Cerebral infarction associated with acute subarachnoid hemorrhage

CircZfp609 contributes to cerebral infarction via sponging miR-145a-5p to regulate BACH1

BACKGROUND

Circular RNAs (circRNA) have been reported to be involved in the progression of cerebral infarction. The purpose of this study was to reveal the role and potential molecular mechanism of circZfp609 (mmu_circ_0001797) in cerebral infarction.

METHODS

C57BL/6J mice was used to construct middle cerebral artery occlusion (MCAO) mice model, and primary mouse astrocytes were treated with oxygen-glucose deprivation/reperfusion (OGD/R) process. The circZfp609, microRNA (miR)-145a-5p and BTB and CNC homology 1 (BACH1) expression levels were detected by quantitative real-time PCR. Cell proliferation and apoptosis were assessed by cell counting kit 8 assay, EdU assay and flow cytometry. Western blot analysis was used to measure protein levels, and ELISA assay was utilized to detect the levels of inflammation factors. Lactate dehydrogenase (LDH) level was measured by LDH Assay Kit. Dual-luciferase reporter assay, RIP assay and RNA pull-down assay were used to evaluate RNA interaction.

RESULTS

CircZfp609 was upregulated in MCAO mice and OGD/R-induced astrocytes. Knockdown of circZfp609 promoted cell proliferation, while suppressed apoptosis and inflammation in OGD/R-induced astrocytes. CircZfp609 served as a sponge for miR-145a-5p, and miR-145a-5p inhibitor reversed the regulation of circZfp609 knockdown on OGD/R-induced astrocyte injury. BACH1 was a target of miR-145a-5p, and its overexpression abolished the inhibition effect of miR-145a-5p on OGD/R-induced astrocyte injury. Besides, circZfp609 downregulation also relieved the brain injury of MCAO mice through miR-145a-5p/BACH1 axis.

CONCLUSION

Our data showed that circZfp609 might promote cerebral infarction by regulating the miR-145a-5p/BACH1 pathway.

MicroRNA cerebrospinal fluid profile during the early brain injury period as a biomarker in subarachnoid hemorrhage patients

Introduction

Delayed cerebral ischemia (DCI) is a dreadful complication present in up to 30% of patients with spontaneous subarachnoid hemorrhage (SAH). Indeed, DCI is one of the main causes of long-term disability in SAH, yet its prediction and prevention are troublesome in poor-grade SAH cases. In this prospective study, we explored the potential role of micro ribonucleic acid (microRNA, abbreviated miRNAs)-small non-coding RNAs involved in clue gene regulation at the post-transcriptional level-as biomarkers of neurological outcomes in SAH patients.

Methods

We analyzed the expression of several miRNAs present in the cerebrospinal fluid (CSF) of SAH patients during the early stage of the disease (third-day post-hemorrhage). NanoString Technologies were used for the characterization of the CSF samples.

Results

We found an overexpression of miRNAs in the acute stage of 57 SAH in comparison with 10 non-SAH controls. Moreover, a differential expression of specific miRNAs was detected according to the severity of clinical onset, but also regarding the development of DCI and the midterm functional outcomes.

Conclusion

These observations reinforce the potential utility of miRNAs as prognostic and diagnostic biomarkers in SAH patients. In addition, the identification of specific miRNAs related to SAH evolution might provide insights into their regulatory functions of pathophysiological pathways, such as the TGF-β inflammatory pathway and blood-brain barrier disruption.

Intravenous Thrombolysis Combined with Arterial Thrombolysis (Bridging Therapy) Effectively Improves Vascular Recanalization Rate in Patients with Cerebral Infarction

Objective

To explore the efficacy of intravenous thrombolysis combined with arterial thrombolysis (bridging therapy) in patients with acute cerebral infarction and its effect on serum inflammatory factors.

Methods

The case data of 138 patients with acute cerebral infarction admitted to our hospital from February 2019 to February 2021 were retrospectively analyzed. According to the treatment plan they received, patients were assigned to two groups, namely, an observation group (n = 71) treated with bridging therapy and a control group (n = 67) treated with intravenous thrombolysis alone. The following indexes were recorded and compared between the two groups: treatment efficacy, National Institutes of Health Stroke Scale (NIHSS) score, activities of daily living, incidence rates of vascular recanalization, intracranial hemorrhage and reembolization after treatment, levels of inflammatory factors before and after treatment, levels of prothrombin time (PT), activated partial thromboplastin time (APTT) and fibrinogen (FIB) before and 1 week after treatment, and modified Rankin Scale scores 1, 3, and 6 months after treatment.

Results

Compared with the control group, the therapeutic efficacy, neurological function, activities of daily living, and vascular recanalization were markedly better in the observation group (P > 0.05). In addition, the incidence of intracranial hemorrhage and reembolization was statistically lower in the observation group (P < 0.05). No marked difference was found between the two groups in terms of pretreatment serum inflammatory factors and coagulation function (P > 0.05), while the above indicators improved statistically after treatment in both groups, with comparatively more obvious improvement in the observation group. It was also observed that, compared with the control group, the modified Rankin Scale score in the observation group was significantly better at 3 and 6 months after treatment (P < 0.05).

Conclusion

Bridging therapy can improve the vascular recanalization rate among patients suffering from acute cerebral infarction, reduce the incidence of intracranial hemorrhage and reembolization, and improve the prognosis and neurological function of patients, which is worthy of clinical application.

Role of endothelial nitric oxide synthase for early brain injury after subarachnoid hemorrhage in mice

The first few hours and days after subarachnoid hemorrhage (SAH) are characterized by cerebral ischemia, spasms of pial arterioles, and a significant reduction of cerebral microperfusion, however, the mechanisms of this early microcirculatory dysfunction are still unknown. Endothelial nitric oxide production is reduced after SAH and exogenous application of NO reduces post-hemorrhagic microvasospasm. Therefore, we hypothesize that the endothelial NO-synthase (eNOS) may be involved in the formation of microvasospasms, microcirculatory dysfunction, and unfavorable outcome after SAH. SAH was induced in male eNOS deficient (eNOS^-/-) mice by endovascular MCA perforation. Three hours later, the cerebral microcirculation was visualized using in vivo 2-photon-microscopy. eNOS^-/- mice had more severe SAHs, more severe ischemia, three time more rebleedings, and a massively increased mortality (50 vs. 0%) as compared to wild type (WT) littermate controls. Three hours after SAH eNOS^-/- mice had fewer perfused microvessels and 40% more microvasospasms than WT mice. The current study indicates that a proper function of eNOS plays a key role for a favorable outcome after SAH and helps to explain why patients suffering from hypertension or other conditions associated with impaired eNOS function, have a higher risk of unfavorable outcome after SAH.

Long-term outcome in patients with aneurysmal subarachnoid hemorrhage requiring mechanical ventilation

BACKGROUND

Patients affected with aneurysmal subarachnoid hemorrhage (aSAH) often require intensive care, and then present distinctive outcome from less severe patients. We aimed to specify their long-term outcome and to identify factors associated with poor outcome.

