Therapeutic approaches to vasospasm in subarachnoid hemorrhage

Real-world data of clazosentan in combination therapy for aneurysmal subarachnoid hemorrhage: a multicenter retrospective cohort study

Aneurysmal subarachnoid hemorrhage (aSAH) may lead to cerebral vasospasm, significantly associated with morbidity and mortality. In double-blind, placebo-controlled phase 3 studies, clazosentan reduces cerebral vasospasm-related morbidity and all-cause mortality in patients with aSAH. There are no reports about the clinical efficacy of clazosentan combination therapy with some other drugs. Initially, we explored the efficacy of clazosentan combination therapy with cilostazol, statin, and antiepileptic drugs. Subsequently, we assessed the add-on effect of fasudil to clazosentan combination therapy for aSAH patients. This multicenter, retrospective, observational cohort study included Japanese patients with aSAH between June 2022 and March 2023. The primary outcome was the ordinal score on the modified Rankin Scale (mRS; range, 0-6, with elevated scores indicating greater disability) at discharge. Among the 47 cases (women 74.5%; age 64.4 ± 15.0 years) undergoing clazosentan combination therapy, 29 (61.7%) resulted in favorable outcomes. Overall, vasospasm occurred in 16 cases (34.0%), with four cases (8.5%) developing vasospasm-related delayed cerebral ischemia (DCI). Both hypotension and vasospasm-related DCI were related to unfavorable outcome at discharge. Fasudil were added in 18 (38.3%) cases. Despite adding fasudil to clazosentan combination therapy, the incidence of aSAH-related vasospasm did not decrease. Added-on fasudil to combination therapy related to pulmonary edema, vasospasm, and vasospasm-related DCI, and unfavorable outcomes. Clazosentan combination therapy could potentially result in favorable outcomes for aSAH patients to prevent post-aSAH vasospasm-related DCI. The add-on effect of fasudil to combination therapy did not demonstrate a significant impact in reducing aSAH-related vasospasm or improving outcomes at discharge.

Efficacy of nimodipine in the treatment of subarachnoid hemorrhage: a meta-analysis

Background Subarachnoid hemorrhage (SAH) is an uncommon and serious subtype of stroke, which leads to the loss of the patient's ability to produce and live for many years.

Objective To investigate the clinical effect of nimodipine in the treatment of SAH.

Methods Electronic databases including China National Knowledge Infrastructure (CNKI), VIP, SinoMed, China Master's Theses Full-text Database (CMFD), China Doctoral Dissertations Full-text Database (CDFD), Cochrane Library, PubMed and Embase were searched from 2010 and 2021. All randomized controlled trials evaluating the efficacy of nimodipine in the treatment of SAH were included in our meta-analysis. The patients were divided into control group and treatment group. Meta-analysis was performed with Stata16.0 software.

Results A total of 10 studies were included. Compared with the control group, the treatment group had higher effective rate (OR = 3.21, 95% CI: 2.25, 4.58; p < 0.001), and lower incidence of adverse reactions (OR = 0.35, 95% CI: 0.19, 0.67; p = 0.001). Before treatment, no significant differences were identified in middle cerebral artery blood flow velocity and Glasgow coma scale (GCS) score between the two groups. However, after treatment, the middle cerebral artery blood flow velocity (SMD = −1.36, 95% CI: −2.28, −0.49; p = 0.002) and GCS score (SMD = 1.24, 95% CI: 0.58, 1.89; p < 0.001) in the treatment group were significantly better than those in the control group.

Conclusions Nimodipine is effective in the treatment of SAH, lowering incidence of adverse reactions and therefore improving the prognosis of patients.

Diagnostic Sensitivity of Plasma Endothelin-1 for Cerebral Vasospasm After Subarachnoid Hemorrhage, a Multicentre Double-Blind Study

The purpose of this study is to establish the diagnostic sensitivity of Endothelin-1 for risk stratification and screening of clinical vasospasm after subarachnoid hemorrhage.This is a multicentre, observational study, correlating daily blood Endothelin-1 with clinical variables. Binary logistic regression used to examine if Endothelin-1 levels could be used to predict clinical vasospasm. Bivariate modelling used to explore associations between patient characteristics and vasospasm. A Receiver Operating Curve used to explore cut-off values for Endothelin-1. Sensitivity and specificity was used to validate the cut-point found in the pilot study. A total of 96 patients were enrolled over two years. Median Endothelin-1 was higher for patients who experienced clinical vasospasm except for day-5, where median endothelin for patients without vasospasm was higher (3.6 IQR = 5.3), compared to patients with vasospasm (3.3 IQR = 8.5) although differences were not significant. The Receiver Operating Curve analysis confirmed that day-5 Endothelin-1 was not a good indicator of vasospasm, with an area under the curve of 0.506 (95% CI: 0.350-0.663, p = 0.938). The levels of Endothelin-1 in blood do not discriminate patients who may develop symptomatic vasospasm. The high variability in Endothelin-1 levels, aligns with the pathophysiological variability of most biomarkers, decreasing their ability to predict a clinical event.

Nimodipine reduces delayed cerebral vasospasm after intracranial tumour surgery: A Retrospective Study

Cerebral vasospasm (CVS) is a frequent and serious neurosurgical complication, without sufficient therapy. This retrospective study was performed to analyze if nimodipine can improve prognosis and reduce ischaemia secondary to delayed CVS after intracranial tumour surgery. A retrospective review was performed over the years 2011 to 2012 for patients with an anterior cranial fossa tumour and underwent intracranial tumour surgery. The surgical field was soaked with nimodipine solution or normal saline. Transcranial Doppler ultrasonography was used to measure velocity in the middle cerebral artery (MCA) and the distal extracranial internal carotid artery (eICA). Follow-up was performed using the Glasgow Outcome Scale (GOS) after discharge. There were 94 patients that met the inclusion criteria. They included 50 males and 44 females, with a mean age of 49.6 years. In the nimodipine group, CVS occurred in 13 patients; 9 patients had CVS between 4 and 7 days, and 4 had CVS between 8 and 14 days. In the normal saline group, 19 patients had CVS, 3 presented with CVS within 3 days, 11 between 4-7 days and 5 between 8-14 days. A significant difference in the occurrence of CVS was observed between the two groups. Preoperative and postoperative the MCA velocities were compared, revealing a significant change in the normal saline group but not in the nimodipine group. Nimodipine markedly improves prognosis and significantly reduces ischaemia secondary to delayed CVS after intracranial tumour surgery, as well as the risks of mortality and morbidity.

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.

The combination of dantrolene and nimodipine effectively reduces 5-HT-induced vasospasms in diabetic rats

Diabetics have a higher risk of developing cerebral vasospasms (CVSP) after subarachnoid hemorrhagic stroke than non-diabetics. Serotonin (5-HT) is one of the key vasoconstrictors released in the hemorrhagic blood and an important contributor to the etiology of CVSP. The combination of the ryanodine receptor blocker dantrolene and the Ca2+ channel blocker nimodipine significantly reduces phenylephrine (PHE)-induced vascular contraction in both diabetic and nondiabetic rats, but the effectiveness of this drug combination in reducing 5-HT-induced contraction is unknown. Dose–response curves for the 5-HT-induced contraction (from 0.1 nM to 100 µM) were performed on aortic rings from diabetic and non-diabetic rats after a 30-min incubation period with dantrolene, nimodipine, and both drugs in combination. In diabetic rats, 10 μM of dantrolene alone failed to reduce 5-HT-induced maximal contraction (E_max), but 50 μM reduced this parameter by 34% (n = 7, p < 0.05). In non-diabetic rats, by contrast, dantrolene did not modify the vascular response to 5-HT. 50 nM of nimodipine alone, however, reduced this parameter by 57% in diabetic rats (n = 10, p < 0.05), and by 34% in non-diabetic rats (n = 10, p < 0.05). In addition, concomitant administration of dantrolene and nimodipine reduced vascular reactivity to a similar extent in both diabetic (~ 60% reduction, n = 10, p < 0.05) and non-diabetic rats (~ 70% reduction, n = 10, p < 0.05). Moreover, the combination of nimodipine with the higher concentration of dantrolene significantly increased the EC₅₀ values for the 5-HT-induced contraction curves in both diabetics (from 10.31 ± 1.17 µM to 19.26 ± 2.82; n = 10, p < 0.05) and non-diabetic rats (5.93 ± 0.54 µM to 15.80 ± 3.24; n = 10, p < 0.05). These results suggest that simultaneous administration of dantrolene and nimodipine has a synergistic effect in reducing 5-HT-induced vascular contraction under both diabetic and non-diabetic conditions. If our findings with rats are applicable to humans, concomitant administration of these drugs may represent a promising alternative for the management of CVSP in both diabetics and non-diabetics.

