Rapid Arterial Occlusion Evaluation Research Articles

Predicting stroke severity of patients using interpretable machine learning algorithms

BackgroundStroke is a significant global health concern, ranking as the second leading cause of death and placing a substantial financial burden on healthcare systems, particularly in low- and middle-income countries. Timely evaluation of stroke severity is crucial for predicting clinical outcomes, with standard assessment tools being the Rapid Arterial Occlusion Evaluation (RACE) and the National Institutes of Health Stroke Scale (NIHSS). This study aims to utilize Machine Learning (ML) algorithms to predict stroke severity using these two distinct scales.MethodsWe conducted this study using two datasets collected from hospitals in Urmia, Iran, corresponding to stroke severity assessments based on RACE and NIHSS. Seven ML algorithms were applied, including K-Nearest Neighbor (KNN), Decision Tree (DT), Random Forest (RF), Adaptive Boosting (AdaBoost), Extreme Gradient Boosting (XGBoost), Support Vector Machine (SVM), and Artificial Neural Network (ANN). Hyperparameter tuning was performed using grid search to optimize model performance, and SHapley Additive Explanations (SHAP) were used to interpret the contribution of individual features.ResultsAmong the models, the RF achieved the highest performance, with accuracies of 92.68% for the RACE dataset and 91.19% for the NIHSS dataset. The Area Under the Curve (AUC) was 92.02% and 97.86% for the RACE and NIHSS datasets, respectively. The SHAP analysis identified triglyceride levels, length of hospital stay, and age as critical predictors of stroke severity.ConclusionsThis study is the first to apply ML models to the RACE and NIHSS scales for predicting stroke severity. The use of SHAP enhances the interpretability of the models, increasing clinicians’ trust in these ML algorithms. The best-performing ML model can be a valuable tool for assisting medical professionals in predicting stroke severity in clinical settings.

The RACE Scale for Large Vessel Stroke Diversion to a Comprehensive Stroke Center by Helicopter Air Ambulance: A Retrospective Cohort Study

ObjectiveAcute ischemic stroke caused by large vessel occlusion (LVO) occurs frequently and benefits from endovascular therapies available at comprehensive stroke centers (CSCs). Prehospital stroke severity tools have been devised to detect LVO. The goal of this study was to assess the value of the Rapid Arterial Occlusion Evaluation (RACE) score in helicopter air ambulance (HAA) activation. MethodsA retrospective assessment of RACE scales > 4 performed by prehospital providers was used in order to activate HAAs. Descriptive statistics were obtained for patients transported, with the primary goal of determining the positive predictive values of the RACE scale for LVO occlusions. The secondary outcomes assessed if patients without LVO had other conditions requiring a CSC. ResultsData from 136 subjects were analyzed; 53 (39.0%) were true LVO cases as defined by computed tomographic imaging, computed tomography angiographic imaging, or magnetic resonance imaging. Mechanical thrombectomy occurred in 30 cases (22.1%), with 63 (46.4%) requiring a neurologic intervention. There were 83 (61%) false positives (no LVO on imaging). Of these false positives, 28 (20.6%) were non-LVO strokes, 22 (16.1%) were intracranial hemorrhages, and 8 (5.9%) had neurologic conditions requiring CSC care. ConclusionA RACE scale > 4 is an effective triage tool that delivers potential thrombectomy candidates to CSCs. When there is a false positive, the majority of patients require CSC care and benefit from direct transport from the scene.

Design and Interrater Reliability of the Pediatric Version of the Race Scale: PedRACE.

Acute ischemic stroke is a leading cause of pediatric death and disability. A clinical scale adapted for children can ensure early detection of candidates for urgent acute ischemic stroke treatment. The Rapid Arterial Occlusion Evaluation (RACE) scale for adults, which scores 5 items (facial palsy 0-2; arm motor function 0-2; leg motor function 0-2; head/gaze deviation 0-1; and aphasia or agnosia 0-2), has good sensitivity and specificity in detecting large vessel occlusion. We adapted the previously validated RACE scale for use in children as the Pediatric RACE scale. This adapted scale was tested by prehospital/emergency room staff attending to patients covered by the Catalan Pediatric Stroke Code and child neurologists for its correlation with the Pediatric National Institutes of Health Stroke Scale and for interrater reliability. The study included 50 children, 18 with confirmed strokes (7 acute ischemic strokes and 11 hemorrhagic strokes). Prehospital/emergency staff and child neurologists agreed fully regarding 82% of patients and 100% regarding head/gaze deviation and agnosia. The Pediatric RACE scale correlated strongly with the Pediatric National Institutes of Health Stroke Scale in evaluations by child neurologists (Spearman ρ, 0.852; P<0.001) and prehospital/emergency staff (Spearman ρ, 0.781; P<0.001). The median Pediatric RACE score was significantly higher in patients with large vessel occlusion (6.5; interquartile range, 6-7) than with other etiologies. Pediatric RACE, showing good interrater reliability and correlation with the Pediatric National Institutes of Health Stroke Scale, is a simple scale to detect candidates for pediatric acute stroke treatment, designed for both prehospital and in-hospital use by non-neurologist medical staff.

