The relationship between delayed infarcts and angiographic vasospasm after aneurysmal subarachnoid hemorrhage

Predictive value of cerebrovascular time constant for delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

Time constant of the cerebral arterial bed (τ) is a transcranial Doppler (TCD) based metric that is expected to quantify the transit time of red blood cells from the insonation point to the arteriole-capillary boundary during a cardiac cycle. This study aims to assess the potential of τ as an early predictor of delayed cerebral ischemia (DCI). Consecutive patients (56 ± 15 years) treated for aneurysmal subarachnoid haemorrhage were included in the study. τ was assessed through a modelling approach that involved simultaneous recordings of arterial blood pressure and cerebral blood flow velocity (CBFV) from TCD's first recordings. 71 patients were included. 17 patients experienced DCI. τ was significantly shorter in patients who later developed DCI: 187 ± 64 ms vs. 249 ± 184 ms; p = 0.040 with moderate effect size (rG = 0.24). Logistic regression showed that there was a significant association between increased CBFV, shortened τ, and the development of DCI (χ2 = 11.54; p = 0.003) with AUC for the model 0.75. Patients who had both shortened τ and increased CBFV were 20 times more likely to develop DCI (OR = 20.4 (2.2-187.7)). Our results suggest that early alterations in τ are associated with DCI after aSAH. The highest performance of the model including both CBFV and τ may suggest the importance of both macrovascular and microvascular changes assessment.

Prognostic factors affecting the ruptured intracranial aneurysms: A 9-year multicenter study in Fujian, China

BACKGROUND

A multicenter retrospective study was conducted to explore the factors affecting short-term prognosis and long-term outcomes of intracranial aneurysms (IA) rupture. Further, the prognosis prediction model was constructed based on survival analysis, contributing to the development of prevention strategies for aneurysmal subarachnoid hemorrhage.

METHODS

Data of 1280 patients with IA rupture were gathered between 2014 and 2022 in Fujian, China. Logistic regression was implemented to study the short-term prognostic factors of IA rupture. Survival analysis of 911 patients among them was performed to explore the long-term outcome status by Cox risk assessment. Nomogram prognosis models were constructed using R software.

RESULTS

The findings displayed that blood type O (OR = 1.79; P = 0.019), high systolic pressure (OR = 1.01; P < 0.001), Glasgow Coma score (GCS) 9-12 (OR = 2.73; P = 0.022), GCS < 9 (OR = 3.222; P = 0.006), diabetes (OR = 2.044; P = 0.040), and high white blood cell count (OR = 1.059, P = 0.040) were core influencing factors for poor short-term prognosis. Survival analysis revealed that age > 60 years (HR = 2.87; P = 0.001), hypertension (HR = 1.95; P = 0.001), conservative (HR = 6.89; P < 0.001) and endovascular treatment (HR = 2.20; P = 0.001), multiple ruptured IAs (HR = 2.37; P = 0.01), Fisher 3 (HR = 1.68; P = 0.09), Fisher 4 (HR = 2.75; P = 0.001), and Hunt-Hess 3 (HR = 0.55; P = 0.05) were the major risk factors for terrible long-term outcomes.

CONCLUSIONS

People over 60 years with characteristics of type O blood, high systolic pressure, diabetes, high white blood cell count, and onset GCS < 12 will have more complications and a worse short-term prognosis. Those aged > 60 years with hypertension, conservative and endovascular treatment, multiple ruptured IAs, Fisher ≥ 3 and Hunt-Hess 3 have a greater risk of poor long-term prognosis.

Diagnosis of Delayed Cerebral Ischemia in Patients with Aneurysmal Subarachnoid Hemorrhage and Triggers for Intervention

INTRODUCTION

Delayed cerebral ischemia (DCI) is a major determinant for poor neurological outcome after aneurysmal subarachnoid hemorrhage (aSAH). Detection and treatment of DCI is a key component in the neurocritical care of patients with aSAH after initial aneurysm repair.

METHODS

Narrative review of the literature.

RESULTS

Over the past 2 decades, there has been a paradigm shift away from macrovascular (angiographic) vasospasm as a main diagnostic and therapeutic target. Instead, the pathophysiology of DCI is hypothesized to derive from several proischemic pathomechanisms. Clinical examination remains the most reliable means for monitoring and treatment of DCI, but its value is limited in comatose patients. In such patients, monitoring of DCI is usually based on numerous neurophysiological and/or radiological diagnostic modalities. Catheter angiography remains the gold standard for the detection of macrovascular spasm. Computed tomography (CT) angiography is increasingly used instead of catheter angiography because it is less invasive and may be combined with CT perfusion imaging. CT perfusion permits semiquantitative cerebral blood flow measurements, including the evaluation of the microcirculation. It may be used for prediction, early detection, and diagnosis of DCI, with yet-to-prove benefit on clinical outcome when used as a screening modality. Transcranial Doppler may be considered as an additional noninvasive screening tool for flow velocities in the middle cerebral artery, with limited accuracy in other cerebral arteries. Continuous electroencephalography enables detection of early signs of ischemia at a reversible stage prior to clinical manifestation. However, its widespread use is still limited because of the required infrastructure and expertise in data interpretation. Near-infrared spectroscopy, a noninvasive and continuous modality for evaluation of cerebral blood flow dynamics, has shown conflicting results and needs further validation. Monitoring techniques beyond neurological examinations may help in the detection of DCI, especially in comatose patients. However, these techniques are limited because of their invasive nature and/or restriction of measurements to focal brain areas.

CONCLUSION

The current literature review underscores the need for incorporating existing modalities and developing new methods to evaluate brain perfusion, brain metabolism, and overall brain function more accurately and more globally.

Prognostic significance of white blood cell to platelet ratio in delayed cerebral ischemia and long-term clinical outcome after aneurysmal subarachnoid hemorrhage

Objectives

The ratio of white blood cell to platelet count (WPR) is considered a promising biomarker in some diseases. However, its prediction of delayed cerebral ischemia (DCI) and prognosis after aneurysmal subarachnoid hemorrhage (aSAH) has not been studied. The primary objective of this study was to investigate the predictive value of WPR in DCI after aSAH and its impact on 90-day functional outcome.

Materials and methods

This study retrospectively analyzed the data of blood biochemical parameters in 447 patients with aSAH at early admission. Univariate and multivariate analyses were used to determine the risk factors for DCI. According to multivariate analysis results, a nomogram for predicting DCI is developed and verified by R software. The influence of WPR on 90-day modified Rankin score (mRS) was also analyzed.

Results

Among 447 patients with aSAH, 117 (26.17%) developed DCI during hospitalization. Multivariate logistic regression analysis showed that WPR [OR = 1.236; 95%CI: 1.058-1.444; p = 0.007] was an independent risk factor for DCI. The receiver operating characteristic (ROC) curve analysis was used to evaluate the predictive ability of WPR for DCI, and the cut-off value of 5.26 (AUC 0.804, 95% CI: 0.757-0.851, p < 0.001). The ROC curve (AUC 0.875, 95% CI: 0.836-0.913, p < 0.001) and calibration curve (mean absolute error = 0.017) showed that the nomogram had a good predictive ability for the occurrence of DCI. Finally, we also found that high WPR levels at admission were closely associated with poor prognosis.

Conclusion

WPR level at admission is a novel serum marker for DCI and the poor prognosis after aSAH. A nomogram model containing early WPR will be of great value in predicting DCI after aSAH.

The Critical Role of Sirt1 in Subarachnoid Hemorrhages: Mechanism and Therapeutic Considerations

The subarachnoid hemorrhage (SAH) is an important cause of death and long-term disability worldwide. As a nicotinamide adenine dinucleotide-dependent deacetylase, silent information regulator 1 (Sirt1) is a multipotent molecule involved in many pathophysiological processes. A growing number of studies have demonstrated that Sirt1 activation may exert positive effects on SAHs by regulating inflammation, oxidative stress, apoptosis, autophagy, and ferroptosis. Thus, Sirt1 agonists may serve as potential therapeutic drugs for SAHs. In this review, we summarized the current state of our knowledge on the relationship between Sirt1 and SAHs and provided an updated overview of the downstream molecules of Sirt1 in SAHs.

Clinical Burden of Angiographic Vasospasm and Its Complications After Aneurysmal Subarachnoid Hemorrhage: A Systematic Review

INTRODUCTION

Angiographic vasospasm (VSP), the narrowing of intracranial arteries, is a complication of aneurysmal subarachnoid hemorrhage (aSAH) and often results in delayed cerebral ischemia (DCI) and cerebral infarction. The objective of this systematic review was to summarize the clinical burden of angiographic VSP and its related complications (DCI and cerebral infarction) after aSAH.

