A review of current and future medical therapies for cerebral vasospasm following aneurysmal subarachnoid hemorrhage

Effect of Cilostazol on Delayed Cerebral Infarction in Aneurysmal Subarachnoid Hemorrhage Using Explainable Predictive Modeling

The studies interpreting DCI, a complication of SAH, and identifying correlations are very limited. This study aimed to investigate the effect of cilostazol on ACV and DCI after coil embolization for ruptured aneurysms (n = 432). A multivariate analysis was performed and explainable artificial intelligence approaches were used to analyze the contribution of cilostazol as a risk factor on the development of ACV and DCI with respect to global and local interpretation. The cilonimo group was significantly lower than the nimo group in ACV (13.5% vs. 29.3; p = 0.003) and DCI (7.9% vs. 20.7%; p = 0.006), respectively. In a multivariate logistic regression, the odds ratio for DCI for the cilonimo group, female sex, and aneurysm size was 0.556 (95% confidence interval (CI), 0.351-0.879; p = 0.012), 3.713 (95% CI, 1.683-8.191; p = 0.001), and 1.106 (95% CI, 1.008-1.214; p = 0.034). The risk of a DCI occurrence was significantly increased with an aneurysm size greater than 10 mm (max 80%). The mean AUC of the XGBoost and logistic regression models was 0.94 ± 0.03 and 0.95 ± 0.04, respectively. Cilostazol treatment combined with nimodipine could decrease the prevalence of ACV (13.5%) and DCI (7.9%) in patients with aSAH.

Aneurysmal subarachnoid haemorrhage-cerebral vasospasm and prophylactic ibuprofen: a randomised controlled pilot trial protocol

INTRODUCTION

Cerebral vasospasm (CVS) is the leading cause of mortality and morbidity following aneurysmal subarachnoid haemorrhage (aSAH). One of the recently implicated underlying mechanisms of CVS is inflammatory cascades. Specific feasibility objectives include determining the ability to recruit 30 participants over 24 months while at least 75% of them comply with at least 75% of the study protocol and being able to follow 85% of them for 3 months after discharge.

METHODS AND ANALYSIS

This is a feasibility study for a randomised controlled trial. Eligible participants are adult patients who are 18 years of age and older with an aSAH confirmed by a brain CT scan, and CT angiography, or magnetic resonance angiography, or digital subtraction angiography who admitted to the emergency department within 12 hours of the ictus. Eligible subjects will be randomised 1:1 for the administration of either ibuprofen or a placebo, while both groups will concomitantly be treated by the standard of care for 2 weeks. Care givers, patients, outcome assessors and data analysts will be blinded. This will be the first study to investigate the preventive effects of a short-acting non-steroidal anti-inflammatory drug on CVS and the key expected outcome of this pilot study is the feasibility and safety assessment of the administration of ibuprofen in patients with aSAH. The objectives of the definitive trial would be to assess the effect of ibuprofen relative to placebo on mortality, CVS, delayed cerebral ischaemia, and level of disability at 3-month follow-up.

ETHICS AND DISSEMINATION

This study is approved by Mashhad University of Medical Sciences ethical committee (IR.MUMS.MEDICAL.REC.1398.225). Results from the study will be submitted for publication regardless of whether or not there are significant findings.

TRIAL REGISTRATION NUMBER

ISRCTN14611625.

Nitric Oxide-Based Treatment of Poor-Grade Patients After Severe Aneurysmal Subarachnoid Hemorrhage

Background

Patients with aneurysmal subarachnoid hemorrhage (aSAH) require close treatment in neuro intensive care units (NICUs). The treatments available to counteract secondary deterioration and delayed ischemic events remain restricted; moreover, available neuro-monitoring of comatose patients is undependable. In comatose patients, clinical signs are hidden, and timing interventions to prevent the evolution of a perfusion disorder in response to fixed ischemic brain damage remain a challenge for NICU teams. Consequently, comatose patients often suffer secondary brain infarctions. The outcomes for long-term intubated patients w/wo pupil dilatation are the worst, with only 10% surviving. We previously added two nitroxide (NO) donors to the standard treatment: continuous intravenous administration of Molsidomine in patients with mild-to-moderate aSAH and, if required as a supplement, intraventricular boluses of sodium nitroprusside (SNP) in high-risk patients to overcome the so-called NO-sink effect, which leads to vasospasm and perfusion disorders. NO boluses were guided by clinical status and promptly reversed recurrent episodes of delayed ischemic neurological deficit. In this study, we tried to translate this concept, the initiation of intraventricular NO application on top of continuous Molsidomine infusion, from awake to comatose patients who lack neurological–clinical monitoring but are primarily monitored using frequently applied transcranial Doppler (TCD).