METHODS

We conducted a retrospective study in a French university hospital intensive care unit. Patients with aSAH requiring mechanical ventilation hospitalized between 2010 and 2015 were included. At least one year after initial bleeding, survival and degree of disability were assessed using the modified Rankin Scale (mRS) via telephone interviews. A multivariable logistic regression analysis was performed to determine independent factors associated with poor outcome defined as mRS≥3.

RESULTS

Two-hundred thirty-six patients were included. Among them, 7 were lost to follow-up, and 229 were analyzed: 73 patients (32%) had a good outcome (mRS<3), and 156 (68%) had a poor outcome (mRS≥3). The estimated 1-year survival rate was 63%. One-hundred sixty-three patients patients (71%) suffered from early brain injuries (EBI), 33 (14%) from rebleeding, 80 (35%) from vasospasm and 63 (27%) from delayed cerebral ischemia (DCI). Multivariable logistic regression identified independent factors associated with poor outcome including delay between aSAH diagnosis and mRS assessment (OR, 0.96; 95% CI, 0.95-0.98; p<.0001), age (OR per 10 points, 1.57; 95% CI, 1.12-2.19; p = 0.008), WFNS V versus WFNS III (OR, 5.71; 95% CI 1.51-21.61; p = 0.004), subarachnoid rebleeding (OR, 6.47; 95% CI 1.16-36.06; p = 0.033), EBI (OR, 4.52; 95% CI 1.81-11.29; p = 0.001) and DCI (OR, 4.73; 95% CI, 1.66-13.49; p = 0.004).

CONCLUSION

Among aSAH patients requiring assisted ventilation, two-third of them survived at one year, and one-third showed good long-term outcome. As it appears as an independant factor associated with poor outcome, DCI shoud retain particular attention in future studies beyond angiographic vasospasm.

Early Transcranial Doppler Evaluation of Cerebral Autoregulation Independently Predicts Functional Outcome After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Cerebral autoregulation (CA) impairment after aneurysmal subarachnoid hemorrhage (SAH) has been associated with delayed cerebral ischemia and an unfavorable outcome. We investigated whether the early transient hyperemic response test (THRT), a transcranial Doppler (TCD)-based CA evaluation method, can predict functional outcome 6 months after aneurysmal SAH.

METHODS

This is a prospective observational study of all aneurysmal SAH patients consecutively admitted to a single center between January 2016 and February 2017. CA was evaluated within 72 h of hemorrhage by THRT, which describes the changes in cerebral blood flow velocity after a brief compression of the ipsilateral common carotid artery. CA was considered to be preserved when an increase ≥ 9% of baseline systolic velocity was present. According to the modified Rankin Scale (mRS: 4-6), the primary outcome was unfavorable 6 months after hemorrhage. Secondary outcomes included cerebral infarction, vasospasm on TCD, and an unfavorable outcome at hospital discharge.

RESULTS

Forty patients were included (mean age = 54 ± 12 years, 70% females). CA was impaired in 19 patients (47.5%) and preserved in 21 (52.5%). Impaired CA patients were older (59 ± 13 vs. 50 ± 9, p = 0.012), showed worse neurological conditions (Hunt&Hess 4 or 5-47.4% vs. 9.5%, p = 0.012), and clinical initial condition (APACHE II physiological score-12 [5.57-13] vs. 3.5 [3-5], p = 0.001). Fourteen patients in the impaired CA group and one patient in the preserved CA group progressed to an unfavorable outcome (73.7% vs. 4.7%, p = 0.0001). The impaired CA group more frequently developed cerebral infarction than the preserved CA group (36.8% vs. 0%, p = 0.003, respectively). After multivariate analysis, impaired CA (OR 5.15 95% CI 1.43-51.99, p = 0.033) and the APACHE II physiological score (OR 1.67, 95% CI 1.01-2.76, p = 0.046) were independently associated with an unfavorable outcome.

CONCLUSIONS

Early CA impairment detected by TCD and admission APACHE II physiological score independently predicted an unfavorable outcome after SAH.

Impact of Postoperative Infarcts in Determining Outcome after Clipping of Anterior Communicating Artery Aneurysms

Background

Development of cerebral infarcts following clipping of ruptured intracranial aneurysm is one of the major determinants of functional outcome in patients with subarachnoid hemorrhage (SAH). The aim of this study is to evaluate the factors affecting development of postoperative infarcts, its incidence, pattern, and functional outcome.

Material and Methods

This study includes 118 patients of spontaneous SAH because of ruptured anterior communicating artery aneurysm, who underwent clipping. Relevant points in history, preoperative and intraoperative findings, and postoperative outcome are evaluated.

Results

29 of 118 (24.5%) patients developed postoperative radiological infarcts. Approximately 37.9%, 17.2%, and 3.4% patients developed isolated infarcts, respectively, in anterior cerebral artery (ACA), middle cerebral artery (MCA), and posterior cerebral artery (PCA) territory. About 20.7% patients developed infarcts in deep perforator territory. Nine of 29 (31.3%) patients developed multiple-vessel territory infarcts. Patients with poor preoperative neurologic status, prior history of seizure, and history of intraoperative rupture had higher chances of development of infarcts. Development of infarct was irrespective of temporary clipping (TC), duration of clipping, and elective versus rescue clipping. Development of infarcts adversely affected the outcome in significant proportions. Among patients with infarcts, unilateral ACA territory infarcts showed best prognosis, whereas all patients with multiple territory infarcts and PCA territory infarcts died. Age or sex of the patients did not affect the functional outcome. Timing of development of infarcts has no influence on functional recovery.

Conclusion

Development of symptomatic infarct is the sole important predictor of functional outcome. A crowded neurovascular neighborhood and complex variations in local angioarchitecture make anterior communication (ACOM) territory predisposed to operative insults. Elective TC and aggressive management of cerebral vasospasm are recommended to prevent development of infarcts.

Magnetic Resonance Imaging in Aneurysmal Subarachnoid Hemorrhage: Current Evidence and Future Directions

BACKGROUND

Aneurysmal subarachnoid hemorrhage (aSAH) is associated with an unacceptably high mortality and chronic disability in survivors, underscoring a need to validate new approaches for treatment and prognosis. The use of advanced imaging, magnetic resonance imaging (MRI) in particular, could help address this gap given its versatile capacity to quantitatively evaluate and map changes in brain anatomy, physiology and functional activation. Yet there is uncertainty about the real value of brain MRI in the clinical setting of aSAH.

METHODS

In this review, we discuss current and emerging MRI research in aSAH. PubMed was searched from inception to June 2017, and additional studies were then chosen on the basis of relevance to the topics covered in this review.

RESULTS

Available studies suggest that brain MRI is a feasible, safe, and valuable testing modality. MRI detects brain abnormalities associated with neurologic examination, outcomes, and aneurysm treatment and thus has the potential to increase knowledge of aSAH pathophysiology as well as to guide management and outcome prediction. Newer pulse sequences have the potential to reveal structural and physiological changes that could also improve management of aSAH.