METHODS

Systematic searches of MEDLINE, Embase, and the Cochrane Library were conducted (in January 2021) in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to identify studies reporting clinical outcomes of angiographic VSP and its related complications after aSAH. Study outcomes included measures of functional status (modified Rankin Scale [mRS], Glasgow Outcome Scale [GOS], extended Glasgow Outcome Scale [GOS-E], modified Barthel Index, or the modified National Institutes of Health Stroke Scale), cognitive status (Montreal Cognitive Assessment or the Mini Mental State Exam), clinical events (rebleeding), and mortality. Study selection, data extraction, and qualitative analyses were conducted.

RESULTS

Of 5704 abstracts reviewed, 110 studies were selected: 20 comparative and 39 regression-based studies were included in the qualitative synthesis, 51 descriptive studies were excluded. Most studies (51) were observational and conducted in a single country (53). The occurrence of angiographic VSP and its related complications after aSAH resulted in significantly poorer functional outcomes in three of nine comparative and 11 of 13 regression-based studies, measured by the mRS, and in five of six comparative and eight of nine regression-based studies, measured by the GOS and GOS-E. Angiographic VSP and its related complications were significantly associated with poor cognitive status in all five regression-based studies. Numerically or significantly higher mortality rates in patients with versus those without angiographic VSP and its related complications were reported in five of ten comparative studies and in eight of nine regression-based studies. Six studies looked at specific VSP populations (e.g., by severity or timing of VSP).

CONCLUSION

Patients with angiographic VSP and its related complications often had poor functional, neurological, and cognitive outcomes and reduced odds of survival both in hospital and at follow-up. We estimate that angiographic VSP and its related complications, DCI and cerebral infarction, lead to an approximately threefold higher odds of poor functional and cognitive outcomes, and about a twofold increase in the odds of death.

Cerebral ischemia after treatment of posterior communicating artery aneurysms: clipping versus coiling

Objection

This study aimed to compare the incidence of cerebral ischemia and outcomes between surgical clipping and endovascular coiling in patients with posterior communicating artery (PCoA) aneurysms.

Methods

Clinical and imaging data of patients with at least one PCoA aneurysm who underwent surgical clipping or endovascular coiling in our institution from January 2017 to December 2019 were analyzed.

Results

Three hundred sixty-three aneurysms in 353 patients were included for analysis, 257 in the clipping group, and 106 in the coiling group. The groups did not differ in terms of baseline characteristics. The incidence of postoperative cerebral ischemia (23.35% vs. 11.32%, p = 0.029) was higher in the clipping group. The proportion of patients with a modified Rankin Scale score ≥ 2 was significantly higher in the clipping group at discharge (35.80% vs. 15.09%; p < 0.05) but not six months after discharge (15.56% vs. 8.49%; p > 0.05). In the clipping group, the mean age was significantly higher in patients who developed cerebral ischemia than in those who did not. In the coiling group, modified Fisher grade and incidence of fetal PCoA were significantly higher in patients who developed ischemia.

Conclusion

The incidence of postoperative cerebral ischemia was higher after PCoA aneurysm clipping than after coiling. The causes and characteristics of postoperative cerebral ischemia after PCoA clipping and coiling are different; therefore, treatment should be selected accordingly.

Utilization of EEG for Monitoring in Subarachnoid hemorrhage Recovery

Seizures and delayed cerebral ischemia following subarachnoid hemorrhage are associated with significant morbidity and mortality. In this article, we briefly review subarachnoid hemorrhage, its complications, and the current literature on information gained from EEG monitoring in subarachnoid hemorrhage. We review when EEG should be used implemented in the multi-modal monitoring of patients with subarachnoid hemorrhage. Finally, we discuss the recent advances and future directions in the field.

Large practice variations in diagnosis and treatment of delayed cerebral ischemia after subarachnoid hemorrhage

BACKGROUND

Delayed cerebral ischemia (DCI) contributes to poor outcomes after subarachnoid hemorrhage (SAH). The pathophysiology of DCI is not fully understood, which has hindered the adoption of a uniform definition. Furthermore, a reliable diagnostic test and an effective evidence-based treatment are lacking. This could lead to variations in care.

METHODS

A web-based survey on the variations in the definition, diagnosis, and treatment of DCI was designed and sent to 314 intensivists, neurologists, and neurosurgeons of all 9 hospitals in the Netherlands who care for patients with SAH. The responders were categorized into physicians responsible for the coordination of SAH care and those who were not. For questions on the definition and diagnosis, only the responses from the coordinating physicians were evaluated. For the treatment questions, all the responses were evaluated.

RESULTS

The response rate was 34% (106 of 314). All 9 hospitals were represented. Of the responses, 27 did not provide answers for the definition, diagnosis, or treatment questions; 79 responses were used for analysis. Signs of vasospasm were required by 21 of the 47 coordinating physicians (44%) when considering DCI. Of the 47 coordinating physicians, 24 (51%) did not use a diagnostic test results for a positive diagnosis of DCI. When patients were discharged within 21 days, 33 of the 73 responders (45%) did not provide a prescription for nimodipine continuation. Finally, all but one hospital had treated DCI with hypertension induction.

CONCLUSIONS

We found large variations in the definition, diagnosis, and treatment of DCI in the Netherlands. In the absence of evidence-based treatment, standardization of management seems warranted in an effort to optimize DCI care.

The Utility of Quantitative EEG in Detecting Delayed Cerebral Ischemia After Aneurysmal Subarachnoid Hemorrhage

SUMMARY

In this review, we discuss the utility of quantitative EEG parameters for the detection of delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage in the context of the complex pathophysiology of DCI and the limitations of current diagnostic methods. Because of the multifactorial pathophysiology of DCI, methodologies solely assessing blood vessel narrowing (vasospasm) are insufficient to detect all DCI. Quantitative EEG has facilitated the exploration of EEG as a diagnostic modality of DCI. Multiple quantitative EEG parameters such as alpha power, relative alpha variability, and alpha/delta ratio show reliable detection of DCI in multiple studies. Recent studies on epileptiform abnormalities suggest that their potential for the detection of DCI. Quantitative EEG is a promising, continuous, noninvasive, monitoring modality of DCI implementable in daily practice. Future work should validate these parameters in larger populations, facilitated by the development of automated detection algorithms and multimodal data integration.

Heparin in the treatment of aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis

OBJECTIVE

Cerebral vasospasm and the resulting infarction remain the most devastating complications of aneurysmal subarachnoid hemorrhage (aSAH). Limited treatment options are available, with nimodipine as the only approved prophylactic medication. In addition to its anticoagulant properties, heparin also has a pleiotropic and anti-inflammatory effect that could be beneficial in vasospasm. In this study, the authors sought to evaluate the efficacy and safety of heparin in the treatment of aSAH.

METHODS

The PubMed, EBSCOhost, Europe PMC, and Cochrane Central databases were searched to find studies including patients with aSAH who were treated with intravenous unfractionated heparin (UFH) after an aneurysm-securing procedure. Studies that did not include a comparison with UFH or low-molecular-weight heparin in deep vein thrombosis prophylactic doses were excluded. The primary outcome was cerebral vasospasm, and the secondary outcomes were cerebral infarction, clinical deterioration caused by delayed cerebral ischemia, bleeding complications, and thromboembolism complications.

RESULTS

Overall, 5 nonrandomized studies were included; 4 studies evaluated the safety and 3 studies evaluated the efficacy of intravenous heparin. From the analysis of 3 studies with a total of 895 patients, administration of intravenous UFH for > 48 hours was related to a significantly lower rate of cerebral infarction (OR 0.44, 95% CI 0.25–0.79). No significant association was found with other efficacy outcomes. Regarding cognitive outcome, one study found a significant improvement in Montreal Cognitive Assessment scores; however, the functional outcome as indicated by the modified Rankin Scale score was not improved by heparin administration. From the analysis of 4 studies with 1099 patients, no significant increases in bleeding and other complications were found.

CONCLUSIONS

Administration of intravenous UFH for more than 48 hours reduced the rate of cerebral infarction with a good safety profile. This result supports the ongoing clinical trial.

Use of the Cascade expandable net to treat cerebral vasospasm - initial clinical experience from a single centre with in vitro benchside tests

Background

The use of self-expanding stents to treat post-hemorrhagic cerebral vasospasm was recently described. We sought to determine the clinical efficacy of the Cascade device to treat delayed cerebral vasospasm (DCV). We performed benchside tests to determine the chronic outward force exerted by the Cascade in comparison to the Solitaire.