Methods

In this observational, retrospective, nonrandomized feasibility study, 18 consecutive aSAH comatose/intubated patients (Hunt and Hess IV/V with/without pupil dilatation) whose poor clinical status precluded clinical monitoring received standard neuro-intensive care, frequent TCD monitoring, continuous intravenous Molsidomine plus intraventricular SNP boluses after TCD-confirmed macrospasm during the daytime and on a fixed nighttime schedule.

Results

Very likely associated with the application of SNP, which is a matter of further investigation, vasospasm-related TCD findings promptly and reliably reversed or substantially weakened (p < 0.0001) afterward. Delayed cerebral ischemia (DCI) occurred only during loose, low-dose or interrupted treatment (17% vs. an estimated 65% with secondary infarctions) in 17 responders. However, despite their worse initial condition, 29.4% of the responders survived (expected 10%) and four achieved Glasgow Outcome Scale Extended (GOSE) 8–6, modified Rankin Scale (mRS) 0–1 or National Institutes of Health Stroke Scale (NIHSS) 0–2.

Conclusions

Even in comatose/intubated patients, TCD-guided dual-compartment administration of NO donors probably could reverse macrospasm and seems to be feasible. The number of DCI was much lower than expected in this specific subgroup, indicating that this treatment possibly provides a positive impact on outcomes. A randomized trial should verify or falsify our results.

A Highly Predictive MicroRNA Panel for Determining Delayed Cerebral Vasospasm Risk Following Aneurysmal Subarachnoid Hemorrhage

Approximately one-third of aneurysmal subarachnoid hemorrhage (aSAH) patients develop delayed cerebral vasospasm (DCV) 3-10 days after aneurysm rupture resulting in additional, permanent neurologic disability. Currently, no validated biomarker is available to determine the risk of DCV in aSAH patients. MicroRNAs (miRNAs) have been implicated in virtually all human diseases, including aSAH, and are found in extracellular biofluids including plasma and cerebrospinal fluid (CSF). We used a custom designed TaqMan Low Density Array miRNA panel to examine the levels of 47 selected brain and vasculature injury related miRNAs in CSF and plasma specimens collected from 31 patients with or without DCV at 3 and 7 days after aSAH, as well as from eight healthy controls. The analysis of the first 18-patient cohort revealed a striking differential expression pattern of the selected miRNAs in CSF and plasma of aSAH patients with DCV from those without DCV. Importantly, this differential expression was observed at the early time point (3 days after aSAH), before DCV event occurs. Seven miRNAs were identified as reliable DCV risk predictors along with a prediction model constructed based on an array of additional 19 miRNAs on the panel. These chosen miRNAs were then used to predict the risk of DCV in a separate, testing cohort of 15 patients. The accuracy of DCV risk prediction in the testing cohort reached 87%. The study demonstrates that our novel designed miRNA panel is an effective predictor of DCV risk and has strong applications in clinical management of aSAH patients.

Therapeutically Targeting Platelet-Derived Growth Factor-Mediated Signaling Underlying the Pathogenesis of Subarachnoid Hemorrhage-Related Vasospasm

INTRODUCTION

Vasospasm accounts for a large fraction of the morbidity and mortality burden in patients sustaining subarachnoid hemorrhage (SAH). Platelet-derived growth factor (PDGF)-β levels rise following SAH and correlate with incidence and severity of vasospasm.

METHODS

The literature was reviewed for studies investigating the role of PDGF in the pathogenesis of SAH-related vasospasm and efficacy of pharmacological interventions targeting the PDGF pathway in ameliorating the same and improving clinical outcomes.

