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.

Quantifying the amount of greater brain ischemia protection time with pre-hospital vs. in-hospital neuroprotective agent start.

The objective of this study is to quantify the increase in brain-under-protection time that may be achieved with pre-hospital compared with the post-arrival start of neuroprotective therapy among patients undergoing endovascular thrombectomy. In order to do this, a comparative analysis was performed of two randomized trials of neuroprotective agents: (1) pre-hospital strategy: Field administration of stroke therapy-magnesium (FAST-MAG) Trial; (2) in-hospital strategy: Efficacy and safety of nerinetide for the treatment of acute ischemic stroke (ESCAPE-NA1) Trial. In the FAST-MAG trial, among 1,041 acute ischemic stroke patients, 44 were treated with endovascular reperfusion therapy (ERT), including 32 treated with both intravenous thrombolysis and ERT and 12 treated with ERT alone. In the ESCAPE-NA1 trial, among 1,105 acute ischemic stroke patients, 659 were treated with both intravenous thrombolysis and ERT, and 446 were treated with ERT alone. The start of the neuroprotective agent was sooner after onset with pre-hospital vs. in-hospital start: 45 m (IQR 38-56) vs. 122 m. The neuroprotective agent in FAST-MAG was started 8 min prior to ED arrival compared with 64 min after arrival in ESCAPE-NA1. Projecting modern endovascular workflows to FAST-MAG, the total time of "brain under protection" (neuroprotective agent start to reperfusion) was greater with pre-hospital than in-hospital start: 94 m (IQR 90-98) vs. 22 m. Initiating a neuroprotective agent in the pre-hospital setting enables a faster treatment start, yielding 72 min additional brain protection time for patients with acute ischemic stroke. These findings provide support for the increased performance of ambulance-based, pre-hospital treatment trials in the development of neuroprotective stroke therapies.