Systematic Review and Meta-Analysis of Prehospital Machine Learning Scores as Screening Tools for Early Detection of Large Vessel Occlusion in Patients With Suspected Stroke.

Enhanced detection of large vessel occlusion (LVO) through machine learning (ML) for acute ischemic stroke appears promising. This systematic review explored the capabilities of ML models compared with prehospital stroke scales for LVO prediction. Six bibliographic databases were searched from inception until October 10, 2023. Meta-analyses pooled the model performance using area under the curve (AUC), sensitivity, specificity, and summary receiver operating characteristic curve. Of 1544 studies screened, 8 retrospective studies were eligible, including 32 prehospital stroke scales and 21 ML models. Of the 9 prehospital scales meta-analyzed, the Rapid Arterial Occlusion Evaluation had the highest pooled AUC (0.82 [95% CI, 0.79-0.84]). Support Vector Machine achieved the highest AUC of 9 ML models included (pooled AUC, 0.89 [95% CI, 0.88-0.89]). Six prehospital stroke scales and 10 ML models were eligible for summary receiver operating characteristic analysis. Pooled sensitivity and specificity for any prehospital stroke scale were 0.72 (95% CI, 0.68-0.75) and 0.77 (95% CI, 0.72-0.81), respectively; summary receiver operating characteristic curve AUC was 0.80 (95% CI, 0.76-0.83). Pooled sensitivity for any ML model for LVO was 0.73 (95% CI, 0.64-0.79), specificity was 0.85 (95% CI, 0.80-0.89), and summary receiver operating characteristic curve AUC was 0.87 (95% CI, 0.83-0.89). Both prehospital stroke scales and ML models demonstrated varying accuracies in predicting LVO. Despite ML potential for improved LVO detection in the prehospital setting, application remains limited by the absence of prospective external validation, limited sample sizes, and lack of real-world performance data in a prehospital setting.

Portable cerebral blood flow monitor to detect large vessel occlusion in patients with suspected stroke

BackgroundEarly detection of large vessel occlusion (LVO) facilitates triage to an appropriate stroke center to reduce treatment times and improve outcomes. Prehospital stroke scales are not sufficiently sensitive, so we...

Sex Differences in Prehospital Identification of Large Vessel Occlusion in Patients With Suspected Stroke.

Differences in clinical presentation of acute ischemic stroke between men and women may affect prehospital identification of anterior circulation large vessel occlusion (aLVO). We assessed sex differences in diagnostic performance of 8 prehospital scales to detect aLVO. We analyzed pooled individual patient data from 2 prospective cohort studies (LPSS [Leiden Prehospital Stroke Study] and PRESTO [Prehospital Triage of Patients With Suspected Stroke Study]) conducted in the Netherlands between 2018 and 2019, including consecutive patients ≥18 years suspected of acute stroke who presented within 6 hours after symptom onset. Ambulance paramedics assessed clinical items from 8 prehospital aLVO detection scales: Los Angeles Motor Scale, Rapid Arterial Occlusion Evaluation, Cincinnati Stroke Triage Assessment Tool, Cincinnati Prehospital Stroke Scale, Prehospital Acute Stroke Severity, gaze-face-arm-speech-time, Conveniently Grasped Field Assessment Stroke Triage, and Face-Arm-Speech-Time Plus Severe Arm or Leg Motor Deficit. We assessed the diagnostic performance of these scales for identifying aLVO at prespecified cut points for men and women. Of 2358 patients with suspected stroke (median age, 73 years; 47% women), 231 (10%) had aLVO (100/1114 [9%] women and 131/1244 [11%] men). The area under the curve of the scales ranged from 0.70 (95% CI, 0.65-0.75) to 0.77 (95% CI, 0.73-0.82) in women versus 0.69 (95% CI, 0.64-0.73) to 0.75 (95% CI, 0.71-0.79) in men. Positive predictive values ranged from 0.23 (95% CI, 0.20-0.27) to 0.29 (95% CI, 0.26-0.31) in women versus 0.29 (95% CI, 0.24-0.33) to 0.37 (95% CI, 0.32-0.43) in men. Negative predictive values were similar (0.95 [95% CI, 0.94-0.96] to 0.98 [95% CI, 0.97-0.98] in women versus 0.94 [95% CI, 0.93-0.95] to 0.96 [95% CI, 0.94-0.97] in men). Sensitivity of the scales was slightly higher in women than in men (0.53 [95% CI, 0.43-0.63] to 0.76 [95% CI, 0.68-0.84] versus 0.49 [95% CI, 0.40-0.57] to 0.63 [95% CI, 0.55-0.73]), whereas specificity was lower (0.79 [95% CI, 0.76-0.81] to 0.87 [95% CI, 0.84-0.89] versus 0.82 [95% CI, 0.79-0.84] to 0.90 [95% CI, 0.88-0.91]). Rapid arterial occlusion evaluation showed the highest positive predictive values in both sexes (0.29 in women and 0.37 in men), reflecting the different event rates. aLVO scales show similar diagnostic performance in both sexes. The rapid arterial occlusion evaluation scale may help optimize prehospital transport decision-making in men as well as in women with suspected stroke.

