Design and validation of a prehospital scale to predict stroke severity: Cincinnati Prehospital Stroke Severity Scale

Large Vessel Occlusion Scales Increase Delivery to Endovascular Centers Without Excessive Harm From Misclassifications

Background and Purpose—

Clinical large vessel occlusion (LVO) triage scales were developed to identify and bypass LVO to endovascular centers. However, there are concerns that scale misclassification of patients may cause excessive harm. We studied the settings where misclassifications were likely to occur and the consequences of these misclassifications in a representative stroke population.

Methods—

Prospective data were collected from consecutive ambulance-initiated stroke alerts at 2 stroke centers, with patients stratified into typical (LVO with predefined severe syndrome and non-LVO without) or atypical presentations (opposite situations). Five scales (Rapid Arterial Occlusion Evaluation [RACE], Los Angeles Motor Scale [LAMS], Field Assessment Stroke Triage for Emergency Destination [FAST-ED], Prehospital Acute Stroke Severity scale [PASS], and Cincinnati Prehospital Stroke Severity Scale [CPSSS]) were derived from the baseline National Institutes of Health Stroke Scale scored by doctors and analyzed for diagnostic performance compared with imaging.

Results—

Of a total of 565 patients, atypical presentations occurred in 31 LVO (38% of LVO) and 50 non-LVO cases (10%). Most scales correctly identified >95% of typical presentations but <20% of atypical presentations. Misclassification attributable to atypical presentations would have resulted in 4 M1/internal carotid artery occlusions, with National Institutes of Health Stroke Scale score ≥6 (5% of LVO) being missed and 9 non-LVO infarcts (5%) bypassing the nearest thrombolysis center.

Conclusions—

Atypical presentations accounted for the bulk of scale misclassifications, but the majority of these misclassifications were not detrimental, and use of LVO scales would significantly increase timely delivery to endovascular centers, with only a small proportion of non-LVO infarcts bypassing the nearest thrombolysis center. Our findings, however, would require paramedics to score as accurately as doctors, and this translation is made difficult by weaknesses in current scales that need to be addressed before widespread adoption.

Mechanical thrombectomy in acute ischemic stroke

Recent randomized trials have demonstrated the efficacy of stent retriever thrombectomy, in association with intravenous thrombolysis, in acute ischemic stroke related to the occlusion of the distal internal carotid artery or the proximal middle cerebral artery within six hours of symptom onset. Mechanical thrombectomy should be performed as soon as possible after symptom onset. High age alone should not be considered as a contraindication for mechanical thrombectomy. Mechanical thrombectomy is recommended in acute ischemic stroke patients with large vessel occlusions and salvageable brain tissue if intravenous thrombolysis is contraindicated. Re-organization of stroke care systems is needed to provide rapid access to endovascular therapy equitably to all eligible patients.

Field Validation of the Los Angeles Motor Scale as a Tool for Paramedic Assessment of Stroke Severity

Background and Purpose—

The Los Angeles Motor Scale (LAMS) is a 3-item, 0- to 10-point motor stroke-deficit scale developed for prehospital use. We assessed the convergent, divergent, and predictive validity of the LAMS when performed by paramedics in the field at multiple sites in a large and diverse geographic region.

Methods—

We analyzed early assessment and outcome data prospectively gathered in the FAST-MAG trial (Field Administration of Stroke Therapy–Magnesium phase 3) among patients with acute cerebrovascular disease (cerebral ischemia and intracranial hemorrhage) within 2 hours of onset, transported by 315 ambulances to 60 receiving hospitals.

Results—

Among 1632 acute cerebrovascular disease patients (age 70±13 years, male 57.5%), time from onset to prehospital LAMS was median 30 minutes (interquartile range 20–50), onset to early postarrival (EPA) LAMS was 145 minutes (interquartile range 119–180), and onset to EPA National Institutes of Health Stroke Scale was 150 minutes (interquartile range 120–180). Between the prehospital and EPA assessments, LAMS scores were stable in 40.5%, improved in 37.6%, and worsened in 21.9%. In tests of convergent validity, against the EPA National Institutes of Health Stroke Scale, correlations were r =0.49 for the prehospital LAMS and r =0.89 for the EPA LAMS. Prehospital LAMS scores did diverge from the prehospital Glasgow Coma Scale, r =−0.22. Predictive accuracy (adjusted C statistics) for nondisabled 3-month outcome was as follows: prehospital LAMS, 0.76 (95% confidence interval 0.74–0.78); EPA LAMS, 0.85 (95% confidence interval 0.83–0.87); and EPA National Institutes of Health Stroke Scale, 0.87 (95% confidence interval 0.85–0.88).

