Global cerebral edema after subarachnoid hemorrhage: frequency, predictors, and impact on outcome

Controversies and evolving new mechanisms in subarachnoid hemorrhage

Despite decades of study, subarachnoid hemorrhage (SAH) continues to be a serious and significant health problem in the United States and worldwide. The mechanisms contributing to brain injury after SAH remain unclear. Traditionally, most in vivo research has heavily emphasized the basic mechanisms of SAH over the pathophysiological or morphological changes of delayed cerebral vasospasm after SAH. Unfortunately, the results of clinical trials based on this premise have mostly been disappointing, implicating some other pathophysiological factors, independent of vasospasm, as contributors to poor clinical outcomes. Delayed cerebral vasospasm is no longer the only culprit. In this review, we summarize recent data from both experimental and clinical studies of SAH and discuss the vast array of physiological dysfunctions following SAH that ultimately lead to cell death. Based on the progress in neurobiological understanding of SAH, the terms "early brain injury" and "delayed brain injury" are used according to the temporal progression of SAH-induced brain injury. Additionally, a new concept of the vasculo-neuronal-glia triad model for SAH study is highlighted and presents the challenges and opportunities of this model for future SAH applications.

SIRT1 inhibition by sirtinol aggravates brain edema after experimental subarachnoid hemorrhage

Secondary brain injury following subarachnoid hemorrhage (SAH) is poorly understood. We utilized a rat model of SAH to investigate whether SIRT1 has a protective role against brain edema via the tumor suppressor protein p53 pathway. Experimental SAH was induced in adult male Sprague-Dawley rats by prechiasmatic cistern injection. Brain SIRT1 protein levels were examined in the sham controls and in rats 6, 12, 24, 48, and 72 hr after SAH induction. The SIRT1 inhibitor sirtinol was administered by intracerebroventricular infusion. Neurological functions, blood-brain barrier (BBB) disruption, and brain water content were assessed. Endothelial cell apoptosis, caspase 3 protein expression, p53 acetylation, and matrix metalloproteinase-9 (MMP-9) activity were examined. Compared with the control, SIRT1 protein expression increased remarkably, reaching a maximum at 24 hr after SAH. Sirtinol treatment significantly lowered SIRT1 expression, accompanied by deteriorated neurologic function, BBB disruption, brain edema, increased endothelial cell apoptosis, and increased MMP-9 gelatinase activity compared with the rats treated with vehicle only. Our results suggest that increased expression of endogenous SIRT1 may play a neuroprotective role against brain edema after SAH.

Protective effect of quercetin against oxidative stress and brain edema in an experimental rat model of subarachnoid hemorrhage

Quercetin has been demonstrated to play an important role in altering the progression of ischemic brain injuries and neurodegenerative diseases by protecting against oxidative stress. The effects of quercetin on brain damage after subarachnoid hemorrhage (SAH), however, have not been investigated. This study was designed to explore the effects of quercetin on oxidative stress and brain edema after experimental SAH using four equal groups (n = 16) of adult male Sprague-Dawley (SD) rats, including a sham group, an SAH + vehicle group, an SAH + quercetin10 group, and an SAH + quercetin50 group. The rat SAH model was induced by injection of 0.3 ml of non-heparinised arterial blood into the prechiasmatic cistern. In the SAH + quercetin10 and SAH + quercetin50 groups, doses of 10 mg/kg and 50 mg/kg quercetin, respectively, were directly administered by intraperitoneal injection at 30 min, 12 h, and 24 h after SAH induction. Cerebral tissue samples were extracted for enzymatic antioxidant determination, lipid peroxidation assay, caspase-3 activity and water content testing 48 h after SAH. Treatment with a high dose (50 mg/kg) of quercetin markedly enhanced the activities of copper/zinc superoxide dismutase (CuZn-SOD) and glutathione peroxidase (GSH-Px), and treatment with this dose significantly reduced the level of malondialdehyde (MDA). Caspase-3 and brain edema was ameliorated and neurobehavioral deficits improved in rats that received the high dose of quercetin. The findings suggest that the early administration of optimal dose of quercetin may ameliorate brain damage and provide neuroprotection in the SAH model, potentially by enhancing the activity of endogenous antioxidant enzymes and inhibiting free radical generation.

The role of the microcirculation in delayed cerebral ischemia and chronic degenerative changes after subarachnoid hemorrhage

The mortality after aneurysmal subarachnoid hemorrhage (SAH) is 50%, and most survivors suffer severe functional and cognitive deficits. Half of SAH patients deteriorate 5 to 14 days after the initial bleeding, so-called delayed cerebral ischemia (DCI). Although often attributed to vasospasms, DCI may develop in the absence of angiographic vasospasms, and therapeutic reversal of angiographic vasospasms fails to improve patient outcome. The etiology of chronic neurodegenerative changes after SAH remains poorly understood. Brain oxygenation depends on both cerebral blood flow (CBF) and its microscopic distribution, the so-called capillary transit time heterogeneity (CTH). In theory, increased CTH can therefore lead to tissue hypoxia in the absence of severe CBF reductions, whereas reductions in CBF, paradoxically, improve brain oxygenation if CTH is critically elevated. We review potential sources of elevated CTH after SAH. Pericyte constrictions in relation to the initial ischemic episode and subsequent oxidative stress, nitric oxide depletion during the pericapillary clearance of oxyhemoglobin, vasogenic edema, leukocytosis, and astrocytic endfeet swelling are identified as potential sources of elevated CTH, and hence of metabolic derangement, after SAH. Irreversible changes in capillary morphology and function are predicted to contribute to long-term relative tissue hypoxia, inflammation, and neurodegeneration. We discuss diagnostic and therapeutic implications of these predictions.

Targeted over-expression of endothelin-1 in astrocytes leads to more severe brain damage and vasospasm after subarachnoid hemorrhage

Background

Endothelin-1 (ET-1) is a potent vasoconstrictor, and astrocytic ET-1 is reported to play a role in the pathogenesis of cerebral ischemic injury and cytotoxic edema. However, it is still unknown whether astrocytic ET-1 also contributes to vasogenic edema and vasospasm during subarachnoid hemorrhage (SAH). In the present study, transgenic mice with astrocytic endothelin-1 over-expression (GET-1 mice) were used to investigate the pathophysiological role of ET-1 in SAH pathogenesis.

Results

The GET-1 mice experienced a higher mortality rate and significantly more severe neurological deficits, blood–brain barrier breakdown and vasogenic edema compared to the non-transgenic (Ntg) mice following SAH. Oral administration of vasopressin V_1a receptor antagonist, SR 49059, significantly reduced the cerebral water content in the GET-1 mice. Furthermore, the GET-1 mice showed significantly more pronounced middle cerebral arterial (MCA) constriction after SAH. Immunocytochemical analysis showed that the calcium-activated potassium channels and the phospho-eNOS were significantly downregulated, whereas PKC-α expression was significantly upregulated in the MCA of the GET-1 mice when compared to Ntg mice after SAH. Administration of ABT-627 (ET_A receptor antagonist) significantly down-regulated PKC-α expression in the MCA of the GET-1 mice following SAH.

