Rescue therapy for vasospasm following aneurysmal subarachnoid hemorrhage: a propensity score-matched analysis with machine learning.

OBJECTIVE: Rescue therapies have been recommended for patients with angiographic vasospasm (aVSP) and delayed cerebral ischemia (DCI) following subarachnoid hemorrhage (SAH). However, there is little evidence from randomized clinical trials that these therapies are safe and effective. The primary aim of this study was to apply game theory-based methods in explainable machine learning (ML) and propensity score matching to determine if rescue therapy was associated with better 3-month outcomes following post-SAH aVSP and DCI. The authors also sought to use these explainable ML methods to identify patient populations that were more likely to receive rescue therapy and factors associated with better outcomes after rescue therapy. METHODS: Data for patients with aVSP or DCI after SAH were obtained from 8 clinical trials and 1 observational study in the Subarachnoid Hemorrhage International Trialists repository. Gradient boosting ML models were constructed for each patient to predict the probability of receiving rescue therapy and the 3-month Glasgow Outcome Scale (GOS) score. Favorable outcome was defined as a 3-month GOS score of 4 or 5. Shapley Additive Explanation (SHAP) values were calculated for each patient-derived model to quantify feature importance and interaction effects. Variables with high SHAP importance in predicting rescue therapy administration were used in a propensity score-matched analysis of rescue therapy and 3-month GOS scores. RESULTS: The authors identified 1532 patients with aVSP or DCI. Predictive, explainable ML models revealed that aneurysm characteristics and neurological complications, but not admission neurological scores, carried the highest relative importance rankings in predicting whether rescue therapy was administered. Younger age and absence of cerebral ischemia/infarction were invariably linked to better rescue outcomes, whereas the other important predictors of outcome varied by rescue type (interventional or noninterventional). In a propensity score-matched analysis guided by SHAP-based variable selection, rescue therapy was associated with higher odds of 3-month GOS scores of 4-5 (OR 1.63, 95% CI 1.22-2.17). CONCLUSIONS: Rescue therapy may increase the odds of good outcome in patients with aVSP or DCI after SAH. Given the strong association between cerebral ischemia/infarction and poor outcome, trials focusing on preventative or therapeutic interventions in these patients may be most able to demonstrate improvements in clinical outcomes. Insights developed from these models may be helpful for improving patient selection and trial design.

Maternal Risk Modeling in Critical Care-Development of a Multivariable Risk Prediction Model for Death and Prolonged Intensive Care.

OBJECTIVES: We aimed to develop and validate an accurate risk prediction model for both mortality and a combined outcome of mortality and morbidity for maternal admissions to critical care. DESIGN: We used data from a high-quality prospectively collected national database, supported with literature review and expert opinion. We tested univariable associations between each risk factor and outcome. We then developed two separate multivariable logistic regression models for the outcomes of acute hospital mortality and death or prolonged ICU length of stay. We validated two parsimonious risk prediction models specific for a maternal population. SETTING: The Intensive Care National Audit and Research Centre Case Mix Programme is the national clinical audit for adult critical care in England, Wales, and Northern Ireland. PATIENTS: All female admissions to adult general critical care units, for the period January 1, 2007-December 31, 2016, 16-50 years old, and admitted either while pregnant or within 42 days of delivery-a cohort of 15,480 women. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We aimed to develop and validate an accurate risk prediction model for both mortality and a combined outcome of mortality and morbidity for maternal admissions to critical care. For the primary outcome of acute hospital mortality, our parsimonious risk model consisting of eight variables had an area under the receiver operating characteristic of 0.96 (95% CI, 0.91-1.00); these variables are commonly available for all maternal admissions. For the secondary composite outcome of death or ICU length of stay greater than 48 hours, the risk model consisting of 17 variables had an area under the receiver operating characteristic of 0.80 (95% CI, 0.78-0.83). CONCLUSIONS: We developed risk prediction models specific to the maternal critical care population. The models compare favorably against general adult ICU risk prediction models in current use within this population.

Compartmentalisation of the inflammatory response following aneurysmal subarachnoid haemorrhage.

