Prehospital Acute Stroke Severity Scale to Predict Large Artery Occlusion

Abstract

Background and Purpose— We designed and validated a simple prehospital stroke scale to identify emergent large vessel occlusion (ELVO) in patients with acute ischemic stroke and compared the scale to other published scales for prediction of ELVO. Methods— A national historical test cohort of 3127 patients with information on intracranial vessel status (angiography) before reperfusion therapy was identified. National Institutes of Health Stroke Scale (NIHSS) items with the highest predictive value of occlusion of a large intracranial artery were identified, and the most optimal combination meeting predefined criteria to ensure usefulness in the prehospital phase was determined. The predictive performance of Prehospital Acute Stroke Severity (PASS) scale was compared with other published scales for ELVO. Results— The PASS scale was composed of 3 NIHSS scores: level of consciousness (month/age), gaze palsy/deviation, and arm weakness. In derivation of PASS 2/3 of the test cohort was used and showed accuracy (area under the curve) of 0.76 for detecting large arterial occlusion. Optimal cut point ≥2 abnormal scores showed: sensitivity=0.66 (95% CI, 0.62–0.69), specificity=0.83 (0.81–0.85), and area under the curve=0.74 (0.72–0.76). Validation on 1/3 of the test cohort showed similar performance. Patients with a large artery occlusion on angiography with PASS ≥2 had a median NIHSS score of 17 (interquartile range=6) as opposed to PASS <2 with a median NIHSS score of 6 (interquartile range=5). The PASS scale showed equal performance although more simple when compared with other scales predicting ELVO. Conclusions— The PASS scale is simple and has promising accuracy for prediction of ELVO in the field.

Predictive Value of Modifications of the Prehospital Rapid Arterial Occlusion Evaluation Scale for Large Vessel Occlusion in Patients with Acute Stroke

“…The RACE scale score was not detailed item-by-item in 16 cases and therefore we studied 341 patients (53.4% men; age (mean±SD) 70±13 years; NIHSS score at admission (median [interquartile range] 8 [3][4][5][6][7][8][9][10][11][12][13][14][15][16] had 85% sensitivity, 68% specificity and correctly classified 71% patients. The RACE and NIHSS scores were strongly correlated (r=0.78; p<0.001).…”

“…Other scales may identify these patients, but have not been validated prospectively or in the field (8)(9)(10)(11)(12). The RACE scale is simple and specifically designed to identify anterior circulation LVO patients (Table 1).…”

Prehospital stroke scale (FAST PLUS Test) predicts patients with intracranial large vessel occlusion

“…The presented test has a higher sensitivity and NPV than other tests (Table 4) (Hastrup et al., 2016; Katz et al., 2015; Lima et al., 2016; McMullan et al., 2017; Nazliel et al., 2008; Pérez de la Ossa et al., 2014; Scheitz et al., 2017; Singer et al., 2005). We found that the FAST PLUS test had a high sensitivity of 93% and high NPV of 94%.…”

“…This is comparable to the RACE study (McMullan et al., 2017) Other studies were performed retrospectively or with small numbers of patients (Hastrup et al., 2016; Katz et al., 2015; Lima et al., 2016; McMullan et al., 2017; Nazliel et al., 2008; Pérez de la Ossa et al., 2014; Singer et al., 2005). …”

“…A series of such tests have been published, but there has not yet been any implementation in prehospital practice (Hastrup, Damgaard, Johnsen, & Andersen, 2016; Katz, McMullan, Sucharew, Adeoye, & Broderick, 2015; Lima et al., 2016; Nazliel et al., 2008; Scheitz et al., 2017; Singer et al., 2005). Only the RACE and Cincinnati tests for LVO have been performed at a prehospital level (McMullan et al., 2017; Pérez de la Ossa et al., 2014).…”