Conclusions

The present study suggests that astrocytic ET-1 involves in SAH-induced cerebral injury, edema and vasospasm, through ET_A receptor and PKC-mediated potassium channel dysfunction. Administration of ABT-627 (ET_A receptor antagonist) and SR 49059 (vasopressin V_1a receptor antagonist) resulted in amelioration of edema and vasospasm in mice following SAH. These data provide a strong rationale to investigate SR 49059 and ABT-627 as therapeutic drugs for the treatment of SAH patients.

The SAH Score: a comprehensive communication tool

BACKGROUND

The Hunt and Hess grade and World Federation of Neurological Surgeons (WFNS) scale are commonly used to predict mortality after aneurysmal subarachnoid hemorrhage (aSAH). Our objective was to improve the accuracy of mortality prediction compared with the aforementioned scales by creating the "SAH score."

METHODS

The aSAH database at our institution was analyzed for factors affecting in-hospital mortality using multiple logistic regression analysis. Scores were weighted based on relative risk of mortality after stratification of each of these variables. Glasgow Coma Scale (GCS) was subdivided into groups of 3-4 (score = 1), 5-8 (score = 2), 9-13 (score = 3), and 14-15 (score = 4). Age was categorized into 4 subgroups: 18-49 (score = 1), 50-69 (score = 2), 70-79 (score = 3), and 80 years or more (score = 4). Medical comorbidities were subdivided into none (score = 1), 1 (score = 2), or 2 or more (score = 3).

RESULTS

In total, 1134 patients were included; all-cause SAH hospital mortality was 18.3%. Admission GCS, age, and medical comorbidities significantly affected mortality after multivariate analysis (P < .05). Summated scores ranged from 0 to 8 with escalating mortality at higher scores (0 = 2%, 1 = 6%, 2 = 8%, 3 = 15%, 4 = 30%, 5 = 58%, 6 = 79%, 7 = 87%, and 8 = 100%). Positive predictive value (PPV) for scores in the range 7-8 was 88.5%, whereas 6-8 was 83%. Negative predictive value (NPV) was 94% for range 0-2 and 92% for 0-3. The area under the curve (AUC) for the SAH score was .821 (good accuracy), compared with the WFNS scale (AUC .777, fair accuracy) and the Hunt and Hess grade (AUC .771, fair accuracy).

CONCLUSIONS

The SAH score was found to be more accurate in predicting aSAH mortality compared with the Hunt and Hess grade and WFNS scale.

Plasma taurine as a predictor of poor outcome in patients with mild neurological deficits after aneurysmal subarachnoid hemorrhage

Object

The object of this study was to determine the relationship between plasma taurine and subarachnoid hemorrhage (SAH) outcome.

Methods

Forty patients with SAH and mild neurological deficits were included in this prospective, blinded cohort study. Plasma taurine levels were measured using high-performance liquid chromatography on admission and were correlated with patient outcomes at discharge.

Results

Twenty-five percent of the patients ultimately had a poor outcome. Plasma taurine concentrations at admission were increased (2-fold) in SAH patients with a favorable outcome and were further increased (6-fold) in those who had a poor outcome. Increased taurine levels identified patients who would be discharged with a poor outcome, with sensitivity and specificity values of approximately 80% and 100%, respectively, and positive and negative predictive values of approximately 90%. Delayed cerebral vasospasm showed an OR of 27.9 (95% CI 1.090–714.9) for a poor outcome, whereas an increased taurine concentration had an OR of 105 for a poor outcome (95% CI 8.3–1328.0, p < 0.001).

Conclusions

Increased plasma taurine concentrations on admission predict a poor outcome in SAH.

Protective effects of urinary trypsin inhibitor on vascular permeability following subarachnoid hemorrhage in a rat model

AIMS

Inflammation and apoptosis play important roles in increasing vascular permeability following subarachnoid hemorrhage (SAH). The objective of this study was to evaluate whether urinary trypsin inhibitor (UTI), a serine protease inhibitor, attenuates vascular permeability by its antiinflammatory and antiapoptotic effects after experimental SAH.

METHODS

Subarachnoid hemorrhage models were established in adult male Sprague-Dawley rats by endovascular perforation. UTI was administered by intraperitoneal injection immediately following SAH. Brain edema was assessed by magnetic resonance imaging (MRI) at 24 h after SAH. Neurological deficits, brain water content, vascular permeability, malondialdehyde (MDA) concentration, and myeloperoxidase (MPO) activity were evaluated. Immunohistochemical staining and Western blot were used to explore the underlying protective mechanism of UTI.

RESULTS

Urinary trypsin inhibitor 50,000 U/kg significantly attenuated brain edema and neurological deficits and reduced vascular permeability at 24 h after SAH. MDA concentration and MPO activity in hippocampus were significantly decreased with UTI treatment. Furthermore, the levels of phosphorylated JNK, NF-κB (p65), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and proapoptotic protein p53, caspase-3 were elevated in the microvascular endothelial cells of the hippocampus after SAH, which were alleviated with UTI treatment.

CONCLUSION

Urinary trypsin inhibitor reduced vascular permeability after SAH through its antiinflammatory and antiapptotic effects via blocking the activity of JNK, NF-κB, and p53.

Pharmacologic Options for Prevention and Management of Cerebral Vasospasm in Aneurysmal Subarachnoid Hemorrhage

Background

Cerebral vasospasm and delayed cerebral ischemia continue to be major contributors to morbidity and mortality after aneurysmal subarachnoid hemorrhage (SAH).

Purpose

The purpose of this review was to evaluate the pharmacotherapy interventions for the prevention and management of cerebral vasospasm in patients with SAH.

Methods

A search of MEDLINE (January 1966-April 2012) and EMBASE (January 1974-April 2012) was conducted to retrieve relevant studies of pharmacotherapy options for prevention or treatment of cerebral vasospasm in SAH.

Results

Triple-H therapy (hypervolemia, hemodilution, hypertension) has been a widely accepted option by many clinicians for the management of cerebral vasospasm and delayed cerebral ischemia. However, implementation of Triple-H therapy varies considerably at individual institutions. Nimodipine and nicardipine have demonstrated the most dependable improvements in patient outcomes to date. High doses of intravenous magnesium have failed to show consistent benefits. Magnesium supplementation to prevent hypomagnesaemia should be employed. Statin therapy should be continued in patients who are taking statins prior to hospital admission. Use of statins in naive patients may be recommended when the results of an ongoing prospective study are available. Of the available locally administered pharmacologic therapies, nicardipine and thrombolytics appear to provide the most intriguing benefit-to-risk ratio. However, the data supporting the use of locally administered therapy are modest at best and require careful consideration prior to application.

Conclusions

Clinical studies have tested a variety of pharmacotherapy interventions for the prevention and treatment of cerebral vasospasm. Of available therapies, nimodipine has demonstrated consistent benefits and should be employed routinely. Demonstration of reduced cerebral vasospasm and improved neurological outcomes in larger prospective studies are needed for most pharmacologic therapy options prior to recommending their routine use.