Methods

The chronic outward force (COF) of the Cascade M agile and Cascade L Agile was tested with equivalent tests of the Solitaire 4x20mm. Further tests to determine the forces generated in pre-formed tubes of 1.5–6 mm were performed using both fully and partially unsheathed Cascades.

A retrospective review to identify all patients with aSAH and DCV treated with a Cascade device between January 2020 and July 2021. We recorded the treatment arterial vessel diameters and hemorrhagic or ischemic complications.

Results

In vitro the Cascade generated greater radial force than the Solitaire. The force generated by the Cascade M Agile at 1.5 mm was approximately 64% higher than the Solitaire 6x40mm and approximately 350% higher than the Solitaire 4x20mm.

4 patients with DCV were identified all of whom were treated with a cascade device. In all cases there was a significant improvement in the diameter of the vasospastic vessels treated with an average diameter increase of approximately 300%. There were no complications from the Cascade. Delayed CT angiography showed persistent dilatation of the segments treated with the Cascade at 24 h.

Conclusion

The Cascade is a safe and effective device when used to treat DCV secondary to aSAH. Larger studies are required to validate our initial results.

Screening Computed Tomography Angiography to Identify Patients at Low Risk for Delayed Cerebral Ischemia Following Aneurysmal Subarachnoid Hemorrhage

Introduction: Delayed cerebral ischemia (DCI) occurs during a risk period of 3-21 days following aneurysmal subarachnoid hemorrhage (aSAH) and is associated with worse outcomes. The identification of patients at low risk for DCI might permit triage to less intense monitoring and management. While large-vessel vasospasm (LVV) is a distinct clinical entity from DCI, the presence of moderate-to-severe LVV is associated with a higher risk of DCI. Our hypothesis was that the absence of moderate-to-severe LVV on screening computed tomographic angiography (CTA) performed within the first few days of the DCI risk period will accurately identify patients at low risk for subsequent DCI. Methods: This was a retrospective cohort study. Our institutional SAH outcomes registry was queried for all aSAH patients admitted in 2016-2019 who underwent screening CTA brain between days 4 and 8 following ictus. We excluded patients diagnosed with DCI prior to the first CTA performed during this time period. All variables are prospectively entered into the registry, and outcomes including DCI and LVV are prospectively adjudicated. We evaluated the predictive value and accuracy of moderate-to-severe LVV on CTA performed 4-8 days following ictus for the prediction of subsequent DCI. Results: A total of 243 aSAH patients were admitted during the study timeframe. Of the 54 patients meeting the eligibility criteria, 11 (20%) had moderate-to-severe LVV on the screening CTA study performed during the risk period. Seven of the 11 (64%) patients with moderate-to-severe LVV on the days 4-8 screening CTA vs. six of 43 (14%) patients without, subsequently developed DCI. On multivariate analysis, the presence of LVV on days 4-8 screening CTA was an independent predictor of DCI (odds ratio 10.26, 95% CI 1.69-62.24, p = 0.011). NPV for the subsequent development of DCI was 86% (95% CI 77-92%). Sensitivity was 54% (25-81%), specificity 90% (77-97%), and positive predictive value 64% (38-83%). Conclusions: The presence of moderate-to-severe LVV on screening CTA performed between days 4 and 8 following aSAH was an independent predictor of DCI, but achieved only moderate diagnostic accuracy, with NPV 86% and sensitivity 54%. Complementary risk-stratification strategies are likely necessary.

Transcranial-Doppler-Measured Vasospasm Severity is Associated with Delayed Cerebral Infarction After Subarachnoid Hemorrhage

BACKGROUND

Angiographic vasospasm after aneurysmal subarachnoid hemorrhage (aSAH) is associated with delayed cerebral ischemia (DCI)-related cerebral infarction (radiological DCI) and worsened neurological outcome. Transcranial Doppler (TCD) measurements of cerebral blood flow velocity are commonly used after aSAH to screen for vasospasm; however, their association with cerebral infarction is not well characterized. We sought to determine whether time-varying TCD-measured vasospasm severity is associated with cerebral infarction and investigate the performance characteristics of different time/severity cutoffs for predicting cerebral infarction.

METHODS

We conducted a retrospective single-center cohort study of consecutive adult patients with aSAH with at least one TCD study between 2011 and 2020. The primary outcome was radiological DCI, defined as a cerebral infarction developing at least 2 days after any surgical or endovascular intervention without an alternative cause. Cox proportional hazards models were used to examine associations between time-varying vasospasm severity and radiological DCI. Optimal TCD-based time/severity thresholds for predicting radiological DCI were then determined.

RESULTS

Of 262 patients with aSAH who underwent TCD studies, 27 (10%) developed radiological DCI. Patients with radiological DCI had higher modified Fisher scale scores and trended toward earlier onset of vasospasm. Adjusted for age, Hunt and Hess scores, and modified Fisher scale scores, the worst-vessel vasospasm severity was associated with radiological DCI (adjusted hazard ratio 1.7 [95% confidence interval 1.1-2.4]). Vasospasm severity within a specific vessel was associated with risk of delayed infarction in the territory supplied by that vessel. Optimal discrimination of patients with radiological DCI was achieved with thresholds of mild vasospasm on days 4-5 or moderate vasospasm on days 6-9, with negative predictive values greater than 90% and positive predictive values near 20%.

CONCLUSIONS

TCD-measured vasospasm severity is associated with radiological DCI after aSAH. An early, mild TCD-based vasospasm severity threshold had a high negative predictive value, supporting its role as a screening tool to identify at-risk patients.

Delayed Cerebral Ischemia after Subarachnoid Hemorrhage

Delayed cerebral ischemia (DCI) is the most feared complication of aneurysmal subarachnoid hemorrhage (aSAH). It increases the mortality and morbidity associated with aSAH. Previously, large cerebral artery vasospasm was thought to be the sole major contributing factor associated with increased risk of DCI. Recent literature has challenged this concept. We conducted a literature search using PUBMED as the prime source of articles discussing various other factors which may contribute to the development of DCI both in the presence or absence of large cerebral artery vasospasm. These factors include microvascular spasm, micro-thrombosis, cerebrovascular dysregulation, and cortical spreading depolarization. These factors collectively result in inflammation of brain parenchyma, which is thought to precipitate early brain injury and DCI. We conclude that diagnostic modalities need to be refined in order to diagnose DCI more efficiently in its early phase, and newer interventions need to be developed to prevent and treat this condition. These newer interventions are currently being studied in experimental models. However, their effectiveness on patients with aSAH is yet to be determined.

Admission serum high mobility group box 1 (HMGB1) protein predicts delayed cerebral ischemia following aneurysmal subarachnoid hemorrhage

High mobility group box 1 protein (HMGB1) is a prototypical damage associated particle and acts as a key player in aseptic inflammation. HMGB1 appears critical for the crosstalk of a prothrombotic and proinflammatory state that is implicated in mediating and exacerbating ischemic brain injury. The role of HMGB1 in aneurysmal subarachnoid hemorrhage (aSAH) remains to be elucidated. A prospective, single blinded observational study was designed to investigate the role of HMGB1 in aSAH. Serial serum HMGB1 level quantification on admission day 0, 4, 8, and 12 was performed. Primary outcome measures were delayed cerebral ischemia (DCI - new infarction on CT) and poor functional outcome (90-day modified Rankin Scale 4-6). The role of HMGB1 levels for DCI, functional outcome and radiological vasospasm prediction was analyzed. Collectively, 83 aSAH patients were enrolled. Five patients died within 48 h. In 29/78 patients (37.2%), DCI was identified. In multivariable analysis, radiological vasospasm and admission HMGB1 were independent predictors for DCI. Younger age and higher white blood cell count, but not insult burden (World Federation of Neurosurgical Societies scale, modified Fisher scale, intraparenchymal or intraventricular hematoma existence) correlated with admission HMGB1 levels. Serial HMGB1 levels did not differ between patients with or without DCI, poor functional outcome or radiological vasospasm development. Admission serum HMGB1 does not reflect initial insult burden but serves as an independent biomarker predictive of DCI. Further studies are warranted to disentangle the role of HMGB1 surrounding the sequelae of aSAH.

Alpha power decrease in quantitative EEG detects development of cerebral infarction after subarachnoid hemorrhage early

OBJECTIVE

In subarachnoid hemorrhage (SAH), transcranial Doppler/color-coded-duplex sonography (TCD/TCCS) is used to detect delayed cerebral ischemia (DCI). In previous studies, quantitative electroencephalography (qEEG) also predicted imminent DCI. This study aimed to compare and analyse the ability of qEEG and TCD/TCCS to early identify patients who will develop later manifest cerebral infarction.