Abstract TMP38: Enhancing Door-In-Door-Out Time in a Rural Primary Stroke Center: Early Activation of a Large Vessel Occlusion Alert/Bundle of Care Utilizing EMS Pre-Alert, Parallel System Processing and Auto-Launch of Transfer Resources

Background: Thrombectomy has become the primary treatment in the management of acute stroke Large Vessel Occlusions (LVO). For a rural primary stroke center that does not have in house thrombectomy services, expedited transfer to a Comprehensive Stroke Center is imperative. The purpose of this quality improvement initiative is aimed at optimizing the Door-In-Door-Out (DIDO) time for stroke patients at a Rural Primary Stroke Center, with a specific goal of DIDO time of &lt;90 minutes, 50% of the time and &lt;120 minutes, 75% of the time. Methods: System inefficiencies in serial event processing, radiology interpretation, teleneurology application and activation of transferring Emergency Medical Services (EMS) were identified. We implemented several systematic changes utilizing multiple Plan Do Study Act cycles. The final implementation was an “LVO-Alert” process, which utilized parallel event processing of emergency medicine, teleneurology, radiology, and transfer center auto-lance of EMS transfer resources. This process is activated based on a positive prehospital modified Rapid Arterial Occlusion Evaluation score prior to the patient’s hospital arrival rather than a positive Computed Tomography Angiogram and can be cancelled in the case of negative imaging or declination of transfer. Pre and post metrics were compared. Results: Pre LVO-Alert implementation, DIDO time averaged 184 minutes (n=21) over 2 years, and anterior circulation LVO’s achieved a &lt;90-minute DIDO time 5% of the time. Post implementation, DIDO averaged 109 minutes (n=21) and anterior circulation LVOs achieved a &lt;90-minute DIDO 48% of the time. Post implementation, anterior circulation LVOs went from 19% to 90% transferred in &lt;120 minutes. Pre implementation, posterior circulation LVO’s achieved a &lt;120-minute DIDO time 0% (n= 2) of the time while post implementation, posterior circulation LVOs achieved a &lt;120-minute DIDO 50% (n=4) of the time. Among LVO alert activations over the post-implementation period, 27.4% resulted in transfer for thrombectomy. Conclusion: The application of a parallel process bundle of care model with early activation from a prehospital positive LVO scale may help to improve DIDO times in this patient population.

A Review of an Interfacility Transport Program Pediatric Stroke Clinical Practice Guideline.

Pediatric acute ischemic stroke is a rare diagnosis that requires timely recognition and definitive management to prevent morbidity and mortality. Children often present to primary care offices, urgent care clinics, and adult emergency departments for evaluation of symptoms that may be signs and symptoms of stroke. Currently, there are no published prehospital or transport protocols specific to pediatric acute ischemic stroke. The Children's Mercy Hospital Critical Care Transport Team (CMCCT) created a pediatric-specific clinical practice guideline (CPG) for suspected acute ischemic stroke. This retrospective, descriptive study reports pediatric patients aged younger than 18 years who met criteria for the pediatric stroke CPG and required interfacility transport by CMCCT over a 4- year period. Large vessel occlusion (LVO) scores used in adults were calculated retrospectively. Seventeen patients met inclusion criteria. Four (24%) of 17 had radiographic evidence of acute thrombus, 3 of whom received alteplase and/or endovascular clot retrieval. Median age of confirmed stroke was 83 months (interquartile range, 65-148) compared with 177 months for nonstroke (interquartile range, 169-191), P = 0.126. The most common presenting symptom was hemiplegia in the confirmed stroke group. The confirmed stroke group scored significantly lower on the Glasgow Coma Scale (median of 8 vs 15, P = 0.014), significantly higher on the Los Angeles Motor Scale LVO score (median 4 vs 0, P = 0.021), and significantly higher on the Rapid Arterial Occlusion Evaluation LVO (median 4 vs 0, P = 0.036). To our knowledge, the CMCCT CPG is the first pediatric transport protocol aimed at recognition and management of pediatric stroke described in the literature. Retrospective calculation of LVO scores show that they may be helpful in application to pediatric patients.