CONCLUSION

Research is needed to confirm the value of MRI-based biomarkers in clinical practice and as endpoints in clinical trials, with the goal of improving outcome for patients with aSAH.

Subarachnoid blood acutely induces spreading depolarizations and early cortical infarction

See Ghoshal and Claassen (doi:10.1093/brain/awx226) for a scientific commentary on this article. Early cortical infarcts are common in poor-grade patients after aneurysmal subarachnoid haemorrhage. There are no animal models of these lesions and mechanisms are unknown, although mass cortical spreading depolarizations are hypothesized as a requisite mechanism and clinical marker of infarct development. Here we studied acute sequelae of subarachnoid haemorrhage in the gyrencephalic brain of propofol-anaesthetized juvenile swine using subdural electrode strips (electrocorticography) and intraparenchymal neuromonitoring probes. Subarachnoid infusion of 1–2 ml of fresh blood at 200 µl/min over cortical sulci caused clusters of spreading depolarizations (count range: 12–34) in 7/17 animals in the ipsilateral but not contralateral hemisphere in 6 h of monitoring, without meaningful changes in other variables. Spreading depolarization clusters were associated with formation of sulcal clots (P < 0.01), a high likelihood of adjacent cortical infarcts (5/7 versus 2/10, P < 0.06), and upregulation of cyclooxygenase-2 in ipsilateral cortex remote from clots/infarcts. In a second cohort, infusion of 1 ml of clotted blood into a sulcus caused spreading depolarizations in 5/6 animals (count range: 4–20 in 6 h) and persistent thick clots with patchy or extensive infarction of circumscribed cortex in all animals. Infarcts were significantly larger after blood clot infusion compared to mass effect controls using fibrin clots of equal volume. Haematoxylin and eosin staining of infarcts showed well demarcated zones of oedema and hypoxic-ischaemic neuronal injury, consistent with acute infarction. The association of spreading depolarizations with early brain injury was then investigated in 23 patients [14 female; age (median, quartiles): 57 years (47, 63)] after repair of ruptured anterior communicating artery aneurysms by clip ligation (n = 14) or coiling (n = 9). Frontal electrocorticography [duration: 54 h (34, 66)] from subdural electrode strips was analysed over Days 0–3 after initial haemorrhage and magnetic resonance imaging studies were performed at ∼ 24–48 h after aneurysm treatment. Patients with frontal infarcts only and those with frontal infarcts and/or intracerebral haemorrhage were both significantly more likely to have spreading depolarizations (6/7 and 10/12, respectively) than those without frontal brain lesions (1/11, P’s < 0.05). These results suggest that subarachnoid clots in sulci/fissures are sufficient to induce spreading depolarizations and acute infarction in adjacent cortex. We hypothesize that the cellular toxicity and vasoconstrictive effects of depolarizations act in synergy with direct ischaemic effects of haemorrhage as mechanisms of infarct development. Results further validate spreading depolarizations as a clinical marker of early brain injury and establish a clinically relevant model to investigate causal pathologic sequences and potential therapeutic interventions.

Delayed Branching Artery Occlusion Caused by Clip Rotation after Intracranial Aneurysm Clippings

Clip rotation after clipping is a major cause of delayed cerebral ischemia and may occur after any of several intraoperative monitoring techniques. We experienced 3 cases of clip rotation in 3 patients after clipping between March 2011 and December 2013. One of these patients has permanent motor weakness of the left upper extremity because of delayed occlusion of the right M1 lenticulostriate artery. The other two developed delayed occlusion of the frontopolar artery or of the A1 perforating artery, but did not have any neurologic deficits. Clinicians need to exercise great care not to compromise distal blood flow after clipping intracranial aneurysms. We present 3 cases in which clip rotation occurred after aneurysm clipping and progressively compromised blood flow of a nearby branching artery.

Effect of Early Brain Infarction After Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis

OBJECTIVE

Aneurysmal subarachnoid hemorrhage (aSAH) is an acute cerebrovascular event that leads to devastating consequences. Early brain infarction (EBI) develops very early, within the first 72 hours after bleeding, and may have a significant impact on long-term outcomes. The incidence and impact of EBI in the prognosis of aSAH remain uncertain. We performed a systematic review and meta-analysis to evaluate the incidence of EBI in patients with aSAH and determine its effect on mortality and functional outcomes.

METHODS

We performed a systematic review and meta-analysis. Inclusion criteria were 1) studies that evaluated aSAH within 72 hours after bleeding; 2) performed a brain imaging study up to 72 hours of hemorrhage; 3) used computed tomography or magnetic resonance imaging; and 4) included a description of the findings of the brain imaging study (whether or not an infarct was present).

RESULTS

Ten studies that met the criteria were included. The incidence of EBI was 17%. The risk ratio for 3-month mortality was 2.18 (95% confidence interval 1.48-3.30). The overall risk ratio for poor outcome was 2.26 (95% confidence interval 1.75-2.93).

CONCLUSIONS

EBI plays an important role in the outcome of patients with aSAH. Its significant impact could represent a new therapeutic frontier for improving outcomes of these patients.

MRI Detection of Cerebral Infarction in Subarachnoid Hemorrhage

OBJECTIVE

To investigate magnetic resonance imaging (MRI) detection of cerebral infarction (CI) in patients presenting with subarachnoid hemorrhage (SAH).

BACKGROUND

CI is a well-known complication of SAH that is typically detected on computed tomography (CT). MRI has improved sensitivity for acute CI over CT, particularly with multiple, small, or asymptomatic lesions.

METHODS

With IRB approval, 400 consecutive SAH patients admitted to our institution from August 2006 to March 2011 were retrospectively reviewed. Traumatic SAH and secondary SAH were excluded. Data were collected on demographics, cause of SAH, Hunt Hess and World Federation of Neurosurgical Societies grades, and neuroimaging results. MRIs were categorized by CI pattern as single cortical (SC), single deep (SD), multiple cortical (MC), multiple deep (MD), and multiple cortical and deep (MCD).

RESULTS

Among 123 (30.8 %) SAH patients who underwent MRIs during their hospitalization, 64 (52 %) demonstrated acute CI. The mean time from hospital admission to MRI was 5.7 days (range 0-29 days). Among the 64 patients with MRI infarcts, MRI CI pattern was as follows: MC in 20 (31 %), MCD in 18 (28 %), SC in 16 (25 %), SD in 3 (5 %), MD in 2 (3 %), and 5 (8 %) did not have images available for review. Most infarcts detected on MRI (39/64 or 61 %) were not visible on CT.

CONCLUSIONS

The use of MRI increases the detection of CI in SAH. Unlike CT studies, MRI-detected CI in SAH tends to involve multiple vascular territories. Studies that rely on CT may underestimate the burden of CI after SAH.

