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.

Common Data Elements for Radiological Imaging of Patients with Subarachnoid Hemorrhage: Proposal of a Multidisciplinary Research Group

INTRODUCTION

Lack of homogeneous definitions for imaging data and consensus on their relevance in the setting of subarachnoid hemorrhage and unruptured intracranial aneurysms lead to a difficulty of data pooling and lack of robust data. The aim of the National Institute of Health/National Institute of Neurological Disorders and Stroke, Unruptured Intracranial Aneurysm (UIA) and Subarachnoid Hemorrhage (SAH) Common Data Elements (CDE) Project was to standardize data elements to ultimately facilitate data pooling and establish a more robust data quality in future neurovascular research on UIA and SAH.

METHODS

For the subcommittee 'Radiological imaging of SAH,' international cerebrovascular specialists with imaging expertise in the setting of SAH were selected by the steering committee. CDEs were developed after reviewing the literature on neuroradiology and already existing CDEs for other neurological diseases. For prioritization, the CDEs were classified into 'Core,' 'Supplemental-Highly Recommended,' 'Supplemental' and 'Exploratory.'

RESULTS

The subcommittee compiled 136 CDEs, 100 out of which were derived from previously established CDEs on ischemic stroke and 36 were newly created. The CDEs were assigned to four main categories (several CDEs were assigned to more than one category): 'Parenchymal imaging' with 42 CDEs, 'Angiography' with 49 CDEs, 'Perfusion imaging' with 20 CDEs, and 'Transcranial doppler' with 55 CDEs. The CDEs were classified into core, supplemental highly recommended, supplemental and exploratory elements. The core CDEs were imaging modality, imaging modality type, imaging modality vessel, angiography type, vessel angiography arterial anatomic site and imaging vessel angiography arterial result.

CONCLUSIONS

The CDEs were established based on the current literature and consensus across cerebrovascular specialists. The use of these CDEs will facilitate standardization and aggregation of imaging data in the setting of SAH. However, the CDEs may require reevaluation and periodic adjustment based on current research and improved imaging quality and novel modalities.

Definition and Prioritization of Data Elements for Cohort Studies and Clinical Trials on Patients with Unruptured Intracranial Aneurysms: Proposal of a Multidisciplinary Research Group

INTRODUCTION

Variability in usage and definition of data characteristics in previous cohort studies on unruptured intracranial aneurysms (UIA) complicated pooling and proper interpretation of these data. The aim of the National Institute of Health/National Institute of Neurological Disorders and Stroke UIA and Subarachnoid Hemorrhage (SAH) Common Data Elements (CDE) Project was to provide a common structure for data collection in future research on UIA and SAH.

METHODS

This paper describes the development and summarization of the recommendations of the working groups (WGs) on UIAs, which consisted of an international and multidisciplinary panel of cerebrovascular specialists on research and treatment of UIAs. Consensus recommendations were developed by review of previously published CDEs for other neurological diseases and the literature on UIAs. Recommendations for CDEs were classified by priority into 'Core,' 'Supplemental-Highly Recommended,' 'Supplemental,' and 'Exploratory.'

RESULTS

Ninety-one CDEs were compiled; 69 were newly created and 22 were existing CDEs. The CDEs were assigned to eight subcategories and were classified as Core (8), Supplemental-Highly Recommended (23), Supplemental (25), and Exploratory (35) elements. Additionally, the WG developed and agreed on a classification for aneurysm morphology.

CONCLUSION

The proposed CDEs have been distilled from a broad pool of characteristics, measures, or outcomes. The usage of these CDEs will facilitate pooling of data from cohort studies or clinical trials on patients with UIAs.

Abstract T P395: Complement Activation in Delayed Cerebral Ischemia After Aneurysmal Subarachnoid Hemorrhage - An Autopsy Study

Background: The pathogenesis of delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH) remains unclear. It has been hypothesized that an inflammatory response in the subarachnoid space and microthrombosis contribute to DCI. Previous studies showed that plasma levels of complement factors are associated with DCI and functional outcome after aSAH. We performed an autopsy study to investigate the relationship between complement activation, microthrombosis and DCI.