Rapid Arterial Occlusion Evaluation (RACE) Tool in Detecting Large Cerebral Vessel Occlusions; a Systematic Review and Meta-Analysis.

Large vessel occlusion (LVO) strokes are linked to higher mortality rates and a greater risk of long-term disability. This study aimed to evaluate the diagnostic performance of the Rapid Arterial Occlusion Evaluation (RACE) tool in detecting LVO through a systematic review and meta-analysis. A comprehensive search was conducted across online databases including PubMed, Embase, Scopus, and Web of Science, up to June 25th, 2023. Additionally, a manual search on Google and Google Scholar was performed to identify studies that assessed the diagnostic accuracy of the RACE scale in detecting LVO among patients with stroke symptoms. Data extracted from 43 studies were analyzed. The optimal cut-off points were determined to be 3 and 4, with a sensitivity of 0.86 (95% confidence interval (CI): 0.78, 0.91) and specificity of 0.57 (95% CI: 0.49, 0.67) for cut-off ≥3, and a sensitivity of 0.78 (95% CI: 0.70, 0.84) and specificity of 0.68 (95% CI: 0.59, 0.75) for cut-off ≥4. Subgroup meta-regression analysis revealed significant variations in sensitivity and specificity. RACE scale's sensitivity was significantly higher in LVO detection in suspected stroke cases, in pre-hospital settings, prospective design studies, and when considering both anterior and posterior occlusions for LVO definition. RACE scale's specificity was significantly higher when evaluating confirmed stroke cases, in-hospital settings, and considering only anterior occlusions for LVO definition and retrospective design studies. Notably, RACE exhibited higher sensitivity and specificity when utilized by neurologists and physicians compared to other emergency staff. Despite these variations, our study found comparable diagnostic accuracy across different conditions. A high level of evidence indicates that the RACE scale lacks promising diagnostic value for detection of LVOs. A sensitivity range of 0.69 to 0.86 is insufficient for a screening tool intended to aid in the diagnosis of strokes, considering the substantial morbidity and mortality associated with this condition.

Prehospital stroke scales outperform National Institutes of Health Stroke Scale in predicting large vessel occlusion in a large academic telestroke network.

Prehospital telestroke evaluations may improve stroke triage compared to paramedic-applied large vessel occlusion scales, but ambulance-based video National Institutes of Health Stroke Scale assessments are challenging. The accuracy of telestroke-administered large vessel occlusion scales has not been investigated, so we sought to evaluate this further. This retrospective study included all in-hospital telestroke encounters in a large academic telestroke network from 2019 to 2020. We retrospectively calculated seven large vessel occlusion scales using the in-hospital telestroke National Institutes of Health Stroke Scale (Rapid Arterial oCclusion Evaluation, Cincinnati Stroke Triage Assessment Tool, Field Assessment Stroke Triage for Emergency Destination, 3-Item Stroke Scale, Prehospital Acute Stroke Severity, Vision-Aphasia-Neglect, and Gaze-Face-Arm-Speech-Time). Diagnostic performance was assessed via sensitivity, specificity, negative predictive value, positive predictive value, positive likelihood ratio, negative likelihood ratio, and accuracy using established scale thresholds. These results were compared to the National Institutes of Health Stroke Scale at thresholds of 6, 8, and 10. The area under curve was calculated using c-statistics by treating scales as continuous variables. A total of 625 patients were included; 111 (17.8%) patients had an anterior large vessel occlusion, 118 (18.9%) patients had any large vessel occlusion, and 182 (29.1%) patients had stroke mimic diagnosis. The mean age (SD) was 67.9 (15.9), 48.3% were female, and 93.4% were white. The Mean National Institutes of Health Stroke Scale (SD) was 14.9 (8.4) for patients with anterior large vessel occlusion, 4.7 (5.0) for patients with non-large vessel occlusion ischemic stroke, and 4.4 (5.8) for stroke mimic (p < 0.001). Compared to the National Institutes of Health Stroke Scale, Field Assessment Stroke Triage for Emergency Destination, and Rapid Arterial oCclusion Evaluation scales demonstrated higher accuracy and area under curve for large vessel occlusion detection. Both the Field Assessment Stroke Triage for Emergency Destination and Rapid Arterial oCclusion Evaluation scales outperformed the National Institutes of Health Stroke Scale for large vessel occlusion detection in patients evaluated by in-hospital telestroke. These scales may be valid alternatives to the National Institutes of Health Stroke Scale examination in this setting.