Circulating MicroRNAs in Delayed Cerebral Infarction After Aneurysmal Subarachnoid Hemorrhage

Background

Delayed cerebral infarction (DCI) is a major cause of morbidities after aneurysmal subarachnoid hemorrhage (SAH) and typically starts at day 4 to 7 after initial hemorrhage. MicroRNAs (miRNAs) play an important role in posttranscriptional gene expression control, and distinctive patterns of circulating miRNA changes have been identified for some diseases. We aimed to investigate miRNAs that characterize SAH patients with DCI compared with those without DCI.

Methods and Results

Circulating miRNAs were collected on day 7 after SAH in healthy, SAH‐free controls (n=20), SAH patients with DCI (n=20), and SAH patients without DCI (n=20). We used the LASSO (least absolute shrinkage and selection operator) method of regression analysis to characterize miRNAs associated with SAH patients with DCI compared with those without DCI. In the 28 dysregulated miRNAs associated with DCI and SAH, we found that a combination of 4 miRNAs (miR‐4532, miR‐4463, miR‐1290, and miR‐4793) could differentiate SAH patients with DCI from those without DCI with an area under the curve of 100% (95% CI 1.000–1.000, P<0.001). This 4‐miRNA combination could also distinguish SAH patients with or without DCI from healthy controls with areas under the curve of 99.3% (95% CI 0.977–1.000, P<0.001) and 82.0% (95% CI 0.685–0.955, P<0.001), respectively.

Conclusions

We found a 4‐miRNA combination that characterized SAH patients with DCI. The findings could guide future mechanistic study to develop therapeutic targets.

Dissociation of Early and Delayed Cerebral Infarction After Aneurysmal Subarachnoid Hemorrhage

Background and Purpose—

Cerebral infarction after aneurysmal subarachnoid hemorrhage is a significant cause of substantial morbidity and mortality. Because early and delayed cerebral infarction after aneurysmal subarachnoid hemorrhage may be mediated by different processes, we evaluated whether aneurysm-securing methods contributed to infarcts and whether long-term outcomes differ between early and delayed infarcts.

Methods—

A post hoc analysis of the CONSCIOUS-1 study (Clazosentan to Overcome Neurological Ischemia and Infarction Occurring After Subarachnoid Hemorrhage) was performed. Using multivariate logistic regression analysis and propensity matching, independent clinical risk factors associated with infarctions were identified, and the contribution of cerebral infarcts to long-term outcomes was evaluated.

Results—

Within the cohort of 413 subjects, early infarcts were present in 76 subjects (18%), whereas delayed infarcts occurred in 79 subjects (19%), and 36 subjects (9%) had new infarctions that were present on both early and delayed imaging. Propensity score matching revealed a significantly higher proportion of early infarcts after clipping (odds ratio, 4.62; 95% confidence interval, 1.99–11.57; P =0.00012). Multivariate logistic regressions identified clipping as an independent risk factor for early cerebral infarction (odds ratio, 0.26; 95% confidence interval, 0.15–0.48; P <0.001), and angiographic vasospasm was an independent risk factor for delayed cerebral infarction (odds ratio, 1.79; 95% confidence interval, 1.03–3.13; P =0.039). Early infarcts were a significant independent risk factor for poor long-term outcomes at 3 months (odds ratio, 2.34; 95% confidence interval, 1.18–4.67; P =0.015).

Conclusions—

Clipping is an independent risk factor for the development of early cerebral infarcts, whereas delayed cerebral infarcts are associated with angiographic vasospasm. Early cerebral infarcts are stronger predictors of worse outcome than delayed infarction.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00111085.

Early Vasospasm after Aneurysmal Subarachnoid Hemorrhage Predicts the Occurrence and Severity of Symptomatic Vasospasm and Delayed Cerebral Ischemia

Background: Cerebral vasospasm usually develops several days after subarachnoid hemorrhage (SAH) and is generally acknowledged as a strong outcome predictor. In contrast, much less is known about the nature and eventual consequences of early angiographic vasospasm (EAVS) seen on admission digital subtraction angiography (DSA). Therefore, we aimed at identifying the risk factors and clinical impact of EAVS after SAH. Methods: Five hundred and thirty-one SAH patients with admission DSA performed within 72 h after the bleeding event were selected from a comprehensive database containing all consecutive SAH patients treated at our institution between January 2005 and December 2012. Predictors of EAVS, as well as associations between EAVS and delayed vasospasm-related complications, and unfavorable outcome (defined as modified Rankin scale >3) were evaluated in univariate and multivariate analyses. Results: EAVS was seen on 60 DSAs (11.3%) and was independently correlated with delayed symptomatic vasospasm requiring intra-arterial spasmolysis (OR 5.24, p < 0.0001), angioplasty (OR 2.56, p = 0.015) and repetitive endovascular treatment (OR 4.71, p < 0.0001). EAVS also increased the risk for multiple versus single territorial infarction on the follow-up CT scan(s) (OR 2.04, p = 0.047) and independently predicted unfavorable outcome (OR 2.93, p = 0.008). The presence of radiographic signs suspicious for fibromuscular dysplasia were independently associated with the occurrence of EAVS (OR 2.98, p = 0.026) and the need for repetitive endovascular vasospasm treatment (OR 3.95, p = 0.019). Conclusions: In view of the strong correlation with delayed symptomatic vasospasm and its ischemic complications, EAVS can be considered an alerting signal for severe symptomatic vasospasm. Therefore, more attention should be paid to the presence of EAVS on admission DSA.

Brain injury visible on early MRI after subarachnoid hemorrhage might predict neurological impairment and functional outcome

BACKGROUND

In subarachnoid hemorrhage (SAH), brain injury visible within 48 h of onset may impact on admission neurological disability and 3-month functional outcome. With volumetric MRI, we measured the volume of brain injury visible after SAH, and assessed the association with admission clinical grade and 3-month functional outcome.

METHODS

Retrospective cohort study conducted in the Neurocritical Care Division, Columbia University Medical Center, New York, USA. On brain MRI acquired within 48 h of SAH-onset and before aneurysm-securing (n = 27), two blinded readers measured DWI and FLAIR-lesion volumes using semi-automated, computer segmentation software.

RESULTS

Compared to post-resuscitation Hunt-Hess grade 1-3 (70 %), high-grade patients (30 %) had higher lesion volumes on DWI (34 ml [IQR: 0-64] vs. 2 ml [IQR: 0.5-7], P = 0.02) and on FLAIR (81 ml [IQR: 24-127] vs. 3 ml [IQR: 0-27], P = 0.02). On DWI, each 10 ml increase in lesion volume was associated with a 101 %-increase in the odds of presenting with 1 grade more in the Hunt-Hess scale (aOR 2.01, 95 % CI 1.10-3.68, P = 0.02), but was not significantly associated with 3-month outcome. On FLAIR, each 10 ml increase in lesion volume was associated with 34 % higher odds of a 1-point increase on the Hunt-Hess scale (aOR 1.34, 95 % CI 1.06-1.68, P = 0.01) and 139 % higher odds of a 1-point increase on the 3-month mRS (aOR 2.39, 95 % CI 1.13-5.07, P = 0.02).

