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Background: Several prehospital scales have been designed to aid paramedics in identifying stroke patients in the ambulance setting. However, external validation and comparison of these scales are largely lacking., Aims: To compare all published prehospital stroke detection scales in a large cohort of unselected stroke code patients., Methods: We conducted a systematic literature search to identify all stroke detection scales. Scales were reconstructed with prehospital acquired data from two observational cohort studies: the Leiden Prehospital Stroke Study (LPSS) and PREhospital triage of patients with suspected STrOke (PRESTO) study. These included stroke code patients from four ambulance regions in the Netherlands, including 15 hospitals and serving 4 million people. For each scale, we calculated the accuracy, sensitivity, and specificity for a diagnosis of stroke (ischemic, hemorrhagic, or transient ischemic attack (TIA)). Moreover, we assessed the proportion of stroke patients who received reperfusion treatment with intravenous thrombolysis or endovascular thrombectomy that would have been missed by each scale., Results: We identified 14 scales, of which 7 (CPSS, FAST, LAPSS, MASS, MedPACS, OPSS, and sNIHSS-EMS) could be reconstructed. Of 3317 included stroke code patients, 2240 (67.5%) had a stroke (1528 ischemic, 242 hemorrhagic, 470 TIA) and 1077 (32.5%) a stroke mimic. Of ischemic stroke patients, 715 (46.8%) received reperfusion treatment. Accuracies ranged from 0.60 (LAPSS) to 0.66 (MedPACS, OPSS, and sNIHSS-EMS), sensitivities from 66% (LAPSS) to 84% (MedPACS and sNIHSS-EMS), and specificities from 28% (sNIHSS-EMS) to 49% (LAPSS). MedPACS, OPSS, and sNIHSS-EMS missed the fewest reperfusion-treated patients (10.3-11.2%), whereas LAPSS missed the most (25.5%)., Conclusions: Prehospital stroke detection scales generally exhibited high sensitivity but low specificity. While LAPSS performed the poorest, MedPACS, sNIHSS-EMS, and OPSS demonstrated the highest accuracy and missed the fewest reperfusion-treated stroke patients. Use of the most accurate scale could reduce unnecessary stroke code activations for patients with a stroke mimic by almost a third, but at the cost of missing 16% of strokes and 10% of patients who received reperfusion treatment., Competing Interests: Declaration of conflicting interestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: N.D.K. reported receiving Grant HA20 15.01.02 from the Dutch Brain Foundation, Grant 3.240 from the Dutch Innovation Funds, and Grant LSHM16041 from Health~Holland during the conduct of the study, paid to the institution. B.R. reported funding from the Dutch Heart Foundation and the Netherlands Organization for Health Research and Development (ZonMw) during the conduct of this study, paid to the institution. M.J.H.W. reported receiving Clinical Established Investigator Grant 2016T086 from the Dutch Heart Foundation and VIDI Grant 9171337 from the Netherlands Organization for Health Research and Development (ZonMw) during the conduct of the original LPSS study. D.W.J.D. reports funding from the Dutch Heart Foundation, Brain Foundation Netherlands, The Netherlands Organization for Health Research and Development, Health~Holland Top Sector Life Sciences & Health, and unrestricted grants from Penumbra Inc., Stryker, Medtronic, Thrombolytic Science, LLC and Cerenovus for research, all paid to the institution outside the submitted work. I.R.W. reports compensation from Philips and from Medtronic for consultant services, and stock holdings in Neurophyxia BV. All other authors report no conflicting interests.