Methods: In autopsy material from 7 patients who died from DCI, we isolated 9 areas of cerebral infarction and 15 areas without infarction. From autopsy material of 5 controls (myocardial infarction: n=3; heart failure: n=1; pulmonary embolism: n=1) we isolated 15 corresponding areas. We performed immunohistochemistry to investigate the presence of C1q, C3c, and fibrin(ogen) (which is strongly correlated with microthrombosis). Optical density measurements were used for quantitative assessments. Optical density values were compared between areas with infarction, without infarction, and controls, and analyzed with a Mann-Whitney U test. Spearman correlation tests were performed to investigate the relationships of C1q and C3c with fibrin(ogen).

Results: Optical density values of C1q, C3c, and fibrin(ogen) were higher in areas of infarction than in areas without infarction or controls (Table 1, p<0.001 for all comparisons). Correlations were found between C1q and fibrin(ogen) (r=0.73, p<0.001) and C3c with fibrin(ogen) (r=0.74, p<0.001).

Conclusion: Our results show that areas of cerebral infarction in patients with aSAH have more complement activation and microthrombosis than areas without infarction or control brains. A strong correlation was found between complement activation and microthrombosis. Future studies are needed to investigate if drugs targeting complement activation decrease the risk of DCI and improve outcome after aSAH.

Genome-wide association study of intracranial aneurysm identifies a new association on chromosome 7

BACKGROUND AND PURPOSE

Common variants have been identified using genome-wide association studies which contribute to intracranial aneurysms (IA) susceptibility. However, it is clear that the variants identified to date do not account for the estimated genetic contribution to disease risk.

METHODS

Initial analysis was performed in a discovery sample of 2617 IA cases and 2548 controls of white ancestry. Novel chromosomal regions meeting genome-wide significance were further tested for association in 2 independent replication samples: Dutch (717 cases; 3004 controls) and Finnish (799 cases; 2317 controls). A meta-analysis was performed to combine the results from the 3 studies for key chromosomal regions of interest.

RESULTS

Genome-wide evidence of association was detected in the discovery sample on chromosome 9 (CDKN2BAS; rs10733376: P<1.0×10(-11)), in a gene previously associated with IA. A novel region on chromosome 7, near HDAC9, was associated with IA (rs10230207; P=4.14×10(-8)). This association replicated in the Dutch sample (P=0.01) but failed to show association in the Finnish sample (P=0.25). Meta-analysis results of the 3 cohorts reached statistical significant (P=9.91×10(-10)).

CONCLUSIONS

We detected a novel region associated with IA susceptibility that was replicated in an independent Dutch sample. This region on chromosome 7 has been previously associated with ischemic stroke and the large vessel stroke occlusive subtype (including HDAC9), suggesting a possible genetic link between this stroke subtype and IA.

Abstract W MP99: Seven-Day Mortality After Ischemic Stroke: International Comparison Among Industrialized Nations

Introduction: Stroke is the 2 nd leading cause of death worldwide, yet best practices for acute stroke care are lacking even among premier hospitals in industrialized countries. We compared 7-day mortality after ischemic stroke between academic medical centers in the Netherlands (NL), United Kingdom (UK), and United States (US).

Methods: This was an observational study using in-hospital administrative data from select academic medical centers in the NL (n=8), UK (n=10), and US (n=11) from 2005-12. Chi-square was used to compare 7-day in-hospital mortality between countries and across years, and to explore the effect of weekend admission. Multiple logistic regression was conducted to further examine factors associated with mortality, including sex, age, weekend admission, year, and country.