Validation of the prehospital stroke scales as a tool for in-hospital large vessel occlusion stroke: whether we satisfied?

Prehospital stroke severity scales have been widely used to identify whether community stroke patients presented with large vessel occlusion (LVO) or not. However, whether these scales are also applicable to in-hospital stroke patients remains unknown. We aim to validate and compare the predictive capability of these scales for these patients. From January 2016 to October 2020, a total of 243 patients who activated in-hospital stroke alerts, were included in this study. The area under the curve (AUC) was used to assess the predictive ability of five scales (Field Assessment Stroke Triage for Emergency Destination [FAST-ED], Rapid Arterial Occlusion Evaluation [RACE], Los Angeles Motor Scale [LAMS], Cincinnati Prehospital Stroke Severity Scale [CPSSS], and Prehospital Acute Stroke Severity scale [PASS]) for LVO. In addition, multivariable logistic analysis was adopted to determine the predictors of LVO in our patients cohort. Finally, 94 (38.7%) patients were confirmed presence of persistent LVO. The AUC for the FAST-ED, RACE, LAMS, CPSSS, and PASS scales to predict the presence of LVO in patients activating in-hospital stroke alerts were 0.82, 0.89, 0.86, 0.81, and 0.79, respectively. After multivariable analysis, baseline NIHSS (adjusted odds ratio [OR] = 1.160, 95% confidence interval [CI] = 1.110-1.212; P < 0.001) atrial fibrillation (adjusted OR = 2.940, 95% CI = 1.387-6.230; P = 0.005) and cardiac/pulmonary procedure (adjusted OR = 6.861, 95% CI = 2.437-19.315; P < 0.001) remained independent predictors of LVO. The prehospital stroke scales also showed good predictive capabilities in discriminating LVO among inpatients who activated stroke alerts. However, given that inpatients' history is more readily available, a specifically designed in-hospital stroke scale that combines stroke severity and history is warranted.

Real-time video analysis allows the identification of large vessel occlusion in patients with suspected stroke: feasibility trial of a "telestroke" pathway in Northwestern Switzerland.

Loss of time is a major obstacle to efficient stroke treatment. Our telestroke path intends to optimize prehospital triage using a video link connecting ambulance personnel and a stroke physician. The objectives were as follows: (1) To identify patients suffering a stroke and (2) in particular large vessel occlusion (LVO) strokes as candidates for endovascular treatment. We have chosen the Rapid Arterial Occlusion Evaluation (RACE) scale for this purpose. This analysis aimed to verify the feasibility of prehospital stroke identification by video assessment. In this prospective telestroke cohort study, we included 97 subjects, in which the RACE score (items: facial palsy, arm and leg motor function, head and gaze deviation, and aphasia or agnosia) was applied, and the assessment videotaped by a trained member of the Emergency Medical Services (EMS) in the field using a mobile device. Each recorded patient video was independently assessed by three experienced stroke physicians from a certified stroke center and compared to the neuroimaging gold standard. Within this feasibility study, the stroke code was not altered by the outcome of the RACE assessment, and all patients underwent the standard procedures within the emergency unit. We analyzed 97 patients (median age 78 years, 53% women), of whom 51 (52.6%) suffered an acute stroke, 12 (23.5%) of which were due to an LVO and 46 patients had symptoms mimicking a stroke. The sensitivity of stroke identification was 77.8%, and specificity was 53.6%. In regard to the identification of an LVO, sensitivity was 69.4% and specificity was 84.3%. The inter-rater agreement in the RACE-score assessment was ICC = 0.82 (intraclass-correlation coefficient). These results confirm our hypothesis that the local telestroke concept is feasible. It allows correct (i) stroke and (ii) LVO identification in the majority of the cases and thus has the potential to assist in efficient prehospital triage.