Depressed mood and quality of life after subarachnoid hemorrhage

BACKGROUND

Cognitive impairment is widely considered the main cause of disability and handicap after subarachnoid hemorrhage (SAH). The impact of depression on recovery after SAH remains poorly defined. We sought to determine the frequency of post-SAH depression, identify risk factors for its development, and evaluate the impact of depression on quality of life (QOL) during the first year of recovery.

METHODS

We prospectively studied 216 of 534 SAH patients treated between July 1996 and December 2001 with complete one-year follow-up data. Depression was evaluated with the Center for Epidemiological Studies Depression (CES-D) scale, cognitive status with the Telephone Interview for Cognitive Status (TICS), and QOL with the Sickness Impact Profile (SIP) 3 and 12 months after SAH.

RESULTS

Depressed mood occurred in 47% of patients during the first year of recovery; 26% were depressed at both 3 and 12 months. Non-white ethnicity predicted early (3 month) and late (12 month) depressions; early depression was also predicted by previously-diagnosed depression, cigarette smoking, and cerebral infarction, whereas late depression was predicted by prior social isolation and lack of medical insurance. Depression was associated with inferior QOL in all domains of the SIP, and changes in depression status were associated with striking parallel changes in QOL, disability, and cognitive function during the first year of recovery. CES-D scores accounted for over 60% of the explained variance in SIP total scores, whereas TICS performance accounted for no more than 6%.

CONCLUSION

Depression affects nearly half of SAH patients during the first year of recovery, and is associated with poor QOL. Systematic screening and early treatment for depression are promising strategies for improving outcome after SAH.

Inflammation, cerebral vasospasm, and evolving theories of delayed cerebral ischemia

Cerebral vasospasm (CVS) is a potentially lethal complication of aneurysmal subarachnoid hemorrhage (aSAH). Recently, the symptomatic presentation of CVS has been termed delayed cerebral ischemia (DCI), occurring as early as 3-4 days after the sentinel bleed. For the past 5-6 decades, scientific research has promulgated the theory that cerebral vasospasm plays a primary role in the pathology of DCI and subsequently delayed ischemic neurological decline (DIND). Approximately 70% of patients develop CVS after aSAH with 50% long-term morbidity rates. The exact etiology of CVS is unknown; however, a well-described theory involves an antecedent inflammatory cascade with alterations of intracellular calcium dynamics and nitric oxide fluxes, though the intricacies of this inflammatory theory are currently unknown. Consequently, there have been few advances in the clinical treatment of this patient cohort, and morbidity remains high. Identification of intermediaries in the inflammatory cascade can provide insight into newer clinical interventions in the prevention and management of cerebral vasospasm and will hopefully prevent neurological decline. In this review, we discuss current theories implicating the inflammatory cascade in the development of CVS and potential treatment targets.

Review and recommendations on management of refractory raised intracranial pressure in aneurysmal subarachnoid hemorrhage

Intracranial hypertension is commonly encountered in poor-grade aneurysmal subarachnoid hemorrhage patients. Refractory raised intracranial pressure is associated with poor prognosis. The management of raised intracranial pressure is commonly referenced to experiences in traumatic brain injury. However, pathophysiologically, aneurysmal subarachnoid hemorrhage is different from traumatic brain injury. Currently, there is a paucity of consensus on the management of refractory raised intracranial pressure in spontaneous subarachnoid hemorrhage. We discuss in this paper the role of hyperosmolar agents, hypothermia, barbiturates, and decompressive craniectomy in managing raised intracranial pressure refractory to first-line treatment, in which preliminary data supported the use of hypertonic saline and secondary decompressive craniectomy. Future clinical trials should be carried out to delineate better their roles in management of raised intracranial pressure in aneurysmal subarachnoid hemorrhage patients.

Inhibiting HIF-1α by 2ME2 ameliorates early brain injury after experimental subarachnoid hemorrhage in rats

Although hypoxia-inducible factor-1α (HIF-1α) has been extensively studied in brain injury following hypoxia-ischemia, the role of HIF-1α in early brain injury (EBI) after subarachnoid hemorrhage (SAH) remains unclear. The present study was under taken to investigate a potential role of HIF-1α in EBI after SAH. Rats (n=60) were randomly divided into sham+vehicle, SAH+2-methoxyestradiol (2ME2), and SAH+vehicle groups. The SAH model was induced by endovascular perforation and all the rats were subsequently sacrificed at 24h after SAH. We found that treatment with 2ME2 suppressed the expression of HIF-1α, BNIP3 and VEGF and reduced cell apoptosis, blood-brain barrier (BBB) permeability, brain edema, and neurologic scores. Double fluorescence labeling revealed that HIF-1α was expressed predominantly in the nuclei of neurons and TUNEL-positive cells. Our work demonstrated that HIF-1α may play a role in EBI after SAH, causing cell apoptosis, BBB disruption, and brain edema by up-regulating its downstream targets, BNIP3 and VEGF. These effects were blocked by the HIF-1α inhibitor, 2ME2.

Pathophysiological Role of Global Cerebral Ischemia following Subarachnoid Hemorrhage: The Current Experimental Evidence

Subarachnoid hemorrhage (SAH) is the subtype of stroke with one of the highest mortality rates and the least well-understood pathophysiologies. One of the very early events which may occur after SAH is a significant decrease of cerebral perfusion pressure (CPP) caused by the excessive increase of intracranial pressure during the initial bleeding. A severely decreased CPP results in global cerebral ischemia, an event also occurring after cardiac arrest. The aim of the current paper is to review the pathophysiological events occurring in experimental models of SAH and global cerebral ischemia and to evaluate the contribution and the importance of global cerebral ischemia for the pathophysiology of SAH.

Decompressive craniectomy: past, present and future

Decompressive craniectomy (DC)--a surgical procedure that involves removal of part of the skull to accommodate brain swelling--has been used for many years in the management of patients with brain oedema and/or intracranial hypertension, but its place in contemporary practice remains controversial. Results from a recent trial showed that early (neuroprotective) DC was not superior to medical management in patients with diffuse traumatic brain injury. An ongoing trial is investigating the clinical and cost effectiveness of secondary DC as a last-tier therapy for post-traumatic refractory intracranial hypertension. With regard to ischaemic stroke (malignant middle cerebral artery infarction), a recent Cochrane review concluded that DC improves survival compared with medical management, but that a higher proportion of DC survivors experience moderately severe or severe disability. Although many patients have a good outcome, the issue of DC-related disability raises important ethical issues. As DC and subsequent cranioplasty are associated with a number of complications, indiscriminate use of this surgery is not appropriate. Here, we review the evidence and present considerations regarding surgical technique, ethics and cost-effectiveness of DC. Prospective clinical trials and cohort studies are essential to enable optimization of patient care and outcomes.

Attenuation of neurological injury with early baicalein treatment following subarachnoid hemorrhage in rats

OBJECT

Baicalein has been shown to offer neuroprotection in the ischemic brain, but its effect in subarachnoid hemorrhage (SAH) is unknown. The authors used a double-hemorrhage model to study the role of early baicalein treatment in SAH.