CONCLUSION

The volume of brain injury visible on DWI and FLAIR within 48 h after SAH is proportional to neurological impairment on admission. Moreover, FLAIR-imaging implicates chronic brain injury-predating SAH-as potentially relevant cause of poor functional outcome.

Circulating microRNA 132-3p and 324-3p Profiles in Patients after Acute Aneurysmal Subarachnoid Hemorrhage

Background

Aneurysmal subarachnoid hemorrhage (SAH) is a highly morbid and fatal condition with high rate of cognitive impairment and negative impact in quality of life among survivors. Delayed cerebral infarction (DCI) is one the major factors for these negative outcomes. In this study we compared the circulating microRNA profiles of SAH patients and healthy individuals, and the circulating microRNA profiles of SAH patients with and without DCI.

Methods

Peripheral blood samples on Day 7 after the onset of SAH were subjected to microarray analysis with Affymetrix miRNA 3.0 array and quantitative PCR analysis. SAH patients with (N = 20) and without DCI (N = 20) and Healthy controls (N = 20) were included for analyses.

Results

We demonstrated that 99 miRNAs were found to be dysregulated in the SAH patient group with DCI. 81 miRNAs were upregulated and 18 were downregulated. Findings from KEGG pathway analysis showed that miRNAs and target genes for axon guidance and TGF-beta signaling were involved, implying that the resulted differential miRNA expression pattern reflect the results of SAH instead of etiology of the disease. miR-132-3p and miR-324-3p showed distinctive upregulations in qPCR [miR-132: 9.5 fold (95%CI: 2.3 to 16.7) in DCI group and 3.4 fold (95%CI: 1.0 to 5.8) in Non-DCI group; miR-324: 4924 fold (95%CI: 2620 to 7228) in DCI group and 4545 fold (95%CI: 2408 to 6683) in non-DCI group]. However, there were no significant differences in fold changes between SAH patients with and without DCI [fold change ratios (mean+/-SD): 2.7+/-4.2 and 1.1+/-1.1 for miRNA-132 and miRNA-324].

Conclusion

Our study demonstrated that as compared to healthy control, miR-132 and miR-324 showed a upregulation in both SAH DCI and Non-DCI groups. However, the differences between the SAH DCI and non-DCI groups were not statistically significant.

Early identification of individuals at high risk for cerebral infarction after aneurysmal subarachnoid hemorrhage: the BEHAVIOR score

Cerebral infarction (CI) is a crucial complication of aneurysmal subarachnoid hemorrhage (SAH) associated with poor clinical outcome. We aimed at developing an early risk score for CI based on clinical characteristics available at the onset of SAH. Out of a database containing 632 consecutive patients with SAH admitted to our institution from January 2005 to December 2012, computed tomography (CT) scans up to day 42 after ictus were evaluated for CIs. Different parameters from admission up to aneurysm treatment were collected with subsequent construction of a risk score. Seven clinical characteristics were independently associated with CI and included in the Risk score (BEHAVIOR Score, 0 to 11 points): Blood on CT scan according to Fisher grade ⩾3 (1 point), Elderly patients (age ⩾55 years, 1 point), Hunt&Hess grade ⩾4 (1 point), Acute hydrocephalus requiring external liquor drainage (1 point), Vasospasm on initial angiogram (3 points), Intracranial pressure elevation >20 mm Hg (3 points), and treatment of multiple aneurysms ('Overtreatment', 1 point). The BEHAVIOR score showed high diagnostic accuracy with respect to the absolute risk for CI (area under curve=0.806, P<0.0001) and prediction of poor clinical outcome at discharge (P<0.0001) and after 6 months (P=0.0002). Further validation in other SAH cohorts is recommended.

Complications and outcomes after early surgical treatment for poor-grade ruptured intracranial aneurysms: A multicenter retrospective cohort

INTRODUCTION

Early surgical treatment has been proposed to improve outcomes of selected patients with poor-grade ruptured intracranial aneurysms. We performed a multicenter retrospective analysis to identify complications and outcomes after early surgery.

METHODS

We analyzed data from the two cohorts of patients with poor-grade ruptured aneurysms. Poor-grade aneurysm was defined as a World Federation of Neurosurgical Society (WFNS) grade of IV or V after resuscitation. Early surgery was defined as surgery performed within 72 h after poor-grade condition.

RESULTS

Of the 144 patients who underwent surgical treatment for poor-grade aneurysm, 80 underwent early surgery and were included in this report. Forty-one (51%) patients presented with a WFNS grade of IV and 39 (49%) presented with a WFNS grade of V. Cerebral infarction occurred in 17 (21%) patients and was the most common complication except for pneumonia. No patients had a good outcome after postoperative aneurysm rebleeding. At follow-up (mean 12.6 months), 37 (46%) patients had a good outcome after early surgery. Multivariate analysis showed that a WFNS grade of V, presence of intraventricular hemorrhage, brain herniation were independent predictors of poor outcome after early surgery. Patients with WFNS grade V more often had a poor outcome after postoperative cerebral infarction, rebleeding or symptomatic vasospasm.

CONCLUSIONS

Patients with a WFNS grade of V, intraventricular hemorrhage, brain herniation were more likely to have a poor outcome after early surgery. Postoperative complications, including rebleeding and cerebral infraction, should be prevented and treated aggressively to maximize the chance of good outcome in poor-grade patients.

Effects of Clot Removal by Meticulous Irrigation and Continuous Low-Dose Intravenous Nicardipine on Symptomatic Cerebral Vasospasm in Patients with Aneurysmal Subarachnoid Hemorrhage Treated by Clipping

BACKGROUND

Symptomatic cerebral vasospasm (SCV) is the second most common of morbidity and mortality in aneurysmal subarachnoid hemorrhage (aSAH) after rebleeding. Blood breakdown products are one of the leading causes of vasospasm. We hypothesized that meticulous subarachnoid clot removal in addition to continuous low-dose intravenous nicardipine (CLIN) could reduce the incidence of SCV.

METHODS

SCV was defined as new focal neurologic signs, consciousness deterioration, or both when the cause was believed to be ischemia attributable to vasospasm after other possible causes of worsening were excluded. Initial brain damage was defined as continued consciousness disturbance after clipping without acute hydrocephalus, ischemic lesions, or focal sign before clipping. Poor outcome was defined as a Glasgow Outcome Scale score of 3-5 at 30 days. We compared the variables for 460 aSAH patients with and without SCV, and with and without poor outcome by multivariate analysis.