Herbal medicines for the prevention and treatment of cerebral vasospasm after subarachnoid hemorrhage: A protocol for systematic review and meta-analysis

BACKGROUND

Despite the rapid advances in medical technology, including endovascular interventions and medications, cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH) is still one of the major threats to the lives of patients with SAH. In East Asian countries, various types of herbal medicines have been used to treat cerebrovascular diseases, including SAH. In this review, we aim to evaluate the efficacy and safety of herbal medicines for the prevention and treatment of CVS after SAH.

METHODS AND ANALYSIS

Seven databases will be searched for relevant studies from inception to the present date "June 2020". Only randomized controlled trials (RCTs) that assess the effect and safety of herbal medicines for the prevention and treatment of CVS after SAH will be included. The methodological quality will be evaluated using the Cochrane risk of bias assessment tool. After selecting the appropriate studies, a meta-analysis of the RCTs will be performed.

RESULTS

This study will provide a high-quality synthesis of current evidence of herbal medicines for CVS after SAH.

CONCLUSION

Our systematic review will provide evidence to judge whether herbal medicines are effective interventions for patients with CVS after SAH.

ETHICS AND DISSEMINATION

Ethical approval is not required, as this study is based on a review of published research. This review will be published in a peer-reviewed journal and disseminated electronically and in print.

TRIAL REGISTRATION NUMBER

Research registry reviewregistry923.

Bibliometric Analysis of the Top 100 Most Cited Articles on Cerebral Vasospasm

OBJECTIVE

Bibliometric analysis reflects the scientific recognition and influential performance of a published article within its field. Our aim is to identify and analyze the top 100 most-cited articles on cerebral vasospasm.

METHODS

A title-specific search was carried out using the Scopus database. The top 100 cited articles including the keywords "Cerebral Vasospasm" AND "Vasospasm" were retrieved and stratified in a descending order: title, authors, institution, publishing journal, country of origin, year of publication, and topic of each article were studied.

RESULTS

The top 100 articles have an accumulative citation count of 20,972, with 209 average citations per article. Publication dates ranged from 1968 to 2012, with the most productive years between 1998 and 2005. Clinical studies are the most frequent category, followed by pathophysiology. The list includes 7 clinical trials, which received accumulative citations of 1525. The top cited article had received 2109 citations, with 52.7 citations per year. The top 100 articles were published across 14 countries, with most originating from the United States. The lead research institution was the University of Alberta. The most used journal was Journal of Neurosurgery.

CONCLUSIONS

Bibliometric analysis has garnered major interest in recent years. It shows the publication trends, knowledge evolution, and evidence-based practice throughout the years. The collection of highly cited articles may assist physicians in gaining a better understanding of the nature of cerebral vasospasm and optimize their clinical practice.

Nimodipine Pharmacokinetic Variability in Various Patient Populations

Nimodipine has been shown to improve outcomes following aneurysmal subarachnoid hemorrhage. Guidelines recommend that all patients receive a fixed dose of oral nimodipine for 21 days. However, pharmacokinetic studies have suggested variability of nimodipine pharmacokinetics in subarachnoid hemorrhage and in other patient populations. The clinical relevance of such variability is unknown. Therefore, the objective of the present review is, first, to conduct a literature review and summarize nimodipine pharmacokinetic data and sources of variability in various patient groups. Second, to determine if there is any evidence reporting an association between nimodipine exposure and clinical outcomes in patients with subarachnoid hemorrhage. A systematic literature search was performed in MEDLINE and EMBASE. The following keywords were used: ("nimodipine" OR "nymalize" OR "nimotop") AND ("pharmacokinetic*", OR "PK"). The search results were limited to English language and human studies. A large interpatient variability in nimodipine pharmacokinetics has been reported. Patient-specific factors that had an influence on pharmacokinetic parameters are age, comorbidities, variabilities in metabolism due to genetic polymorphism and co-administered medications, as well as nimodipine administration technique. The association between nimodipine exposure and clinical outcomes remains unclear and data available are too scarce to reach a firm conclusion. Here, we present a narrative review with a systematic literature search discussing nimodipine pharmacokinetic variability in various patient populations. It is not clear if minimal or lack of systemic exposure to nimodipine denies its benefit and contributes to worsening outcomes in patients with subarachnoid hemorrhage. Further studies are needed to determine if such an association exists.

Nicardipine Loaded Solid Phospholipid Extrudates for the Prevention of Cerebral Vasospasms: In Vitro Characterization

The aim of the study was to develop nicardipine loaded phospholipid extrudates as an alternative for PLA/PLGA-based implants for the prevention of cerebral vasospasms. Extrudates of different mixtures of saturated and unsaturated phosphatidylcholine (PC) were produced and characterized by DSC, microscopy and texture analysis. Single phospholipid components were identified by ELSD-HPLC. Extrudates of 2 mm diameter were obtained by twin screw extrusion temperatures below 50 °C. The ratio of unsaturated and saturated phosphatidylcholine components determines the physicochemical properties of the extrudates as well as the rate of erosion. Nicardipine loaded phospholipids extrudates released the drug over several weeks in vitro. The phospholipid composition of the remaining extrudate changed during the release, the content of unsaturated phospholipids decreased faster compared to the saturated ones. In conclusion, solid phospholipid extrudates are promising materials for the development of new parenteral controlled release systems.

Milrinone for refractory cerebral vasospasm with delayed cerebral ischemia

OBJECTIVE

Intravenous (IV) milrinone is a promising option for the treatment of cerebral vasospasm with delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH). However, data remain limited on the efficacy of treating cases that are refractory to standard therapy with IV milrinone. The aim of this study was to determine predictors of refractory vasospasm/DCI despite treatment with IV milrinone, and to analyze the outcome of rescue therapy with intraarterial (IA) milrinone and/or mechanical angioplasty.

METHODS

The authors conducted a retrospective cohort study of all patients with aSAH admitted between 2010 and 2016 to the Montreal Neurological Institute and Hospital. Patients were stratified into 3 groups: no DCI, standard therapy, and rescue therapy. The primary outcome was frequency of DCI-related cerebral infarction identified on neuroimaging before hospital discharge. Secondary outcomes included functional outcome reported as modified Rankin Scale (mRS) score, and segment reversal of refractory vasospasm.

RESULTS

The cohort included 322 patients: 212 in the no DCI group, 89 in the standard therapy group, and 21 in the rescue therapy group. Approximately half (52%, 168/322) were admitted with poor-grade aSAH at treatment decision (World Federation of Neurosurgical Societies grade III-V). Among patients with DCI and imaging assessing severity of vasospasm, 62% (68/109) had moderate/severe radiological vasospasm on DCI presentation. Nineteen percent (21/110) of patients had refractory vasospasm/DCI and were treated with rescue therapy. Targeted rescue therapy with IA milrinone reversed 32% (29/91) of the refractory vasospastic vessels, and 76% (16/21) of those patients experienced significant improvement in their neurological status within 24 hours of initiating therapy. Moderate/severe radiological vasospasm independently predicted the need for rescue therapy (OR 27, 95% CI 8.01-112). Of patients with neuroimaging before discharge, 40% (112/277) had developed new cerebral infarcts, and only 21% (23/112) of these were vasospasm-related. Overall, 65% (204/314) of patients had a favorable functional outcome (mRS score 0-2) assessed at a median of 4 months (interquartile range 2-8 months) after aSAH, and there was no difference in functional outcome between the 3 groups (p = 0.512).