Background: 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., Methods: 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., Results: 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., Conclusions: 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., Competing Interests: Disclosures Dr Wermer reports receiving Clinical Established Investigator grant 2016T086 from the Dutch Heart Foundation and VIDI grant 9171337 from the Netherlands Organization for Health Research and Development (ZonMw) during the conduct of the original LPSS (Leiden Prehospital Stroke Study). Dr Kruyt reports receiving grant HA20 15.01.02 from the Dutch Brain Foundation, grant 3.240 from the Dutch Innovation Funds, and grant LSHM16041 from Health-Holland during the conduct of the study. Dr Roozenbeek reports funding from the Dutch Heart Foundation and the Netherlands Organization for Health Research and Development (ZonMw) during the conduct of this study, paid to the institution. Dr Dippel reports funding from the Dutch Heart Foundation, Brain Foundation Netherlands, the Netherlands Organisation for Health Research and Development, Health-Holland Top Sector Life Sciences & Health, and unrestricted grants from Penumbra Inc, Stryker, Medtronic, Thrombolytic Science, LLC, and Cerenovus for research, all paid to institution outside the submitted work. Dr van den Wijngaard reports compensation from Philips for consultant services, compensation from Medtronic for consultant services, and stock holdings in Neurophyxia BV. The other authors report no conflicts.

Background: It is unknown if ambulance paramedics adequately assess neurological deficits used for prehospital stroke scales to detect anterior large-vessel occlusions. We aimed to compare prehospital assessment of these stroke-related deficits by paramedics with in-hospital assessment by physicians., Methods: We used data from 2 prospective cohort studies: the LPSS (Leiden Prehospital Stroke Study) and PRESTO study (Prehospital Triage of Patients With Suspected Stroke). In both studies, paramedics scored 9 neurological deficits in stroke code patients in the field. Trained physicians scored the National Institutes of Health Stroke Scale (NIHSS) at hospital presentation. Patients with transient ischemic attack were excluded because of the transient nature of symptoms. Spearman rank correlation coefficient (r s ) was used to assess correlation between the total prehospital assessment score, defined as the sum of all prehospital items, and the total NIHSS score. Correlation, sensitivity and specificity were calculated for each prehospital item with the corresponding NIHSS item as reference., Results: We included 2850 stroke code patients. Of these, 1528 had ischemic stroke, 243 intracranial hemorrhage, and 1079 stroke mimics. Correlation between the total prehospital assessment score and NIHSS score was strong (r s =0.70 [95% CI, 0.68-0.72]). Concerning individual items, prehospital assessment of arm (r s =0.68) and leg (r s =0.64) motor function correlated strongest with corresponding NIHSS items, and had highest sensitivity (arm 95%, leg 93%) and moderate specificity (arm 71%, leg 70%). Neglect (r s =0.31), abnormal speech (r s =0.50), and gaze deviation (r s =0.51) had weakest correlations. Neglect and gaze deviation had lowest sensitivity (52% and 66%) but high specificity (84% and 89%), while abnormal speech had high sensitivity (85%) but lowest specificity (65%)., Conclusions: The overall prehospital assessment of stroke code patients correlates strongly with in-hospital assessment. Prehospital assessment of neglect, abnormal speech, and gaze deviation differed most from in-hospital assessment. Focused training on these deficits may improve prehospital triage., Competing Interests: Disclosures Dr Kruyt reported receiving grant HA20 15.01.02 from the Dutch Brain Foundation, grant 3.240 from the Dutch Innovation Funds, and grant LSHM16041 from Health~Holland during the conduct of the study. Dr Roozenbeek reported funding from the Dutch Heart Foundation and the Netherlands Organization for Health Research and Development (ZonMw) during the conduct of this study, paid to the institution. Dr Wermer reported receiving Clinical Established Investigator grant 2016T086 from the Dutch Heart Foundation and VIDI grant 9171337 from the Netherlands Organization for Health Research and Development (ZonMw) during the conduct of the original LPSS study (Leiden Prehospital Stroke Study). Dr Dippel reports funding from the Dutch Heart Foundation, Brain Foundation Netherlands, the Netherlands Organization for Health Research and Development, Health Holland Top Sector Life Sciences and Health, and unrestricted grants from Penumbra Inc, Stryker, Medtronic, Thrombolytic Science, LLC, and Cerenovus for research, all paid to institution outside the submitted work. Dr van den Wijngaard reports compensation from Philips and Medtronic for consultant services, and stock holdings in Neurophyxia BV. The other authors report no conflicts.

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.