METHODS

Subarachnoid hemorrhage was induced in male Wistar rats through a repeat injection of autologous blood at a 48-hour interval. Rats subjected or not subjected to SAH received a 30-mg/kg baicalein injection 3 hours after SAH and daily for 6 consecutive days, and results were compared with those obtained in vehicle-treated control rats. Mortality of the rats was recorded. Neurological outcome was assessed daily. Cerebrospinal fluid dialysates were collected and examined for glutamate concentrations. Cerebral vasospasm (CVS), brain water content, neuron variability, expression of glutamate transporter-1 (GLT-1), immunoreactivity of astrocyte, and level of malondialdehyde, activities of superoxide dismutase (SOD), and catalase in brain tissues content were determined on post-SAH Day 7.

RESULTS

Mortality rate, neuronal degeneration, brain water content, and CVS were decreased and neurological function improved in the baicalein-treated rats. Baicalein increased astrocyte activity and preserved GLT-1, which attenuated the glutamate surge after SAH. Baicalein also provided antioxidative stress by preserving activities of SOD and catalase and decreased malondialdehydelevel after SAH. The glutamate, body weight, neurological scores, and glial fibrillary acidic protein activity were significantly correlated. The CVS was correlated with neuronal degeneration, and GLT-1 was correlated with oxidative stress.

CONCLUSIONS

Early baicalein treatment attenuated CVS and limited neurological injury following SAH. These data may indicate clinical utility for baicalein as an adjunct therapy to reduce brain injury and improve patient outcomes.

Role of SCH79797 in maintaining vascular integrity in rat model of subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Plasma thrombin concentration is increased after subarachnoid hemorrhage (SAH). However, the role of thrombin receptor (protease-activated receptor-1 [PAR-1]) in endothelial barrier disruption has not been studied. The aims of this study were to investigate the role of PAR-1 in orchestrating vascular permeability and to assess the potential therapeutics of a PAR-1 antagonist, SCH79797, through maintaining vascular integrity.

METHODS

SCH79797 was injected intraperitoneally into male Sprauge-Dawley rats undergoing SAH by endovascular perforation. Assessment was conducted at 24 hours after SAH for brain water content, Evans blue content, and neurobehavioral testing. To explore the role of PAR-1 activation and the specific mechanism of SCH79797's effect after SAH, Western blot, immunoprecipitation, and immunofluorescence of hippocampus tissue were performed. A p21-activated kinase-1 (PAK1) inhibitor, IPA-3, was used to explore the underlying protective mechanism of SCH79797.

RESULTS

At 24 hours after SAH, animals treated with SCH79797 demonstrated a reduction in brain water content, Evans blue content, and neurobehavioral deficits. SCH79797 also attenuated PAR-1 expression and maintained the level of vascular endothelial-cadherin, an important component of adherens junctions. Downstream to PAR-1, c-Src-dependent activation of p21-activated kinase-1 led to an increased serine/threonine phosphorylation of vascular endothelial-cadherin; immunoprecipitation results revealed an enhanced binding of phosphorylated vascular endothelial-cadherin with endocytosis orchestrator β-arrestin-2. These pathological states were suppressed after SCH79797 treatment.

CONCLUSIONS

PAR-1 activation after SAH increases microvascular permeability, at least, partly through a PAR-1-c-Src-p21-activated kinase-1-vascular endothelial-cadherin phosphorylation pathway. Through suppressing PAR-1 activity, SCH79797 plays a protective role in maintaining microvascular integrity after SAH.

Early neurological deterioration after subarachnoid haemorrhage: risk factors and impact on outcome

BACKGROUND

Early neurological deterioration occurs frequently after subarachnoid haemorrhage (SAH). The impact on hospital course and outcome remains poorly defined.

METHODS

We identified risk factors for worsening on the Hunt-Hess grading scale within the first 24 h after admission in 609 consecutively admitted aneurysmal SAH patients. Admission risk factors and the impact of early worsening on outcome was evaluated using multivariable analysis adjusting for age, gender, admission clinical grade, admission year and procedure type. Outcome was evaluated at 12 months using the modified Rankin Scale (mRS).

RESULTS

211 patients worsened within the first 24 h of admission (35%). In a multivariate adjusted model, early worsening was associated with older age (OR 1.02, 95% CI 1.001 to 1.03; p=0.04), the presence of intracerebral haematoma on initial CT scan (OR 2.0, 95% CI 1.2 to 3.5; p=0.01) and higher SAH and intraventricular haemorrhage sum scores (OR 1.05, 95% CI 1.03 to 1.08 and 1.1, 95% CI 1.01 to 1.2; p<0.001 and 0.03, respectively). Early worsening was associated with more hospital complications and prolonged length of hospital stay and was an independent predictor of death (OR 12.1, 95% CI 5.7 to 26.1; p<0.001) and death or moderate to severe disability (mRS 4-6, OR 8.4, 95% CI 4.9 to 14.5; p=0.01) at 1 year.

CONCLUSIONS

Early worsening after SAH occurs in 35% of patients, is predicted by clot burden and is associated with mortality and poor functional outcome at 1 year.

Update on the management of subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) is a devastating cerebrovascular disease. Outcome after SAH is mainly determined by the initial severity of the hemorrhage. Neuroimaging, in particular computed tomography, and aneurysm repair techniques, such as coiling and clipping, as well as neurocritical care management, have improved during the last few years. The management of a patient with SAH should have an interdisciplinary approach with case discussions between the neurointensivist, interventionalist and the neurosurgeon. The patient should be treated in a specialized neurointensive care unit of a center with sufficient SAH case volume. Poor-grade patients can be observed for complications and delayed cerebral ischemia through continuous monitoring techniques in addition to transcranial Doppler ultrasonography such as continuous electroencephalography, brain tissue oxygenation, cerebral metabolism, cerebral blood flow and serial vascular imaging. Neurocritical care should focus on neuromonitoring for delayed cerebral ischemia, management of hydrocephalus, seizures and intracranial hypertension, as well as of medical complications such as hyperglycemia, fever and anemia.

Early brain injury: a common mechanism in subarachnoid hemorrhage and global cerebral ischemia

Early brain injury (EBI) has become an area of extreme interest in the recent years and seems to be a common denominator in the pathophysiology of global transient ischemia and subarachnoid hemorrhage (SAH). In this paper, we highlight the importance of cerebral hypoperfusion and other mechanisms that occur in tandem in both pathologies and underline their possible roles in triggering brain injury after hemorrhagic or ischemic strokes.

Extracellular matrix metalloproteinase inducer is associated with severity of brain oedema following experimental subarachnoid haemorrhage in rats

OBJECTIVE

Brain oedema is a major cause of clinical deterioration and death following brain trauma; cellular mechanisms involved in its development remain elusive. This study investigated the role of extracellular matrix metalloproteinase inducer (EMMPRIN) in brain oedema.