CONCLUSIONS

The aggressive use of milrinone was safe and effective based on this retrospective study cohort and is a promising therapy for the treatment of vasospasm/DCI after aSAH.

Itaconate modulates tricarboxylic acid and redox metabolism to mitigate reperfusion injury

OBJECTIVES

Cerebral ischemia/reperfusion (IR) drives oxidative stress and injurious metabolic processes that lead to redox imbalance, inflammation, and tissue damage. However, the key mediators of reperfusion injury remain unclear, and therefore, there is considerable interest in therapeutically targeting metabolism and the cellular response to oxidative stress.

METHODS

The objective of this study was to investigate the molecular, metabolic, and physiological impact of itaconate treatment to mitigate reperfusion injuries in in vitro and in vivo model systems. We conducted metabolic flux and bioenergetic studies in response to exogenous itaconate treatment in cultures of primary rat cortical neurons and astrocytes. In addition, we administered itaconate to mouse models of cerebral reperfusion injury with ischemia or traumatic brain injury followed by hemorrhagic shock resuscitation. We quantitatively characterized the metabolite levels, neurological behavior, markers of redox stress, leukocyte adhesion, arterial blood flow, and arteriolar diameter in the brains of the treated/untreated mice.

RESULTS

We demonstrate that the "immunometabolite" itaconate slowed tricarboxylic acid (TCA) cycle metabolism and buffered redox imbalance via succinate dehydrogenase (SDH) inhibition and induction of anti-oxidative stress response in primary cultures of astrocytes and neurons. The addition of itaconate to reperfusion fluids after mouse cerebral IR injury increased glutathione levels and reduced reactive oxygen/nitrogen species (ROS/RNS) to improve neurological function. Plasma organic acids increased post-reperfusion injury, while administration of itaconate normalized these metabolites. In mouse cranial window models, itaconate significantly improved hemodynamics while reducing leukocyte adhesion. Further, itaconate supplementation increased survival in mice experiencing traumatic brain injury (TBI) and hemorrhagic shock.

CONCLUSIONS

We hypothesize that itaconate transiently inhibits SDH to gradually "awaken" mitochondrial function upon reperfusion that minimizes ROS and tissue damage. Collectively, our data indicate that itaconate acts as a mitochondrial regulator that controls redox metabolism to improve physiological outcomes associated with IR injury.

The important role of connexin 43 in subarachnoid hemorrhage-induced cerebral vasospasm

Background

Gap junctions are involved in the development of cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH). However, the specific roles and regulatory functions of related connexin isoforms remain unknown. The aim of this study was to investigate the importance of connexin 43 (Cx43) in CVS and determine whether Cx43 alterations are modulated via the protein kinase C (PKC) signaling transduction pathway.

Methods

Oxyhemoglobin (OxyHb)-induced smooth muscle cells of basilar arterial and second-injection model in rat were used as CVS models in vitro and in vivo. In addition, dye transfer assays were used for gap junction-mediated intercellular communication (GJIC) observation in vitro and delayed cerebral ischemia (DCI) was observed in vivo by perfusion-weighted imaging (PWI) and intravital fluorescence microscopy.

Results

Increase in Cx43 mediated the development of SAH-induced CVS was found in both in vitro and in vivo CVS models. Enhanced GJIC was observed in vitro CVS model, this effect and increased Cx43 were reversed by preincubation with specific PKC inhibitors (chelerythrine or GF 109203X). DCI was observed in vivo on day 7 after SAH. However, DCI was attenuated by pretreatment with Cx43 siRNA or PKC inhibitors, and the increased Cx43 expression in vivo was also reversed by Cx43 siRNA or PKC inhibitors.

Conclusions

These data provide strong evidence that Cx43 plays an important role in CVS and indicate that changes in Cx43 expression may be mediated by the PKC pathway. The current findings suggest that Cx43 and the PKC pathway are novel targets for developing treatments for SAH-induced CVS.

Outcomes of Endovascular Therapy versus Microsurgical Treatment for Aneurysmal Subarachnoid Hemorrhage in Patients ≥70 Years of Age

Purpose

This retrospective research aimed to compare the efficacy of endovascular therapy (EVT) versus microsurgical treatment (MST) for elderly patients with aneurysmal subarachnoid hemorrhage (aSAH).

Methods

Elderly (>70 years) patients with aSAH who underwent aneurysm obliteration during 2007-2017 were selected from our hospital database and enrolled in this retrospective study. We reviewed each patient's background, the severity of the aSAH, and aneurysmal characteristics that compelled EVT or microsurgery treatment and then compared the two treatment groups. A favorable primary outcome was defined by a modified Rankin scale (mRS) score of 0-3 at hospital discharge. The 78 patients formed two cohorts (39 patients each) based on their propensity scores for EVT or MST. We estimated the adjusted odds ratio, followed by a sensitivity analysis of the original 201 patients (118 with EVT and 83 with MST).

Results

In the propensity score-matched cohorts, favorable outcomes were observed in 33.3% and 7.7% of patients in the EVT and MST groups, respectively (p = 0.01). Results of the sensitivity analysis were similar to the main results.

Conclusion

The clinical outcomes for the elderly aSAH patients were better in the EVT group than in MST group.

Delayed Cerebral Ischemia and Vasospasm After Spontaneous Angiogram-Negative Subarachnoid Hemorrhage: An Updated Meta-Analysis

OBJECTIVE

To report clinical outcomes of delayed cerebral ischemia (DCI) and vasospasm in angiogram-negative subarachnoid hemorrhage (SAH) according to hemorrhage patterns, perimesencephalic hemorrhage (PMH) and non-PMH.

METHODS

Online databases from January 1990 to December 2017 were systematically reviewed. A fixed-effects model was used to control heterogeneity. To resolve publication bias, the trim and fill method was used to estimate number of missing studies and adjusted odds ratio (OR). Subgroup analysis of data from studies that defined angiogram-negative subarachnoid hemorrhage by angiography repeated at least twice or computed tomography angiography was performed.

RESULTS

Among 24 studies including 2083 patients, 23/985 patients (2.3%) with PMH and 144/1098 patients (13.1%) with non-PMH had DCI, indicating that patients with PMH experienced significantly lower DCI than patients with non-PMH (OR = 0.219; 95% confidence interval [CI], 0.144-0.334). Regarding vasospasm, 99/773 patients (12.8%) with PMH and 231/922 patients (25.1%) with non-PMH exhibited vasospasm, indicating that patients with PMH experienced significantly lower vasospasm than patients with non-PMH (OR = 0.445; 95% CI, 0.337-0.589). Funnel plots show asymmetry indicating possible publication bias. After trimming 10 studies for DCI and 7 for vasospasm, the adjusted ORs remained significant between PMH and lower risks of DCI and vasospasm. Subgroup analysis of 789 patients in 8 studies showed a lower risk of DCI (OR = 0.268; 95% CI, 0.151-0.473) and vasospasm (OR = 0.346; 95% CI, 0.221-0.538) in patients with PMH.

CONCLUSIONS

PMH showed a significantly lower risk of DCI and vasospasm than non-PMH. Clinical outcomes of angiogram-negative subarachnoid hemorrhage, based on meta-analysis of individual patient data, need to be investigated.

Acute impairment of saccadic eye movements is associated with delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

OBJECTIVE

Delayed cerebral ischemia (DCI) causing cerebral infarction remains a significant cause of morbidity and mortality following aneurysmal subarachnoid hemorrhage (aSAH). Early brain injury in the first 72 hours following rupture is likely to play a key role in the pathophysiology underlying DCI but remains difficult to quantify objectively. Current diagnostic modalities are based on the concept of vasoconstriction causing cerebral ischemia and infarction and are either invasive or have a steep learning curve and user variability. The authors sought to determine whether saccadic eye movements are impaired following aSAH and whether this measurement in the acute period is associated with the likelihood of developing DCI.