RESULTS

Release of blood under high pressure into the subarachnoid space activates the complement cascade, which results in release of PDGF. Abluminal contact of blood with cerebral vessels increases their contractile response to PDGF-β and thrombin, with the latter upregulating PDGF-β receptors and augmenting effects of PDGF-β. PDGF-β figures prominently in the early and late phases of post-SAH vasospasm. PDGF-β binding to the PDGF receptor-β results in receptor tyrosine kinase domain activation and consequent stimulation of intracellular signaling pathways, including p38 mitogen-activated protein kinase, phosphatidylinositol-3-kinase, Rho-associated protein kinase, and extracellular regulated kinase 1 and 2. Consequent increases in intracellular calcium and increased expression of genes mediating cellular growth and proliferation mediate PDGF-induced augmentation of vascular smooth muscle cell contractility, hypertrophy, and proliferation.

CONCLUSION

Treatments with statins, serine protease inhibitors, and small molecular pathway inhibitors have demonstrated varying degrees of efficacy in prevention of cerebral vasospasm, which is improved with earlier institution.

Delivery of xenon-containing echogenic liposomes inhibits early brain injury following subarachnoid hemorrhage

Xenon (Xe), a noble gas, has promising neuroprotective properties with no proven adverse side-effects. We evaluated neuroprotective effects of Xe delivered by Xe-containing echogenic liposomes (Xe-ELIP) via ultrasound-controlled cerebral drug release on early brain injury following subarachnoid hemorrhage (SAH). The Xe-ELIP structure was evaluated by ultrasound imaging, electron microscopy and gas chromatography-mass spectroscopy. Animals were randomly divided into five groups: Sham, SAH, SAH treated with Xe-ELIP, empty ELIP, or Xe-saturated saline. Treatments were administrated intravenously in combination with ultrasound application over the common carotid artery to trigger Xe release from circulating Xe-ELIP. Hematoma development was graded by SAH scaling and quantitated by a colorimetric method. Neurological evaluation and motor behavioral tests were conducted for three days following SAH injury. Ultrasound imaging and electron microscopy demonstrated that Xe-ELIP have a unique two-compartment structure, which allows a two-stage Xe release profile. Xe-ELIP treatment effectively reduced bleeding, improved general neurological function, and alleviated motor function damage in association with reduced apoptotic neuronal death and decreased mortality. Xe-ELIP alleviated early SAH brain injury by inhibiting neuronal death and bleeding. This novel approach provides a noninvasive strategy of therapeutic gas delivery for SAH treatment.

Preventive effect of continuous cisternal irrigation with magnesium sulfate solution on angiographic cerebral vasospasms associated with aneurysmal subarachnoid hemorrhages: a randomized controlled trial

OBJECT Although cerebral vasospasm (CV) is one of the most important predictors for the outcome in patients with subarachnoid hemorrhage (SAH), no treatment has yet been established for this condition. This study investigated the efficacy of continuous direct infusion of magnesium sulfate (MgSO4) solution into the intrathecal cistern in patients with an aneurysmal SAH. METHODS An SAH caused by a ruptured aneurysm was identified on CT scans within 72 hours after SAH onset. All patients were treated by surgical clipping and randomized into 2 groups: a control group of patients undergoing a standard treatment and a magnesium (Mg) group of patients additionally undergoing continuous infusion of 5 mmol/L MgSO4 solution for 14 days. The Mg(2+) concentrations in serum and CSF were recorded daily. Neurological examinations were performed by intensive care clinicians. Delayed cerebral ischemia was monitored by CT or MRI. To assess the effect of the Mg treatment on CV, the CVs were graded on the basis of the relative degree of constriction visible on cerebral angiograms taken on Day 10 after the SAH, and transcranial Doppler ultrasonography was performed daily to measure blood flow velocity in the middle cerebral artery (MCA). Neurological outcomes and mortality rates were evaluated with the Glasgow Outcome Scale and modified Rankin Scale at 3 months after SAH onset. RESULTS Seventy-three patients admitted during the period of April 2008 to March 2013 were eligible and enrolled in this study. Three patients were excluded because of violation of protocol requirements. The 2 groups did not significantly differ in age, sex, World Federation of Neurosurgical Societies grade, or Fisher grade. In the Mg group, the Mg(2+) concentration in CSF gradually increased from Day 4 after initiation of the continuous MgSO4 intrathecal administration. No such increase was observed in the control group. No significant changes in the serum Mg(2+) levels were observed for 14 days, and no cardiovascular complications such as bradycardia or hypotension were observed in any of the patients. However, bradypnea was noted among patients in the Mg group. The Mg group had a significantly better CV grade than the control group (p < 0.05). Compared with the patients in the Mg group, those in the control group had a significantly elevated blood flow velocity in the MCA. Both groups were similar in the incidences of cerebral infarction, and the 2 groups also did not significantly differ in clinical outcomes. CONCLUSIONS Continuous cisternal irrigation with MgSO4 solution starting on Day 4 and continuing to Day 14 significantly inhibited CV in patients with aneurysmal SAH without severe cardiovascular complications. However, this improvement in CV neither reduced the incidence of delayed cerebral ischemia nor improved the functional outcomes in patients with SAH.