METHODS

The monofilament puncture model was used to induce subarachnoid haemorrhage. Adult male Sprague-Dawley rats were divided into five groups (n = 20 per group): sham-operated, sacrificed immediately after surgery (sham group); sacrificed 12, 24 or 72 h after subarachnoid haemorrhage induction (SAH-12, SAH-24 and SAH-72 groups, respectively); treated with EMMPRIN inhibitor immediately after subarachnoid haemorrhage, sacrificed at 24 h (SAH-inhibition group). Mean brain water content, and EMMPRIN mRNA and protein levels, were determined.

RESULTS

Compared with the sham group, mean brain water content, EMMPRIN mRNA and protein levels in the SAH-12, SAH-24 and SAH-72 groups increased rapidly and significantly (maximal at 24 h). EMMPRIN inhibition significantly reduced mean brain water content and EMMPRIN mRNA and protein levels in the SAH-inhibition group, compared with the SAH-24 group.

CONCLUSIONS

EMMPRIN upregulation may be important in the formation of brain oedema; inhibition of EMMPRIN activity may provide a potential approach to reduce oedema after subarachnoid haemorrhage.

Delayed cerebral ischaemia after subarachnoid haemorrhage: looking beyond vasospasm

Despite improvements in the clinical management of aneurysmal subarachnoid haemorrhage over the last decade, delayed cerebral ischaemia (DCI) remains the single most important cause of morbidity and mortality in those patients who survive the initial bleed. The pathological mechanisms underlying DCI are still unclear and the calcium channel blocker nimodipine remains the only therapeutic intervention proven to improve functional outcomes after SAH. The recent failure of the drug clazosentan to improve functional outcomes despite reducing vasoconstriction has moved the focus of research into DCI away from cerebral artery constriction towards a more multifactorial aetiology. Novel pathological mechanisms have been suggested, including damage to cerebral tissue in the first 72 h after aneurysm rupture ('early brain injury'), cortical spreading depression, and microthrombosis. A greater understanding of the significance of these pathophysiological mechanisms and potential genetic risk factors is required, if new approaches to the prophylaxis, diagnosis, and treatment of DCI are to be developed. Furthermore, objective and reliable biomarkers are needed for the diagnosis of DCI in poor grade SAH patients requiring sedation and to assess the efficacy of new therapeutic interventions. The purpose of this article is to appraise these recent advances in research into DCI, relate them to current clinical practice, and suggest potential novel avenues for future research.

Real time estimation of brain water content in comatose patients

OBJECTIVE

Although brain swelling is an important cause of neurological deterioration, real time measurement of brain edema does not currently exist. Because thermal conductivity is proportional to percentage water content, we used the thermal conductivity constant to estimate brain water content (BWC).

METHODS

Between June 2008 and November 2010, 36 comatose brain-injured patients underwent cerebral blood flow monitoring using a thermal diffusion probe in our neurocritical care unit. BWC was estimated hourly utilizing the measured thermal conductivity and the known temperature-adjusted thermal conductivity of water. In vitro experiments were performed to validate this formula using agar, glycerol, and water mixtures with different water content.

RESULTS

Thermal conductivity was highly correlated (R(2) = 0.99) and estimated water content was well correlated with actual water content (mean difference, 0.58%) in the in vitro preparations. The majority of the 36 patients (median age, 57 years; 44% female) had subarachnoid hemorrhage (n = 14) or cardiac arrest (n = 9). Initial BWC at the time of monitoring ranged from 67.3 to 85.5%. Brain regions appearing edematous on computed tomography showed higher estimated BWC than normal-appearing brain regions (79.1 vs 70.2%; p < 0.01). Bolus osmotherapy (20% mannitol or 23.4% hypertonic saline) decreased BWC from 77.2 ± 0.7% (mean ± standard error) at baseline to 76.1 ± 0.5% at 1 hour, 76.5 ± 0.3% at 2 hours, and 76.7 ± 0.2% at 3 hours (all p ≤ 0.03).

INTERPRETATION

Real time monitoring of BWC is feasible using thermal conductivity. Further studies are needed to confirm the clinical utility of this technique.

Brain edema formation correlates with perfusion deficit during the first six hours after experimental subarachnoid hemorrhage in rats

Background

Severe brain edema is observed in a number of patients suffering from subarachnoid hemorrhage (SAH). Little is known about its pathogenesis and time-course in the first hours after SAH. This study was performed to investigate the development of brain edema and its correlation with brain perfusion after experimental SAH.

Methods

Male Sprague–Dawley rats, randomly assigned to one of six groups (n = 8), were subjected to SAH using the endovascular filament model or underwent a sham operation. Animals were sacrificed 15, 30, 60, 180 or 360 minutes after SAH. Intracranial pressure (ICP), mean arterial blood pressure (MABP), cerebral perfusion pressure (CPP) and bilateral local cerebral blood flow (LCBF) were continuously measured. Brain water content (BWC) was determined by the wet/dry-weight method.

Results

After SAH, CPP and LCBF rapidly decreased. The decline of LCBF markedly exceeded the decline of CPP and persisted until the end of the observation period. BWC continuously increased. A significant correlation was observed between the BWC and the extent of the perfusion deficit in animals sacrificed after 180 and 360 minutes.

Conclusions

The significant correlation with the perfusion deficit after SAH suggests that the development of brain edema is related to the extent of ischemia and acute vasoconstriction in the first hours after SAH.

Hydrogen-rich saline alleviates early brain injury via reducing oxidative stress and brain edema following experimental subarachnoid hemorrhage in rabbits

Background

Increasing experimental and clinical data indicate that early brain injury (EBI) after subarachnoid hemorrhage (SAH) largely contributes to unfavorable outcomes, and it has been proved that EBI following SAH is closely associated with oxidative stress and brain edema. The present study aimed to examine the effect of hydrogen, a mild and selective cytotoxic oxygen radical scavenger, on oxidative stress injury, brain edema and neurology outcome following experimental SAH in rabbits.

Results

The level of MDA, caspase-12/3 and brain water content increased significantly at 72 hours after experimental SAH. Correspondingly, obvious brain injury was found in the SAH group by terminal deoxynucleotidyl transferase-mediated uridine 5’-triphosphate-biotin nick end-labeling (TUNEL) and Nissl staining. Similar results were found in the SAH + saline group. In contrast, the upregulated level of MDA, caspase-12/3 and brain edema was attenuated and the brain injury was substantially alleviated in the hydrogen treated rabbits, but the improvement of neurology outcome was not obvious.

Conclusion

The results suggest that treatment with hydrogen in experimental SAH rabbits could alleviate brain injury via decreasing the oxidative stress injury and brain edema. Hence, we conclude that hydrogen possesses the potential to be a novel therapeutic agent for EBI after SAH.