METHODS

As part of a prospective, observational cohort study, 24 male and female patients (mean age 53 years old, range 31–70 years old) were recruited. Inclusion criteria included presentation with World Federation of Neurosurgical Societies (WFNS) Grades 1 or 2 (“good grade”) aSAH on admission and endovascular treatment within 72 hours of aneurysmal rupture. DCI and DCI-related cerebral infarction were defined according to consensus guidelines. Saccadometry data were collected at 3 time points in patients: in the first 72 hours, between Days 5 and 10, and at 3 months after aSAH. Data from 10 healthy controls was collected on 1 occasion for comparison.

RESULTS

Age-adjusted saccadic latency in patients was significantly prolonged in the first 72 hours following aSAH when compared with controls (188.7 msec [95% CI 176.9–202.2 msec] vs 160.7 msec [95% CI 145.6–179.4 msec], respectively; p = 0.0054, t-test). By 3 months after aSAH, there was no significant difference in median saccadic latency compared with controls (188.7 msec [95% CI 176.9–202.2 msec] vs 180.0 msec [95% CI 165.1–197.8 msec], respectively; p = 0.4175, t-test). Patients diagnosed with cerebral infarction due to DCI had a significantly higher age-adjusted saccadic latency in the first 72 hours than those without infarction (240.6 msec [95% CI 216.7–270.3 msec] vs 204.1 msec [95% CI 190.7–219.5 msec], respectively; p = 0.0157, t-test). This difference was more pronounced during Days 5–10 following aSAH, the peak incidence for DCI (303.7 msec [95% CI 266.7–352.7 msec] vs 207.6 msec [95% CI 193.7–223.6 msec], respectively; p < 0.0001, t-test). A binary generalized linear model showed that latency in the first 72 hours was the only significant predictor of cerebral infarction (p = 0.0185).

CONCLUSIONS

This is the first study to use saccadometry to measure the saccadic latency of eye movements in patients with aSAH during the acute period following aneurysm rupture. The results showed that median saccadic latency is associated with the risk of developing cerebral infarction due to DCI and may act as a potential objective biomarker to guide the need for intensive care admission and treatment. Future studies will look to formally validate saccadic latency as a biomarker of DCI in a larger cohort and assess whether the addition of saccades improves current clinical models for predicting patients at risk.

Numerical Investigation of Vasospasm Detection by Extracranial Blood Velocity Ratios

BACKGROUND

Early diagnosis of vasospasm following subarachnoid hemorrhage can prevent cerebral ischemia and improve neurological outcomes. This study numerically evaluates the relevance of extracranial blood velocity indices to detect vasospasm.

METHODS

A numerical model of cerebral blood flow was used to evaluate the hemodynamics associated with anterior and posterior vasospasm under normal and impaired cerebral autoregulation conditions. Extracranial blood velocities at the carotid and vertebral arteries and their ratios between ipsilateral and contralateral, anterior and posterior, and downstream and upstream arteries were monitored during vasospasm progression.

RESULTS

For current clinical indices that track blood velocities at vasospastic arterial segments using transcranial Doppler (TCD), we observed that velocities increased initially and then decreased with vasospasm progression. This nonmonotonic behavior can lead to false-negative decisions in moderate to severe vasospasm. Alternatively, volumetric flow decreased monotonically at the affected arteries, leading to blood velocities upstream of the vasospastic artery also decreasing monotonically. Based on this principle, we demonstrate that velocity ratios between the carotid and vertebral arteries may better identify moderate to severe vasospasm and improve sensitivity and specificity of vasospasm detection.

CONCLUSION

The velocity indices proposed in this study may enable new or improved noninvasive diagnosis of vasospasm using extracranial Doppler ultrasound. Compared to current clinical indices, the new indices may improve the handling of (1) scenarios of severe vasospasm or impaired cerebral autoregulation, (2) systemic changes in blood pressure and cardiac output, (3) vasospasm occurring in arteries distal to the cerebral circle region, and (4) cases with insufficient acoustic bone window for TCD. The results provide a concrete basis for future clinical evaluation of extracranial indices for vasospasm detection.

Detection of Neuroinflammation in a Rat Model of Subarachnoid Hemorrhage Using [18F]DPA-714 PET Imaging

Subarachnoid hemorrhage (SAH) can lead to delayed cerebral ischemia, which increases the rate of morbidity and mortality. The detection of microglial activation may serve as a biomarker for the identification of patients at risk of this deleterious consequence. We assessed this hypothesis in a rat model of SAH in which the exploration of neuroinflammation related to microglial activation was correlated with the degree of bleeding. We used the rat filament model and evaluated (at 48 hours postsurgery) the intensity of neuroinflammation using positron emission tomography (PET) imaging with the 18-kDa translocator protein (TSPO) tracer [¹⁸F]DPA-714, quantitative autoradiography with [³H]PK-11195, and SAH grade by postmortem brain picture. High SAH grades were strongly and positively correlated with in vivo PET imaging of TSPO in the cortex and striatum. In addition, a positive correlation was found in the cortex in TSPO, with densities determined by imaging and autoradiographic approaches. Qualitative immunofluorescence studies indicated that overexpression of TSPO was linked to astrocytic/microglial activation. In this model, PET imaging of TSPO using [¹⁸F]DPA-714 appeared to be a relevant index of the degree of bleeding, indicating that this imaging method could be used in human patients to improve the management of patients with SAH.

A Case of Hyperacute Onset of Vasospasm After Aneurysmal Subarachnoid Hemorrhage and Refractory Vasospasm Treated with Intravenous and Intraventricular Nitric Oxide: A Mini Review

BACKGROUND

A case of hyperacute vasospasm, indicating a poor prognosis after aneurysmal subarachnoid hemorrhage (SAH), is reported, and a review is presented of the literature addressing use of nitric oxide (NO) donors in cases of refractory vasospasm and recurrent delayed cortical ischemias (DCI).

CASE DESCRIPTION

A 65-year-old woman was admitted within 1 hour after aneurysmal SAH (Hunt and Hess grade III, Fisher modified by Frontera grade IV). A hyperacute vasospasm had been confirmed arteriographically, the right middle cerebral artery (MCA) aneurysm was immediately coiled and a standard antivasospastic therapy was started. Within 48 hours, the patient developed cerebral vasospasm with DCI. Because the standard therapy failed to control clinical symptoms and to address severe vasospasm, an individualized rescue treatment with NO donors was initiated. A continuous intravenous molsidomine infusion was started and clinical stabilization was achieved for a week (Hunt and Hess grade I; World Federation of Neurological Surgeons grade I; Glasgow Coma Scale score, 15) after which vasospasm and DCI recurred. During a subsequent DCI, we escalated NO donor therapy by adding intraventricular boluses of sodium nitroprusside (SNP). Over the course of the following 22 days, 7 transient DCIs (Glasgow Coma Scale score, 8) were treated with boluses of SNP during continued molsidomine therapy and each time vasospasm and DCI were completely reversed. Despite initial poor prognosis, the clinical outcome was excellent; at 3, 6, and 12 months follow-up the patient's modified National Institutes of Health-Stroke Scale and modified Rankin Scale scores were 0, with no cognitive deficits.

CONCLUSIONS

The review of the literature suggested that combined intravenous molsidomine with intraventricular SNP treatment reversed refractory, recurrent vasospasm and DCIs probably by addressing the hemoglobin NO sink effect, NO depletion, and decreased NO availability after aneurysmal SAH.

Poor outcome is associated with less negative fluid balance in patients with aneurysmal subarachnoid hemorrhage treated with prophylactic vasopressor-induced hypertension

Background

Aneurysmal subarachnoid hemorrhage (SAH) is a serious condition associated with high mortality rates and long-term disability. We investigated the impact of fluid balance on neurologic outcome after adjustment for possible confounders related to intensive care therapy and extra-cerebral organ failure during the early phase after SAH.