Effect of Bypassing the Closest Stroke Center in Patients with Intracerebral Hemorrhage

Prehospital transfer protocols are based on rapid access to reperfusion therapies for patients with ischemic stroke. The effect of different protocols among patients receiving a final diagnosis of intracerebral hemorrhage (ICH) is unknown. To determine the effect of direct transport to an endovascular treatment (EVT)-capable stroke center vs transport to the nearest local stroke center. This was a prespecified secondary analysis of RACECAT, a multicenter, population-based, cluster-randomized clinical trial conducted from March 2017 to June 2020 in Catalonia, Spain. Patients were evaluated by a blinded end point assessment. All consecutive patients suspected of experiencing a large vessel occlusion stroke (Rapid Arterial Occlusion Evaluation Scale [RACE] score in the field >4 on a scale of 0 to 9, with lower to higher stroke severity) with final diagnosis of ICH were included. A total of 1401 patients were enrolled in RACECAT with suspicion of large vessel occlusion stroke. The current analysis was conducted in October 2022. Direct transport to an EVT-capable stroke center (n = 137) or to the closest local stroke center (n = 165). The primary outcome was tested using cumulative ordinal logistic regression to estimate the common odds ratio (OR) and 95% CI of the shift analysis of disability at 90 days as assessed by the modified Rankin Scale (mRS) score (range, 0 [no symptoms] to 6 [death]) in the intention-to-treat population. Secondary outcomes, included 90-day mortality, death or severe functional dependency, early neurological deterioration, early mortality, ICH volume and enlargement, rate of neurosurgical treatment, rate of clinical complications during initial transport, and rate of adverse events until day 5. Of 1401 patients enrolled, 1099 were excluded from this analysis (32 rejected informed consent, 920 had ischemic stroke, 29 had transient ischemic attack, 12 had subarachnoid hemorrhage, and 106 had stroke mimic). Thus, 302 patients were included (204 [67.5%] men; mean [SD] age 71.7 [12.8] years; and median [IQR] RACE score, 7 [6-8]). For the primary outcome, direct transfer to an EVT-capable stroke center (mean [SD] mRS score, 4.93 [1.38]) resulted in worse functional outcome at 90 days compared with transfer to the nearest local stroke center (mean [SD] mRS score, 4.66 [1.39]; adjusted common OR, 0.63; 95% CI, 0.41-0.96). Direct transfer to an EVT-capable stroke center also suggested potentially higher 90-day mortality compared with transfer to the nearest local stroke center (67 of 137 [48.9%] vs 62 of 165 [37.6%]; adjusted hazard ratio, 1.40; 95% CI, 0.99-1.99). The rates of medical complications during the initial transfer (30 of 137 [22.6%] vs 9 of 165 patients [5.6%]; adjusted OR, 5.29; 95% CI, 2.38-11.73) and in-hospital pneumonia (49 of 137 patients [35.8%] vs 29 of 165 patients [17.6%]; OR, 2.61; 95% CI, 1.53-4.44) were higher in the EVT-capable stroke center group. In this secondary analysis of the RACECAT randomized clinical trial, bypassing the closest stroke center resulted in reduced chances of functional independence at 90 days for patients who received a final diagnosis of ICH. ClinicalTrials.gov Identifier: NCT02795962.

Prehospital Triage of Intracranial Hemorrhage and Anterior Large‐Vessel Occlusion Ischemic Stroke: Value of the Rapid Arterial Occlusion Evaluation

Background The Rapid Arterial oCclusion Evaluation (RACE) score can identify patients with anterior circulation large‐vessel occlusion (aLVO) ischemic stroke for transportation to a comprehensive stroke center for endovascular thrombectomy. However, patients with intracranial hemorrhage (ICH) may also benefit from direct transportation to a comprehensive stroke center for neurosurgical treatment. We aimed to assess if the RACE score can distinguish patients with ICH in addition to aLVO stroke from other patients with suspected stroke. Methods We analyzed data from the LPSS (Leiden Prehospital Stroke Study), a multicenter, prospective, observational cohort study in 2 Dutch ambulance regions. Ambulance paramedics documented prehospital observations in all patients aged ≥18 years with suspected stroke. We calculated the sensitivity, specificity, positive predictive value, and negative predictive value of a positive RACE score (≥5 points) for a diagnosis of ICH or aLVO stroke, compared with patients with non‐aLVO stroke, transient ischemic attack, or stroke mimic. In addition, we performed a multivariable logistic regression analysis and calculated adjusted odds ratios (ORs). Results We included 2004 patients with a stroke code, of whom 149 had an ICH, 153 had an aLVO stroke, 687 had a non‐aLVO stroke, 262 had a transient ischemic attack, and 753 had a stroke mimic. Patients with ICH and aLVO stroke more often had a positive RACE score than other patients with suspected stroke (46.2% and 58.0%, respectively, versus 6.4%; P &lt;0.01). A positive RACE score had a sensitivity of 52.7%, a specificity of 93.6%, a positive predictive value of 55.4%, and a negative predictive value of 92.9% for a diagnosis of ICH or aLVO stroke. In multivariable analysis, a positive RACE score had the strongest association with ICH or aLVO stroke (adjusted OR, 10.11 [95% CI, 6.84–14.93]). Conclusions Our study shows that the RACE score can also identify patients with ICH in addition to aLVO stroke. This emphasizes the potential of the RACE score for improving prehospital triage and allocation of patients with stroke.