Bilateral middle cerebral artery aneurysms: a comparative study of unilateral and bilateral approaches

The best surgical method for the treatment of patients with bilateral middle cerebral artery (bMCA) aneurysms has not been fully determined yet. The main purpose of this study is to compare the surgical results of unilateral and bilateral approaches to bMCA aneurysms including mean operation time, mean hospital stay, and mean cost, in the experience of the same neurosurgical team. Between January 2001 and June 2010, 22 patients with bMCA aneurysms were surgically treated in our institution. In 12 cases (54.5 %), ipsilateral and contralateral MCA aneurysms were successfully clipped via unilateral approach. In the remaining 10 cases, bilateral approach was necessary because of some technical difficulties. Although the surgical results were almost the same, mean operation time and mean hospital stay were, respectively, 46 and 37 % shorter and mean cost per person was 23 % lower for the patients in the unilateral group. In addition, the severity of brain edema, total length of the contralateral (A1+M1) segment, and the configuration of contralateral aneurysm were found to be the determinant parameters affecting the feasibility of the unilateral approach. To our knowledge, this is the first study in the literature that compares the clinical outcomes of unilateral and bilateral approaches to bMCA aneurysms. The results of surgery for both approaches are almost the same. However, the unilateral approach has certain advantages compared to the bilateral approach. Therefore, the unilateral approach may be a good alternative in surgical management of patients with bMCA aneurysms in selected cases and the abovementioned parameters can help the neurosurgeon in patient selection.

Guidelines for the management of aneurysmal subarachnoid hemorrhage: a guideline for healthcare professionals from the American Heart Association/american Stroke Association

PURPOSE

The aim of this guideline is to present current and comprehensive recommendations for the diagnosis and treatment of aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

A formal literature search of MEDLINE (November 1, 2006, through May 1, 2010) was performed. Data were synthesized with the use of evidence tables. Writing group members met by teleconference to discuss data-derived recommendations. The American Heart Association Stroke Council's Levels of Evidence grading algorithm was used to grade each recommendation. The guideline draft was reviewed by 7 expert peer reviewers and by the members of the Stroke Council Leadership and Manuscript Oversight Committees. It is intended that this guideline be fully updated every 3 years.

RESULTS

Evidence-based guidelines are presented for the care of patients presenting with aSAH. The focus of the guideline was subdivided into incidence, risk factors, prevention, natural history and outcome, diagnosis, prevention of rebleeding, surgical and endovascular repair of ruptured aneurysms, systems of care, anesthetic management during repair, management of vasospasm and delayed cerebral ischemia, management of hydrocephalus, management of seizures, and management of medical complications.

CONCLUSIONS

aSAH is a serious medical condition in which outcome can be dramatically impacted by early, aggressive, expert care. The guidelines offer a framework for goal-directed treatment of the patient with aSAH.

Intensive care unit management of aneurysmal subarachnoid hemorrhage

The emergence of dedicated neurologic-neurosurgical intensive care units, advancements in endovascular therapies, and aggressive brain resuscitation and monitoring have contributed to overall improved outcomes for patients with aneurysmal subarachnoid hemorrhage (aSAH) over the past 20 to 30 years. Still, this feared neurologic emergency is associated with substantial mortality and morbidity. Emergency care for patients with aSAH focuses on stabilization, treatment of the aneurysm, controlling intracranial hypertension to optimize cerebral perfusion, and limiting secondary brain injury. This complex disorder can be associated with many neurologic complications such as acute hydrocephalus, rebleeding, global cerebral edema, seizures, vasospasm, and delayed cerebral ischemia in addition to systemic complications such as electrolyte imbalances, cardiopulmonary injury, and infections. Background routine intensive care practices such as avoidance of hyperthermia, venous thromboembolism prophylaxis, and avoidance of severe blood glucose derangements are additional important elements of care.

Intraoperative mild hypothermia for postoperative neurological deficits in intracranial aneurysm patients

BACKGROUND

Rupture of an intracranial aneurysm causes aneurysmal subarachnoid haemorrhage, which is one of the most devastating clinical conditions. Clinically, it can be classified into five grades using the Hunt-Hess or World Federation of Neurological Surgeons (WFNS) scale. Grades 4 and 5 predict poor prognosis and are called 'poor grade', while grade 1, 2, and 3 are known as 'good grade'. Disturbances of intracranial homeostasis and brain metabolism are known to play certain roles in the sequelae. Hypothermia has a long history of being used to reduce metabolism rate, thereby protecting organs in cases where metabolism is disturbed and potentially harmful.

OBJECTIVES

To assess the effect of intraoperative mild hypothermia on postoperative death and neurological deficits in patients with intracranial aneurysms (ruptured or unruptured).

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (September 2011), the Cochrane Central Register of Controlled Trials (CENTRAL 2011, Issue 3), MEDLINE (1950 to September 2011), EMBASE (1980 to September 2011), Science Citation Index (1900 to September 2011) and 11 Chinese databases (September 2011). We also searched ongoing trials registers (September 2011) and scanned reference lists of retrieved records.

SELECTION CRITERIA

We included only randomised controlled trials comparing intraoperative mild hypothermia (32°C to 35°C) with control (no hypothermia) in patients with intracranial aneurysms (ruptured or unruptured).

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials and assessed the risk of bias for each included study. We presented data as risk ratio (RR) with 95% confidence intervals (CI).

MAIN RESULTS

We included three studies enrolling 1158 patients. Each study observed an increased rate of good recovery with intraoperative mild hypothermia, but the effect sizes were not sufficient for statistical significance. A total of 76 of 577 patients (13.1%) who received hypothermia and 93 of 581 patients (16.0%) who did not receive hypothermia were dead or dependent. A total of 1086 of the1158 patients (93.8%) had good-grade aneurysmal subarachnoid haemorrhage. A random-effects meta-analysis resulted in a summarised RR of 0.82 (95% CI 0.62 to 1.09, P value 0.17). In patients with poor-grade aneurysmal subarachnoid haemorrhage, one of seven in the hypothermia group and one of six in the control group were dead or dependent (RR 0.86, 95% CI 0.07 to 10.96, P value 0.91). In patients without subarachnoid haemorrhage, three of 30 patients (10%) in the hypothermia group, and four of 29 patients (13.8%) in the control group were dead or dependent (RR 0.72, 95% CI 0.18 to 2.96, P value 0.65).

AUTHORS' CONCLUSIONS

In patients with good-grade aneurysmal subarachnoid haemorrhage, intraoperative mild hypothermia might prevent death or dependency in activities of daily living for a few of them. However, the confidence intervals include the possibility of both benefit and harm. There is no evidence that intraoperative mild hypothermia is harmful. This treatment should not be routinely applied. In patients with poor-grade aneurysmal subarachnoid haemorrhage or without subarachnoid haemorrhage, there are insufficient data to draw any conclusions. A high-quality randomised clinical trial of intraoperative mild hypothermia for postoperative neurological deficits in patients with poor-grade aneurysmal subarachnoid haemorrhage might be feasible.

Cortisol and adrenocorticotropic hormone dynamics in the acute phase of subarachnoid haemorrhage

OBJECTIVE

An adequate response of hypothalamic-pituitary-adrenal (HPA) axis is important for survival and recovery after a severe disease. The hypothalamus and the pituitary glands are at risk of damage after subarachnoid haemorrhage (SAH). A better understanding of the hormonal changes would be valuable for optimising care in the acute phase of SAH.