METHODS

We analysed cohorts of two previous qEEG studies. Continuous six-channel-EEG with artefact rejection and a detrending procedure was applied. Alpha power decline of ≥ 40% for ≥ 5 hours compared to a 6-hour-baseline was defined as significant EEG event. Median reduction and duration of alpha power decrease in each channel was determined. Vasospasm was diagnosed by TCD/TCCS, identifying the maximum frequency and days of vasospasm in each territory.

RESULTS

34 patients were included (17 male, mean age 56 ± 11 years, Hunt and Hess grade: I-V, cerebral infarction: 9). Maximum frequencies in TCD/TCCS and alpha power reduction in qEEG were correlated (r = 0.43; p = 0.015). Patients with and without infarction significantly differed in qEEG parameters (maximum alpha power decrease: 78% vs 64%, p = 0.019; summed hours of alpha power decline: 236 hours vs 39 hours, p = 0.006) but showed no significant differences in TCD/TCCS parameters.

CONCLUSIONS

There was a moderate correlation of TCD/TCCS frequencies and qEEG alpha power reduction but only qEEG differentiated between patients with and without cerebral infarction.

SIGNIFICANCE

qEEG represents a non-invasive, continuous tool to identify patients at risk of cerebral infarction.

Delayed Cerebral Infarction is Systematically Associated with a Cerebral Vasospasm of Large Intracranial Arteries

BACKGROUND

Whether delayed cerebral infarction (DCIn) after aneurysmal subarachnoid hemorrhage (aSAH) is driven by large artery vasospasm is still controversial.

OBJECTIVE

To study the association between DCIn and vasospasm by using quantitative assessment of vasospasm up to distal arteries with time and territorial-based correlation.

METHODS

Clinical and imaging data of 392 patients with aSAH treated at our center between 2012 and 2017 were reviewed. DCIn was defined as any cerebral infarction occurring within 3 to 21 d after ictus and not related to other specific cause. In patients with DCIn, vasospasm was assessed within 24 h around DCIn for each cerebral artery up to the end of the 2nd segments. DCIn and vasospasm analyses were blinded.

RESULTS

DCIn was found in 11% of patients (inter-rater k = 0.90, computed tomography (CT)-scan = 100%, follow-up MRI = 91%). Vasospasm was quantified in 258 artery territories including 66 with and 192 without DCIn (DSA = 93%, computed tomography angiography = 7%). Vasospasm was more severe in DCIn than in non-DCIn territories (60% [55-69] vs 20% [0-50], P < .001). Vasospasm was associated with DCIn in a "dose-dependent" manner (P for trend = .022). Every DCIn territory had a vasospasm ≥ 50%, including 39% only of distal artery segments. Only 9% of non-DCIn territories had vasospasm ≥ vasospasm in DCIn territories.

CONCLUSION

The necessary association between severe vasospasm and DCIn in our study brings additional arguments in favor of large artery vasospasm (especially of distal segments) as a major determinant of DCIn and a potential therapeutic target.

Compromised regulation of the rat brain parenchymal arterioles in vasopressin-associated acute hyponatremia

OBJECTIVE

In this study, we examined the effect of acute hyponatremia associated with vasopressin (AVP) on the responses of the isolated rat's MCAs and PAs to acidosis, nitric oxide donor (SNAP) and to endothelium-dependent vasodilator ATP.

METHODS

The studies were performed on isolated, perfused and pressurized MCAs and PAs in control conditions and during AVP-associated hyponatremia. Hyponatremia was induced in vitro by lowering Na⁺ concentration from 144 to 121 mmol/L in intra- and extravascular fluid in the presence of AVP.

RESULTS

Parenchymal arterioles showed greater response to an increase in H⁺ and K⁺ ions concentration and to ATP in comparison with MCAs in control normonatremic conditions. Both PAs and MCAs constricted in response to acute hyponatremia associated with AVP. Interestingly, disordered regulation of vascular tone was observed in PAs but not in MCAs. The abnormalities in the regulation comprised a significant reduction of PA response to acidosis and the absence of the response to the administration of SNAP or ATP.

CONCLUSIONS

Arginine vasopressin-associated hyponatremia leads to constriction and dysregulation of PAs which may impair neurovascular coupling.

Optimal intracranial pressure in patients with aneurysmal subarachnoid hemorrhage treated with coiling and requiring external ventricular drainage

Optimal management of intracranial pressure (ICP) among aneurysmal subarachnoid hemorrhage (aSAH) patients requiring external ventricular drainage (EVD) is controversial. To analyze predictors of delayed cerebral ischemia (DCI)-related cerebral infarction after aSAH and the influence of ICP values on DCI, we prospectively collected consecutive patients with aSAH receiving coiling and requiring EVD. Predictors of DCI-related cerebral infarction (new CT hypodensities developed within the first 3 weeks not related to other causes) were studied. Vasospasm and brain hypoperfusion were studied with CT angiography and CT perfusion (RAPID-software). Among 50 aSAH patients requiring EVD, 21 (42%) developed DCI-related cerebral infarction, while 27 (54%) presented vasospasm. Mean ICP ranged between 2 and 19 mmHg. On the multivariate analysis, the mean ICP (OR = 2, 95%CI = 1.01-3.9, p = 0.042) and the mean hypoperfusion volume on Tmax delay > 6 (OR = 1.2, 95%CI = 1.01-1.3, p = 0.025) were independent predictors of DCI. To predict DCI-related cerebral infarction, Tmax delay > 6 s presented the highest AUC (0.956, SE = 0.025), with a cutoff value of 18 ml showing sensitivity, specificity, PPV, NPV, and accuracy of 90.5% (95%CI = 69-98.8%), 86.2% (95%CI = 68.4-96%), 82.6% (95%CI = 65.4-92%), 92.5% (95%CI = 77-98%), and 88% (95%CI = 75-95%), respectively. The AUC of the mean ICP was 0.825 (SE = 0.057), and the best cutoff value was 6.7 mmHg providing sensitivity, specificity, PPV, NPV, and accuracy of 71.4% (95%CI = 48-89%), 62% (95%CI = 42-79%), 58% (95%CI = 44-70%), 75% (95%CI = 59-86%), and 66% (95%CI = 51-79%) for the prediction of DCI-related cerebral infarction, respectively. Among aSAH patients receiving coiling and EVD, lower ICP (< 6.7 mmHg in our study) could potentially be beneficial in decreasing DCI-related cerebral infarction. Brain hypoperfusion with a volume > 18 ml at Tmax delay > 6 s presents a high sensibility and specificity in prediction of DCI-related cerebral infarction.

Cerebral Vasospasm After Spontaneous Subarachnoid Hemorrhage: Angiographic Pattern and Its Impact on the Clinical Course

OBJECTIVE

To analyze angiographic characteristics of cerebral vasospasm (CVS) after spontaneous subarachnoid hemorrhage (sSAH) and their potential impact on secondary infarction and functional outcome.

METHODS

Demographic, clinical, and imaging data of sSAH patients with angiographic CVS admitted over a 6-year period were retrospectively analyzed.

RESULTS

A total of 85 patients were included in the final analysis. A total of 311 arterial territories in 85 angiographies demonstrated angiographic CVS. The anterior cerebral artery (ACA) was the most common site of angiographic CVS (42.1%), followed by the middle cerebral artery (MCA) (26.7%). In 29 angiographies (34%) CVS was found in more than 3 vessels and a bilateral pattern was identified in 53 cases (62%). Older age (OR 3.24 [95% CI 1.30-8.07], P = 0.012) was identified as the only significant risk factor for CVS-related infarction (OR 22.67, P = 0.015). Unfavorable outcome was associated with older age (OR 3.24, P = 0.023) and poor World Federation of Neurosurgical Societies grade (OR 3.64, P = 0.015). Analyses of angiographic characteristics did not reveal any risk factors for unfavorable outcome. We identified distal CVS as a significant risk factor for CVS-related infarction (OR 2.89, P = 0.026).

CONCLUSIONS

Angiographic CVS after sSAH shows a specific distribution pattern in favor of ACA and MCA and in most cases 2-3 affected vessels are affected, often bilaterally. Patients exhibiting distal CVS have a higher risk for CVS-related infarction and should be observed closely. Nonetheless, the majority of angiographic characteristics did not allow conclusions about functional outcome nor the occurrence of CVS-related infarction in sSAH patients.