INTRODUCTION: There is some evidence to suggest that a systemic and central nervous system (CNS) inflammatory response occurs following aneurysmal subarachnoid haemorrhage (aSAH) which may be related to the pathophysiology of early brain injury and delayed ischaemic neurological deficit (DIND). The aim of this study was to measure inflammatory mediator levels in plasma and cerebrospinal fluid (CSF) in the days following aSAH and to determine their association with aSAH, DIND and clinical outcome. MATERIAL AND METHODS: Plasma and CSF samples were obtained prospectively from patients with aSAH on days 1-3, 5, 7 and 9 and profiled for interleukin (IL)-1α, IL-1ß, IL-4, IL-6, IL-8, IL-10, IL-15, IL-17, IL-18, macrophage chemotactic protein (MCP)-1, vascular endothelial growth factor (VEGF) and tumour necrosis factor (TNF)-α. Plasma and CSF samples from non-aSAH patients undergoing spinal anaesthesia were used as controls. RESULTS: The CSF levels of all cytokines investigated except for IL-1α were significantly higher in aSAH compared to controls in the first seven days of ictus. CSF levels of IL-1α (p = 0.014), IL-18 (p = 0.016), IL-6 (p = 0.0006) and IL-8 (p = 0.006) showed significant increases in the days following aSAH. Conversely IL-17 demonstrated a decrease. In particular, IL-4 was higher in the CSF of patients who had DIND at all time-points (p = 0.032). Plasma IL-6 and IL-8 levels were higher, and IL-1α levels lower, than controls at most time-points. All mediators demonstrated persistent elevation in the CSF compared to plasma apart from IL-1α and IL-18 which followed the opposite trend. Day 3 plasma IL-6 levels predicted poor outcome at six months (Exp(B) 1.12 1.03-1.22, P = 0.012), although this association was lost in the second analysis incorporating Fisher grade, WFNS grade and age. CONCLUSION: The post aSAH inflammatory response peaks on days 5-7 post ictus and remains largely compartmentalised within the CNS. IL-4 may have a particular association with DIND although its precise role in the pathophysiology of the disorder remains unclear. IL-6 predicted poor outcome but not independently of clinical grade, suggesting that it may be a surrogate marker of early brain injury.

Obstetric early warning systems to prevent bad outcome.

PURPOSE OF REVIEW: Early warning scores, early warning systems and rapid response systems, were established in 1999. In the UK, a National Early Warning Score was launched in 2013 and is now used throughout the National Health Service. In 2007, a firm recommendation was made by the maternal confidential death enquiry that maternity units should incorporate a modified early obstetric warning score chart into clinical practice. Although there was enthusiastic uptake of this recommendation, local recording systems vary throughout the country and there is now a need to revisit revise and standardize an obstetric early warning system (ObsEWS). RECENT PROJECT: The intercollegiate Maternal Critical Care group of the Obstetric Anaesthetists' Association have produced an ObsEWS in line with the aggregate UK National Early Warning Score. Six physiological parameters are incorporated: respiratory rate, oxygen saturations, temperature, systolic blood pressure, diastolic blood pressure, and pulse rate. However, robust physiological thresholds for the measured parameters are currently lacking but required for a more sensitive and specific ObsEWS. SUMMARY: A greater focus and study on the management of maternal morbidity (in addition to mortality data) and the development of better systems within and across the multidisciplinary team to detect early deterioration should improve management of serious illness in obstetrics. It is imperative that we undertake robust ObsEWS and data collection, including electronic systems with research and evidence-based recommendations to underpin this system. This should improve patient safety and result in more efficient, cost-effective management of sicker patients in our complex modern healthcare systems.

The Subarachnoid Hemorrhage International Trialists (SAHIT) Repository: advancing clinical research in subarachnoid hemorrhage.

Researchers and other stakeholders continue to express concern about the failure of randomized clinical trials (RCT) in subarachnoid hemorrhage (SAH) to show efficacy of new treatments. Pooled data may be particularly useful to generate hypotheses about causes of poor outcomes and reasons for failure of RCT in SAH, and strategies to improve them. Investigators conducting SAH research collaborated to share data with the intent to develop a large repository of pooled individual patient data for exploratory analysis and testing of new hypotheses relevant to improved trial design and analysis in SAH. This repository currently contains information on 11,443 SAH patients from 14 clinical databases, of which 9 are datasets of recent RCTs and 5 are datasets of prospective observational studies and hospital registries. Most patients were managed in the last 15 years. Data validation and quality checks have been conducted and are satisfactory. Data is available on demographic, clinical, neuroimaging, and laboratory results and various outcome measures. We have compiled the largest known dataset of patients with SAH. The SAHIT repository may be an important resource for advancing clinical research in SAH and will benefit from contributions of additional datasets.

