit < 30%).

RESULTS

Anemia developed in 47% of 243 patients with SAH after a mean of 3.5 days (median 2 days). Admission variables independently associated with anemia were female gender (OR 3.7, 95% CI 1.8-7.6), baseline hematocrit < 36% (OR 3.9, 1.5-10.1 compared to 36-45%), history of hypertension (OR 2.1, 1.05-4.2), and poor clinical grade (OR 5.9, 2.3-15.0). Surgical aneurysm treatment (OR 13.5, 6.0-30.3) and greater admission SIRS score (OR 5.7, 1.7-19.2 if 3-4 criteria for systemic inflammatory response syndrome were met on day of admission compared to none) were also associated with fall in hematocrit.

CONCLUSIONS

It may be possible to predict those most likely to develop anemia using simple baseline clinical variables. Anemia was strongly related to surgery, likely through greater blood loss, and greater systemic inflammatory response on admission, possibly explained by cytokine-mediated inhibition of RBC production.

Prior use of statins and outcome in patients with intracerebral haemorrhage

BACKGROUND

Pre-treatment with cholesterol lowering drugs of the statin family may exert protective effects in patients with ischaemic stroke and subarachnoid haemorrhage but their effects are not clear in patients with intracerebral haemorrhage (ICH).

METHODS

We recruited patients admitted to our University Hospital with an acute ICH and analysed pre-admission demographic variables, pre-morbid therapy, clinical and radiological prognostic markers and outcome variables including 90-day modified Rankin score and NIH stroke scale score (NIHSS).

RESULTS

We recruited 399 patients with ICH of which 101 (25%) were using statins. Statin users more often had vascular risk factors, had significantly lower haematoma volumes (P = 0.04) and had lower mortality rates compared with non-users (45.6% vs. 56.1%; P = 0.11). However, statin treatment did not have a statistically significant impact on mortality or functional outcome on multiple logistic regression analysis.

CONCLUSIONS

Treatment with statins prior to ICH failed to show a significant impact on outcome in this analysis despite lower haematoma volumes.

Simvastatin for the prevention of symptomatic cerebral vasospasm following aneurysmal subarachnoid hemorrhage: a single-institution prospective cohort study

OBJECT

Vasospasm is the major cause of disability and death after aneurysmal subarachnoid hemorrhage (aSAH). Although the results of 2 randomized clinical trials demonstrated that statin decreases the incidence of symptomatic cerebral vasospasm after aSAH, retrospective studies have failed to confirm this. The authors conducted a prospective observational study to determine whether a standardized regimen of simvastatin would reduce the incidence of cerebral vasospasm and improve neurological outcomes in patients with aSAH.

METHODS

Since 1991, all patients with aSAH admitted to the authors' institution have been prospectively followed up with standardized outcomes recording. Starting in September 2005, all patients admitted with aSAH were given enteral simvastatin (80 mg/day for 14 days) in addition to the standard care. The incidence of symptomatic cerebral vasospasm, length of hospitalization, in-hospital mortality rate, and discharge Glasgow Outcome Scale scores in these 170 patients were compared to data obtained in 170 consecutive patients who underwent treatment in our unit prior to the introduction of statin therapy.

RESULTS

The 5-year study period included 340 consecutively treated patients (170 who received statins and 170 who did not). Patients who received simvastatin therapy were more frequently male (29 vs 20%) and had a smaller median aneurysm diameter (6 vs 7 mm). Baseline characteristics were otherwise similar between the cohorts. There were no differences in the incidence of symptomatic vasospasm (25.3 vs 30.5%; p = 0.277), in-hospital mortality rate (18 vs 15%; p = 0.468), length of hospitalization (21 +/- 15 vs 19 +/- 12 days; p = 0.281), or poor outcome at discharge (Glasgow Outcome Scale Scores 1-2: 21.7 vs 18.2%; p = 0.416) between the simvastatin and nonstatin cohorts. There were no statin-related complications.

CONCLUSIONS

The uniform introduction of simvastatin did not reduce the incidence of symptomatic cerebral vasospasm, death, or poor outcome in patients with aSAH. Simvastatin was well tolerated, but its benefit may be less than has been previously reported.

Withdrawal of statins and risk of subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Vascular endothelium, which can be affected by statins, is believed to play a substantial role in subarachnoid hemorrhage (SAH). Our objective was to estimate the association between use and withdrawal of statins and the risk of SAH.