Methods

In this retrospective study, we analyzed data from all 142 adult patients admitted to our university hospital surgical intensive care unit (ICU) with SAH between March 2004 and November 2010.

Results

The mean patient age was 54 ± 14 years, 62.7 % were female, and the median Hunt and Hess score was 3. The proportions of patients with poor outcome (Glasgow Outcome Score ≤3) were 58.4, 54.2, and 52.1 % at 3, 6, and 12 months, respectively, after the SAH. The ICU and hospital mortality rates were both 12.7 %, and the median lengths of stay in the ICU and the hospital were 16 (IQ 7–25) and 26 (IQ 18–34) days, respectively. In multivariable analysis, older age and greater cumulative fluid balance within the first 7 days in the ICU were independently associated with a greater risk of poor outcome.

Conclusion

In this cohort of patients, older age and greater cumulative fluid balance were independently associated with a greater risk of poor outcome up to 1 year after the initial insult. Our data suggest that mild hypovolemia may be beneficial in the management of these patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13613-016-0128-6) contains supplementary material, which is available to authorized users.

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.

Molsidomine for the prevention of vasospasm-related delayed ischemic neurological deficits and delayed brain infarction and the improvement of clinical outcome after subarachnoid hemorrhage: a single-center clinical observational study

OBJECT Delayed ischemic neurological deficits (DINDs) and cerebral vasospasm (CVS) are responsible fora poor outcome in patients with aneurysmal subarachnoid hemorrhage (SAH), most likely because of a decreased availability of nitric oxide (NO) in the cerebral microcirculation. In this study, the authors examined the effects of treatment with the NO donor molsidomine with regard to decreasing the incidence of spasm-related delayed brain infarctions and improving clinical outcome in patients with SAH. METHODS Seventy-four patients with spontaneous aneurysmal SAH were included in this post hoc analysis. Twenty-nine patients with SAH and proven CVS received molsidomine in addition to oral or intravenous nimodipine. Control groups consisted of 25 SAH patients with proven vasospasm and 20 SAH patients without. These patients received nimodipine therapy alone. Cranial computed tomography (CCT) before and after treatment was analyzed for CVS-related infarcts. A modified National Institutes of Health Stroke Scale (mNIHSS) and the modified Rankin Scale (mRS) were used to assess outcomes at a 3-month clinical follow-up. RESULTS Four of the 29 (13.8%) patients receiving molsidomine plus nimodipine and 22 of the 45 (48%) patients receiving nimodipine therapy alone developed vasospasm-associated brain infarcts (p < 0.01). Follow-up revealed a median mNIHSS score of 3.0 and a median mRS score of 2.5 in the molsidomine group compared with scores of 11.5 and 5.0, respectively, in the nimodipine group with CVS (p < 0.001). One patient in the molsidomine treatment group died, and 12 patients in the standard care group died (p < 0.01). CONCLUSIONS In this post hoc analysis, patients with CVS who were treated with intravenous molsidomine had a significant improvement in clinical outcome and less cerebral infarction. Molsidomine offers a promising therapeutic option in patients with severe SAH and CVS and should be assessed in a prospective study.

Role of L-type Ca(2+) channels, sarcoplasmic reticulum and Rho kinase in rat basilar artery contractile properties in a new model of subarachnoid hemorrhage

We have previously described that L-type Ca(2+) channels' (LTCCs) activation and metabotropic Ca(2+) release from the sarcoplasmic reticulum (SR) regulate RhoA/Rho kinase (ROCK) activity and sustained arterial contraction. We have investigated whether this signaling pathway can be altered in a new experimental model of subarachnoid hemorrhage (SAH). For this purpose, arterial reactivity was evaluated on days 1 to 5 after surgery. A significant increase of basal tone, measured 4 and 60min after normalization, was observed on day 5 after SAH and at 60min on days 2 and 3 after SAH. This phenomenon was suppressed with LTCCs and ROCK inhibitors. We have also studied arterial rings vasoreactivity in response to high K(+) solutions. Interestingly, there were no significant differences in the phasic component of the high K(+)-induced contraction between sham and SAH groups, whereas a significant increase in the sustained contraction was observed on day 5 after SAH. This latter component was sensitive to fasudil, and selectively reduced by low nifedipine concentration, and phospholipase C and SR-ATPase inhibitors. Therefore, our data suggest that the metabotropic function of LTCCs is potentiated in SAH. Our results could provide a new strategy to optimize the pharmacological treatment of this pathological process.

Cerebral vasospasm

Cerebral vasospasm causes delayed ischemic neurologic deficits after aneurysmal subarachnoid hemorrhage. This is a well-established clinical entity with significant associated morbidity and mortality. The underlying patholphysiology is highly complex and poorly understood. Large-vessel vasospasm, autoregulatory dysfunction, inflammation, genetic predispositions, microcirculatory failure, and spreading cortical depolarization are aspects of delayed neurologic deterioration that have been described in the literature. This article presents a perspective on cerebral vasospasm, as guided by the literature to date, specifically examining the mechanism, diagnosis, and treatment of cerebral vasospasm.

Intravenous flat-detector computed tomography angiography for symptomatic cerebral vasospasm following aneurysmal subarachnoid hemorrhage

The study evaluated the diagnostic accuracy of intravenous flat-detector computed tomography (IV FDCT) angiography in assessing hemodynamically significant cerebral vasospasm in patients with subarachnoid hemorrhage (SAH) with digital subtraction angiography (DSA) as the reference. DSA and IV FDCT were conducted concurrently in patients suspected of having symptomatic cerebral vasospasm postoperatively. The presence and severity of vasospasm were estimated according to location (proximal versus distal). Vasospasm >50% was defined as having hemodynamic significance. Vasospasms <30% were excluded from this analysis to avoid spectrum bias. Twenty-nine patients (311 vessel segments) were measured. The intra- and interobserver agreements were excellent for depicting vasospasm (k = 0.84 and 0.74, resp.). IV FDCT showed a sensitivity of 95.7%, specificity of 92.3%, positive predictive value of 93.6%, and negative predictive value of 94.7% for detecting vasospasm (>50%) with DSA as the reference. Bland-Altman plots revealed good agreement of assessing vasospasm between the two tests. The discrepancy of vasospasm severity was more noted in the distal location with high-severity. However, it was not statistically significant (Spearman's rank test; r = 0.15, P = 0.35). Therefore, IV FDCT could be a feasible noninvasive test to evaluate suspected significant vasospasm in SAH.

Early brain injury, an evolving frontier in subarachnoid hemorrhage research

Subarachnoid hemorrhage (SAH), predominantly caused by a ruptured aneurysm, is a devastating neurological disease that has a morbidity and mortality rate higher than 50%. Most of the traditional in vivo research has focused on the pathophysiological or morphological changes of large-arteries after intracisternal blood injection. This was due to a widely held assumption that delayed vasospasm following SAH was the major cause of delayed cerebral ischemia and poor outcome. However, the results of the CONSCIOUS-1 trial implicated some other pathophysiological factors, independent of angiographic vasospasm, in contributing to the poor clinical outcome. The term early brain injury (EBI) has been coined and describes the immediate injury to the brain after SAH, before onset of delayed vasospasm. During the EBI period, a ruptured aneurysm brings on many physiological derangements such as increasing intracranial pressure (ICP), decreased cerebral blood flow (CBF), and global cerebral ischemia. These events initiate secondary injuries such as blood-brain barrier disruption, inflammation, and oxidative cascades that all ultimately lead to cell death. Given the fact that the reversal of vasospasm does not appear to improve patient outcome, it could be argued that the treatment of EBI may successfully attenuate some of the devastating secondary injuries and improve the outcome of patients with SAH. In this review, we provide an overview of the major advances in EBI after SAH research.