Self-perceived health status following aneurysmal subarachnoid haemorrhage: a cohort study.

OBJECTIVE: The objective of the study was to assess the long-term self-reported health status and quality of life (QoL) of patients following an aneurysmal subarachnoid haemorrhage (ASAH) using a self-completed questionnaire booklet. DESIGN: A two-cohort study. SETTING: A regional tertiary neurosurgical centre. PARTICIPANTS: 2 cohorts of patients with ASAH treated between 1998 and 2008 and followed up at approximately 1 year. INTERVENTIONS: Routine care. PRIMARY AND SECONDARY OUTCOMES: A range of standardised scales included: AKC Short Sentences Test, the Barthel Index, the Self-Report Dysexecutive Questionnaire, the Everyday Memory Questionnaire, Stroke Symptom Checklist, Wimbledon Self-Report Scale, Modified Rankin Score (MRS) and a new Stroke-QoL. The data from summated scales were fit to the Rasch measurement model to validate the summed score. RESULTS: 214 patients (48%) returned the questionnaires; the majority (76%) had a World Federation of Neurosurgeons grade of 1 or 2. The most frequent aneurysm type was that of the anterior communicating artery (28%) with approximately 90% of aneurysms of the anterior circulation. Of those previously in full or part-time employment, 48.9% were unemployed at follow-up. All summated scales satisfied the Rasch measurement model requirements, such that their summed scores were a sufficient statistic. Given this, one-third of patients were noted to have a significant mood disorder and 25% had significant dysexecutive function. Patients with an MRS of 3, 4 or 5 had significantly worse scores on most outcome measures, but a significant minority of those with a score of zero had failed to return to work and displayed significant mood disorder. CONCLUSIONS: A range of self-reported cognitive and physical deficits have been highlighted in a cohort of patients with ASAH. While the MRS has been shown to provide a reasonable indication of outcome, in routine clinical follow-up it requires supplementation by instruments assessing dysexecutive function, memory and mood.

SAHIT Investigators--on the outcome of some subarachnoid hemorrhage clinical trials.

Outcome of patients with aneurysmal subarachnoid hemorrhage (SAH) has improved over the last decades. Yet, case fatality remains nearly 40% and survivors often have permanent neurological, cognitive and/or behavioural sequelae. Other than nimodipine drug or clinical trials have not consistently improved outcome. We formed a collaboration of SAH investigators to create a resource for prognostic analysis and for studies aimed at optimizing the design and analysis of phase 3 trials in aneurysmal SAH. We identified investigators with data from randomized, clinical trials of patients with aneurysmal SAH or prospectively collected single- or multicentre databases of aneurysmal SAH patients. Data are being collected and proposals to use the data and to design future phase 3 clinical trials are being discussed. This paper reviews some issues discussed at the first meeting of the SAH international trialists (SAHIT) repository meeting. Investigators contributed or have agreed to contribute data from several phase 3 trials including the tirilazad trials, intraoperative hypothermia for aneurysmal SAH trial, nicardipine clinical trials, international subarachnoid aneurysm trial, intravenous magnesium sulphate for aneurysmal SAH, magnesium for aneurysmal SAH and from prospectively-collected data from four institutions. The number of patients should reach 15,000. Some industry investigators refused to provide data and others reported that their institutional research ethics boards would not permit even deidentified or anonymized data to be included. Others reported conflict of interest that prevented them from submitting data. The problems with merging data were related to lack of common definitions and coding of variables, differences in outcome scales used, and times of assessment. Some questions for investigation that arose are discussed. SAHIT demonstrates the possibility of SAH investigators to contribute data for collaborative research. The problems are similar to those already documented in other similar collaborative efforts such as in head injury research. We encourage clinical trial and registry investigators to contact us and participate in SAHIT. Key issues moving forward will be to use common definitions (common data elements), outcomes analysis, and to prioritize research questions, among others.

Maternal critical care: who cares?

With rising birth rates, and greater numbers of increasingly challenging mothers, the need for maternal critical care is rising. In the light of several major reports, this article looks at current provision, as well as areas for future development.