Cerebral Arterial Compliance in Polytraumazed Patients with Cerebral Vasospasm

The purpose was to determine the status of the cerebral arterial compliance (cAC) in a concomitant head injury and cerebral vasospasm (CVS) with and without the development of intracranial hematomas (ICH). In Materials and Methods, we examined 80 polytrauma patients with severe TBI and CVS. During or immediately after dynamic helical computed tomography angiography (DHCTA), the monitoring of the transcranial Doppler of the MCA was recorded bilaterally with 2-MHz probes. The cerebral blood volumes were calculated from the DHCTA data with complex mathematical procedures using the "direct flow model" algorithm. In Results, CAC was significantly decreased (p < 0.001) in both the first and second group TBI and CVS (with or without ICH) in comparison with normal data (p < 0.001) and TBI without CVS. The cAC was significantly decreased on the side of the former hematoma with CVS than on the contralateral side with CVS (р = 0.003). In Conclusion, the cAC in TBI and CVS gets significantly lower as compared to the normal condition (p < 0.001). After removal of the ICH and development of CVS, the compliance in the perifocal zone remains much lower (р = 0.003) as compared to compliance of the other brain hemisphere.

Clinical and morphological profile of aneurysms of the anterior communicating artery treated at a neurosurgical service in Southern Brazil

Background:

The aim of the study was to characterize the clinical profile of patients with anterior communicating artery (ACoA) aneurysms and examine potential correlations between clinical findings, aneurysm morphology, and outcome.

Methods:

A review of medical records and diagnostic neuroimaging reports of patients treated at a neurosurgical service in Porto Alegre, Brazil, between August 2008 and January 2015 was performed.

Results:

During the period, 100 patients underwent surgery for ACoA aneurysms. Fifteen had unruptured aneurysms and 85 had ruptured aneurysms. Ruptured aneurysms had a higher aspect ratio than unruptured ones (2.37 ± 0.71 vs. 1.93 ± 0.51, P = 0.02). Intraoperative rupture occurred in 3%, and temporary clipping was performed in 15%. Clinical vasospasm occurred in 43 patients with ruptured aneurysms (50.6%). Overall, mortality was 26%; 25 patients in the ruptured group (29.4%) and one in the unruptured group (6%). The Glasgow Outcome Scale (GOS) was favorable (GOS 4 or 5) in 54% of patients, significantly more so in those with unruptured aneurysms (P = 0.01). In patients with ruptured aneurysms, mortality was associated with preoperative Hunt and Hess (HH) score (P < 0.001), hydrocephalus (P < 0.001), and clinical complications (P < 0.001). Unfavorable outcomes were associated with HH score (P < 0.001), Fisher grade (P = 0.015), clinical vasospasm (P = 0.012), external ventricular drain (P = 0.015), hydrocephalus (P < 0.001), and presence of clinical complications (P = 0.001). In patients with unruptured aneurysms, presence of clinical complications was the only factor associated with mortality (P < 0.001).

Conclusion:

Despite advances in the management of subarachnoid hemorrhage and surgical treatment of aneurysms, mortality is still high, especially due to clinical complications.

Burden of cerebral hypoperfusion in patients with delayed cerebral ischemia after subarachnoid hemorrhage

OBJECTIVE

Delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH) may result in focal neurological deficits and cerebral infarction, believed to result from critical regional rather than global impairments in cerebral blood flow (CBF). However, the burden of such regional hypoperfusion has not been evaluated by gold-standard voxel-by-voxel CBF measurements. Specifically, the authors sought to determine whether the proportion of brain affected by hypoperfusion was greater in patients with DCI than in SAH controls without DCI and whether the symptomatic hemisphere (in those with lateralizing deficits) exhibited a greater cerebral hypoperfusion burden.

METHODS

Sixty-one patients with aneurysmal SAH underwent 15O PET to measure regional CBF during the period of risk for DCI (median 8 days after SAH, IQR 7-10 days). Regions of visibly abnormal brain on head CT studies, including areas of hemorrhage and infarction, were excluded. Burden of hypoperfusion was defined as the proportion of PET voxels in normal-appearing brain with CBF < 25 ml/100 g/min. Global CBF and hypoperfusion burden were compared between patients with and those without DCI at the time of PET. For patients with focal impairments from DCI, the authors also compared average CBF and hypoperfusion burden in symptomatic versus asymptomatic hemispheres.

RESULTS

Twenty-three patients (38%) had clinical DCI at the time of PET. Those with DCI had higher mean arterial pressure (MAP; 126 ± 14 vs 106 ± 12 mm Hg, p < 0.001) and 18 (78%) were on vasopressor therapy at the time of PET study. While global CBF was not significantly lower in patients with DCI (mean 39.4 ± 11.2 vs 43.0 ± 8.3 ml/100 g/min, p = 0.16), the burden of hypoperfusion was greater (20%, IQR 12%-23%, vs 12%, 9%-16%, p = 0.006). Burden of hypoperfusion performed better than global CBF as a predictor of DCI (area under the curve 0.71 vs 0.65, p = 0.044). Neither global CBF nor hypoperfusion burden differed in patients who responded to therapy compared to those who had not improved by the time of PET. Although hemispheric CBF was not lower in the symptomatic versus contralateral hemisphere in the 13 patients with focal deficits, there was a trend toward greater burden of hypoperfusion in the symptomatic hemisphere (21% vs 18%, p = 0.049).

CONCLUSIONS

The burden of hypoperfusion was greater in patients with DCI, despite hemodynamic therapies, higher MAP, and equivalent global CBF. Similarly, hypoperfusion burden was greater in the symptomatic hemisphere of DCI patients with focal deficits even though the average CBF was similar to that in the contralateral hemisphere. Evaluating the proportion of the brain with critical hypoperfusion after SAH may better capture the extent of DCI than averaging CBF across heterogenous brain regions.

Neuroprotective Role of the Nrf2 Pathway in Subarachnoid Haemorrhage and Its Therapeutic Potential

The mechanisms underlying poor outcome following subarachnoid haemorrhage (SAH) are complex and multifactorial. They include early brain injury, spreading depolarisation, inflammation, oxidative stress, macroscopic cerebral vasospasm, and microcirculatory disturbances. Nrf2 is a global promoter of the antioxidant and anti-inflammatory response and has potential protective effects against all of these mechanisms. It has been shown to be upregulated after SAH, and Nrf2 knockout animals have poorer functional and behavioural outcomes after SAH. There are many agents known to activate the Nrf2 pathway. Of these, the actions of sulforaphane, curcumin, astaxanthin, lycopene, tert-butylhydroquinone, dimethyl fumarate, melatonin, and erythropoietin have been studied in SAH models. This review details the different mechanisms of injury after SAH including the contribution of haemoglobin (Hb) and its breakdown products. It then summarises the evidence that the Nrf2 pathway is active and protective after SAH and finally examines the evidence supporting Nrf2 upregulation as a therapy after SAH.

Clinical complications and outcomes of angiographically negative subarachnoid hemorrhage

OBJECTIVE

To define the in-hospital course, complications, short- and long-term functional outcomes of patients with angiographically negative subarachnoid hemorrhage (anSAH), particularly those with aneurysmal-pattern anSAH (aanSAH).

METHODS

Retrospective cohort study of patients with aneurysmal subarachnoid hemorrhage (aSAH), aanSAH, and perimesencephalic-pattern anSAH (panSAH) treated at a single tertiary referral center between January 2006 and April 2018. Ninety-nine patients with anSAH (33 aanSAH and 66 panSAH) and 464 patients with aSAH were included in this study. Outcomes included symptomatic hydrocephalus requiring CSF drainage, need for ventriculoperitoneal shunt, radiographic vasospasm, delayed cerebral ischemia (DCI), radiographic infarction, disability level within 1 year of ictus, and at last clinical follow-up as defined by the modified Rankin Scale.

RESULTS

Patients with aanSAH and panSAH had similar rates of DCI and radiologic infarction, and patients with aanSAH had significantly lower rates compared to aSAH (p ≤ 0.018). Patients with aanSAH were more likely than those with panSAH to require temporary CSF diversion and ventriculoperitoneal shunt (p ≤ 0.03), with similar rates to those seen in aSAH. Only one patient with anSAH died in the hospital. Compared to those with aSAH, patients with aanSAH were significantly less likely to have a poor functional outcome within 1 year of ictus (odds ratio 0.26, 95% confidence interval 0.090-0.75) and at last follow-up (hazard ratio 0.30, 95% confidence interval 0.19-0.49, p = 0.002).

CONCLUSIONS

DCI is very uncommon in anSAH, but patients with aanSAH have a similar need for short- and long-term CSF diversion to patients with aSAH. Nevertheless, patients with aanSAH have significantly better short- and long-term outcomes.