Endothelin-1 gene polymorphisms influence cerebrospinal fluid endothelin-1 levels following aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage is a type of stroke with high morbidity and mortality. Increased endothelin-1 (ET-1) levels have been associated with increased risk of cerebral vasospasm, which is associated with increased morbidity. The purpose of this study was to investigate the relationships between ET-1 genotypes and ET-1 protein levels in cerebrospinal fluid (CSF) measured 72 hr before angiographic vasospasm measurement in subjects at high risk of cerebral vasospasm. Specifically, this study evaluated the differences between variant positive and variant negative groups of nine different ET-1 single-nucleotide polymorphisms (SNPs) in relationship with the ET-1 protein exposure rate. The CSF ET-1 protein levels were quantified using enzyme-linked immunosorbent assay. One functional SNP and eight ET-1 tagging SNPs were selected because they represent genetic variability in the entire ET-1 gene. The variant negative group of SNP rs2070699 was associated with a significantly higher ET-1 exposure rate than the variant positive group (p = 0.004), while the variant positive group of the rs5370 group showed a trend toward association with a higher ET-1 exposure rate (p = 0.051). Other SNPs were not informative. This is the first study to show differences in ET-1 exposure rate 72 hr before angiography in relation to ET-1 genotypes. These exploratory findings need to be replicated in a larger study; if replicated, these differences in genotypes may be a way to inform clinicians of those patients at a higher risk of increased ET-1 protein levels, which may lead to a higher risk of angiographic vasospasm.

Effect of cervical sympathetic block on cerebral vasospasm after subarachnoid hemorrhage in rabbits

PURPOSE

Cerebral vasospasm (CVS) is a major complication after subarachnoid hemorrhage (SAH) induced by the rupture of intracranial aneurysms. The aim of the present study was to investigate the effect and mechanism of cervical sympathetic block on cerebral vasospasm of the rabbits after SAH.

METHODS

After successful modeling of cervical sympathetic block, 18 healthy male white rabbits were randomly divided into three groups (n=6), ie, sham operation group (Group A), SAH group (Group B) and SAH with cervical sympathetic block group (Group C). Models of delayed CVS were established by puncturing cisterna magna twice with an injection of autologous arterial blood in Groups B and C. A sham injection of blood through cisterna magna was made in Group A. 0.5 ml saline was injected each time through a catheter for cervical sympathetic block after the first injection of blood three times a day for 3 d in Group B (bilateral alternating). 0.5 ml of 0.25% bupivacaine was injected each time through a catheter for cervical sympathetic block after the first injection of blood three times a day for 7 d in Group B. 2 ml venous blood and cerebrospinal fluid were obtained before (T1), 30 min (T2) and 7 d (T3) after the first injection of blood, respectively, and conserved in a low temperature refrigerator. Basilar artery value at T1, T2 and T3 was measured via cerebral angiography. The degree of damage to nervous system at T1 and T3 was recorded.

RESULTS

There was no significant difference in diameter of basilar artery at T1 among three groups. The diameters of basilar artery at T2 and T3 of Groups B and C were all smaller than that in Group A, which was smaller than Group C, with a significant difference. There was no significant difference in NO and NOS in plasma and cerebrospinal fluid among three groups. The NO and NOS contents at T2 and T3 of Groups B and C were all lower than Group A; Group C was higher than Group B, with a significant difference. The nerve function at T3 of Groups B and C were all lower than Group A and that of Group C higher than Group B, with a significant difference.

CONCLUSION

Cervical sympathetic block can relieve cerebral vasospasm after subarachnoid hemorrhage and increase NO content and NOS activity in plasma and cerebrospinal fluid to promote neural functional recovery.

Vasospasm following aneurysmal subarachnoid hemorrhage: Thrombocytopenia a marker

Background:

Symptomatic vasospasm (SV) is often seen after aneurysmal subarachnoid hemorrhage (aSAH). The pathophysiology suggests that platelets initiate the process and are consumed. This is likely to result in thrombocytopenia. The objective of this study was to find out if thrombocytopenia preceded or followed SV and to analyze the relationship between the two.

Materials and Methods:

The platelet counts of 74 patients were studied on day 1, 3, 5, 7, 9, 11, and 14 following aSAH. Clinical symptoms and raised velocities on transcranial Doppler were studied on the same days to determine SV. The relationship of platelet counts and SV were analyzed.

Results:

Thirty-nine (52.7%) patients developed SV. Platelet counts dropped on postictal day (PID) 3-7 and SV was commonly seen on PID 5-9. The median platelet counts were significantly lower in patients with SV when compared to those without SV. Platelet count <150,000/mm³ on PID 1 and 7 had statistically significant association (P < 0.001) with SV. The odds ratio was 5.1, 6.9, and 5.1 on PID 5, 7, and 9, respectively, for patients with relative thrombocytopenia (P < 0.001).

Conclusions:

There is a strong correlation between thrombocytopenia and SV. A platelet count < 150,000/mm³ on PID 1 and 7 predicts presence of SV. The relative risk of developing SV is >5 times for a patient with relative thrombocytopenia especially on PID 5-9. Additionally, it appears that thrombocytopenia precedes vasospasm and may be an independent predictor. However, this requires further studies for validation.

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

OBJECTIVES

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

METHOD

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

RESULTS

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

DISCUSSION

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

Endovascular treatment of subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a common and devastating form of stroke. A large number of patients with aSAH develop angiographic or clinical vasospasm responsible for high morbidity and mortality. Rapid advances in the field of interventional neurology and the development of minimally invasive techniques have resulted in expansion of potential therapeutic applications. Treatment of aSAH has benefited from this rapid advance in the field of endovascular therapies. In the first section of the review, we discuss the therapeutic options and techniques for embolizations of intracranial aneurysms. In the second section, we discuss evolving endovascular treatment methods employed to intervene in delayed complications of cerebral vasospasm in patients with aSAH.

Pseudo-continuous arterial spin labelling MRI for non-invasive, whole-brain, serial quantification of cerebral blood flow following aneurysmal subarachnoid haemorrhage

Delayed cerebral ischaemia (DCI) is the major cause of mortality and morbidity following aneurysmal subarachnoid haemorrhage (SAH). Recent experimental evidence from animal models has highlighted the need for non-invasive and robust measurements of brain tissue perfusion in patients in order to help understand the pathophysiology underlying DCI. Quantitative, serial, whole-brain cerebral perfusion measurements were obtained with pseudo-continuous arterial spin labelling (PCASL) magnetic resonance imaging (MRI) in six SAH patients acutely following endovascular coiling. This technique requires no injected contrast or radioactive isotopes. MRI scanning was well tolerated. Artefact from endovascular coils was minimal. PCASL MRI was able to detect time-dependent and patient-specific changes in voxel-wise and regional cerebral blood flow. These changes reflected changes in clinical condition. Data obtained in healthy controls using the same experimental protocol confirm the reliability and reproducibility of these results. This is the first study to use whole-brain, quantitative PCASL to identify time-dependent changes in cerebral blood flow at the tissue level in the acute period following SAH. This technique has the potential to better understand changes in cerebral pathophysiology as a consequence of aneurysm rupture.

Lack of functional patency of the lamina terminalis after fenestration following clipping of anterior circulation aneurysms

OBJECT

Fenestration of the lamina terminalis (FLT) during aneurysm surgery for subarachnoid hemorrhage can, in theory, improve CSF circulation from the lateral and third ventricles to the cortical subarachnoid space, which may, in turn, decrease the incidence of hydrocephalus and vasospasm. However, the actual effects of FLT on CSF circulation have been difficult to determine, due to confounding factors. In addition, it is unclear whether the lamina terminalis remains functionally patent when the brain resumes its normal position. The goal of this study was to assess the functional patency of the fenestrated lamina terminalis in patients who underwent surgery for ruptured aneurysms.