Subarachnoid Hemorrhage International Trialists data repository (SAHIT).

The outcome of patients with aneurysmal subarachnoid hemorrhage (SAH) has improved slowly over the past 25 years. This improvement may be due to early aneurysm repair by endovascular or open means, use of nimodipine, and better critical care management. Despite this improvement, mortality remains at about 40%, and many survivors have permanent neurologic, cognitive, and neuropsychologic deficits. Randomized clinical trials have tested pharmacologic therapies, but few have been successful. There are numerous explanations for the failure of these trials, including ineffective interventions, inadequate sample size, treatment side effects, and insensitive or inappropriate outcome measures. Outcome often is evaluated on a good-bad dichotomous scale that was developed for traumatic brain injury 40 years ago. To address these issues, we established the Subarachnoid Hemorrhage International Trialists (SAHIT) data repository. The primary aim of the SAHIT data repository is to provide a unique resource for prognostic analysis and for studies aimed at optimizing the design and analysis of phase III trials in aneurysmal SAH. With this aim in mind, we convened a multinational investigator meeting to explore merging individual patient data from multiple clinical trials and observational databases of patients with SAH and to create an agreement under which such a group of investigators could submit data and collaborate. We welcome collaboration with other investigators.

Identifying patient report outcomes relevant to aneurysmal subarachnoid hemorrhage follow-up.

Patients recovered from subarachnoid hemorrhage can be assessed for neuropsychological dysfunction using postal questionnaires. We assessed 214 patients using various tests of memory, mood and strategic thinking. Patients in good outcome categories (modified Rankin Scale [mRS] 0-1) nevertheless exhibited mood disorder (28%), memory deficit and executive dysfunction (20%). Return to work (49%) was most influenced by previous employment status, Rankin scale and mood.

Clinical prediction models for aneurysmal subarachnoid hemorrhage: a systematic review.

BACKGROUND: Clinical prediction models can enhance clinical decision-making and research. However, available prediction models in aneurysmal subarachnoid hemorrhage (aSAH) are rarely used. We evaluated the methodological validity of SAH prediction models and the relevance of the main predictors to identify potentially reliable models and to guide future attempts at model development. METHODS: We searched the EMBASE, MEDLINE, and Web of Science databases from January 1995 to June 2012 to identify studies that reported clinical prediction models for mortality and functional outcome in aSAH. Validated methods were used to minimize bias. RESULTS: Eleven studies were identified; 3 developed models from datasets of phase 3 clinical trials, the others from single hospital records. The median patient sample size was 340 (interquartile range 149-733). The main predictors used were age (n = 8), Fisher grade (n = 6), World Federation of Neurological Surgeons grade (n = 5), aneurysm size (n = 5), and Hunt and Hess grade (n = 3). Age was consistently dichotomized. Potential predictors were prescreened by univariate analysis in 36 % of studies. Only one study was penalized for model optimism. Details about model development were often insufficiently described and no published studies provided external validation. CONCLUSIONS: While clinical prediction models for aSAH use a few simple predictors, there are substantial methodological problems with the models and none have had external validation. This precludes the use of existing models for clinical or research purposes. We recommend further studies to develop and validate reliable clinical prediction models for aSAH.

Lumbar drainage of cerebrospinal fluid after aneurysmal subarachnoid hemorrhage: a prospective, randomized, controlled trial (LUMAS).

