3 A High Los Angeles Motor Scale Score is an Effective Tool for Triaging Stroke Patients in the Out-of-Hospital Setting

Abstract

To evaluate the ability of the Los Angeles Motor Scale (LAMS) score in identifying large vessel occlusions (LVOs) in the field, and correlating the score to hospital interventions for acute stroke. This Institutional Review Board (IRB)-approved prospective study included all patients (n=2464) transported for stroke by our county Emergency Medical Services (EMS) system from January 2016-March 2019 to one of our eight receiving hospitals. Paramedics administered the LAMS prior to hospital arrival. Our EMS system has agreements with our receiving hospitals to provide hospital discharge outcomes on all patients transported to a given facility for stroke, including NIHSS at hospital arrival and discharge, hospital length of stay, and the ultimate disposition of the patient. For the purposes of this study, patients were split into two groups: high LAMS (4-5), or low LAMS (0-3). Statistical analysis was performed using JMP Pro 14 for Windows. The median age was 71.5, with an interquartile range (IQR) of 60-81 and a range of 13-108. Our cohort was 52% female. The median scene time was 15 minutes, with an IQR of 12-19 minutes and a range of 1-74 minutes. The LAMS score breakdown (n=2206) was as follows:LAMS 0: 19%LAMS 1: 14%LAMS 2: 13%LAMS 3: 17%LAMS 4: 16%LAMS 5: 21% For the patients which there was data, 40% received computed tomography (CT) perfusion imaging, 12% received tissue plasminogen activator (tPA), and 14% received mechanical intervention. 10% of strokes were hemorrhagic, 45% were ischemic, and 10% were transient ischemic attacks (TIA). The median National Institute of Health Stroke Scale (NIHSS) at hospital arrival was 6, with an IQR of 2-13 and a range of 0-40. 49% of patients were discharged home, 19% were sent to a skilled nursing facility, 13% were discharged to rehab, and 7% expired. Table 1 summarizes the relative risk of various outcomes associated with a high LAMS score.Table 1Relative risk of outcomes associated with LAMS of 4-5.Relative Risk (95% CI)p-valueMechanical Intervention3.61 (2.67-4.87)<.0001In-hospital death3.15 (2.21-4.52)<.0001CT perfusion imaging2.11 (1.84-2.41)<.0001Receiving tPA2.07 (1.64-2.62)<.0001Ischemic stroke1.45 (1.32-1.60)<.0001Not being discharged home1.36 (1.24-1.49)<.0001 Open table in a new tab The median NIHSS for low LAMS was 4 (IQR 1-8), whereas for high LAMS it was 13 (IQR 7-21). Using Wilcoxon’s rank-sum test, the high LAMS group had a significantly higher NIHSS (p < .0001). The median hospital length of stay for low LAMS was 3 (IQR 1-5), whereas for high LAMS it was 5 (IQR 2-9). Using Wilcoxon’s rank-sum test, the high LAMS group had a significantly longer hospital stay (p < .0001). There was no significant association between LAMS score and age, sex, or EMS Rankin score. The LAMS is a powerful out-of-hospital tool for prediction of intervention and neurological outcomes after acute stroke.