Threshold for NIH Stroke Scale in Predicting Vessel Occlusion and Functional Outcome after Stroke Thrombolysis

164

138

Background and Purpose-It remains debated whether clinical scores can help identify acute ischemic stroke patients with large-artery occlusion and hence improve triage in the era of thrombectomy. We aimed to determine the accuracy of published clinical scores to predict large-artery occlusion. Methods-We assessed the performance of 13 clinical scores to predict large-artery occlusion in consecutive patients with acute ischemic stroke undergoing clinical examination and magnetic resonance or computed tomographic angiography ≤6 hours of symptom onset. When no cutoff was published, we used the cutoff maximizing the sum of sensitivity and specificity in our cohort. We also determined, for each score, the cutoff associated with a false-negative rate ≤10%. Results-Of 1004 patients (median National Institute of Health Stroke Scale score, 7; range, 0-40), 328 (32.7%) had an occlusion of the internal carotid artery, M1 segment of the middle cerebral artery, or basilar artery. The highest accuracy (79%; 95% confidence interval, 77-82) was observed for National Institute of Health Stroke Scale score ≥11 and Rapid Arterial Occlusion Evaluation Scale score ≥5. However, these cutoffs were associated with false-negative rates >25%. Cutoffs associated with an false-negative rate ≤10% were 5, 1, and 0 for National Institute of Health Stroke Scale, Rapid Arterial Occlusion Evaluation Scale, and Cincinnati Prehospital Stroke Severity Scale, respectively. Conclusions-Using published cutoffs for triage would result in a loss of opportunity for ≥20% of patients with large-artery occlusion who would be inappropriately sent to a center lacking neurointerventional facilities. Conversely, using cutoffs reducing the false-negative rate to 10% would result in sending almost every patient to a comprehensive stroke center. Our findings, therefore, suggest that intracranial arterial imaging should be performed in all patients with acute ischemic stroke presenting within 6 hours of symptom onset.

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Clinical Scales Do Not Reliably Identify Acute Ischemic Stroke Patients With Large-Artery Occlusion

Turc

Maïer

Naggara

et al. 2016

164

138

“…In such cases, determining emergent large vessel occlusion from the baseline National Institutes of Health Stroke Scale is imperfect; however, the cut off of 12 was conservative (positive predictive value 64%). 8 It is difficult to anticipate future practice evolution. This study was based on average time metrics (door-to-needle and door-to-reperfusion) assuming futile reperfusion beyond 7 hours, but some may benefit beyond this after selection by multimodal imaging.…”

Section: May 2016mentioning

confidence: 99%

Determining the Number of Ischemic Strokes Potentially Eligible for Endovascular Thrombectomy

Chia

Leyden

Newbury

et al. 2016

122

Factors influencing eligibility for ET were extracted from medical records and neuroimaging. Two algorithms were prospectively created to discriminate patients potentially eligible for ET-a restrictive algorithm incorporating the most stringent inclusion and exclusion criteria and a permissive algorithm reflecting the greater lenience that may occur in clinical practice (Figure 1 and Table). Ethics ApprovalEthical approval was obtained from all Adelaide hospitals and from the University of Adelaide (H 155 2008). Informed consent was obtained from patients (or next-of-kin when the patient was unable to consent). No patients (or proxies) declined participation.Background and Purpose-Endovascular thrombectomy (ET) is standard-of-care for ischemic stroke patients with large vessel occlusion, but estimates of potentially eligible patients from population-based studies have not been published. Such data are urgently needed to rationally plan hyperacute services. Retrospective analysis determined the incidence of ET-eligible ischemic strokes in a comprehensive population-based stroke study (Adelaide, Australia 2009-2010. Methods-Stroke patients were stratified via a prespecified eligibility algorithm derived from recent ET trials comprising stroke subtype, pathogenesis, severity, premorbid modified Rankin Score, presentation delay, large vessel occlusion, and target mismatch penumbra. Recognizing centers may interpret recent ET trials either loosely or rigidly; 2 eligibility algorithms were applied: restrictive (key criteria modified Rankin Scale score 0-1, presentation delay <3.5 hours, and target mismatch penumbra) and permissive (modified Rankin Scale score 0-3 and presentation delay <5 hours). Results-In a population of 148 027 people, 318 strokes occurred in the 1-year study period (crude attack rate 215 per 100 000 person-years). The number of ischemic strokes eligible by restrictive criteria was 17/258 (7%; 95% confidence intervals 4%-10%) and by permissive criteria, an additional 16 were identified, total 33/258 (13%; 95% confidence intervals 9%-18%). Two of 17 patients (and 6/33 permissive patients) had thrombolysis contraindications. Using the restrictive algorithm, there were 11 (95% confidence intervals 4-18) potential ET cases per 100 000 person-years or 22 (95% confidence intervals 13-31) using the permissive algorithm. Conclusions-In this cohort, ≈7% of ischemic strokes were potentially eligible for ET (13% with permissive criteria).In similar populations, the permissive criteria predict that ≤22 strokes per 100 000 person-years may be eligible for ET.

“…The association between higher baseline NIHSS and the presence of vessel occlusion was recently shown in another publication from our group. 25 The importance of future studies separately investigating the association between score prediction and outcome after endovascular thrombectomy is evident.…”

Section: Strokementioning

confidence: 99%

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

Cooray

Mazya

Bottai

et al. 2016

Self Cite

The 2 most recently developed scores were designed to predict functional outcome after acute stroke, one in unselected acute ischemic stroke patients (Acute Stroke Registry and Analysis of Lausanne [ASTRAL]), 10 and the other in acute stroke patients treated with intravenous tPA (DRAGON includes dense middle cerebral artery sign, 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