Background: The usefulness of prehospital scales for identifying anterior circulation large vessel occlusion (aLVO) in patients with suspected stroke may vary depending on the severity of their presentation. The performance of these scales across the spectrum of deficit severity is unclear. The aim of this study was to evaluate the diagnostic performance of 8 prehospital scales for identifying aLVO across the spectrum of deficit severity., Methods: We used data from the PRESTO study (Prehospital Triage of Patients With Suspected Stroke Symptoms), a prospective observational study comparing prehospital stroke scales in detecting aLVO in suspected stroke patients. We used the National Institutes of Health Stroke Scale (NIHSS) score, assessed in-hospital, as a proxy for the Clinical Global Impression of stroke severity during prehospital assessment by paramedics. We calculated the sensitivity, specificity, positive predictive value, negative predictive value, and the difference in aLVO probabilities with a positive or negative prehospital scale test (ΔP aLVO ) for each scale for mild (NIHSS 0-4), intermediate (NIHSS 5-9), moderate (NIHSS 10-14), and severe deficits (NIHSS≥15)., Results: Among 1033 patients with suspected stroke, 119 (11.5%) had an aLVO, of whom 19 (16.0%) had mild, 25 (21.0%) had intermediate, 30 (25.2%) had moderate, and 45 (37.8%) had severe deficits. The scales had low sensitivity and positive predictive value in patients with mild-intermediate deficits, and poor specificity, negative predictive value, and accuracy with moderate-severe deficits. Positive results achieved the highest ΔP aLVO in patients with mild deficits. Negative results achieved the highest ΔP aLVO with severe deficits, but the probability of aLVO with a negative result in the severe range was higher than with a positive test in the mild range., Conclusions: Commonly-used prehospital stroke scales show variable performance across the range of deficit severity. Probability of aLVO remains high with a negative test in severely affected patients. Studies reporting prehospital stroke scale performance should be appraised in the context of the NIHSS distribution of their samples.

Objective: Awareness campaigns advise the public to call emergency medical services (EMS) directly in case of suspected stroke. We aimed to explore patient and notification characteristics that influence direct EMS notification, the time to alert, and the time to treatment., Methods: We performed a secondary analysis with data from the PRESTO study, a multi-center prospective observational cohort study that included patients with suspected stroke. We used multivariable binary logistic regression analyses to assess the association with direct EMS notification and multivariable linear regression analyses to assess the association with the onset-to-alert time, onset-to-needle time and onset-to-groin time., Results: Of 436 included patients, 208 patients (48%) contacted EMS directly. FAST scores (aOR 1.45 for every point increase, 95%CI: 1.14-1.86), alert outside office hours (aOR 1.64 [1.05-2.55]), and onset-to-alert time (aOR for every minute less [≤55 min]: 0.96 [0.95-0.97]) were independently associated with direct EMS notification. Direct EMS call was independently associated with shorter onset-to-alert times (27 min [54-0.84]) and with shorter onset-to-needle times (-30 min [-51 to -10]). The association between direct EMS call and the onset-to-groin time was almost similar to the association with onset-to-needle time, though not statistically significant (univariable analysis: 23.7 min decrease [-103.7 to 56.2])., Conclusion: More than half of all patients with suspected stroke do not call EMS directly but call their GP instead. Patients with higher FAST scores, alert outside office hours, and a rapid alert, more often call EMS directly. Patients who call EMS directly are treated with IVT 30 min faster than patients who call the GP first., Trial Registration Number: Netherlands Trial Register: NL7387, (www.trialregister.nl)., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Due to the time-sensitive effect of endovascular treatment, rapid prehospital identification of large-vessel occlusion in individuals with suspected stroke is essential to optimise outcome. Interhospital transfers are an important cause of delay of endovascular treatment. Prehospital stroke scales have been proposed to select patients with large-vessel occlusion for direct transport to an endovascular-capable intervention centre. We aimed to prospectively validate eight prehospital stroke scales in the field., Methods: We did a multicentre, prospective, observational cohort study of adults with suspected stroke (aged ≥18 years) who were transported by ambulance to