Quantitative EEG After Subarachnoid Hemorrhage Predicts Long-Term Functional Outcome

PURPOSE

Delayed cerebral ischemia is a major complication after subarachnoid hemorrhage. Our previous study showed that alpha power reduction in continuous quantitative EEG predicts delayed cerebral ischemia. In this prospective cohort, we aimed to determine the prognostic value of alpha power in quantitative EEG for the long-term outcome of patients with subarachnoid hemorrhage.

METHODS

Adult patients with nontraumatic subarachnoid hemorrhage were included if admitted early enough for EEG to start within 72 hours after symptom onset. Continuous six-channel EEG was applied. Unselected EEG signals underwent automated artifact rejection, power spectral analysis, and detrending. Alpha power decline of ≥40% for ≥5 hours was defined as critical EEG event based on previous findings. Six-month outcome was obtained using the modified Rankin scale.

RESULTS

Twenty-two patients were included (14 male; mean age, 59 years; Hunt and Hess grade I-IV; duration of EEG monitoring, median 14 days). Poor outcome (modified Rankin scale, 2-5) was noted in 11 of 16 patients (69%) with critical EEG events. All six patients (100%) without EEG events achieved an excellent outcome (modified Rankin scale 0, 1) (P = 0.0062; sensitivity 100%, specificity 54.5%). Vasospasm detected with transcranial Doppler/Duplex sonography appeared 1.5 days after EEG events and showed weaker association with outcome (P = 0.035; sensitivity 100%, specificity 45.5%). There was no significant association between EEG events and ischemic lesions on imaging (P = 0.1). Also, no association between ischemic lesions and outcome was seen (P = 0.64).

CONCLUSIONS

Stable alpha power in quantitative EEG reflects successful therapy and predicts good functional outcome after subarachnoid hemorrhage. Critical alpha power reduction indicates an increased risk of poor functional outcome.

Predictive Value of Cerebral Autoregulation Impairment for Delayed Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage: A Meta-Analysis

OBJECTIVE

Delayed cerebral ischemia (DCI) happens in about 30% of patients with aneurysmal subarachnoid hemorrhage (SAH) and is related to higher mortality and disability. Some studies have shown cerebral autoregulation impairment can be a predictor of DCI in aneurysmal SAH. We conducted this meta-analysis to evaluate the predictive value of cerebral autoregulation impairment for DCI based on the current literature.

METHODS

A systematic literature search was performed in PubMed and Embase. According to inclusion and exclusion criteria, 2 authors screened the records and extracted data from the included studies. Pooled sensitivity, specificity, and their 95% confidence intervals (CIs) were obtained. To investigate the overall accuracy, a summary receiver operating characteristic (SROC) curve was built and the area under SROC curve was calculated. Deeks' linear regression was used to assess the publication bias. All statistical analyses were performed with Stata 14.0.

RESULTS

A total of 7 studies were finally included in this meta-analysis. The pooled sensitivity and specificity values of impaired cerebral autoregulation for DCI prediction were 0.79 (95% CI, 0.65-0.88) and 0.85 (95% CI, 0.615-0.96). Moreover, the area under the SROC curve of cerebral autoregulation impairment for DCI prediction was 0.87 (95% CI, 0.835-0.89). No obvious publication bias was found in Deeks' linear regression (P = 0.99).

CONCLUSIONS

Cerebral autoregulation impairment can be a helpful predictor of DCI in aneurysmal SAH. Its accuracy for DCI prediction should be verified by more studies in the future.

Imaging predictors of outcome in acute spontaneous subarachnoid hemorrhage: a review of the literature

Spontaneous subarachnoid hemorrhage (SAH) accounts for about 5% of strokes, but has a very high morbidity and mortality. Many survivors are left with important cognitive impairment and are severely incapacitated. Prediction of complications such as vasospasm and delayed cerebral ischemia, and of clinical outcome after SAH, is challenging. Imaging studies are essential in the initial evaluation of SAH patients and are increasingly relevant in assessing for complications and prognosis. In this article, we reviewed the role of imaging studies in evaluating early brain injury and predicting complications as well as clinical and neuropsychological prognosis after acute SAH.

Prediction of Delayed Cerebral Ischemia with Cerebral Angiography: A Meta-Analysis

OBJECT

Cerebral catheter angiography is the gold standard for diagnosing cerebral artery vasospasm (vasospasm) in aneurysmal subarachnoid hemorrhage (SAH). We have previously published a meta-analysis of prediction of delayed cerebral ischemia (DCI) from transcranial Doppler (TCD) evidence of vasospasm. Analogous data relating to prediction of DCI have not been previously collated for cerebral angiography nor reconciled against TCD.

METHODS

We searched PUBMED, the Cochrane database, and clinicaltrials.gov for studies that used cerebral angiography for diagnosis of vasospasm and evaluated DCI in patients with SAH. We performed a random-effects meta-analysis of prediction of DCI with cerebral angiography, reconciling its accuracy against that of TCD. We also report quality of evidence for the value of cerebral angiography and TCD in SAH based on pooled data from our meta-analyses.

RESULTS

A total of 15 studies (n = 5463) were included in the meta-analysis. Sensitivity (SN), specificity (SP), positive predictive value (PPV), and negative predictive value (NPV) of cerebral angiography for prediction of DCI are 57, 68, 32, and 90%. These metrics for TCD, based on our previous meta-analysis, are 90, 71, 57, and 92%. We report that test accuracy estimates are "moderate" for TCD and "low" for angiography based on pooled data from our meta-analyses.

CONCLUSION

TCD evidence of vasospasm is a better predictor of DCI than angiographic vasospasm. Future comparative effectiveness studies can better define the value of these diagnostic tools in patients with SAH.

A case report of delayed cortical infarction adjacent to sulcal clots after traumatic subarachnoid hemorrhage in the absence of proximal vasospasm

BACKGROUND

Cortical ischemic lesions represent the predominant pathomorphological pattern of focal lesions after aneurysmal subarachnoid hemorrhage (aSAH). Autopsy studies suggest that they occur adjacent to subarachnoid blood and are related to spasm of small cortical rather than proximal arteries. Recent clinical monitoring studies showed that cortical spreading depolarizations, which induce cortical arterial spasms, are involved in lesion development. If subarachnoid blood induces adjacent cortical lesions, it would be expected that (i) they also develop after traumatic subarachnoid hemorrhage (tSAH), and (ii) lesions after tSAH can occur in absence of angiographic vasospasm, as was found for aSAH.

CASE PRESENTATION

An 86-year-old woman was admitted to our hospital with fluctuating consciousness after hitting her head during a fall. The initial computed tomography (CT) was significant for tSAH in cortical sulci. On day 8, the patient experienced a secondary neurological deterioration with reduced consciousness and global aphasia. Whereas the CT scan on day 9 was still unremarkable, magnetic resonance imaging (MRI) on day 10 revealed new cortical laminar infarcts adjacent to sulcal blood clots. Proximal vasospasm was ruled out using MR and CT angiography and Doppler sonography. CT on day 14 confirmed the delayed infarcts.

CONCLUSIONS

We describe a case of delayed cortical infarcts around sulcal blood clots after tSAH in the absence of proximal vasospasm, similar to results found previously for aSAH. As for aSAH, this case suggests that assessment of angiographic vasospasm is not sufficient to screen for risk of delayed infarcts after tSAH. Electrocorticography is suggested as a complementary method to monitor the hypothesized mechanism of spreading depolarizations.

Early serum miR-1297 is an indicator of poor neurological outcome in patients with aSAH

Objective: MiRNAs are important regulators of translation and have been described as biomarkers of a number of cardiovascular diseases, including stroke. The purpose of the study was to determine expression levels of serum miR-1297 in patients with aneurysmal subarachnoid hemorrhage (aSAH), and to assess whether miR-1297 was the prognostic indicator of aSAH. Methods: We treated 128 aSAH patients with endovascular coiling. The World Federation of Neurological Surgeons (WFNS) grades, Hunt-Hess grades, and modified Fisher scores were used to assess aSAH severity. Neurologic outcome was assessed using the Modified Rankin Scale (mRS) at 1-year post-aSAH. Serum was taken at various time points (24, 72, and 168 h, and 14 days). Serum samples from aSAH patients and healthy controls were subjected to reverse transcription (RT) quantitative real-time PCR (RT-qPCR). Results: A poor outcome at 1 year was associated with significantly higher levels of miR-1297 value at the four time points, higher WFNS grade, higher Hunt-Hess grade, and higher Fisher score. Serum miR-1297 levels were significantly higher in patients, compared with healthy controls. There were significant correlations of miR-1297 concentrations in serum with severity in aSAH. The AUCs of miR-1297 at the four time points for distinguishing the aSAH patients from healthy controls were 0.80, 0.94, 0.77, and 0.59, respectively. After multivariate logistic regression analysis, only miR-1297 at 24 and 72 h enabled prediction of neurological outcome at 1 year. Conclusion: Serum was an independent predictive factor of poor outcome at 1 year following aSAH. This result supports the use of miR-1297 in aSAH to aid determination of prognosis.