Neuroprotective effect of hydrogen-rich saline against neurologic damage and apoptosis in early brain injury following subarachnoid hemorrhage: possible role of the Akt/GSK3β signaling pathway

Backgrounds

Early brain injury (EBI) plays a key role in the pathogenesis of subarachnoid hemorrhage (SAH). Neuronal apoptosis is involved in the pathological process of EBI. Hydrogen can inhibit neuronal apoptosis and attenuate EBI following SAH. However, the molecular mechanism underlying hydrogen-mediated anti-apoptotic effects in SAH has not been elucidated. In the present study, we aimed to evaluate whether hydrogen alleviates EBI after SAH, specifically neuronal apoptosis, partially via the Akt/GSK3β signaling pathway.

Methods

Sprague-Dawley rats (n = 85) were randomly divided into the following groups: sham group (n = 17), SAH group (n = 17), SAH + saline group (n = 17), SAH + hydrogen-rich saline (HS) group (n = 17) and SAH + HS + Ly294002 (n = 17) group. HS or an equal volume of physiological saline was administered immediately after surgery and repeated 8 hours later. The PI3K inhibitor, Ly294002, was applied to manipulate the proposed pathway. Neurological score and SAH grade were assessed at 24 hours after SAH. Western blot was used for the quantification of Akt, pAkt, GSK3β, pGSK3β, Bcl-2, Bax and cleaved caspase-3 proteins. Neuronal apoptosis was identified by double staining of terminal deoxynucleotidyl transferase mediated nick end labeling (TUNEL) staining and NeuN, and quantified by apoptosis index. Immunohistochemistry and immunofluorescent double-labeling staining was performed to clarify the relationships between neuronal apoptosis and pAkt or pGSK3β.

Results

HS significantly reduced neuronal apoptosis and improved neurological function at 24 hours after SAH. The levels of pAkt and pGSK3β, mainly expressed in neurons, were markedly up-regulated. Additionally, Bcl-2 was significantly increased while Bax and cleaved caspase-3 was decreased by HS treatment. Double staining of pAkt and TUNEL showed few colocalization of pAkt-positive cells and TUNEL-positive cells. The inhibitor of PI3K, Ly294002, suppressed the beneficial effects of HS.

Conclusions

HS could attenuate neuronal apoptosis in EBI and improve the neurofunctional outcome after SAH, partially via the Akt/GSK3β pathway.

Estradiol reduces ferrous citrate complex-induced NOS2 up-regulation in cerebral endothelial cells by interfering the nuclear factor kappa B transactivation through an estrogen receptor β-mediated pathway

Hemorrhagic stroke caused leakage of red blood cells which converts to hemoglobin, heme, and iron accumulated at the lesions. High concentration of ferrous iron from subarachnoid hemorrhage (SAH) induced cerebral vasospasm. Using the two-hemorrhage SAH model in rats, we previously demonstrated that estradiol (E2) significantly attenuated the SAH-induced vasospasm by inhibiting the NOS2 expression. Adding ferrous citrate (FC) complexes to the primary cultured mouse cerebral endothelial cells (CEC) to mimic the SAH conditions, we also showed that FC up-regulates NOS2 through nuclear translocation of NFκB induced by free radicals generation. Here, we further studied the molecular mechanism underlying E2-mediated reduction of the FC-induced up-regulation of NOS2. Treatment with E2 (100 nM) reduced the FC (100 µM)-induced increases of free radical generation and the levels of NOS2 mRNA and protein in the CEC. Moreover, E2 also prevented the FC-induced increases of IκBα phosphorylation, NFκB nuclear translocation, NFκB binding onto the NOS2 promoter, and the NOS2 promoter luciferase activity. However, knock-down the estrogen receptor β (ERβ), but not ERα, abolished the E2-mediated prevention on the FC-induced increases of NOS2 mRNA and protein. The data from the present study suggest that E2 inhibited NOS2 gene expression by interfering with NFκB nuclear translocation and NFκB binding onto the NOS2 through an ERβ-mediated pathway. Our results provide the molecular basis for designing the applicable therapeutic or preventive strategies in the treatment SAH patients.