Conclusions—

In this multicenter, prospective, prehospital study, the LAMS showed good to excellent convergent, divergent, and predictive validity, further establishing it as a validated instrument to characterize stroke severity in the field.

Clinical Selection Strategies to Identify Ischemic Stroke Patients With Large Anterior Vessel Occlusion

Background and Purpose—

The National Institutes of Health Stroke Scale (NIHSS) correlates with presence of large anterior vessel occlusion (LAVO). However, the application of the full NIHSS in the prehospital setting to select patients eligible for treatment with thrombectomy is limited. Therefore, we aimed to evaluate the prognostic value of simple clinical selection strategies.

Methods—

Data from the Safe Implementation of Thrombolysis in Stroke International Stroke Thrombolysis Registry (January 2012–May 2014) were analyzed retrospectively. Patients with complete breakdown of NIHSS scores and documented vessel status were included. We assessed the association of prehospital stroke scales and NIHSS symptom profiles with LAVO (internal carotid artery, carotid-terminus or M1-segment of the middle cerebral artery).

Results—

Among 3505 patients, 23.6% (n=827) had LAVO. Pathological finding on the NIHSS item best gaze was strongly associated with LAVO (adjusted odds ratio 4.5, 95% confidence interval 3.8–5.3). All 3 face–arm–speech–time test (FAST) items identified LAVO with high sensitivity. Addition of the item best gaze to the original FAST score (G-FAST) or high scores on other simplified stroke scales increased specificity. The NIHSS symptom profiles representing total anterior syndromes showed a 10-fold increased likelihood for LAVO compared with a nonspecific clinical profile. If compared with an NIHSS threshold of ≥6, the prehospital stroke scales performed similarly or even better without losing sensitivity.

Conclusions—

Simple modification of the face–arm–speech–time score or evaluating the NIHSS symptom profile may help to stratify patients’ risk of LAVO and to identify individuals who deserve rapid transfer to comprehensive stroke centers. Prospective validation in the prehospital setting is required.

Treatment of Acute Ischemic Stroke

Although stroke declined from the third to fifth most common cause of death in the United States, the annual incidence and overall prevalence continue to increase. Since the available US Food and Drug Administration-approved treatment options are time dependent, improving early stroke care may have more of a public health impact than any other phase of care. Timely and efficient stroke treatment should be a priority for emergency department and prehospital providers. This article discusses currently available and emerging treatment options in acute ischemic stroke focusing on the preservation of salvageable brain tissue, minimizing complications, and secondary prevention.

Pre and intrahospital workflow for acute stroke treatment

PURPOSE OF REVIEW

With the recent demonstration of the effectiveness of rapid recanalization of large vessel occlusions in acute ischemic stroke, it is important to assess the current status of pre and intrahospital workflow for acute stroke.

RECENT FINDINGS

We will review trends in the evaluation and treatment of acute stroke and offer suggestions for how best to advance the workflow for acute stroke care in the coming years.

SUMMARY

Future research is needed for: field use of clinical scores for predicting large vessel occlusions, telemedicine to facilitate prehospital triage, and pre and intrahospital processes for optimizing stroke care delivery.

Stroke Treatment Academic Industry Roundtable: The Next Generation of Endovascular Trials

BACKGROUND AND PURPOSE

The STAIR (Stroke Treatment Academic Industry Roundtable) meeting aims to advance acute stroke therapy development through collaboration between academia, industry, and regulatory institutions. In pursuit of this goal and building on recently available level I evidence of benefit from endovascular therapy (ET) in large vessel occlusion stroke, STAIR IX consensus recommendations were developed that outline priorities for future research in ET.

METHODS

Three key directions for advancing the field were identified: (1) development of systems of care for ET in large vessel occlusion stroke, (2) development of therapeutic approaches adjunctive to ET, and (3) exploring clinical benefit of ET in patient population insufficiently studied in recent trials. Methodological issues such as optimal trial design and outcome measures have also been addressed.

RESULTS

Development of systems of care strategies should be geared both toward ensuring broad access to ET for eligible patients and toward shortening time to reperfusion to the minimum possible. Adjunctive therapy development includes neuroprotective approaches, adjuvant microcirculatory/collateral enhancing strategies, and periprocedural management. Future research priorities seeking to expand the eligible patient population are to determine benefit of ET in patients presenting beyond conventional time windows, in patients with large baseline ischemic core lesions, and in other important subgroups.