Results: From 2005-12, 51,409 patients were discharged with ischemic stroke from hospitals in the NL (n=6331), UK (n=25574), and US (n=19204). Mortality was significantly higher in the UK (8.1%) compared to the NL (6.4%) and US (4.8%) (p<0.0001). Moreover, mortality was higher in patients admitted on week-ends compared to weekdays in the UK (9.2% vs. 7.7%, p=0.0001), but not in the NL (6.8% vs. 6.3%, p=0.44) or US (4.8% vs. 4.9%, p=0.73). This “week-end effect” was consistent throughout all hospitals in the UK (p=0.0002) but much more variable in hospitals in the other two countries. In the UK, 7-day mortality improved with time, declining from 10.7% in 2006 to 6.3% in 2012 (p<0.0001). A decline in mortality was also seen in the NL (p=0.03), but remained unchanged in the US (p=0.72). The UK “weekend effect” also disappeared with time. Multiple logistic regression demonstrated that country and weekend admission remained a significant risk factor associated with mortality after controlling for age, gender, and year.

Conclusions: A comparison of 7-day mortality among academic medical centers in industrialized counties reveals stark variability. Although 2006 stroke mortality in UK hospitals was almost double that of US hospitals, dramatic reductions were subsequently seen. Further analysis of national policy or practice changes that have driven these improvements promise to be revealing.

Cardiac dysfunction after aneurysmal subarachnoid hemorrhage: relationship with outcome

OBJECTIVE

To assess whether cardiac abnormalities after aneurysmal subarachnoid hemorrhage (aSAH) are associated with delayed cerebral ischemia (DCI) and clinical outcome, independent from known clinical risk factors for these outcomes.

METHODS

In a prospective, multicenter cohort study, we performed echocardiography and ECG and measured biochemical markers for myocardial damage in patients with aSAH. Outcomes were DCI, death, and poor clinical outcome (death or dependency for activities of daily living) at 3 months. With multivariable Poisson regression analysis, we calculated risk ratios (RRs) with corresponding 95% confidence intervals. We used survival analysis to assess cumulative percentage of death in patients with and without echocardiographic wall motion abnormalities (WMAs).

RESULTS

We included 301 patients with a mean age of 57 years; 70% were women. A wall motion score index ≥1.2 had an adjusted RR of 1.2 (0.9-1.6) for DCI, 1.9 (1.1-3.3) for death, and 1.8 (1.1-3.0) for poor outcome. Midventricular WMAs had adjusted RRs of 1.1 (0.8-1.4) for DCI, 2.3 (1.4-3.8) for death, and 2.2 (1.4-3.5) for poor outcome. For apical WMAs, adjusted RRs were 1.3 (1.1-1.7) for DCI, 1.5 (0.8-2.7) for death, and 1.4 (0.8-2.5) for poor outcome. Elevated troponin T levels, ST-segment changes, and low voltage on the admission ECGs had a univariable association with death but were not independent predictors for outcome.

CONCLUSION

WMAs are independent risk factors for clinical outcome after aSAH. This relation is partly explained by a higher risk of DCI. Further study should aim at treatment strategies for these aSAH-related cardiac abnormalities to improve clinical outcome.

European Stroke Organization guidelines for the management of intracranial aneurysms and subarachnoid haemorrhage

BACKGROUND

Intracranial aneurysm with and without subarachnoid haemorrhage (SAH) is a relevant health problem: The overall incidence is about 9 per 100,000 with a wide range, in some countries up to 20 per 100,000. Mortality rate with conservative treatment within the first months is 50-60%. About one third of patients left with an untreated aneurysm will die from recurrent bleeding within 6 months after recovering from the first bleeding. The prognosis is further influenced by vasospasm, hydrocephalus, delayed ischaemic deficit and other complications. The aim of these guidelines is to provide comprehensive recommendations on the management of SAH with and without aneurysm as well as on unruptured intracranial aneurysm.