Is the circulating plasma volume sufficiently maintained? Fluid management of an aneurysmal subarachnoid hemorrhage in the acute phase

Cerebral vasospasm is a well-known cause of mortality and morbidity following aneurysmal subarachnoid hemorrhage (SAH). Prevention of symptomatic cerebral vasospasm is the basic management after SAH. Numerous pharmaceutical therapies and endovascular treatments are available against cerebral vasospasm, but none of them have so far proven to improve the outcome. We have focused on maintaining the circulation volume in order to prevent cerebral vasospasm. But to maintain the central venous pressure, huge infusion volume was required, and hyponatremia was frequently observed due to natriuresis and osmotic diuresis. Excessive natriuresis and diuresis cannot be managed through sodium and water replacement, since sodium replacement induces further natriuresis and diuresis (desalination), and water replacement induces hyponatremia. We therefore administered fludrocortisone and hydrocortisone to inhibit excessive natriuresis and diuresis. The efficacy of sodium reabsorption therapy is extremely high to maintain the circulation volume that might have a therapeutic effect to prevent cerebral vasospasm. In this article, we review our institution's experience regarding the management of patients with aneurysmal SAH and also discuss the importance of water and sodium balance when managing such patients.

A randomized outcome study of enteral versus intravenous nimodipine in 171 patients after acute aneurysmal subarachnoid hemorrhage

BACKGROUND

Delayed ischemic neurologic deficit (DIND) is a serious complication of acute aneurysmal subarachnoid hemorrhage (aSAH). Although oral nimodipine is accepted as standard care for the prevention of DIND, the intravenous route is preferred by several centers. In the present study we compared the clinical efficacy between enteral and intravenous nimodipine after aSAH.

METHODS

A total of 171 aSAH patients were randomly assigned to either the enteral (84 patients) or the intravenous (87 patients) nimodipine group and were compared regarding the incidence of DIND, number of new ischemic lesions on 12-month brain magnetic resonance image, and clinical outcome 12 months after aSAH as assessed by Glasgow Outcome scale, modified Rankin scale, and Karnofsky scale. Health-related quality of life was also assessed by the 15D questionnaire 12 months after aSAH.

RESULTS

The incidence of DIND did not differ significantly between the groups (20% in the enteral versus 16% in the intravenous group, P=0.61), whereas no differences were observed, neither in the number of new ischemic lesions (34% in both groups, P=0.99), nor in the clinical outcome 12 months after aSAH (P=0.34 for Glasgow Outcome scale, P=0.74 for modified Rankin scale, and P=0.71 for Karnofsky scale). The mean 15D health-related quality of life sums were also similar in the 2 groups (P=0.43).

CONCLUSIONS

Our pilot study suggested no differences in the clinical efficacy of enteral and intravenous nimodipine after aSAH. However, a much larger phase III clinical trial would be needed to show or exclude meaningful clinical differences.

Effect of intrathecal magnesium sulfate solution injection via a microcatheter in the cisterna magna on cerebral vasospasm in the canine subarachnoid haemorrhage model

OBJECTIVE

To evaluate intracisternal injection of magnesium sulfate (MgSO(4)) solution via a lumbar catheter for the treatment of cerebral vasospasm in the canine subarachnoid haemorrhage (SAH) model.

MATERIALS AND METHODS

SAH was induced in 7 beagle dogs using the dual haemorrhage model. Vertebral angiography was repeated on Day 1 (before SAH), and on Day 7 (during cerebral vasospasm) before and 1.5 hours after injection of 0.5 mL/kg of 15 mmol/L MgSO(4) in Ringer solution via the tip of a microcatheter placed in the cisterna magna from the lumbar spine.