CONCLUSIONS

Research priorities in ET for large vessel occlusion stroke are to improve systems of care, investigate effective adjuvant therapies, and explore whether patient eligibility could be expanded.

Field Assessment Stroke Triage for Emergency Destination: A Simple and Accurate Prehospital Scale to Detect Large Vessel Occlusion Strokes

BACKGROUND AND PURPOSE

Patients with large vessel occlusion strokes (LVOS) may be better served by direct transfer to endovascular capable centers avoiding hazardous delays between primary and comprehensive stroke centers. However, accurate stroke field triage remains challenging. We aimed to develop a simple field scale to identify LVOS.

METHODS

The Field Assessment Stroke Triage for Emergency Destination (FAST-ED) scale was based on items of the National Institutes of Health Stroke Scale (NIHSS) with higher predictive value for LVOS and tested in the Screening Technology and Outcomes Project in Stroke (STOPStroke) cohort, in which patients underwent computed tomographic angiography within the first 24 hours of stroke onset. LVOS were defined by total occlusions involving the intracranial internal carotid artery, middle cerebral artery-M1, middle cerebral artery-2, or basilar arteries. Patients with partial, bihemispheric, and anterior+posterior circulation occlusions were excluded. Receiver operating characteristic curve, sensitivity, specificity, positive predictive value, and negative predictive value of FAST-ED were compared with the NIHSS, Rapid Arterial Occlusion Evaluation (RACE) scale, and Cincinnati Prehospital Stroke Severity (CPSS) scale.

RESULTS

LVO was detected in 240 of the 727 qualifying patients (33%). FAST-ED had comparable accuracy to predict LVO to the NIHSS and higher accuracy than RACE and CPSS (area under the receiver operating characteristic curve: FAST-ED=0.81 as reference; NIHSS=0.80, P=0.28; RACE=0.77, P=0.02; and CPSS=0.75, P=0.002). A FAST-ED ≥4 had sensitivity of 0.60, specificity of 0.89, positive predictive value of 0.72, and negative predictive value of 0.82 versus RACE ≥5 of 0.55, 0.87, 0.68, and 0.79, and CPSS ≥2 of 0.56, 0.85, 0.65, and 0.78, respectively.

CONCLUSIONS

FAST-ED is a simple scale that if successfully validated in the field, it may be used by medical emergency professionals to identify LVOS in the prehospital setting enabling rapid triage of patients.

External Validation of the ASTRAL and DRAGON Scores for Prediction of Functional Outcome in Stroke

Background and Purpose—

ASTRAL (Acute Stroke Registry and Analysis of Lausanne) and DRAGON (includes dense middle cerebral artery sign, prestroke modified Rankin Scale score, age, glucose, onset to treatment, National Institutes of Health Stroke Scale score) are 2 recently developed scores for predicting functional outcome after acute stroke in unselected acute ischemic stroke patients and in patients treated with intravenous thrombolysis, respectively. We aimed to perform external validation of these scores to assess their predictive performance in the large multicentre Safe Implementation of Thrombolysis in Stroke-International Stroke Thrombolysis Register.

Methods—

We calculated the ASTRAL and DRAGON scores in 36 131 and 33 716 patients, respectively, registered in Safe Implementation of Thrombolysis in Stroke-International Stroke Thrombolysis Register between 2003 and 2013. The proportion of patients with 3-month modified Rankin Scale scores of 3 to 6 was observed for each score point and compared with the predicted proportion according to the risk scores. Calibration was assessed using calibration plots, and predictive performance was assessed using area under the curve of the receiver operating characteristic. Multivariate logistic regression coefficients for the variables in the 2 scores were compared with the original derivation cohorts.

Results—

The ASTRAL showed an area under the curve of 0.790 (95% confidence interval, 0.786–0.795) and the DRAGON an area under the curve of 0.774 (95% confidence interval, 0.769–0.779). All ASTRAL parameters except range of visual fields and all DRAGON parameters were significantly associated with functional outcome in multivariate analysis.

Conclusions—

The ASTRAL and DRAGON scores show an acceptable predictive performance. ASTRAL does not require imaging-data and therefore may have an advantage for the use in prehospital patient assessment. Prospective studies of both scores evaluating the impact of their use on patient outcomes after intravenous thrombolysis and endovascular therapy are needed.