Cost-effectiveness of Direct Transfer to Angiography Suite of Patients With Suspected Large Vessel Occlusion.

Patients with acute ischemic stroke due to large vessel occlusion (LVO) deemed eligible for endovascular thrombectomy (EVT) are transferred from the emergency room to the angiography suite to undergo the procedure. Recently, the strategy of direct transfer of patients with suspected LVO to the angiography suite (DTAS) has been shown to improve functional outcomes. This study aims to evaluate the cost-effectiveness of the DTAS strategy vs initial transfer of patients with suspected LVO (Rapid Arterial Occlusion Evaluation score >4 and NIH Stroke Scale >10) to the emergency room (ITER). A decision-analytic Markov model was developed to estimate the cost-effectiveness of the DTAS strategy vs the ITER strategy from a Dutch health care perspective with a 10-year time horizon. The primary outcome was the incremental cost-effectiveness ratio (ICER) using Dutch thresholds of $59,135 (€50,000) and $94,616 (€80,000) per quality-adjusted life year (QALY). Uncertainty of input parameters was assessed using 1-way sensitivity analysis, scenario analysis, and probabilistic sensitivity analysis. The DTAS strategy yielded 0.65 additional QALYs at an additional $16,089, resulting in an ICER of $24,925/QALY compared with the ITER strategy. The ICER varied from $27,169 to $38,325/QALY across different scenarios. The probabilistic sensitivity analysis showed that the DTAS strategy had a 91.8% and 97.0% likelihood of being cost-effective at a decision threshold of $59,135/QALY and $94,616/QALY, respectively. The cost-effectiveness of the DTAS strategy over ITER is robust for patients with suspected LVO. Together with recently published clinical results, this means that implementation of the DTAS strategy may be considered to improve the workflow and outcome of EVT.

Prehospital Stroke Triage: A Modeling Study on the Impact of Triage Tools in Different Regions

Background and purpose Direct transportation to a thrombectomy-capable intervention center is beneficial for patients with ischemic stroke due to large vessel occlusion (LVO), but can delay intravenous thrombolytics (IVT). The aim of this modeling study was to estimate the effect of prehospital triage strategies on treatment delays and overtriage in different regions. Methods We used data from two prospective cohort studies in the Netherlands: the Leiden Prehospital Stroke Study and the PRESTO study. We included stroke code patients within 6 h from symptom onset. We modeled outcomes of Rapid Arterial oCclusion Evaluation (RACE) scale triage and triage with a personalized decision tool, using drip-and-ship as reference. Main outcomes were overtriage (stroke code patients incorrectly triaged to an intervention center), reduced delay to endovascular thrombectomy (EVT), and delay to IVT. Results We included 1798 stroke code patients from four ambulance regions. Per region, overtriage ranged from 1-13% (RACE triage) and 3-15% (personalized tool). Reduction of delay to EVT varied by region between 24 ± 5 min (n = 6) to 78 ± 3 (n = 2), while IVT delay increased with 5 (n = 5) to 15 min (n = 21) for non-LVO patients. The personalized tool reduced delay to EVT for more patients (25 ± 4 min [n = 8] to 49 ± 13 [n = 5]), while delaying IVT with 3-14 min (8-24 patients). In region C, most EVT patients were treated faster (reduction of delay to EVT 31 ± 6 min (n = 35), with RACE triage and the personalized tool. Conclusions In this modeling study, we showed that prehospital triage reduced time to EVT without disproportionate IVT delay, compared to a drip-and-ship strategy. The effect of triage strategies and the associated overtriage varied between regions. Implementation of prehospital triage should therefore be considered on a regional level.

The Rapid Arterial oCclusion Evaluation (RACE) scale accuracy for diagnosis of acute ischemic stroke in emergency department – A multicenter study

ObjectiveIt seems that the available data on performance of the Rapid Arterial oCclusion Evaluation (RACE) as a prehospital stroke scale for differentiating all AIS cases, not only large vessel occlusion (LVO), from the stroke mimics is lacking. As a result, we intend to evaluate the accuracy of the RACE criteria in diagnosing of AIS in patients transferred to the emergency department (ED).MethodThe present study was a diagnostic accuracy cross-sectional study during 2021 in Iran. The study population consist of all suspected acute ischemic stroke (AIS) patients who transferred to the ED by emergency medical services (EMS). A 3-part checklist consisting of the basic and demographic information of the patients, items related to the RACE scale, and the final diagnosis of the patients based on interpretation of patients’ brain MRI was used for data collection. All data were entered in Stata 14 software. We used the ROC analysis to evaluate the diagnostic power of the test.ResultIn this study, data from 805 patients with the mean age of 66.9 ± 13.9 years were studied of whom 57.5% were males. Of all the patients suspected of stroke who transferred to the ED, 562 (69.8%) had a definite final diagnosis of AIS. The sensitivity and specificity of the RACE scale for the recommended cut-off point (score ≥ 5) were 50.18% and 92.18%, respectively. According to the Youden J index, the best cut-off point for this tool for differentiating AIS cases was a score > 2, at which sensitivity and specificity were 74.73% and 87.65%, respectively.ConclusionIt seems that, the RACE scale is an accurate diagnostic tool to detect and screen AIS patients in ED, Of course, not at the previously suggested cut-off point (score ≥ 5), but at the score > 2.