RESULTS

All patients underwent clipping with meticulous irrigation for clot removal, and SCV was observed in 56 patients (12%). SCV was observed in 2 patients (2.9%) among 70 patients treated with CLIN. There was a higher proportion of patients who were older than 65 years (P = 0.032) and female (P = 0.038), and a lower proportion of patients with CLIN (P = 0.026) among patients with SCV. The outcomes for 109 patients (27%) were poor; age greater than 65 years (P < 0.0001) and initial brain damage (P = 0.008) were related to the poor outcomes.

CONCLUSIONS

The present study showed that meticulous irrigation for clot removal and CLIN might reduce the incidence of SCV in patients with aSAH.

Redefining secondary injury after subarachnoid hemorrhage in light of multimodal advanced neuroimaging, intracranial and transcranial neuromonitoring: beyond vasospasm

The classic idea that arterial narrowing, called vasospasm (VSP), represents the hallmark of secondary injury after subarachnoid hemorrhage, has been challenged. The more complex and pleiotropic pathophysiological repercussions from the irruption of arterial blood into the subarachnoid layers go beyond the ascribed VSP. Putting adjectives in front of this term, such as "symptomatic," "microdialytic," or "angiographic" VSP, is misleading. Delayed cerebral ischemia (DCI) is a better term but remains restrictive to severe hypoperfusive injury and neglects oligemia, edema, and metabolic nonischemic injuries. In recognition of these issues, the international conference on VSP integrated "neurovascular events" into its name ( www.vasospasm2013.com ) and a multidisciplinary research group was formed in 2010 to study subgroups of DCI/VSP and their respective significance.In three parts, this tiered article provides a broader definitional envelope for DCI and secondary neurovascular insults after SAH, with a rubric for each subtype of delayed neuronal dysfunction. First, it pinpoints the need for nosologic precision and covers current terminological inconsistency. Then, it highlights the input of neuroimaging and neuromonitoring in defining secondary injurious processes. Finally, a new categorization of deteriorating patients is proposed, going beyond a hierarchical or dichotomized definition of VSP/DCI, and common data elements are suggested for future trials.

Acute ischaemia after subarachnoid haemorrhage, relationship with early brain injury and impact on outcome: a prospective quantitative MRI study

OBJECTIVE

To determine if ischaemia is a mechanism of early brain injury at the time of aneurysm rupture in subarachnoid haemorrhage (SAH) and if early MRI ischaemia correlates with admission clinical status and functional outcome.

METHODS

In a prospective, hypothesis-driven study patients with SAH underwent MRI within 0-3 days of ictus (prior to vasospasm) and a repeat MRI (median 7 days). The volume and number of diffusion weighted imaging (DWI) positive/apparent diffusion coefficient (ADC) dark lesions on acute MRI were quantitatively assessed. The association of early ischaemia, admission clinical status, risk factors and 3-month outcome were analysed.

RESULTS

In 61 patients with SAH, 131 MRI were performed. Early ischaemia occurred in 40 (66%) with a mean DWI/ADC volume 8.6 mL (0-198 mL) and lesion number 4.3 (0-25). The presence of any early DWI/ADC lesion and increasing lesion volume were associated with worse Hunt-Hess grade, Glasgow Coma Scale score and Acute Physiology and Chronic Health Evaluation II physiological subscores (all p<0.05). Early DWI/ADC lesions significantly predicted increased number and volume of infarcts on follow-up MRI (p<0.005). At 3 months, early DWI/ADC lesion volume was significantly associated with higher rates of death (21% vs. 3%, p=0.031), death/severe disability (modified Rankin Scale 4-6; 53% vs. 15%, p=0.003) and worse Barthel Index (70 vs. 100, p=0.004). After adjusting for age, Hunt-Hess grade and aneurysm size, early infarct volume correlated with death/severe disability (adjusted OR 1.7, 95% CI 1.0 to 3.2, p=0.066).

CONCLUSIONS

Early ischaemia is related to poor acute neurological status after SAH and predicts future ischaemia and worse functional outcomes. Treatments addressing acute ischaemia should be evaluated for their effect on outcome.

The pathophysiology and treatment of delayed cerebral ischaemia following subarachnoid haemorrhage

Cerebral vasospasm has traditionally been regarded as an important cause of delayed cerebral ischaemia (DCI) which occurs after aneurysmal subarachnoid haemorrhage, and often leads to cerebral infarction and poor neurological outcome. However, data from recent studies argue against a pure focus on vasospasm as the cause of delayed ischaemic complications. Findings that marked reduction in the incidence of vasospasm does not translate to a reduction in DCI, or better outcomes has intensified research into other possible mechanisms which may promote ischaemic complications. Early brain injury and cell death, blood-brain barrier disruption and initiation of an inflammatory cascade, microvascular spasm, microthrombosis, cortical spreading depolarisations and failure of cerebral autoregulation, have all been implicated in the pathophysiology of DCI. This review summarises the current knowledge about the mechanisms underlying the development of DCI. Furthermore, it aims to describe and categorise the known pharmacological treatment options with respect to the presumed mechanism of action and its role in DCI.

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.

Early vs Delayed Cerebral Infarction After Aneurysm Repair After Subarachnoid Hemorrhage

BACKGROUND:

Cerebral infarction is a major contributor to poor outcome after subarachnoid hemorrhage (SAH). Although usually considered a complication of delayed cerebral ischemia, infarcts may also occur early, in relation to initial brain injury or aneurysm-securing procedures.

OBJECTIVE:

We analyzed the relative frequency and volume of early vs delayed infarcts after SAH and their relationship to hospital outcome.

METHODS:

Retrospective review of consecutive patients admitted with aneurysmal SAH over 4 years who had follow-up brain imaging 7 days or later after admission. Imaging 24 to 48-hours after aneurysm-securing procedures was reviewed to classify infarcts seen on final imaging as early or delayed. Infarct volumes were measured by perimeter tracing and infarct burden calculated for each patient.

RESULTS:

Of 250 eligible patients, 205 had follow-up imaging; infarcts were present in 61 patients. Of these, 29 had early infarcts, 16 had delayed infarcts, and 5 had both early and delayed infarcts. Eleven patients with infarcts did not undergo postprocedure computed tomography; these were presumptively classified as having late infarcts. Early and delayed infarcts contributed equally to infarct burden. Early infarcts were associated with aneurysm clipping (odds ratio: 4.2, 95% confidence interval: 1.8-9.5 compared with coiling), whereas delayed infarcts were almost always seen in association with angiographic vasospasm (odds ratio: 3.3, 95% confidence interval: 1.5-7.3). Patients with early as well as late infarcts, especially those with infarct burden more than 30 cm3 had worse hospital discharge disposition.

CONCLUSION:

Early infarction occurs frequently after SAH and contributes as much as delayed cerebral ischemia to infarct burden and hospital outcome. Efforts to better understand and modify contributors to early infarction appear warranted.

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.