METHODS

We conducted a population-based case-control study within the PHARMO database. A case was defined as a person hospitalized for SAH (ICD-9-CM code 430) in the period January 1, 1998 to December 31, 2006. Ten randomly chosen controls were matched to each case on age, gender, and calendar date.

RESULTS

During the study period 1004 incident cases of SAH were identified. Current use of statins did not significantly decrease the risk of SAH (OR=0.77, 95% CI 0.55 to 1.07). The odds ratio for recent withdrawal compared to nonusers was 1.62 (95% CI 0.96 to 2.73). Compared to current use, recent withdrawal was associated with an increased risk of SAH (OR=2.34, 95% CI 1.35 to 4.05). Interaction analysis showed that the effect of statin withdrawal was highest in patients who had also recently stopped antihypertensive drugs (OR=6.77, 95% CI 2.10 to 21.8).

CONCLUSIONS

Current use of statins seems to lower the risk of SAH, although the reduction was not significant in new users. Statin withdrawal increased the risk of SAH by a factor 2, even more in patients who had also recently stopped their antihypertensive treatment.

Simvastatin attenuates cerebral vasospasm and improves outcomes by upregulation of PI3K/Akt pathway in a rat model of subarachnoid hemorrhage

BACKGROUND

Cerebral vasospasm is a common sequelae of subarachonoid hemorrhage (SAH), however, the mechanism of cerebral vasospasm is still unclear. Recently, statins have been shown to have efficacy in ameliorating cerebral vasospasm. The present study investigates whether simvastatin attenuates cerebral vasospasm after subarachnoid hemorrhage (SAH) via upregulation of the PI3K/Akt pathway.

METHODS

47 adult male Sprague-Dawley rats were divided into 6 groups: sham-operated, SAH treated with vehicle, SAH treated with low dose simvastatin (1 mg/kg), high dose simvastatin (20 mg/kg), SAH treated with simvastatin plus the PI3K inhibitor (wortmannin), and sham-operated plus wortmannin. Simvastatin was administered intraperitoneally 30 minutes after SAH created by the standard endovascular perforation model. Histological parameters of the ipsilateral internal carotid artery (ICA-diameter, perimeter, and wall thickness) and neurological score were assessed at 24 hours.

FINDINGS

Mortality was reduced to zero in both the treated groups as compared to 20% in the vehicle-treated and 36% in the simvastatin plus wortmannin-treated groups. The decrease in ICA diameter and perimeter observed in vehicle-treated group (203.2 +/- 10.3 microm, 652.7 +/- 29.0 microm) as compared to sham (259.7 +/- 10.6, 865.4 +/- 39.5) were significantly attenuated by high-dose simvastatin (267.4 +/- 8.0, 882.4 +/- 30.0). The increase in wall thickness (vehicle 29.50 +/- 2.42 microm v/s sham 9.52 +/- 0.56 microm) was significantly attenuated by both high and low dose simvastatin (11.87 +/- 1.56, 19.75 +/- 1.40). These effects of simvastatin were blocked with the addition of wortmannin (162.7 +/- 20.6, 528.9 +/- 65.9, 29.19 +/- 1.97). High dose simvastatin improved the neurological deficits after SAH, but this was also blocked by wortmannin.

CONCLUSIONS

The beneficial effects of high dose simvastatin in ameliorating cerebral vasospasm are likely mediated by upregulation of the PI3K/Akt pathway.

Cerebral vasospasm following subarachnoid hemorrhage: time for a new world of thought

OBJECTIVE

Delayed cerebral vasospasm has long been recognized as an important cause of poor outcome after an otherwise successful treatment of a ruptured intracranial aneurysm, but it remains a pathophysiological enigma despite intensive research for more than half a century.

METHOD

Summarized in this review are highlights of research from North America, Europe and Asia reflecting recent advances in the understanding of delayed ischemic deficit.

RESULT

It will focus on current accepted mechanisms and on new frontiers in vasospasm research.

CONCLUSION

A key issue is the recognition of events other than arterial narrowing such as early brain injury and cortical spreading depression and of their contribution to overall mortality and morbidity.