Bypassing primary stroke centre reduces delay and improves outcomes for patients with large vessel occlusion

Objective

In large-vessel occlusion, endovascular therapy is superior to medical management alone in achieving recanalisation. Reducing time delays to revascularisation in patients with large-vessel occlusion is important to improving outcome.

Patients and methods

A campaign was implemented in the Central Denmark Region targeting the identification of patients with large-vessel occlusion for direct transport to a comprehensive stroke centre. Time delays and outcomes before and after the intervention were assessed.

Results

A total of 476 patients (153 pre-intervention and 323 post-intervention) were included. They were treated with either intravenous tissue plasminogen activator or endovascular treatment (alone or in combination with intravenous tissue plasminogen activator). Endovascular therapy patients' median system delay was reduced from 234 to 185 min (adjusted relative risk delay 0.79 (95% confidence interval: 0.67-0.93)). The in-hospital delay was the main driver with an adjusted relative risk delay of 0.76 (confidence interval: 0.62-0.94), while pre-hospital delay was almost significantly reduced with an adjusted relative delay of 0.86 (confidence interval: 0.71-1.04). This was achieved without increasing the intravenous tissue plasminogen activator-treated patients' delay. Significantly more patients treated with endovascular therapy in the post-interventional period achieved functional independence (62% versus 43%), corresponding to an adjusted odds ratio of 3.08 (95% confidence interval: 1.08-8.78).

Conclusion

Direct transfer of patients with suspected large-vessel occlusion to a comprehensive stroke centre leads to shorter treatment times for endovascular therapy patients and is, in turn, associated with an increase in functional independence. We recorded no adverse effects on intravenous tissue plasminogen activator treatment times or outcome.

External Validation of the Cincinnati Prehospital Stroke Severity Scale

BACKGROUND

The Cincinnati Prehospital Stroke Severity Scale (CPSSS) was recently developed to predict large-vessel occlusions (LVOs) in patients with acute ischemic stroke (AIS). In its derivation study, which consisted of patients enrolled in thrombolysis and endovascular therapy trials, the CPSSS had excellent discriminatory performance. We sought to externally validate the CPSSS in an independent cohort.

METHODS

Using our institution's prospective stroke registry, we calculated CPSSS scores for all patients diagnosed with AIS at Weill Cornell Medical Center in 2013 and 2014. The primary outcome was presence of LVO and the secondary outcome was a National Institutes of Health Stroke Scale (NIHSS) score of 15 or higher. Harrell's c-statistic was calculated to determine the CPSSS score's discriminatory performance. Using the previously defined cut-point of 2 or higher (range 0-4), we evaluated the test properties of the CPSSS for predicting study outcomes.

RESULTS

Among 751 patients with AIS, 664 had vessel imaging and were included in the final analysis. Of these patients, 80 (14.2%) had LVOs and 117 (17.6%) had an NIHSS score of 15 or higher. The median CPSSS score was 0 (interquartile range 0-1) and 133 patients (20%) had scores of 2 or higher. c-statistic was .85 (95% confidence interval [CI] .81-.90) for predicting LVO and .94 (95% CI .92-.97) for predicting an NIHSS score of 15 or higher. Using a cut-point of 2 or higher, the CPSSS was 70.0% sensitive and 86.8% specific for predicting LVO, and 87.2% sensitive and 94.3% specific for predicting an NIHSS score of 15 or higher.

CONCLUSIONS

In a cohort of patients with AIS treated at a tertiary-care stroke center, the CPSSS had reasonable sensitivity and specificity for predicting LVO and severe stroke. Future studies should aim to prospectively validate the score in emergency responders.

Acute Stroke: Current Evidence-based Recommendations for Prehospital Care

Introduction

In the United States, emergency medical services (EMS) protocols vary widely across jurisdictions. We sought to develop evidence-based recommendations for the prehospital evaluation and treatment of a patient with a suspected stroke and to compare these recommendations against the current protocols used by the 33 EMS agencies in the state of California.

Methods

We performed a literature review of the current evidence in the prehospital treatment of a patient with a suspected stroke and augmented this review with guidelines from various national and international societies to create our evidence-based recommendations. We then compared the stroke protocols of each of the 33 EMS agencies for consistency with these recommendations. The specific protocol components that we analyzed were the use of a stroke scale, blood glucose evaluation, use of supplemental oxygen, patient positioning, 12-lead electrocardiogram (ECG) and cardiac monitoring, fluid assessment and intravenous access, and stroke regionalization.