RESULTS

After injection of MgSO(4) solution, the cerebrospinal fluid magnesium ion concentration significantly increased to 3.89 ± 0.97 mEq/L (P < 0.01) from the baseline value (1.49 ± 0.07 mEq/L). The arterial diameters of the basilar artery (BA), vertebral artery (VA), and superior cerebral artery (SCA) on Day 1 were 1.26 ± 0.19 mm, 1.10 ± 0.13 mm, and 0.74 ± 0.21 mm, respectively. On Day 7 before injection, the arterial diameters of the BA, VA, and SCA significantly decreased to 0.75 ± 0.27 mm, 0.74 ± 0.25 mm, and 0.36 ± 0.21 mm, respectively (P < 0.01), due to vasospasm, and were significantly increased to 0.91 ± 0.27 mm (P < 0.01), 0.91 ± 0.31 mm (P < 0.05), and 0.54 ± 0.14 mm (P < 0.01), respectively, after intracisternal injection of MgSO(4) solution.

CONCLUSIONS

Intracisternal MgSO(4) therapy using a microcatheter from the lumbar spine may be effective against vasospasm in the clinical setting of endovascular treatment of ruptured aneurysm.

Sphingosylphosphorylcholine is a proinflammatory mediator in cerebral arteries

Inflammation has an important function in the development of cerebral vasospasm after subarachnoid hemorrhage (SAH); however, the mediators of this inflammatory response have not been clearly identified. In this study, we have investigated the potential function of two sphingolipids, which occur naturally in plasma and serum, sphingosylphosphorylcholine (SPC) and sphingosine 1-phosphate (S1P), to act as proinflammatory mediators in cerebral artery vascular smooth muscle (VSM) cells. In rat cerebral arteries, SPC but not S1P activated p38 mitogen-activated protein kinase (MAPK). Using transcription factor arrays, two proinflammatory transcription factors activated by SPC in cerebral arteries were identified--nuclear factor-κB and CCAAT-enhancer-binding protein. Both these transcription factors were activated by SPC in a p38MAPK-dependent manner. To determine whether this contributed to vascular inflammation, an inflammatory protein array was performed, which showed that SPC increased release of the chemokine monocyte chemoattractant protein-1 (MCP-1) in cultured rat VSM cells. This increase in MCP-1 expression was confirmed in cerebral arteries. The S1P did not increase MCP-1 release. Taken together, our results suggest that SPC, but not S1P, can act as a proinflammatory mediator in cerebral arteries. This may contribute to inflammation observed after SAH and may be part of the initiating event in vasospasm.

Platelet-derived growth factor-induced severe and chronic vasoconstriction of cerebral arteries: proposed growth factor explanation of cerebral vasospasm

OBJECTIVE

After subarachnoid hemorrhage (SAH), platelet-derived growth factor-BB (PDGF-BB) is secreted in and around the cerebral arteries. To clarify the role of PDGF-BB in the development of vasospasm after SAH, we determined whether PDGF-BB alone can cause long-lasting vasoconstriction of a severity similar to that of vasospasm. In addition, the anti-vasospastic effect of trapidil, an antagonist of PDGF-BB function, was investigated.

METHODS

We infused recombinant PDGF-BB (10 microg/mL saline as the vehicle) (n = 14) into the subarachnoid space of rabbits and analyzed alterations in the caliber of the basilar artery using repeated angiography. To study the role of PDGF-BB on the development of vasospasm, trapidil was administered continuously starting 1 hour after SAH, on day 0 (0.63-1.25 mg/kg /h or vehicle) for 47 hours (n = 24), or after the full development of cerebral vasospasm on day 2 (3.0 mg/kg/h or vehicle) for 0.5 hours (n = 17), and alterations in the caliber of the basilar artery were monitored.

RESULTS

PDGF-BB caused long-lasting vasoconstriction, with maximum constriction of 56% (P < .001) of the control value (= 100%) on day 2, resembling vasospasm seen after SAH. Prolonged administration of intravenous trapidil, starting soon after SAH, prevented the development of vasospasm in a dose-dependent manner (P < .05, .01, or .001). Intravenous or intra-arterial administration of trapidil significantly dilated vasospasm (P < .01) on day 2, at least transiently.