Simvastatin attenuation of cerebral vasospasm after subarachnoid hemorrhage in rats via increased phosphorylation of Akt and endothelial nitric oxide synthase

The mechanisms involved in simvastatin-mediated attenuation of cerebral vasospasm after subarachnoid hemorrhage (SAH) are unclear. We investigated the role of the phosphatidylinositol 3-kinase/Akt (PI3K/Akt) pathway and endothelial nitric oxide synthase (eNOS) in the cerebral vasculature in statin-mediated attenuation of cerebral vasospasm using wortmannin, an irreversible pharmacological PI3K inhibitor, and a rat SAH endovascular perforation model. Simvastatin was administered intraperitoneally in two dosages (1 mg/kg and 20 mg/kg) at 0.5, 24, and 48 hr after SAH and histological parameters of ipsilateral intracranial carotid artery (ICA) were assessed at 24 and 72 hr. SAH significantly decreased ICA diameter and perimeter while increasing wall thickness at both 24 and 72 hr. High-dosage simvastatin prevented the reduction of ICA diameter and perimeter following SAH, whereas both high and low dosages reduced wall thickness significantly at 24 and 72 hr. The effects of simvastatin were significantly reversed by wortmannin. High-dosage simvastatin increased pAkt and peNOS (phosphorylated forms) levels without increasing Akt and eNOS expression compared with the SAH group and also improved neurological deficits at 24 and 72 hr. Simvastatin did not affect protein levels by itself compared with untreated sham group. The present study elucidates the critical role of the PI3K activation leading to phosphorylation of Akt and eNOS in simvastatin-mediated attenuation of cerebral vasospasm after SAH.

The burden of the systemic inflammatory response predicts vasospasm and outcome after subarachnoid hemorrhage

INTRODUCTION

Subarachnoid hemorrhage (SAH) can trigger immune activation sufficient to induce the systemic inflammatory response syndrome (SIRS). This may promote both extra-cerebral organ dysfunction and delayed cerebral ischemia, contributing to worse outcome. We ascertained the frequency and predictors of SIRS after spontaneous SAH, and determined whether degree of early systemic inflammation predicted the occurrence of vasospasm and clinical outcome.

METHODS

Retrospective analysis of prospectively collected data on 276 consecutive patients admitted to a neurosciences intensive care unit with acute, non-traumatic SAH between 2002 and 2005. A daily SIRS score was derived by summing the number of variables meeting standard criteria (HR >90, RR >20, Temperature >38 degrees C, or <36 degrees C, WBC count <4,000 or >12,000). SIRS was considered present if two or more criteria were met, while SIRS burden over the first four days was calculated by averaging daily scores. Regression modeling was used to determine the relationship among SIRS burden (after controlling for confounders including infection, surgery, and corticosteroid use), symptomatic vasospasm, and outcome, determined by hospital disposition.

RESULTS

SIRS was present in over half the patients on admission and developed in 85% within the first four days. Factors associated with SIRS included poor clinical grade, thick cisternal blood, larger aneurysm size, higher admission blood pressure, and surgery for aneurysm clipping. Higher SIRS burden was independently associated with death or discharge to nursing home (OR 2.20/point, 95% CI 1.27-3.81). All of those developing clinical vasospasm had evidence of SIRS, with greater SIRS burden predicting increased risk for delayed ischemic neurological deficits (OR 1.77/point, 95% CI 1.12-2.80).

CONCLUSIONS

Systemic inflammatory activation is common after SAH even in the absence of infection; it is more frequent in those with more severe hemorrhage and in those who undergo surgical clipping. Higher burden of SIRS in the initial four days independently predicts symptomatic vasospasm and is associated with worse outcome.

Do Statins Improve Outcomes and Reduce the Incidence of Vasospasm After Aneurysmal Subarachnoid Hemorrhage

Background and Purpose— Subarachnoid hemorrhage (SAH) is a relatively rare cause of stroke with a high rate of morbidity and mortality, primarily due to the occurrence of delayed vasospasm. To date, many therapies have been proposed to help prevent vasospasm, but very few have been proven effective. The initiation of statin therapy after SAH may be effective in reducing the incidence of vasospasm; however, the only studies that have examined this effect have been small. This meta-analysis attempted to determine whether statins reduce morbidity and mortality after aneurysmal SAH.

Methods— MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were searched for randomized, controlled trials relating to the use of statins in SAH. Foreign language and abstract articles were included. Two independent reviewers assessed studies for eligibility, data extraction, and quality. Primary outcome was the incidence of radiographically confirmed clinical vasospasm; secondary outcomes were incidence of delayed ischemic deficits and mortality.