Prevalence, timing, risk factors, and mechanisms of anterior cerebral artery infarctions following subarachnoid hemorrhage

Anterior cerebral artery (ACA) ischemia may be underdiagnosed following subarachnoid hemorrhage (SAH). The purpose of this study is to characterize the prevalence, timing, and risk factors for ACA infarction, following primary spontaneous SAH. This was a retrospective study of consecutive SAH patients. Final admission CT scans were reviewed for the presence of ACA infarction, and prior scans serially reviewed to determine timing of infarct. Infarctions were categorized as any, early (days 0-3), late (days 4-15), or perioperative (2 days after aneurysm treatment). Demographic and clinical variables were statistically interrogated to identify predictors of infarct types. Of the 474 study patients, ACA infarctions occurred in 8 % of patients, with 42 % occurring during the early period. Multivariate logistic regression identified H/H grade 4/5 (p < 0.001), ACA/ACom aneurysm location (p < 0.001), and surgical clipping (p = 0.011) as independent predictors of any ACA infarct. In Cox hazards analysis, H/H grade 4/5 (p < 0.001), CT score 3/4 (p = 0.042), ACA/ACom aneurysm location (p < 0.001), and surgical clipping (p = 0.012) independently predicted any ACA infarct. Bivariate logistic regression identified non-Caucasian race (p = 0.032), H/H grade 3/4 (p < 0.001), CT score 3/4 (p = 0.006), IVH (p = 0.027), and ACA/ACom aneurysm (p = 0.001) as predictors of early infarct (EI). Late infarct (LI) was predicted by H/H grade 4/5 (p = 0.040), ACA/ACom aneurysm (p < 0.001), and vasospasm (p = 0.027), while postoperative infarct (PI) was predicted by surgical clipping (p = 0.044). Log-rank analyses confirmed non-Caucasian race (p = 0.024), H/H grade 3/4 (p < 0.001), CT score 3/4 (p = 0.003), IVH (p = 0.010), and ACA/ACom aneurysm (p < 0.001) as predictors of EI. LI was predicted by ACA/ACom aneurysm (p < 0.001) while surgical clipping (p = 0.046) again predicted PI. Clinical severity/grade and ACA/ACom aneurysm location are the most consistent predictors of ACA infarctions. Vasospastic and non-vasospastic processes may concurrently contribute to ACA infarcts.

Acute ischemic injury on diffusion-weighted magnetic resonance imaging after poor grade subarachnoid hemorrhage

BACKGROUND

Poor clinical condition is the most important predictor of neurological outcome and mortality after subarachnoid hemorrhage (SAH). Rupture of an intracranial aneurysm was shown to be associated with acute ischemic brain injury in poor grade patients in autopsy studies and small magnetic resonance imaging series.

METHODS

We performed diffusion-weighted magnetic resonance imaging (DWI) within 96 h of onset in 21 SAH patients with Hunt-Hess grade 4 or 5 enrolled in the Columbia University SAH Outcomes Project between July 2004 and February 2007. We analyzed demographic, radiological, clinical data, and 3 months outcome.

RESULTS

Of the 21 patients 13 were Hunt-Hess grade 5, and eight were grade 4. Eighteen patients (86%) displayed bilateral and symmetric abnormalities on DWI, but not on computed tomography (CT). Involved regions included both anterior cerebral artery territories (16 patients), and less often the thalamus and basal ganglia (4 patients), middle (6 patients) or posterior cerebral artery territories (2 patients), or cerebellum (2 patients). At 1-year, 15 patients were dead (life support had been withdrawn in 6), 2 were moderately to severely disabled (modified Rankin Scale [mRS] = 4-5), and 4 had moderate-to-no disability (mRS = 1-3).

CONCLUSIONS

Admission DWI demonstrates multifocal areas of acute ischemic injury in poor grade SAH patients. These ischemic lesions may be related to transient intracranial circulatory arrest, acute vasoconstriction, microcirculatory disturbances, or decreased cerebral perfusion from neurogenic cardiac dysfunction. Ischemic brain injury in poor grade SAH may be a feasible target for acute resuscitation strategies.

Left ventricular dysfunction and cerebral infarction from vasospasm after subarachnoid hemorrhage

BACKGROUND

Although neurogenic stunned myocardium (NSM) after aneurysmal subarachnoid hemorrhage (SAH) is well described, its clinical significance remains poorly defined. We investigated the influence of left ventricular (LV) dysfunction and cerebral vasospasm on cerebral infarction, serious cardiovascular events, and functional outcome after SAH.

METHODS

Of the 481 patients enrolled in the University Columbia SAH Outcomes Project between 10/96 and 05/02, we analyzed a subset of 119 patients with at least one echocardiogram, serial transcranial Doppler (TCD) data, and with no prior history of cardiac disease. LV dysfunction was defined as an ejection fraction <40% on echocardiography. Infarction from vasospasm was adjudicated by the study team after comprehensive review of all clinical and imaging data. Functional outcome was assessed at 15 and 90 days with the modified Rankin Scale (mRS).

RESULTS

Eleven percent of patients had LV dysfunction (N = 13). Younger age, hydrocephalus, and complete filling of the quadrigeminal and fourth ventricles were associated with LV dysfunction (all P < 0.05). Despite a similar frequency of pre-existing hypertension, 0% of patients with LV dysfunction reported taking antihypertensive medication, compared to 35% of those without (P = 0.009). There was a significant association between LV dysfunction and infarction from vasospasm after adjusting for clinical grade, age, and peak TCD flow velocity (P = 0.03). Patients with LV dysfunction also had higher rates of hypotension requiring vasopressors (P = 0.001) and pulmonary edema (P = 0.002). However, there was no association between LV dysfunction and outcome at 14 days after adjustment for established prognostic variables.

CONCLUSIONS

LV dysfunction after SAH increases the risk of cerebral infarction from vasospasm, hypotension, and pulmonary edema, but with aggressive ICU support does not affect short-term survival or functional outcome. Antihypertensive medication may confer cardioprotection and reduce the risk of catecholamine-mediated injury after SAH.

Proximity to the treating centre and outcomes following subarachnoid hemorrhage

BACKGROUND

In the management of subarachnoid hemorrhage (SAH), the potential for early complications and the centralization of limited resources often challenge the delivery of timely neurosurgical care. We sought to determine the impact of proximity to the accepting neurosurgical centre on outcomes following aneurysmal SAH.

METHODS

Using administrative data, we analyzed patients undergoing treatment for aneurysmal subarachnoid hemorrhage at neurosurgical centres in Ontario between 1995 and 2004. We compared mortality for patients receiving treatment at a centre in their county (in-county) versus those treated from outside counties (out-of-county). We also examined the impact of distance from the patient's residence to the treating centre.

RESULTS

The mortality rates were significantly lower for in-county versus out-of-county patients (23.5% vs. 27.6%, p=0.009). This advantage remained significant after adjusting for potential confounders (HR=0.84, p=0.01). The relationship between distance from the treating centre and mortality was biphasic. Under 300 km, mortality increased with increasing distance. Over 300 km, a survival benefit was observed.

CONCLUSIONS

Proximity to the treating neurosurgical centre impacts survival after aneurysmal SAH. These results have significant implications for the triage of these critically ill patients.