one of eight hospitals in southwest Netherlands. Suspected stroke was defined by a positive Face-Arm-Speech-Time (FAST) test. We included individuals with blood glucose of at least 2·5 mmol/L. People who presented more than 6 h after symptom onset were excluded from the analysis. After structured training, paramedics used a mobile app to assess items from eight prehospital stroke scales: Rapid Arterial oCclusion Evaluation (RACE), Los Angeles Motor Scale (LAMS), Cincinnati Stroke Triage Assessment Tool (C-STAT), Gaze-Face-Arm-Speech-Time (G-FAST), Prehospital Acute Stroke Severity (PASS), Cincinnati Prehospital Stroke Scale (CPSS), Conveniently-Grasped Field Assessment Stroke Triage (CG-FAST), and the FAST-PLUS (Face-Arm-Speech-Time plus severe arm or leg motor deficit) test. The primary outcome was the clinical diagnosis of ischaemic stroke with a proximal intracranial large-vessel occlusion in the anterior circulation (aLVO) on CT angiography. Baseline neuroimaging was centrally assessed by neuroradiologists to validate the true occlusion status. Prehospital stroke scale performance was expressed as the area under the receiver operating characteristic curve (AUC) and was compared with National Institutes of Health Stroke Scale (NIHSS) scores assessed by clinicians at the emergency department. This study was registered at the Netherlands Trial Register, NL7387., Findings: Between Aug 13, 2018, and Sept 2, 2019, 1039 people (median age 72 years [IQR 61-81]) with suspected stroke were identified by paramedics, of whom 120 (12%) were diagnosed with aLVO. Of all prehospital stroke scales, the AUC for RACE was highest (0·83, 95% CI 0·79-0·86), followed by the AUC for G-FAST (0·80, 0·76-0·84), CG-FAST (0·80, 0·76-0·84), LAMS (0·79, 0·75-0·83), CPSS (0·79, 0·75-0·83), PASS (0·76, 0·72-0·80), C-STAT (0·75, 0·71-0·80), and FAST-PLUS (0·72, 0·67-0·76). The NIHSS as assessed by a clinician in the emergency department did somewhat better than the prehospital stroke scales with an AUC of 0·86 (95% CI 0·83-0·89)., Interpretation: Prehospital stroke scales detect aLVO with acceptable-to-good accuracy. RACE, G-FAST, and CG-FAST are the best performing prehospital stroke scales out of the eight scales tested and approach the performance of the clinician-assessed NIHSS. Further studies are needed to investigate whether use of these scales in regional transportation strategies can optimise outcomes of patients with ischaemic stroke., Funding: BeterKeten Collaboration and Theia Foundation (Zilveren Kruis)., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Introduction: The efficacy of both intravenous treatment (IVT) and endovascular treatment (EVT) for patients with acute ischaemic stroke strongly declines over time. Only a subset of patients with ischaemic stroke caused by an intracranial large vessel occlusion (LVO) in the anterior circulation can benefit from EVT. Several prehospital stroke scales were developed to identify patients that are likely to have an LVO, which could allow for direct transportation of EVT eligible patients to an endovascular-capable centre without delaying IVT for the other patients. We aim to prospectively validate these prehospital stroke scales simultaneously to assess their accuracy in predicting LVO in the prehospital setting., Methods and Analysis: Prehospital triage of patients with suspected stroke symptoms (PRESTO) is a prospective multicentre observational cohort study in the southwest of the Netherlands including adult patients with suspected stroke in the ambulance. The paramedic will assess a combination of items from five prehospital stroke scales, without changing the normal workflow. Primary outcome is the clinical diagnosis of an acute ischaemic stroke with an intracranial LVO in the anterior circulation. Additional hospital data concerning the diagnosis and provided treatment will be collected by chart review. Logistic regression analysis will be performed, and performance of the prehospital stroke scales will be expressed as sensitivity, specificity and area under the receiver operator curve., Ethics and Dissemination: The Institutional Review Board of the Erasmus MC University Medical Centre has reviewed the study protocol and confirmed that the Dutch Medical Research Involving Human Subjects Act (WMO) is not applicable. The findings of this study will be disseminated widely through peer-reviewed publications and conference presentations. The best performing scale, or the simplest scale in case of clinical equipoise, will be integrated in a decision model with other clinical characteristics and real-life driving times to improve prehospital triage of suspected stroke patients., Trial Registration Number: NTR7595., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)