Results— The incidence of vasospasm (relative risk [RR]=0.73; 95% CI, 0.54 to 0.99), delayed ischemic deficits (RR=0.38; 95% CI, 0.17 to 0.83), and mortality (RR=0.22; 95% CI, 0.06 to 0.82) were significantly reduced in the statin group. For these outcomes, we calculated a number needed to treat of 6.25, 5, and 6.7, respectively.

Conclusions— Initiation of statin therapy after aneurysmal SAH significantly reduces the incidence of vasospasm, delayed ischemic deficits, and mortality. This is consistent with animal research and retrospective studies and supports the routine use of statins in the care of patients with aneurysmal SAH.

STATIN USE WAS NOT ASSOCIATED WITH LESS VASOSPASM OR IMPROVED OUTCOME AFTER SUBARACHNOID HEMORRHAGE

OBJECTIVE

The development of delayed ischemia caused by cerebral vasospasm remains a common cause of morbidity and mortality after aneurysmal subarachnoid hemorrhage. Preliminary studies suggest that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) may decrease the risk of vasospasm, but additional study is required.

METHODS

Beginning in May 2006, our treatment protocol for patients presenting with subarachnoid hemorrhage was altered to routinely include the use of 80 mg of simvastatin per day for 14 days. Before this time, only patients with other indications for statins were treated. The charts of 203 consecutive patients over a period of 27 months were retrospectively reviewed, and 150 patients were included in the analysis, of whom 71 patients received statins. These patients were compared with 79 untreated patients to determine whether or not the use of statins was associated with a reduction in the occurrence of vasospasm, delayed infarction, or poor outcome (death, vegetative state, or severe disability).

RESULTS

Patients who were treated with statins and those who were not had similar baseline characteristics, although more patients in the former group were managed with endovascular coil embolization. There were no statistically significant differences in the proportion of patients developing at least moderate radiographic vasospasm (41% with statins versus 42% without, P = 0.91), symptomatic vasospasm (32% with statins versus 25% without, P = 0.34), delayed infarction (23% with statins versus 28% without, P = 0.46), or poor outcome (39% with statins versus 35% without, P = 0.61). After adjustment for differences in baseline characteristics, including the method of aneurysm treatment, statins were still not significantly protective.

CONCLUSION

The addition of statins to standard care was not associated with any reduction in the development of vasospasm or improvement in outcomes after aneurysmal subarachnoid hemorrhage. If there is a benefit to statin use, it may be smaller than suggested by previous studies. However, further randomized controlled trials are awaited.

Biological effects of acute pravastatin treatment in patients after aneurysmal subarachnoid hemorrhage: a double-blind, placebo-controlled trial

OBJECT

The authors previously demonstrated that acute pravastatin therapy in patients after aneurysmal subarachnoid hemorrhage (SAH) ameliorates vasospasm-related delayed ischemic neurological deficits. The object of this study was to continue to examine potential mechanisms of these beneficial effects.

METHODS

Eighty patients with aneurysmal SAH (age range 18-84 years; time to onset 1.8 +/- 1.3 days) were enrolled in a double-blind study and randomized to receive 40 mg of oral pravastatin or placebo daily for as long as 14 days. Daily transcranial Doppler ultrasonography and blood tests every 3 days (including full blood cell counts, coagulation profiles, fasting glucose and lipid profiles, and serum biochemistry) were performed during the trial period.

RESULTS

No significant differences were found in baseline laboratory data between the trial groups. Subsequent measurements during the 14-day trial showed reduced low-density lipoprotein (LDL) cholesterol levels and total/high-density lipoprotein cholesterol ratios between Days 3 and 15 (p < 0.05), and increased D-dimer levels (p < 0.05) on Day 6, in the pravastatin group. Patients who received pravastatin but developed vasospasm had significantly lower baseline LDL cholesterol levels or a less extensive reduction in LDL cholesterol levels (p < 0.05), and greater increases in plasma fibrinogen (p = 0.009) and serum C-reactive protein on Day 3 (p = 0.007), compared with those patients without vasospasm. The reduction in LDL cholesterol levels on Day 3 in the placebo group correlated with the duration of normal cerebral autoregulation on the ipsilateral side of the ruptured aneurysm (p = 0.002).

CONCLUSIONS

In addition to functioning through a cholesterol-independent pathway, cerebrovascular protection from acute statin therapy following aneurysmal SAH may also function through cholesterol-dependent mechanisms.