PATIENTS

Fifty-five patients with spontaneous SAH were evaluated regarding morning concentrations of serum (S)-cortisol and P-adrenocorticotropic hormone (ACTH) 7 days after the bleeding. In a subgroup of 20 patients, the diurnal changes of S-cortisol and P-ACTH were studied and urine (U)-cortisol was measured. The relationships of hormone concentrations to clinical and radiological parameters and to outcome were assessed.

RESULTS

S-cortisol and P-ACTH were elevated the day of SAH. S-cortisol concentrations below reference range were uncommon. Early global cerebral oedema was associated with higher S-cortisol concentrations at admission and a worse World Federation of Neurological Surgeons (WFNS) and Reaction Level Scale 85 grade. Global cerebral oedema was shown to be a predictor of S-cortisol at admittance. Patients in better WFNS grade displayed higher U-cortisol. All patients showed diurnal variations of S-cortisol and P-ACTH. A reversed diurnal variation of S-cortisol was more frequently found in mechanically ventilated patients. Periods of suppressed P-ACTH associated with S-cortisol peaks occurred especially in periods of secondary brain ischaemia.

CONCLUSION

There was an HPA response acutely after SAH with an increase in P-ACTH and S-cortisol. Higher U-cortisol in patients in a better clinical grade may indicate a more robust response of the HPA system. Global cerebral oedema was associated with higher S-cortisol at admission and was a predictor of S-cortisol concentrations. Global cerebral oedema may be the result of the stress response initiated by the brain injury. Periods of suppressed P-ACTH occurred particularly in periods of brain ischaemia, indicating a possible connection between brain ischaemia and ACTH suppression.

Nutritional support and brain tissue glucose metabolism in poor-grade SAH: a retrospective observational study

Introduction

We sought to determine the effect of nutritional support and insulin infusion therapy on serum and brain glucose levels and cerebral metabolic crisis after aneurysmal subarachnoid hemorrhage (SAH).

Methods

We used a retrospective observational cohort study of 50 mechanically ventilated poor-grade (Hunt-Hess 4 or 5) aneurysmal SAH patients who underwent brain microdialysis monitoring for an average of 109 hours. Enteral nutrition was started within 72 hours of admission whenever feasible. Intensive insulin therapy was used to maintain serum glucose levels between 5.5 and 7.8 mmol/l. Serum glucose, insulin and caloric intake from enteral tube feeds, dextrose and propofol were recorded hourly. Cerebral metabolic distress was defined as a lactate to pyruvate ratio (LPR) > 40. Time-series data were analyzed using a general linear model extended by generalized estimation equations (GEE).

Results

Daily mean caloric intake received was 13.8 ± 6.9 cal/kg and mean serum glucose was 7.9 ± 1 mmol/l. A total of 32% of hourly recordings indicated a state of metabolic distress and < 1% indicated a state of critical brain hypoglycemia (< 0.2 mmol/l). Calories received from enteral tube feeds were associated with higher serum glucose concentrations (Wald = 6.07, P = 0.048), more insulin administered (Wald = 108, P < 0.001), higher body mass index (Wald = 213.47, P < 0.001), and lower body temperature (Wald = 4.1, P = 0.043). Enteral feeding (Wald = 1.743, P = 0.418) was not related to brain glucose concentrations after accounting for serum glucose concentrations (Wald = 67.41, P < 0.001). In the presence of metabolic distress, increased insulin administration was associated with a relative reduction of interstitial brain glucose concentrations (Wald = 8.26, P = 0.017), independent of serum glucose levels.

Conclusions

In the presence of metabolic distress, insulin administration is associated with reductions in brain glucose concentration that are independent of serum glucose levels. Further study is needed to understand how nutritional support and insulin administration can be optimized to minimize secondary injury after subarachnoid hemorrhage.

Effect of increased ICP and decreased CPP on DND and outcome in ASAH

BACKGROUND

When clipping is done early in aneurysmal SAH (ASAH), postoperative increased ICP and decreased CPP may present and influence development of delayed neurological deficit (DND), irreversible neurological deficit (IRND) and poor outcome.

METHODS

A retrospective study was performed in 30 early clipping ASAH with postoperative ICP monitoring, flow velocity measurement, triple H-nimodipine therapy, ICP-CPP orientated strategy and a 3-month follow-up period. Chi-squared test was performed on increased ICP, decreased CPP, combination of increased ICP+ decreased CPP and DND, IRND and poor outcome.

RESULTS

Two (7%), 19 (63%) and 9 (30%) patients were H&H 2, 3 and 4 respectively. Mean ICP and CPP were 34.2 and 71.3 mmHg. Mean ICP in H&H 2, 3 and 4 was 17.6, 34.3 and 50.2 mmHg respectively. 58.3%, 58.8% and 70% of patients with ICP ≥ 20, 30 and 40 mmHg had DND. 64.7%, 63.3% and 80% of patients with CPP ≤ 80, 70 and 60 mmHg had DND. 37.5%, 41.1% and 40% of patients with ICP ≥ 20, 30 and 40 mmHg had poor outcome. 41.1%, 27.2% and 40% of patients with CPP ≤ 80, 70 and 60 mmHg had poor outcome. Statistical analysis could not demonstrate a significant relationship among any of the parameters.

CONCLUSION

Postoperative increased ICP is frequent in early clipping especially in poor-grade ASAH; decreased CPP is less frequent, possibly owing to triple H therapy and ICP-CPP orientated strategy. Increased ICP seems to be more detrimental than decreased CPP. Increased ICP and decreased CPP may affect deterioration of neurological function in terms of DND, IRND and poor outcome as secondary insult.

Inhibition of Rho kinase by hydroxyfasudil attenuates brain edema after subarachnoid hemorrhage in rats

The blood-brain barrier (BBB) disruption and brain edema are important pathophysiologies of early brain injury after subarachnoid hemorrhage (SAH). This study is to evaluate whether Rho kinase (Rock) enhances BBB permeability via disruption of tight junction proteins during early brain injury. Adult male rats were assigned to five groups; Sham-operated, SAH treated with saline, a Rock inhibitor hydroxyfasudil (HF) (10 mg/kg) treatment at 0.5 h after SAH, HF treatment at 0.5 and 6 h (10 mg/kg, each) after SAH, and another Rock inhibitor Y27632 (10 mg/kg) treatment at 0.5 h after SAH. The perforation model of SAH was performed and neurological score and brain water content were evaluated 24 and 72 h after surgery. Evans blue extravasation, Rock activity assay, and western blotting analyses were evaluated 24 h after surgery. Treatment of HF significantly improved neurological scores 24 h after SAH. Single treatment with HF and Y27632, and two treatments with HF reduced brain water content in the ipsilateral hemisphere. HF reduced Evans blue extravasation in the ipsilateral hemisphere after SAH. Rock activity increased 24 h after SAH, and HF reversed the activity. SAH significantly decreased the levels of tight junction proteins, occludin and zonula occludens-1 (ZO-1), and HF preserved the levels of occluding and ZO-1 in ipsilateral hemisphere. In conclusion, HF attenuated BBB permeability after SAH, possibly by protection of tight junction proteins.