A nomogram-based clinical tool for acute ischemic stroke screening in prehospital setting.

Background: We believe that designing a new tool which is comparable in terms of both sensitivity and specificity may play an important role in rapid and more accurate diagnosis of acute ischemic stroke (AIS) in prehospital stage. Therefore, we intended to develop a new clinical tool for the diagnosis of AIS in the prehospital stage. Methods: This was a cross-sectional diagnostic accuracy study. All patients transferred to the emergency department (ED) who underwent brain magnetic resonance imaging (MRI) with impression of AIS were evaluated by 9 clinical tools for stroke diagnosis in the pre-hospital phase including Rapid Arterial Occlusion Evaluation (RACE), Cincinnati Prehospital Stroke Scale (CPSS), Los Angeles Prehospital Stroke Screen (LAPSS), Melbourne Ambulance Stroke Screen (MASS), Medic Prehospital Assessment for Code Stroke (Med PACS), Ontario Prehospital Stroke Screening Tool (OPSS), PreHospital Ambulance Stroke Test (PreHAST), Recognition of Stroke in the Emergency Room (ROSIER), and Face Arm Speech Test (FAST), and totally 19 items were reviewed and recorded. The new clinical tool was developed based on backward method of multivariable logistic regression analysis. The discrimination power of the new clinical tool for diagnosis of AIS was assessed with the area under the receiver operating characteristic curve (AUC-ROC). Results: Data from 806 patients were analyzed; of them, 57.4% were men. The mean age of the study patients was 66.9 years [standard deviation (SD) = 13.9]. In the multivariable model, 8 items remained. The AUC-ROC of the new clinical tool was 0.893 [95% confidence interval (CI): 0.869-0.917], and its best cut-off point was score ≥ 3 for positive AIS. At this cut-off point, sensitivity and specificity were 84.42% and 79.72%, respectively. Conclusion: We introduced a new nomogram-based clinical tool for the diagnosis of AIS in the prehospital stage, which has acceptable specificity and sensitivity; moreover, it is comparable with previous tools.

Evaluation of the Rapid Arterial oCclusion Evaluation (RACE) scale in Upstate South Carolina, USA

ObjectivesSeveral stroke assessments have been designed for Emergency Medical Services to identify stroke patients with large vessel occlusion in the prehospital setting. The Rapid Arterial oCclusion Evaluation scale was developed in Spain, yet only few United States-based studies have confirmed findings from Spain. This study was designed to determine if the Rapid Arterial oCclusion Evaluation scale is a valid prehospital stroke assessment for identifying large vessel occlusion patients in South Carolina, USA. Materials and methodsThe performance of the Rapid Arterial oCclusion Evaluation scale was determined by calculating the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy at each score. The discriminative power of the Rapid Arterial oCclusion Evaluation score was evaluated using receiver operator characteristics. Comparison of the Rapid Arterial oCclusion Evaluation Scale to the National Institute of Health Stroke Scale was assessed using the Spearman's coefficient. ResultsThe Rapid Arterial oCclusion Evaluation scale had an acceptable discriminative power (c = 0.71). A score of ≥5 had a sensitivity of 0.71, specificity of 0.65, positive predictive value of 0.24, negative predictive value of 0.93, and accuracy of 0.66. There was a significant correlation between the Rapid Arterial Cclusion Evaluation score and the National Institute of Health Stroke Scale (rho = 0.60). ConclusionThe Rapid Arterial oCclusion Evaluation scale performed comparably to the National Institute of Health Stroke Scale in South Carolina; however, performed lower than Spain. Future studies should investigate patient demographics and emergency medical services training to determine if these variables contribute to the results found in this study.

Large vessel occlusion prediction scales provide high negative but low positive predictive values in prehospital suspected stroke patients

IntroductionWe studied a registry of Emergency Medical Systems (EMS) identified prehospital suspected stroke patients brought to an academic endovascular capable hospital over 1 year to assess the prevalence of disease...