METHODS

We performed an extensive literature search from 1960 to 2011 using Medline and Embase. Members of the writing group met in person and by teleconferences to discuss recommendations. Search results were graded according to the criteria of the European Federation of Neurological Societies. Members of the Guidelines Committee of the European Stroke Organization reviewed the guidelines.

RESULTS

These guidelines provide evidence-based information on epidemiology, risk factors and prognosis of SAH and recommendations on diagnostic and therapeutic methods of both ruptured and unruptured intracranial aneurysms. Several risk factors of aneurysm growth and rupture have been identified. We provide recommendations on diagnostic work up, monitoring and general management (blood pressure, blood glucose, temperature, thromboprophylaxis, antiepileptic treatment, use of steroids). Specific therapeutic interventions consider timing of procedures, clipping and coiling. Complications such as hydrocephalus, vasospasm and delayed ischaemic deficit were covered. We also thought to add recommendations on SAH without aneurysm and on unruptured aneurysms.

CONCLUSION

Ruptured intracranial aneurysm with a high rate of subsequent complications is a serious disease needing prompt treatment in centres having high quality of experience of treatment for these patients. These guidelines provide practical, evidence-based advice for the management of patients with intracranial aneurysm with or without rupture. Applying these measures can improve the prognosis of SAH.

Association of the Jun dimerization protein 2 gene with intracranial aneurysms in Japanese and Korean cohorts as compared to a Dutch cohort

In a previous study a linkage region for association to IA patients was found on chromosome 14q22. In this study, we report the findings of a positional candidate gene, Jun dimerization Protein 2 (JDP2), and single nucleotide polymorphisms (SNP) of that gene that are associated with intracranial aneurysms in different ethnic populations. We screened the linkage region around chromosome 14q22 and narrowed it down to JDP2. We then genotyped case and control groups of three different ethnic populations: 403 Japanese intracranial aneurysm (IA) cases and 412 controls, 181 Korean IA cases and 181 controls, 379 Dutch cases and 642 Dutch controls. Genotyping was performed using polymerase chain reaction and direct sequencing technology. The allele distribution of three SNPs (two intronic: rs741846; P=0.0041 and rs175646; P=0.0014, and one in the untranslated region: rs8215; P=0.019) and their genotype distribution showed significant association in the Japanese IA patients. The allelic and genotypic frequency of one intronic SNP (rs175646; P=0.0135 and P=0.0137, respectively) and the genotypic frequency for the SNP in the UTR region (rs8215; P=0.049) was also significantly different between cases and controls of the Korean cohort. There was no difference in allelic or genotypic frequencies in the Dutch population. These SNPs in JDP2 are associated with intracranial aneurysms, suggesting that variation in or near JDP2 play a role in susceptibility to IAs in East Asian populations.

Do Intraindividual Variation in Disease Progression and the Ensuing Tight Window of Opportunity Affect Estimation of Screening Benefits?

Background . The effects of variation in disease progression between individuals on the effectiveness of screening have been assessed extensively in the literature. For several diseases, progression may also vary within individuals over time. The authors study the effects of intraindividual variation and the combined effects of inter- and intraindividual variation in disease progression on the effectiveness of screening. Methods . The authors investigated the risk reduction of aneurysmal subarachnoid hemorrhage (SAH) achieved by screening for intracranial aneurysms in a simulation study as a function of the inter- and intraindividual variation in the risk of aneurysm rupture. They also extended a previously constructed Markov model for the cost-effectiveness analysis of screening for new aneurysms in patients with clipped aneurysms after SAH. A time-varying risk of aneurysm rupture was introduced, and the influence of this variation on cost-effectiveness was assessed. Results . The risk reduction provided by screening decreased with increasing intraindividual variation in disease progression. The expected number of prevented instances of SAH was overestimated by 58% in this simulation study when high degrees of inter- and intraindividual variation were present. Interindividual variation alone resulted in up to 33% overestimation and intraindividual variation in up to 43% overestimation. In the extended Markov model, screening benefits were overestimated by 24% when a high degree of intraindividual variation was present but ignored. Conclusions . If intraindividual variation in disease progression is ignored in decision models, subsequent cost-effectiveness analyses of screening strategies will overestimate the benefits provided by screening. This bias is comparable to, but partially independent of, the bias caused by ignoring interindividual heterogeneity.