METHODS

This prospective study included 15 patients who underwent surgical clipping of ruptured anterior circulation aneurysms, with FLT performed during surgery. On postoperative Day 1, the external ventricular drain of each patient was closed, and 1 ml of Omnipaque 300, an iodine based contrast agent, was injected intraventricularly, accompanied by cranial maneuvering designed to position the contrast agent adjacent to the lamina terminalis. Three to 5 minutes after cranial maneuvering, the flow of contrast agent into the basal cisterns was assessed with CT imaging. Flow was verified by an increase in Hounsfield units in a prespecified "region of interest" within the basal cisterns on the CT scan. This procedure was performed using a standardized protocol designed in consultation with the Department of Radiology and approved by the institutional review board. One patient who underwent endoscopic third ventriculostomy was recruited as a positive control to validate the technique, and 1 patient who underwent aneurysm clipping but not FLT was recruited as a negative control.

RESULTS

Seventeen patients consented to study participation. In the 15 patients who underwent aneurysm clipping and FLT, and the negative control patient who underwent aneurysm clipping but not FLT, the contrast agent followed the normal ventricular pathway from the lateral ventricles into the fourth ventricle, and did not appear in the basal cisterns. In the positive control patient, the contrast agent robustly and immediately filled the basal cisterns.

CONCLUSIONS

Fenestration of the lamina terminalis did not result in functional patency of the lamina terminalis when performed as part of surgical clipping for ruptured aneurysms.

Intra-arterial dantrolene for refractory cerebral vasospasm after aneurysmal subarachnoid hemorrhage

BACKGROUND

Intravenous dantrolene has been used to prevent and treat cerebral vasospasm. We report a case of refractory cerebral vasospasm treated with intra-arterial dantrolene after aneurysmal subarachnoid hemorrhage.

METHODS

A 56-year-old woman suffered a diffuse subarachnoid hemorrhage from a ruptured anterior communicating artery aneurysm which was successfully treated with coil embolization. She subsequently developed bilateral severe angiographic vasospasm which was treated with intra-arterial vasodilators. However, owing to the recurrence of vasospasm, intra-arterial dantrolene followed by balloon angioplasty was used.

RESULTS

There was moderate improvement of the severe vasospasm in bilateral A1 segments of the anterior cerebral arteries after microcatheter-based intra-arterial infusion of 30 ml (1 mg/ml) dantrolene. Patient's hemodynamic parameters were monitored during and after the procedure and no significant changes were seen after dantrolene infusion. A follow up cerebral angiogram after 1 day demonstrated the persistence of therapeutic effect.

CONCLUSION

Intra-arterial dantrolene induced a sustained improvement in cerebral vasospasm secondary to ruptured aneurysm. No significant side effects were observed during or after the infusion of the drug.

Relevance of animal models of subarachnoid hemorrhage for examining neurobehavioral changes

BACKGROUND AND PURPOSE

For many years survival and neurological functionality of patients were the main outcome measures after treatment of intracranial aneurysms. But, the variable outcomes of patients operated on in a delayed fashion or before the aneurysm rupture indicate that more precise measures are needed for assessment of not only the neurological but also the neuropsychological outcome. However, development and testing of such new tools requires better understanding of pathomechanisms of neurobehavioral changes evoked by aneurysmal subarachnoid hemorrhage (aSAH), which can be achieved using animal models.

METHODS

We reviewed and selected (1) animal models developed to investigate delayed cerebral vasospasm that could be useful for examining effects of brain injury evoked by aSAH and (2) a battery of neurobehavioral animal testing that can be used for assessment of patients after aSAH.

RESULTS

For every species used as an aSAH model, a battery of neurobehavioral test exists.

CONCLUSION

Albeit some limitations must be recognized, research using animal models of SAH should continue to play a critical role in assessment of cognitive and behavioral functions after aSAH.

Intraventricular nicardipine for aneurysmal subarachnoid hemorrhage related vasospasm: assessment of 90 days outcome

BACKGROUND

Delayed cerebral arterial vasospasm is one of the leading causes of death and disability after aneurysmal subarachnoid hemorrhage (aSAH). We evaluated the safety of intraventricular nicardipine (IVN) for vasospasm (VSP) in aSAH patients, and outcomes compared with a control population.

METHODS

A retrospective case-control study was conducted for aSAH patients treated with IVN at Mayo Clinic, Jacksonville, FL, from March 2009 to January 2011. Controls were matched by age, gender, and Fisher grade. Safety was evaluated by the incidence of intracranial bleeding and infection. Outcome was measured by Glasgow Outcome Scale at 30 and 90 days. IVN effects on VSP were evaluated by transcranial Doppler (TCD).

RESULTS

Thirteen aSAH patients and one arteriovenous malformation (AVM)-related SAH patient received IVN for VSP and were matched with 14 aSAH patients without IVN therapy for a total of 28 cases. Median dose was 4 mg (range 3-7), and median number of doses was seven (range 1-17). Mean flow velocity decreased after IVN (120.2 and 101.6 cm/s-82.0 and 72.8 cm/s, right and left middle cerebral arteries, respectively). No significant difference was seen in clinical outcomes between controls and cases at 30 days (P = 0.443) and 90 days (P = 0.153). There were no incidences of bleeding or infection with 111 nicardipine injections.

CONCLUSIONS

IVN appears relatively safe and effective in treating VSP by TCD, but there was no difference in clinical outcomes between nicardipine and control patients at 30 and 90 days. In the future, larger studies are needed to evaluate the clinical outcome with IVN.

Milrinone and homeostasis to treat cerebral vasospasm associated with subarachnoid hemorrhage: the Montreal Neurological Hospital protocol

INTRODUCTION

For the treatment of cerebral vasospasm, current therapies have focused on increasing blood flow through blood pressure augmentation, hypervolemia, the use of intra-arterial vasodilators, and angioplasty of proximal cerebral vessels. Through a large case series, we present our experience of treating cerebral vasospasm with a protocol based on maintenance of homeostasis (correction of electrolyte and glucose disturbances, prevention and treatment of hyperthermia, replacement of fluid losses), and the use of intravenous milrinone to improve microcirculation (the Montreal Neurological Hospital protocol). Our objective is to describe the use milrinone in our practice and the neurological outcomes associated with this approach.

METHODS

Large case series based on the review of all patients diagnosed with delayed ischemic neurologic deficits after aneurysmal subarachnoid hemorrhage between April 1999 and April 2006.

RESULTS

88 patients were followed for a mean time of 44.6 months. An intravenous milrinone infusion was used for a mean of 9.8 days without any significant side effects. No medical complications associated with this protocol were observed. There were five deaths; of the surviving patients, 48.9 % were able to go back to their previous baseline and 75 % had a good functional outcome (modified Rankin scale ≤ 2).

CONCLUSION

A protocol using intravenous milrinone, and the maintenance of homeostasis is simple to use and requires less intensive monitoring and resources than the standard triple H therapy. Despite the obvious limitations of this study's design, we believe that it would be now appropriate to proceed with formal prospective studies of this protocol.

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.

Endothelin-1 and endothelin receptor gene variants and their association with negative outcomes following aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a devastating disease that affects approximately 30,000 people a year in the United States. Delayed cerebral ischemia (DCI) and cerebral vasospasm (CV) are common complications after aSAH. In addition, aSAH patients have a high risk of poor long-term outcomes. Endothelin-1 (ET-1), a potent vasoconstrictor, or its two types of receptors, ET receptor A (ETA) and ET receptor B (ETB), may play a role in the pathogenesis of DCI and CV. Genetic variations within the ET-1, ETA, or ETB genes may also account for variance observed in the outcomes of aSAH patients. The purpose of this study was to describe the distribution of the Lys198Asn polymorphism, a known functional SNP in the ET-1 gene, and tagging SNPs of the ET-1, ETA, and ETB genes in individuals recovering from aSAH. This study also investigated the relationships among the ET polymorphisms, DCI, and global functional outcomes measured at 3 and 6 months after aSAH. Participants included individuals aged 18-75 years with a diagnosis of aSAH. There was a trend found between the variant allele of an ET-1 SNP (rs6912834) and angiographic vasospasm. There were also associations found between two ETB SNPs (rs9574124 and rs3027111) and poor outcomes as measured by the Glasgow Outcome scale at 3 months. These findings support the role of ET-1 and ETB in recovery following aSAH.