BACKGROUND AND PURPOSE: A single-center prospective randomized controlled trial has been conducted to determine if lumbar drainage of cerebrospinal fluid after aneurysmal subarachnoid hemorrhage reduces the prevalence of delayed ischemic neurological deficit and improves clinical outcome. METHODS: Patients with World Federation of Neurological Surgeons Grade 1 to 3 aneurysmal subarachnoid hemorrhage and modified Fisher Grades 2, 3, 4, and 3+4 were randomized to either the study group of standard therapy plus insertion of a lumbar drain or the control group of standard therapy alone. The primary outcome measure was the prevalence of delayed ischemic neurological deficit. RESULTS: Two hundred ten patients with aneurysmal subarachnoid hemorrhage (166 female, 44 male; median age, 54 years; interquartile range, 45-62 years) were recruited into the control (n=105) and study (n=105) groups of the trial. World Federation of Neurological Surgeons grade was: 1 (n=139), 2 (n=60), and 3 (n=11); Fisher grade was: 2 (n=87), 3 (n=85), and 4 (n=38). The prevalence of delayed ischemic neurological deficit was 35.2% and 21.0% in the control and study groups, respectively (P=0.021). The prevalence of a modified Rankin Scale score of 4, 5, or 6 at Day 10 and 6 months, respectively, was 62.5% and 18.6% in the control group and 44.8% and 19.8% in the study group (P=0.009 and 0.83, respectively). CONCLUSIONS: Lumbar drainage of cerebrospinal fluid after aneurysmal subarachnoid hemorrhage has been shown to reduce the prevalence of delayed ischemic neurological deficit and improve early clinical outcome but failed to improve outcome at 6 months after aneurysmal subarachnoid hemorrhage. CLINICAL TRIAL REGISTRATION: URL: www.clinicaltrials.gov. Unique identifier: NCT00842049.

New modalities to assess efficacy of triple-h therapy: early experience.

The traditional axiom that vasospasm induced reduction of blood flow leads to poor tissue oxygenation and ischaemic cellular injury culminating in delayed neurological deficits has been challenged and the efficacy of triple H therapy in reversal of the above is debated. In this study we assess cerebral physiology before and during onset of DIND and with application of triple H therapy with real time neuro-monitoring tools. Patients with Fisher grade 3/4/3 + 4/rebleed were consented. Probes for measuring rCBF, pTiO2, and Microdialysis parameters - glucose, glycerol, lactate, and pyruvate were inserted at time of coiling/clipping. Subsequent monitoring was done in HDU/ITU setting. Return of parameters to baseline was regarded as effective triple H therapy. Study is ongoing and the current paper presents our experience with first five patients. The results suggest safety and feasibility of multimodal monitoring in clinical setting to establish an understanding of relationship between clinical symptoms, brain perfusion, oxygenation, and metabolism in real time to test and guide therapy in future.

A review of delayed ischemic neurologic deficit following aneurysmal subarachnoid hemorrhage: historical overview, current treatment, and pathophysiology.

Delayed ischemic neurologic deficit (DIND) is a serious and poorly understood complication of aneurysmal subarachnoid hemorrhage. Although advances in treatment have improved prognosis for these patients, long-term clinical outcomes remain disappointing. Historically, angiographic vasospasm was thought to result in a DIND, although an increasing body of evidence suggests that this is an oversimplification, because interventions that have effectively targeted angiographic vasospasm have not improved outcome. Consequently, the relationship between angiographic vasospasm and neurologic outcome may be associative rather than causative. Although our understanding of the underlying molecular processes and pathophysiology is improving, responsible mediators or pathways have yet to be identified. The aim of this review is to summarize the key historical events that have helped shape our understanding of the pathophysiology of this phenomenon (microcirculation, autoregulation, microthrombosis, inflammation, apoptosis, spreading depolarization, oxidative stress) and to present the evidence underlying current treatment strategies (hemodynamic therapy, oral nimodipine, endovascular therapy, statins, cerebrospinal fluid drainage, thrombolysis, magnesium) and the translational and clinical research investigating DIND.

A comparison of the outcome of aneurysmal subarachnoid haemorrhage before and after the introduction of an endovascular service.

There has been a rapid change from predominantly surgical to endovascular treatment of ruptured intracranial aneurysms giving the opportunity to assess change in patient outcome during this transition. We identified and followed 139 patients with subarachnoid haemorrhage (SAH) treated in the year prior to (group 1) and following (group 2) the introduction of an endovascular service in a retrospective, cross-sectional study. A total of 78.7% of patients in group 1 underwent surgical treatment, 10.7% underwent endovascular treatment and 10.7% received no treatment, whereas patients in group 2 received 29.7%, 65.7% and 4.7%, respectively. MRS scores were obtained in 91% of patients in group 1 and in 89% of patients in group 2. A total of 30.7% and 24.0% of patients had a poor outcome in groups 1 and 2 respectively (p=0.34). The overall change in the management of ruptured cerebral aneurysms in the post-International Subarachnoid Aneurysm Trial (ISAT) era has not significantly changed cross-sectional outcome, although absolute differences appear to reflect difference in outcome noted in the ISAT.