CONCLUSION

PDGF-BB, a growth factor synthesized in the subarachnoid space after SAH, can cause severe and long-lasting vasoconstriction. Significant prevention and resolution of vasospasm can be achieved by the PDGF-BB antagonist trapidil. We propose that excessive production of PDGF-BB, essentially aiming to repair injured arteries, causes cerebral vasospasm. Although the half-life of trapidil in serum may be shorter than that of PDGFG-BB-derived spasmogenic signaling, trapidil is a candidate drug for constructing a new therapeutic modality for preventing and resolving vasospasm.

A review of medical treatments of cerebral vasospasm

We review the literature on the established perioperative therapies for cerebral vasospasm (CV) following aneurysmal subarachnoid hemorrhage (aSAH). Despite aSAH treatment advances, CV continues to be a significant source of post-SAH morbidity and mortality. In fact, CV has been correlated with a 7.5- to three-fold increase in mortality in the first 2 weeks after SAH. As new treatment modalities show promise in animal models and early clinical trials, greater efforts are needed to test these new approaches. Few evidence-based indications for the treatment of vasospasm currently exist. Large-scale randomized clinical trials are needed to determine whether therapies such as magnesium, statins, nitric oxide modulators, endothelin antagonists and others will become standard of care in the prevention and/or treatment of CV.

Novel vasodilatory effect of intracisternal injection of magnesium sulfate solution on spastic cerebral arteries in the canine two-hemorrhage model of subarachnoid hemorrhage

Object

The extracellular Mg++ has a vasodilatory effect on the cerebral artery. The present study investigated the effect of intracisternal injection of MgSO4 solution on cerebral vasospasm in a canine model of subarachnoid hemorrhage (SAH).

Methods

Subarachnoid hemorrhage was induced in 10 beagles using the two-hemorrhage model. Angiography of the vertebrobasilar artery was performed on Day 1 (baseline values before SAH) and on Day 7 (during cerebral vasospasm after induced SAH) before and after intracisternal injection of 0.5 ml/kg of 15 mmol/L MgSO4 solution into the cerebellomedullary cistern.

Results

The cerebrospinal fluid Mg++ concentration was significantly increased to 3.15 ± 1.14 mEq/L after intracisternal injection from the preinjection value (1.45 ± 0.09 mEq/L; p < 0.01). The diameters of the basilar artery, vertebral artery, and superior cerebellar artery on Day 7 were significantly decreased to 58.0 ± 10.9%, 71.0 ± 10.1%, and 60.9 ± 13.8%, respectively, of their baseline diameters on Day 1 (p < 0.01). After intracisternal injection of MgSO4, these diameters significantly increased to 73.8 ± 14.3%, 83.0 ± 14.8%, and 74.1 ± 13.5%, respectively (p < 0.01).

Conclusions

Intracisternal injection of MgSO4 solution causes significant dilation of spastic cerebral arteries in the canine two-hemorrhage model of SAH.

Detection of phosphorylated NF-H in the cerebrospinal fluid and blood of aneurysmal subarachnoid hemorrhage patients

Blood and cerebrospinal fluid (CSF) of 30 Fisher grade 3 aneurysmal subarachnoid hemorrhage (ASAH) patients were analyzed for the presence of the phosphorylated axonal form of the major neurofilament subunit NF-H (pNF-H), a promising biomarker of axonal injury. Patient demographic data including development of vasospasm and outcome scores at 6 months after aneurysmal rupture (AR) were evaluated. Higher pNF-H blood levels in the first few days after AR were strongly predictive of a negative outcome. Blood pNF-H levels in most recovering patients showed a steady increase into the second week after AR, presumably reflecting axonal degeneration secondary to the original insult. Almost half of the patients studied showed sudden dramatic peaks of pNF-H protein release into CSF in the 3- to 14-day time period after AR, which must reflect profound, coordinated, and secondary loss of axons. Patients in whom vasospasm was detected had significantly more pNF-H in both blood and CSF compared with those in whom vasospasm was not detected. We conclude that the analysis of pNF-H levels in blood and CSF differentiates between patients with poor and favorable outcomes and also reveals several novel features of ASAH progression and recovery.