Autoregulation in the Neuro ICU

PURPOSE OF REVIEW

The purpose of this review is to briefly describe the concept of cerebral autoregulation, to detail several bedside techniques for measuring and assessing autoregulation, and to outline the impact of impaired autoregulation on clinical and functional outcomes in acute brain injury. Furthermore, we will review several autoregulation studies in select forms of acute brain injuries, discuss the potential for its use in patient management in the ICU, and suggest further avenues for research.

RECENT FINDINGS

Cerebral autoregulation plays a critical role in regulating cerebral blood flow, and impaired autoregulation has been associated with worse functional and clinical outcomes in various acute brain injuries. There exists a multitude of methods to assess the autoregulatory state in patients using both invasive and non-invasive modalities. Continuous monitoring of patients in the ICU has yielded autoregulatory-derived optimal perfusion pressures that may prevent secondary injury and improve outcomes. Measuring autoregulation continuously at the bedside is now a feasible option for clinicians working in the ICU, although there exists a great need to standardize autoregulatory measurement. While the clinical benefits await prospective and randomized trials, autoregulation-derived parameters show enormous potential for creating an optimal physiological environment for the injured brain.

Persistent High Levels of miR-502-5p Are Associated with Poor Neurologic Outcome in Patients with Aneurysmal Subarachnoid Hemorrhage

OBJECTIVE

To investigate the temporal changes in miR-502-5p expression after aneurysmal subarachnoid hemorrhage (aSAH) and to find the time to peak level.

METHODS

We collected serum from patients with aSAH (n = 129) at various time points (1, 3, 7, and 14 days postevent) and healthy controls (n = 40) at the Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College, from May 1, 2015 to January 31, 2016. We measured expression levels of miR-502-5p by polymerase chain reaction. We used the 2-ΔCt method and calculated correlations among variables using Spearman rank correlation coefficient analysis. We used receiver operating characteristic curves to identify optimal levels of miR-502-5p for aSAH and multivariate logistic regression to analyze risk factors on the modified Rankin scale. We measured miR-502-5p expression at all 4 time points post-aSAH.

RESULTS

Levels rose moderately from day 1 to day 7, with a substantial decrease from day 7 to day 14. The peak was at day 7. Multivariate logistic regression revealed that higher miR-502-5p levels at 7 days were associated with a significantly high risk for poor outcome post-aSAH.

CONCLUSIONS

Our data suggest that persistent elevated levels of miR-502-5p participate in the development of aSAH and may help physicians to adjust therapy for aSAH.

Effect of intrathecal milrinone injection via lumbar catheter on delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

OBJECTIVE

Delayed cerebral ischemia (DCI) is an important complication after aneurysmal subarachnoid hemorrhage (aSAH). Although intrathecal milrinone injection via lumbar catheter to prevent DCI has been previously reported to be safe and feasible, its effectiveness remains unknown. The goal of this study was to evaluate whether intrathecal milrinone injection treatment after aSAH significantly reduced the incidence of DCI.

METHODS

The prospectively maintained aSAH database was used to identify patients treated between January 2010 and December 2015. The cohort included 274 patients, with group assignment based on treatment with intrathecal milrinone injection or not. A propensity score model was generated for each patient group, incorporating relevant patient variables.

RESULTS

After propensity score matching, 99 patients treated with intrathecal milrinone injection and 99 without treatment were matched on the basis of similarities in their demographic and clinical characteristics. There were significantly fewer DCI events (4% vs 14%, p = 0.024) in patients treated with intrathecal milrinone injection compared with those treated without it. However, there were no significant differences between the 2 groups with respect to their 90-day functional outcomes (46% vs 36%, p = 0.31). The likelihood of chronic secondary hydrocephalus, meningitis, and congestive heart failure as complications of intrathecal milrinone injection therapy was also similar between the groups.

CONCLUSIONS

In propensity score–matched groups, the intrathecal administration of milrinone via lumbar catheter showed significant reduction of DCI following aSAH, without an associated increase in complications.

Early matrix metalloproteinase-9 concentration in the first 48 h after aneurysmal subarachnoid haemorrhage predicts delayed cerebral ischaemia: An observational study

BACKGROUND

Delayed cerebral ischaemia from vasospasm is an important cause of complications and death after aneurysmal subarachnoid haemorrhage. There is currently no established biomarker for identifying patients at high risk of delayed cerebral ischaemia.

OBJECTIVE

Considering the important role of inflammation in the pathogenesis of delayed cerebral ischaemia, we investigated whether matrix metalloproteinase-9 (MMP-9) may be an efficient biomarker for predicting elayed cerebral ischaemia after subarachnoid haemorrhage.

DESIGN

Single-centre prospective observational study.

SETTING

Neuroscience Critical Care Unit of a teaching hospital.

PARTICIPANTS

Thirty consecutive patients with severe subarachnoid haemorrhage requiring external ventricular drainage were enrolled during 2013 and 2014.

INTERVENTIONS

Blood and cerebrospinal fluid (CSF) were sampled within the first 24 h and between 48 and 72 h after admission. We evaluated the activity and concentrations of MMP-9 and endothelin-1 with zymography and ELISA. Patients were allocated to groups with delayed cerebral ischaemia (n = 16) or without delayed cerebral ischaemia (n = 14).

RESULTS

Within 24 h, median [interquartile range] MMP-9 concentrations in CSF were significantly higher in patients with delayed cerebral ischaemia (47 [21 to 102] ng ml) than in those without delayed cerebral ischaemia (4 [2 to 13] ng ml, P = 0.001). CSF MMP-9 activity and endothelin-1 concentrations were correlated (r = 0.6, P = 0.02). The areas under the receiver operating characteristic curves were 0.73 (95% confidence interval [0.53 to 0.87]) and 0.91 (95% confidence interval [0.75 to 0.98]) for MMP-9 concentrations in plasma and CSF, respectively, at 24 h to predict delayed cerebral ischaemia CSF MMP-9 concentrations more than 14.3 ng ml at 24 h predicted the occurrence of delayed cerebral ischaemia with a sensitivity and specificity of 88 and 86%, respectively. After multivariate logistic analysis, only CSF MMP-9 concentrations at 24 h predicted the occurrence of delayed cerebral ischaemia (P = 0.01).

CONCLUSION

MMP-9 concentrations in both plasma and CSF, measured within 48 h after subarachnoid haemorrhage, were highly predictive of the occurrence of delayed cerebral ischaemia within the first 2 weeks.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT02397759.

Early abnormal transient hyperemic response test can predict delayed ischemic neurologic deficit in subarachnoid hemorrhage

Background

Early detection of vasospasm is crucial to prevent significant delayed ischemic neurological deficit post subarachnoid hemorrhage. The standard methods of detection, including cerebral angiogram and computed tomography are invasive and not safe to be repeated, as is very often indicated clinically. Transient hyperemic response test has been previously used to predict autoregulation failure in traumatic brain injury and subarachnoid hemorrhage.

Aims

We investigate the usability of transient hyperemic response test as a predictor of clinical vasospasm in a cohort of patients with aneurismal subarachnoid hemorrhage.

Methods

A retrospective review of all THRT examinations done between January 2011 and July 2012 conducted at Montreal Neurological Institute and Hospital and the Montreal General Hospital. Patients diagnosed with aSAH in which the THRT was performed within the first 24–48 h of admission were included in the study. Two-dimensional transcranial Doppler images were obtained and velocities were recorded. A positive response was one in which the velocity was increased by more than 9% of the baseline systolic velocity, indicating an intact cerebral autoregulation. Lindegaard ratio > 3 is considered abnormal and in the context of elevated systolic velocity of the MCA, is highly suggestive of DIND.

Results

Fifteen patients met the inclusion criteria. A total of 6 patients developed clinical and radiological vasospasm. Out of these 6 patients, 5 (83%) had an abnormal THRT in the initial TCD assessment (p = 0.0406). We found that abnormal transient hyperemic response test readings are predictive of subsequent vasospasm development.

Conclusions

The results of this small retrospective study support the notion that transient hyperemic response test has predictive value in vasospasm development and may prove useful in patient monitoring and successful clinical management.