Early infarction detected by diffusion-weighted imaging in patients with subarachnoid hemorrhage

PURPOSE

Early infarction that occurs at the time of initial subarachnoid hemorrhage (SAH) due to rupture of an aneurysm is a poorly understood phenomenon. We investigate the frequency of early infarction using diffusion-weighted images (DWI) at the time of admission. We then discuss the pathogenesis of infarction.

MATERIALS AND METHODS

This study included 85 SAH patients who underwent serial DWI on admission. Early infarction detected by DWI and clinical features were investigated retrospectively.

RESULTS

The overall incidence of DWI-detected early infarction at the time of SAH onset was 8% (7 of 85 cases). In all seven patients, early infarctions were asymptomatic on admission. Types of early infarction seen on DWI included infarcts occurring in the territory of the vessel harboring a ruptured aneurysm (solitary, three cases) and infarcts occurring outside the territory of the vessel (multiple, two cases; solitary, two cases). Six of seven patients eventually developed delayed ischemic neurological deficit (DIND) and computed tomography (CT)-detected and DWI-detected delayed extensive infarction. Four of seven patients with early infarction had an unfavorable outcome. The occurrence of DWI-detected early infarction on admission was significantly correlated with delayed angiographic vasospasm, DIND, CT-detected delayed infarction, DWI-detected delayed infarction, and unfavorable outcome.

CONCLUSIONS

In the present study, DWI-detected early infarction at the time of SAH onset was correlated with the occurrence of delayed extensive ischemic lesions. We believe that performing DWI at the time of admission is useful for evaluating the primary ischemic insult, which might play an important role in the pathogenesis of early brain injury and delayed vasospasm-related complications.

Brainstem control of cerebral blood flow and application to acute vasospasm following experimental subarachnoid hemorrhage

Symptomatic ischemia following aneurysmal subarachnoid hemorrhage (SAH) is common but poorly understood and inadequately treated. Severe constriction of the major arteries at the base of the brain, termed vasospasm, traditionally has been thought to be a proximal event underlying these ischemias, although microvascular changes also have been described. The vast majority of studies aimed at understanding the pathogenesis of ischemic deficits, and vasospasm have focused on the interaction of the "spasmogen" of the extravasated blood with the smooth muscle and endothelium of the arteries. This has led to a comparative neglect of the contribution of the CNS to the maintenance of cerebral perfusion. In the present study, we focused on the role of the rostral ventromedial medulla (RVM) in modulating cerebral perfusion at rest and following an experimental SAH in the rat. Changes in cerebral blood flow (CBF) were measured using laser-Doppler flowmetry and three-dimensional optical microangiography. Focal application of a GABA(A) receptor agonist and antagonist was used to respectively inactivate and activate the RVM. We show here that the RVM modulates cerebral blood flow under resting conditions, and further, contributes to restoration of cerebral perfusion following a high-grade SAH. Failure of this brainstem compensatory mechanism could be significant for acute perfusion deficits seen in patients following subarachnoid hemorrhage.

RESUSCITATION AND CRITICAL CARE OF POOR-GRADE SUBARACHNOID HEMORRHAGE

AS OUTCOMES HAVE improved for patients with aneurysmal subarachnoid hemorrhage, most mortality and morbidity that occur today are the result of severe diffuse brain injury in poor-grade patients. The premise of this review is that aggressive emergency cardiopulmonary and neurological resuscitation, coupled with early aneurysm repair and advanced multimodality monitoring in a specialized neurocritical care unit, offers the best approach for achieving further improvements in subarachnoid hemorrhage outcomes. Emergency care should focus on control of elevated intracranial pressure, optimization of cerebral perfusion and oxygenation, and medical and surgical therapy to prevent rebleeding. In the postoperative period, advanced monitoring techniques such as continuous electroencephalography, brain tissue oxygen monitoring, and microdialysis can detect harmful secondary insults, and may eventually be used as end points for goal-directed therapy, with the aim of creating an optimal physiological environment for the comatose injured brain. As part of this paradigm shift, it is essential that aggressive surgical and medical support be linked to compassionate end-of-life care. As neurosurgeons become confident that comfort care can be implemented in a straightforward fashion after a failed trial of early maximal intervention, the usual justification for withholding treatment (survival with neurological devastation) becomes less relevant, and lives may be saved as more patients recover beyond expectations.

Monitoring with the Somanetics INVOS 5100C after aneurysmal subarachnoid hemorrhage

INTRODUCTION

Vasospasm is a major cause of morbidity after subarachnoid hemorrhage (SAH), and current screening techniques (angiography, transcranial Doppler [TCD], and clinical examination) have serious limitations. Brain oximetry is a promising noninvasive tool to detect reduced brain oxygenation from vasospasm.

METHODS

Consecutive SAH patients at high risk for vasospasm were monitored with the INVOS (Somanetics, IL, USA) 5100C cerebral oximeter. We prospectively collected oximeter readings (rO2) with concurrent values for vital signs, intracerebral pressure (ICP), arterial blood gas measurement, and hemoglobin (HGB). Data were prospectively collected every 12 h and at clinical events (angiography, transfusion, etc.). We prospectively recorded clinical history, clinical events, radiology results, and outcomes.

RESULTS

Six patients were measured 123 times. rO2 values were correlated with the contralateral side, HGB, blood pressure, and PaO2, but not with ICP or perfusion pressure. There were no measured effects of angiography or transfusion. Patterns relating rO2 readings to clinical, angiographic, or TCD evidence of vasospasm were unclear, and there were no associations with the outcome (cerebral infarction, NIH Stroke Scale, or modified Rankin Scale).

CONCLUSION

INVOS rO2 readings are associated with other factors that relate to cerebral oxygen delivery but seem to be of limited use as a screening tool for vasospasm or cerebral infarction after SAH.

The clinical significance of acute brain injury in subarachnoid hemorrhage and opportunity for intervention

Aneurysmal subarachnoid hemorrhage (SAH) is a devastating neurological event that accounts for 3-7% of all strokes and carries a mortality rate as high as 40%. Delayed cerebral vasospasm has traditionally been recognized as the most treatable cause of morbidity and mortality from SAH. However, evidence is mounting that the physiological and cellular events of acute brain injury, which occur during the 24-72 h following aneurysm rupture, make significant contributions to patient outcomes, and may even be a more significant factor than delayed cerebral vasospasm. Acute brain injury in aneurysmal SAH is the result of physiological derangements such as increased intracranial pressure and decreased cerebral blood flow that result in global cerebral ischemia, and lead to the acute development of edema, oxidative stress, inflammation, apoptosis, and infarction. The consequence of these events is often death or significant neurological disability. In this study of acute brain injury, we elucidate some of the complex molecular signaling pathways responsible for these poor outcomes. Continued research in this area and the development of therapies to interrupt these cascades should be a major focus in the future as we continue to seek effective therapies for aneurysmal SAH.