Intensive care management of patients with subarachnoid haemorrhage

PURPOSE OF REVIEW

The aim of this article is to summarize recent concepts regarding the intensive care management of patients with subarachnoid haemorrhage, emphasizing the detection and treatment of cerebral vasospasm and the management of systemic complications.

RECENT FINDINGS

Aneurysmal subarachnoid haemorrhage is a potentially devastating disease that requires complex treatment strategies and extended monitoring. The prognosis of subarachnoid haemorrhage depends on the severity of the initial bleed, the success of the procedure to secure the aneurysm and the occurrence and severity of sequelae, including cerebral vasospasm. Patients with subarachnoid haemorrhage benefit from multidisciplinary neurointensive care where management is targeted at securing the ruptured aneurysm, optimizing cardiovascular variables, detecting and treating cerebral vasospasm and managing systemic complications.

SUMMARY

The complex treatment strategies applied after subarachnoid haemorrhage call for interdisciplinary collaboration between neurosurgeons, neuroradiologists, neurointensivists and specialist nurses. Specialized neuromonitoring and neuroimaging techniques must also be available. The neurointensive care unit serves as the focal point for these combined efforts.

Does the blood-brain barrier play a role in Glaucoma?

The optic nerve head, although part of the central nervous system, lacks classical blood-brain barrier properties. The tissue of Elschnig does not totally separate the optic nerve head from fenestrated peripapillary choriocapillaries. The microvessels in the prelaminar region of the optic nerve head have less effective barriers than those in the laminar or retrolaminar regions. In glaucoma, the blood-brain barrier in the optic nerve head may even be weaker. Incomplete blood-brain barrier renders circulating molecules, such as endothelin-1 (ET-1), direct access to smooth vascular muscle cells and pericytes both in the prelaminar part of the optic nerve head and to adjacent retinal tissue. This potentially leads to some vasoconstriction as observed in the peri-papillary retinal vessel in glaucoma patients. In extreme situations, this may provoke retinal vein occlusion. The direct access of these molecules also influences the barrier function. If, simultaneously, ET-1 reduces endothelial tight-junctions and matrix-metalloproteinase (MMP)-9 degrades the basement membrane, not only macromolecules but even red blood cells may cross the blood-brain barrier and lead to what is clinically observed as optic disk hemorrhages.

Statin treatment of cerebral vasospasm after aneurysmal subarachnoid hemorrhage

OBJECTIVE

To evaluate the evidence for use of hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) for the prevention and management of cerebral vasospasm after aneurysmal subarachnoid hemorrhage (aSAH).

DATA SOURCES

Literature searches were conducted using MEDLINE (1966-July 2007) and the Cochrane Database (2007, Issue 2). Search terms included HMG-CoA reductase inhibitors, statins, subarachnoid hemorrhage, and vasospasm. Other data sources were identified from select bibliographies.

STUDY SELECTION AND DATA EXTRACTION

All controlled trials evaluating statins for the prevention and management of cerebral vasospasm after aSAH and published in the English language were included for review. Clinical and surrogate markers for cerebral vasospasm and outcomes were assessed.

DATA SYNTHESIS

Cerebral vasospasm, which may occur after aSAH, is associated with serious morbidity and significant mortality. Evidence suggests that statins have noteworthy biochemical effects through inhibition of nicotinamide adenine dinucleotide phosphate oxidase and superoxide production and up-regulation and activation of endothelial nitric oxidase synthase and nitric oxidase production via inhibition of geranylgeranylation of RhoA and Rac1 guanosine triphosphatases. Researchers have proposed that these effects may have a role in preventing or reducing vasospasm after aSAH. One matched control study and 3 placebo-controlled trials (1 with an additional post hoc analysis) have described use of statins for the prevention and management of cerebral vasospasm after aSAH. These data focused on differing primary endpoints; however, reductions in clinical vasospasm and middle cerebral artery transcranial doppler velocity, improved functional outcomes, enhanced autoregulation indices incidence, improvements in duration and time of impaired cerebral autoregulation, and reductions in rescue therapy have been reported.

CONCLUSIONS

Current data suggest that statins may be a reasonable treatment option for the prevention and management of cerebral vasospasm after aSAH. However, results from large, well-controlled trials have not been published.