Perfusion-CT assessment of blood-brain barrier permeability in patients with aneurysmal subarachnoid hemorrhage

BACKGROUND

The goal of this study was to determine which clinical and radiographic variables in patients with subarachnoid hemorrhage (SAH) are associated with in vivo blood-brain barrier permeability (BBBP) assessments obtained using perfusion-CT (PCT) technology.

METHODS

SAH patients with confirmed aneurysm etiology and with PCT and angiogram within 24 hours of each other were included, and relationships between clinical and imaging variables were analyzed using random-effects generalized linear models.

RESULTS

One thousand one hundred and sixty two vascular territories from 83 patients were evaluated in this study. The mean BBBP increased by severity of vasospasm on DSA, however, in multivariate analysis, only mean transit time (MTT), cerebral blood volume (CBV), and severity of hydrocephalus were significantly associated with BBBP. Increased BBBP was not associated with angiographic vasospasm severity in multivariate analysis.

CONCLUSION

Perfusion-CT assessment of BBBP may serve as a unique and useful biomarker in conjunction with angiography, additional perfusion-CT parameters, and clinical assessments, especially in characterizing microvascular dysfunction, or even in targeting treatments. However, future prospective studies will be required to definitively establish its clinical utility in the care of SAH patients.

Treatment with sodium orthovanadate reduces blood-brain barrier disruption via phosphatase and tensin homolog deleted on chromosome 10 (PTEN) phosphorylation in experimental subarachnoid hemorrhage

Attenuation of blood-brain barrier (BBB) disruption is one of the therapeutic candidates for treatment of subarachnoid hemorrhage (SAH). In this study, the protective effect of sodium orthovanadate (SOV) on BBB disruption was investigated in SAH using the endovascular perforation model. Fifty-five rats were randomly assigned to sham-operated, SAH treated with saline (as a vehicle), or 10 mg/kg SOV groups and were evaluated for neurofunction and Evans blue dye extravasation. The phosphorylation of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and mitogen-activated protein kinase (MAPK) and the expression of matrix metalloproteinase-9 (MMP-9), occludin, and collagen-IV were examined by Western blot analyses. Cell death among endothelial cells was revealed by immunofluorescence and terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end-labeling staining. SOV significantly improved neurofunction and reduced Evans blue dye extravasation in brains after SAH. SOV phosphorylated PTEN, decreased phospho-JNK and MMP-9, and preserved occludin expression. SOV also attenuated SAH-induced capillary endothelial cell death. The current study showed that SOV was protective against BBB disruption after SAH, possibly via PTEN phosphorylation.

Long term outcome after subarachnoid haemorrhage of unknown aetiology

BACKGROUND AND PURPOSE

The aim of this study was to assess the long term outcome after non-aneurysmal subarachnoid haemorrhage (SAH).

METHODS

1154 patients with SAH were treated in our hospital between 1989 and 1999. From this patient population, 97 patients had a non-aneurysmal SAH. All hospital records and death certificates were studied and 33 patients were examined by MRI and MR angiography more than 9 years (mean 12 years) after the initial bleeding.

RESULTS

The cohort consisted of 97 patients. Mean follow-up time was 9 years (range 0-19). During the follow-up period, 13 patients (13%) died. Four (4%) died from the initial bleeding less than 5 weeks after the initial haemorrhage. There was no delayed mortality due to SAH or subsequent bleedings. MR angiography revealed no new findings in 33 surviving patients.

CONCLUSIONS

Excess mortality during the first year after SAH was higher than 4%, and remained thereafter comparable with the general population. There were no rebleedings and MR imaging did not reveal any vascular pathology that could explain the earlier SAH.

Vasopressin V(1a) receptors mediate posthemorrhagic systemic hypertension thereby determining rebleeding rate and outcome after experimental subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Arginine vasopressin V(1) receptors have been suggested to be involved in the pathophysiology of acute brain injury. Therefore, we aimed to determine the role of arginine vasopressin V(1) receptors after experimental subarachnoid hemorrhage (SAH).

METHODS

Sprague-Dawley rats subjected to SAH by endovascular puncture received either vehicle or a V(1) receptor antagonist intravenously from 1 minute before until 3 hours after SAH. Intracranial pressure, cerebral blood flow, and mean arterial blood pressure were monitored until 60 minutes after SAH. Brain water content was quantified 24 hours after SAH and neurological function and mortality were assessed daily for 7 days after hemorrhage.

RESULTS

In control rats, SAH induced high intracranial pressure, a brief increase in plasma arginine vasopressin, a subsequent increase in systemic blood pressure (Cushing response), a high rebleeding rate (30%), severe neurological deficits, and a 7-day mortality rate of 50%. V(1) receptor antagonist-treated animals exhibited a far less pronounced Cushing response, a less severe increase of intracranial pressure, did not exhibit rebleedings, had less severe brain edema formation and neurological deficits, and a mortality rate of only 20% (all P<0.05 versus vehicle).

CONCLUSIONS

Inhibition of arginine vasopressin V(1a) receptors reduces the severity of SAH and prevents rebleedings by blunting the posthemorrhagic hypertonic response (Cushing reflex), thereby reducing mortality and secondary brain damage after experimental SAH. Because the severity of the initial bleeding and rebleedings are major factors contributing to an unfavorable outcome after SAH, inhibition of V(1a) receptors may represent a novel strategy to treat SAH.

Contribution of matrix metalloproteinase-9 to cerebral edema and functional outcome following experimental subarachnoid hemorrhage

BACKGROUND

Cerebral edema is an important risk factor for death and poor outcome following subarachnoid hemorrhage (SAH). However, underlying mechanisms are still poorly understood. Matrix metalloproteinase (MMP)-9 is held responsible for the degradation of microvascular basal lamina proteins leading to blood-brain barrier dysfunction and, thus, formation of vasogenic cerebral edema. The current study was conducted to clarify the role of MMP-9 for the development of cerebral edema and for functional outcome after SAH.

METHODS

SAH was induced in FVB/N wild-type (WT) or MMP-9 knockout (MMP-9(-/-)) mice by endovascular puncture. Intracranial pressure (ICP), regional cerebral blood flow (rCBF), and mean arterial blood pressure (MABP) were continuously monitored up to 30 min after SAH. Mortality was quantified for 7 days after SAH. In an additional series neurological function and body weight were assessed for 3 days after SAH. Subsequently, ICP and brain water content were quantified.

RESULTS

Acute ICP, rCBF, and MABP did not differ between WT and MMP-9(-/-) mice, while 7 days' mortality was lower in MMP-9(-/-) mice (p = 0.03; 20 vs. 60%). MMP-9(-/-) mice also exhibited better neurological recovery, less brain edema formation, and lower chronic ICP.

CONCLUSIONS

The results of the current study suggest that MMP-9 contributes to the development of early brain damage after SAH by promoting cerebral edema formation. Hence, MMP- 9 may represent a novel molecular target for the treatment of SAH.