The risk of rebleeding after external lumbar drainage in patients with untreated ruptured cerebral aneurysms

BACKGROUND

Does continuous external lumbar CSF drainage before aneurysm repair in patients with aneurysmal subarachnoid hemorrhage increase the risk of rebleeding?

METHOD

The study population, consisting of 18 patients treated by External Lumbar Drainage (ELD) after SAH before aneurysm repair, was compared with an independent control group of 324 SAH patients treated in another clinic. Control patients were selected for not being treated for the ruptured aneurysm yet and not having undergone any form of CSF drainage during the exposure time in the case patients. We calculated hazard ratios with the Cox regression model, adjusted for age and clinical condition on admission and hydrocephalus.

FINDINGS

The cox regression analysis shows a non-adjusted hazard ratio of 2.1 (95% CI 0.8 to 5.3) in the model with 5 rebleedings in 18 patients. Adjustment for age, clinical condition on admission and hydrocephalus did not alter the hazard ratio estimate importantly in either analyses.

CONCLUSIONS

An increased risk of rebleeding by external lumbar drainage in the acute phase after aneurysmal SAH could not be confirmed, but the data are too imprecise to rule out an increased risk. The potential benefits of early drainage should be weighed against the risks if the aneurysm is not occluded before or early after the start of drainage.

Endovascular coiling versus neurosurgical clipping for patients with aneurysmal subarachnoid haemorrhage

BACKGROUND

Patients who have had an aneurysmal subarachnoid haemorrhage (SAH) are at very high risk of rebleeding if the aneurysm is not treated. The standard treatment for several decades has been surgical clipping of the neck of the aneurysm. In recent years, an alternative, the introduction of detachable coils to occlude the aneurysm, has become more common.

OBJECTIVES

To compare the effects of endovascular coiling versus neurosurgical clipping in patients with aneurysmal subarachnoid haemorrhage.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched in February 2005). In addition we searched MEDLINE (1966 to January 2004) and EMBASE (1980 to January 2004), and contacted trialists.

SELECTION CRITERIA

We included randomised trials in which endovascular coiling of aneurysms was compared with neurosurgical clipping in patients with SAH who have proven aneurysm.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted the data and assessed trial quality. Trialists were contacted to obtain missing information.

MAIN RESULTS

We identified three randomised trials: two published and one unpublished. The trials included a total of 2272 patients (range per trial: 20 to 2143 patients). Most of the patients were in good clinical condition and had an aneurysm on the anterior circulation. After one year of follow up, the relative risk (RR) of poor outcome for coiling versus clipping was 0.76 (95% confidence interval (CI) 0.67 to 0.88). The absolute risk reduction was 7% (95% CI 4% to 11%). In the worst-case scenario analysis for poor outcome overall, the relative risk for coiling versus clipping was 0.81 (95% CI 0.70 to 0.92) and the absolute risk reduction was 6% (95% CI 2% to 10%). For patients with anterior circulation aneurysm the relative risk of poor outcome was 0.78 (95% CI 0.68 to 0.90) and the absolute risk decrease was 7% (95% CI 3% to 10%). For those with a posterior circulation aneurysm the relative risk was 0.41 (95% CI 0.19 to 0.92) and the absolute decrease in risk 27% (95% CI 6% to 48%).

AUTHORS' CONCLUSIONS

The evidence comes mainly from one large trial. For patients in good clinical condition with ruptured aneurysms of either the anterior or posterior circulation we have firm evidence that, if the aneurysm is considered suitable for both surgical clipping and endovascular treatment, coiling is associated with a better outcome.