A new percutaneous model of Subarachnoid Haemorrhage in rats

OBJECTIVE

Describe the results obtained with a new percutaneous, intracisternal model of Subarachnoid Haemorrhage (SAH) in Wistar rats by a single injection of non-heparinised, autologous blood.

METHODS

Once anaesthetized the rat was fixed prone in a stereotaxic frame. After identifying the projection of the occipital bone, the needle of the stereotaxic frame aspirated towards the foramen magnum until it punctured through the atlanto-occipital membrane and obtained cerebrospinal fluid. Autologous blood (100 μl) was withdrawn from the tail and injected intracisternally. This procedure was repeated in the sham group, injecting 100 μl of isotonic saline. On the fifth day post-intervention, the rats were anaesthetized and the brain was exposed. After a lethal injection of ketamine the brain was explanted and fixed in paraformaldehyde. Gross and microscopic inspection of the slices revealed the existence or non-existence of pathological findings.

RESULTS

A total of 26 rats were operated on (13 in the SAH group/13 in the sham group). The average time between obtaining the blood and the start of the intracisternal injection was 10 (±1.2)s. The mortality rate was 16.12%. Intra- and extraparenchymal ischemic-haemorrhagic lesions were found in three animals (23.07%)--all from the SAH group--with ischemic neuronal cell injury detected in two of the three.

CONCLUSIONS

The new murine model of SAH is easy to perform, with low mortality, minimally invasive, which makes it interesting for future studies on vasospasm-related delayed SAH complications.

The importance of early brain injury after subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a medical emergency that accounts for 5% of all stroke cases. Individuals affected are typically in the prime of their lives (mean age 50 years). Approximately 12% of patients die before receiving medical attention, 33% within 48 h and 50% within 30 days of aSAH. Of the survivors 50% suffer from permanent disability with an estimated lifetime cost more than double that of an ischemic stroke. Traditionally, spasm that develops in large cerebral arteries 3-7 days after aneurysm rupture is considered the most important determinant of brain injury and outcome after aSAH. However, recent studies show that prevention of delayed vasospasm does not improve outcome in aSAH patients. This finding has finally brought in focus the influence of early brain injury on outcome of aSAH. A substantial amount of evidence indicates that brain injury begins at the aneurysm rupture, evolves with time and plays an important role in patients' outcome. In this manuscript we review early brain injury after aSAH. Due to the early nature, most of the information on this injury comes from animals and few only from autopsy of patients who died within days after aSAH. Consequently, we began with a review of animal models of early brain injury, next we review the mechanisms of brain injury according to the sequence of their temporal appearance and finally we discuss the failure of clinical translation of therapies successful in animal models of aSAH.

Safety and efficacy of sildenafil citrate in reversal of cerebral vasospasm: A feasibility study

Objective:

Cerebral vasospasm is the commonest cause for mortality and morbidity in patients following clipping of a ruptured aneurysm. Selective phosphodiesterase (PDE) inhibitor like sildenafil acts as a vasodilator. The objective of this study was to evaluate the safety and feasibility of oral sildenafil citrate in patients with symptomatic refractory vasospasm.

Methods:

A total of 832 patients with aneurysmal subarachnoid bleed were operated in 4 years. Two hundred and seventy-three patients had vasospasm. Of these, 72 patients had refractory cerebral vasospasm. Vasospasm was defined as refractory when institution of “HHH” failed to reverse the transcranial Doppler (TCD) values even after 24 hours. Computed tomography (CT) scan showed no infarct, hematoma, or hydrocephalus, and the serum electrolytes were within normal limits. They received 100–150 mg of sildenafil every 4 hours. Response was evaluated by 2-hourly TCD.

Results:

Eight patients had sustained (TCD values normal for >48 hours) and four had temporary relief in vasospasm, as suggested. Four patients developed complications significant enough to terminate the therapy.

Conclusions:

Sildenafil citrate may be effective in patients with refractory symptomatic vasospasm. It calls upon the pharmacologists and scientists to discover newer supraselective PDE inhibitors, specific to PDE receptors in brain vessels.

Transcranial Doppler ultrasonography for diagnosis of cerebral vasospasm after aneurysmal subarachnoid hemorrhage: mean blood flow velocity ratio of the ipsilateral and contralateral middle cerebral arteries

BACKGROUND

Transcranial Doppler (TCD) is widely accepted to monitor cerebral vasospasm after subarachnoid hemorrhage (SAH); however, its predictive value remains controversial.

OBJECTIVE

To investigate the predictive reliability of an increase in the mean blood flow velocity (mBFV) ratio of the ipsilateral to contralateral middle cerebral arteries (I/C mBFV) compared with the conventional absolute flow velocity.

METHODS

We retrospectively investigated the clinical and radiologic data of consecutive patients with SAH admitted from July 2003 to August 2009 who underwent TCD ultrasonography. The highest mBFV value in bilateral middle cerebral arteries was recorded, while delayed cerebral ischemia (DCI) was defined as neurological deficits or computed tomographic evidence of cerebral infarction caused by vasospasm. The ipsilateral side was defined as the side with higher mBFV value when evaluating the I/C mBFV. We thus elucidated the reliability of this rate in comparison with the conventional method for predicting DCI with receiver operating characteristic (ROC) analysis.

RESULTS

One hundred and forty-two patients were retrospectively analyzed with specific data from 1262 TCD studies. The ROC curve showed that the overall predictive value for DCI had an area under the curve of 0.86 (95% confidence interval: 0.76-0.96) when the I/C mBFV was used vs 0.80 (0.71-0.88) when the absolute flow velocity was used. The threshold value that best discriminated between patients with and without DCI was I/C mBFV of 1.5.

CONCLUSION

In patients with SAH, the I/C mBFV demonstrated a more significant correlation to vasospasm than the absolute mean flow velocity.

A Simplified Method for Administration of Intra-Arterial Nicardipine for Vasospasm With Cervical Catheter Infusion

BACKGROUND:

Cerebral vasospasm is a major cause of morbidity and mortality after aneurysmal subarachnoid hemorrhage. Nicardipine has previously been used to treat vasospasm through superselective intracranial microcatheter injections.

OBJECTIVE:

To evaluate a simple method of treatment of vasospasm with slow infusion of nicardipine from a cervical catheter.

METHODS:

Twenty-seven patients with symptomatic vasospasm were treated over 4 years with cervical catheter infusions. Nicardipine was infused at 20 mg/h for 30 to 60 minutes. Angioplasty was used in severe cases at the operator's discretion. Outcome at discharge and follow-up was evaluated with Glasgow Outcome Scale.

RESULTS:

Twenty-seven patients (17 women, 12 men) received intra-arterial therapy for vasospasm. Vasospasm treatment was done at a mean post-hemorrhage date of 7.2 days (range, 4-15 days). They underwent 48 sessions of treatment (mean, 1.8 per patient) in 72 separate arterial territories. Twelve patients underwent multiple treatments. The mean dose used per session was 19.2 mg (range, 5-50 mg). Four patients underwent angioplasty for severe vasospasm. Twenty-two patients (81.5%) had clinical improvement after the infusion. Angiographic improvement was seen in 86.1% of the vessels analyzed, which had moderate or severe spasm before infusion. Overall, 17 patients (62.9%) had good outcome (Glasgow Outcome Scale score, 4 and 5) at discharge, 11 had poor outcome, and 1 patient died. Follow-up was available in 19 patients, and 18 were doing well (Glasgow Outcome Scale score, 4 and 5).

CONCLUSION:

Intra-arterial nicardipine is an effective and safe treatment for cerebral vasospasm. In most patients, infusion can be performed from the cervical catheter, with microcatheter infusion and angioplasty reserved for the more severe and resistant cases.