Association of Plasminogen Activator Inhibitor 1 (SERPINE1) Polymorphisms and Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Genetic variations of the serine proteinase inhibitor family E member 1 (SERPINE1) gene, which encodes plasminogen activator inhibitor 1, correlate with serum levels of its product and are associated with thrombophilia and coronary atherosclerosis. Various SERPINE1 ;gene polymorphisms have been identified. However, only the functional 5G/4G polymorphism has been assessed in the context of aneurysmal subarachnoid hemorrhage (aSAH). We assessed associations of 6 SERPINE1 polymorphisms with the clinical sequelae of aSAH.

METHODS

From 2012 to 2015, patients with aSAH were prospectively enrolled into the CARAS (Cerebral Aneurysm Renin Angiotensin System) study at 2 major academic institutions. Blood samples were used to evaluate 6 common SERPINE1 single nucleotide polymorphisms via 5' exonuclease (Taqman) genotyping assays.

RESULTS

There was an association of the AA genotype of rs2227631 with the 4G/4G genotype and of the GG genotype of rs7242 with the AA genotype of rs2227684. In multivariable analysis, patients with the AA genotype of rs2227631 and 4G/4G genotype had an increased risk for developing delayed cerebral ischemia. Patients with the GG genotype of rs7242 and AA genotype of rs2227684 had a decreased risk for a poor functional outcome.

CONCLUSIONS

SERPINE1 gene polymorphisms were associated with delayed cerebral ischemia and functional outcome after aSAH. These associations may arise from alterations of plasminogen activator inhibitor 1 levels.

Temporal evolution of vasospasm and clinical outcome after intra-arterial vasodilator therapy in patients with aneurysmal subarachnoid hemorrhage

Intra-arterial (IA) vasodilator therapy is one of the recommended treatments to minimize the impact of aneurysmal subarachnoid hemorrhage-induced cerebral vasospasm refractory to standard management. However, its usefulness and efficacy is not well established. We evaluated the effect IA vasodilator therapy on middle cerebral artery blood flow and on discharge outcome. We reviewed records for 115 adults admitted to Neurointensive Care Unit to test whether there was a difference in clinical outcome (discharge mRS) in those who received IA infusions. In a subset of 19 patients (33 vessels) treated using IA therapy, we tested whether therapy was effective in reversing the trends in blood flow. All measures of MCA blood flow increased from day -2 to -1 before infusion (maximum Peak Systolic Velocity (PSV) 232.2±9.4 to 262.4±12.5 cm/s [p = 0.02]; average PSV 202.1±8.5 to 229.9±10.9 [p = 0.02]; highest Mean Flow Velocity (MFV) 154.3±8.3 to 172.9±10.5 [p = 0.10]; average MFV 125.5±6.3 to 147.8±9.5 cm/s, [p = 0.02]) but not post-infusion (maximum PSV 261.2±14.6 cm/s [p = .89]; average PSV 223.4±11.4 [p = 0.56]; highest MFV 182.9±12.4 cm/s [p = 0.38]; average MFV 153.0±10.2 cm/s [p = 0.54]). After IA therapy, flow velocities were consistently reduced (day X infusion interaction p<0.01 for all measures). However, discharge mRS was higher in IA infusion group, even after adjusting for sex, age, and admission grades. Thus, while IA vasodilator therapy was effective in reversing the vasospasm-mediated deterioration in blood flow, clinical outcomes in the treated group were worse than the untreated group. There is need for a prospective randomized controlled trial to avoid potential confounding effect of selection bias.

Comparison of Initial Vasopressors Used for Delayed Cerebral Ischemia after Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

The main reason for morbidity after aneurysmal subarachnoid hemorrhage (aSAH) is delayed cerebral ischemia (DCI). The mainstay of medical therapy for treating DCI is induced hypertension with vasopressors to restore cerebral perfusion. Both phenylephrine (PE) and norepinephrine (NE) are commonly used for induced hypertension, but the impact of the initial choice of vasopressor on the efficacy, adverse effects, or outcome after hemodynamic therapy for DCI is unknown.

METHODS

Sixty-three patients with aSAH between January 2012 and October 2014, who developed DCI (defined as new focal deficit or decline in Glasgow Coma Score) and in which PE (n = 45) or NE (n = 18) treatment was initiated were evaluated in this retrospective study. Baseline characteristics, adverse effects, the need to change or add vasopressors, the response to therapy, the need for endovascular therapy, new infarct development, discharge disposition, and 3 months modified Rankin score were all compared between pressor groups.

RESULTS

Baseline characteristics (e.g., Hunt Hess and Fisher grades) were similar. There were no differences in the overall rate of complications including arrhythmia, pulmonary edema, or kidney injury. However, those initiated on PE were more likely to be changed to an alternate vasopressor (64 vs. 33%, p = 0.016), mostly for bradycardia or failure to reach therapeutic targets. Patients initially treated with PE were less likely to respond neurologically (71 vs. 94%, p = 0.01) or to be discharged to home or acute rehabilitation facilities (73 vs. 94%, p = 0.02) and were more likely to have a delayed infarct on imaging (62 vs. 33%, p = 0.04).

CONCLUSIONS

Our study suggests that patients with DCI after aSAH initiated on PE are more likely to require treatment change to another vasopressor and are at greater risk for poor clinical outcomes compared to patients started on NE. Larger comparative studies are warranted.

Endothelial Nitric Oxide Synthase Polymorphism Is Associated with Delayed Cerebral Ischemia Following Aneurysmal Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

Nitric oxide is critical in the regulation of cerebral blood flow and smooth muscle proliferation. It is synthesized by 3 nitric oxide synthase (NOS) isoforms: neuronal, inducible, and endothelial NOS (eNOS). Aneurysmal subarachnoid hemorrhage (aSAH) causes endothelial dysfunction that, in turn, contributes to pathophysiologic processes surrounding aSAH. Previous studies reported an association of an eNOS single nucleotide polymorphism (SNP) with the clinical sequelae of aSAH. Here, we further elucidate the impact of this eNOS SNP on the clinical course after aSAH.

METHODS

The Cerebral Aneurysm Renin Angiotensin System study prospectively enrolled aSAH patients at 2 academic institutions in the United States from 2012-2015. Blood samples from all patients enrolled in the study were used for genetic evaluation using 5'exonuclease (Taqman) genotyping assays. Associations between the eNOS SNP rs2070744 (786 T->C) and clinical course after aSAH were analyzed.

RESULTS

Samples from 149 aSAH patients were available for analysis. The C allele of the eNOS SNP independently predicted an increased risk for delayed cerebral ischemia (OR = 2.936, 95% CI 1.048-8.226, P = 0.040). The eNOS SNP rs2070744 was not associated with functional outcome or size of aneurysm at the time of rupture.

CONCLUSIONS

The present study is the first to demonstrate that the C allele of the eNOS SNP 786 T->C rs2070744 is independently associated with an increased risk for delayed cerebral ischemia following aSAH.

Impact of High-Mobility Group Box 1 Polymorphism on Delayed Cerebral Ischemia After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND AND OBJECTIVE

The high-mobility group box 1 (HMGB1) protein is a eukaryotic, ubiquitously expressed protein that serves as a biomarker for various diseases and is involved in the promotion of a proinflammatory response to cell injury. In aneurysmal subarachnoid hemorrhage (aSAH), increased HMGB1 levels have been linked to poor outcome and an increased risk for cerebral vasospasm. The role of HMGB1 polymorphisms in aSAH has not been previously investigated.

METHODS

Patients with aSAH and controls enrolled in the prospective, 2-center CARAS (Cerebral Aneurysm Renin Angiotensin System) study were evaluated. The 3814 C/G HMGB1 single nucleotide polymorphism (SNP) rs2249825 was detected using 5'exonuclease (Taqman) genotyping assays from blood samples from patients with aSAH and controls. Associations between aSAH and its clinical sequelae with the HMGB1 SNP were assessed.

RESULTS

Samples from 149 patients with aSAH and 50 controls were available for analysis. No increased risk for aSAH associated with the SNP was found compared with the control group. Delayed cerebral ischemia (DCI) was defined as a cerebral infarction at the time of discharge from the intensive care unit and identified in 21.2% of patients with aSAH. In multivariable logistic regression analysis, the G allele of rs2249825 was independently associated with DCI (odds ratio, 5.695; 95% confidence interval, 1.804-17.975; P = 0.003).

CONCLUSIONS

The minor allele G of rs2249825 was associated with an increased risk for DCI, or cerebral infarction, after aSAH. This finding may be attributable to an increased HMGB1 protein expression in these patients.