Results

Protocols across EMS agencies in California varied widely. Most used some sort of stroke scale with the majority using the Cincinnati Prehospital Stroke Scale (CPSS). All recommended the evaluation of blood glucose with the level for action ranging from 60 to 80mg/dL. Cardiac monitoring was recommended in 58% and 33% recommended an ECG. More than half required the direct transport to a primary stroke center and 88% recommended hospital notification.

Conclusion

Protocols for a patient with a suspected stroke vary widely across the state of California. The evidence-based recommendations that we present for the prehospital diagnosis and treatment of this condition may be useful for EMS medical directors tasked with creating and revising these protocols.

Stroke vision, aphasia, neglect (VAN) assessment-a novel emergent large vessel occlusion screening tool: pilot study and comparison with current clinical severity indices

Background

Identification of emergent large vessel occlusion (ELVO) stroke has become increasingly important with the recent publications of favorable acute stroke thrombectomy trials. Multiple screening tools exist but the length of the examination and the false positive rate range from good to adequate. A screening tool was designed and tested in the emergency department using nurse responders without a scoring system.

Methods

The vision, aphasia, and neglect (VAN) screening tool was designed to quickly assess functional neurovascular anatomy. While objective, there is no need to calculate or score with VAN. After training participating nurses to use it, VAN was used as an ELVO screen for all stroke patients on arrival to our emergency room before physician evaluation and CT scan.

Results

There were 62 consecutive code stroke activations during the pilot study. 19 (31%) of the patients were VAN positive and 24 (39%) had a National Institutes of Health Stroke Scale (NIHSS) score of ≥6. All 14 patients with ELVO were either VAN positive or assigned a NIHSS score ≥6. While both clinical severity thresholds had 100% sensitivity, VAN was more specific (90% vs 74% for NIHSS ≥6). Similarly, while VAN and NIHSS ≥6 had 100% negative predictive value, VAN had a 74% positive predictive value while NIHSS ≥6 had only a 58% positive predictive value.

Conclusions

The VAN screening tool accurately identified ELVO patients and outperformed a NIHSS ≥6 severity threshold and may best allow clinical teams to expedite care and mobilize resources for ELVO patients. A larger study to both validate this screening tool and compare with others is warranted.

Neuron-Specific Enolase, S100 Calcium-Binding Protein B, and Heat Shock Protein 70 Levels in Patients With Intracranial Hemorrhage

The authors evaluated neuron-specific enolase (NSE), S100 calcium-binding protein B (S100B), and heat shock protein 70 (HSP 70) levels and their relationships with in-hospital mortality, Glasgow Coma Scale (GCS) scores, and National Institute of Health Stroke Scale (NIHSS) scores. In total, 35 patients older than 18 years were presented to our emergency department and were diagnosed with non-traumatic intracranial hemorrhage (ICH) and 32 healthy controls were included. Blood samples were drawn on days 0 and 5. S100 calcium-binding protein B and HSP levels were significantly higher in patients than in controls on days 0 and 5. Neuron-specific enolase levels were higher in patients than in controls on day 0, but there was no significant difference on day 5. S100 calcium-binding protein B was negatively correlated with GCS, whereas it was positively correlated with NIHSS and bleeding volume. There was also a negative correlation between NSE and GCS, but it was not statistically significant. In addition, no significant correlation was found in terms of bleeding volume or NIHSS. Heat shock protein 70 was negatively correlated with GCS and positively correlated with bleeding volume and NIHSS, but these results were not statistically significant. S100 calcium-binding protein B and HSP 70 levels were significantly higher in those who died compared with survivors. The areas under the curve of S100 B, NSE, and HSP 70 for mortality were 0.635, 0.477, and 0.770, respectively. Neuron-specific enolase, S100B, and HSP 70 levels are simple, inexpensive, and objective measures in cases of ICH. These tests can be used to support an assessment for screening ICH patients with clinical scoring systems, such as GCS and NIHSS.

[From stroke to reperfusion : How can we be faster?]

BACKGROUND

During the last two decades major efforts in clinical research have led to the establishment of intravenous thrombolysis as the first line acute therapy for ischemic stroke. More recently, data from successful phase III trials have provided proof of the efficiency of mechanical recanalization in acute stroke. The fact that the efficiency of the available therapies can be increased through faster delivery is well documented; however, many institutions dealing with the emergency care of stroke patients lack organizational or infrastructural arrangements to optimize time efficiency in the diagnostic and therapeutic workup.

CONCLUSION

Many of these arrangements have been well evaluated, can be implemented at reasonable costs and have been proven to increase the beneficial effects of thrombolytic therapy.