The Los Angeles Motor Scale as a predictor of angiographically determined large vessel occlusion


Recent advances in time-sensitive mechanical thrombectomy for the treatment of emergent large vessel occlusion (ELVO) have changed the role of prehospital providers from simply identifying a stroke to identifying the likely presence of ELVO. No one method for identifying ELVO in the field has been demonstrated to be superior. We sought to describe how this might be best accomplished using the Los Angeles Motor Scale (LAMS) in concert with other physical exam findings by paramedics and emergency medical technicians (EMTs). We had paramedics and EMTs examine patients with suspected stroke in the hospital. We compared their exams to the standard neurologist exams and to the results of angiography. We performed multiple analyses to identify the exam elements that would best identify large vessel occlusions. Using LAMS with a threshold score of 4, sensitivity for stroke and ELVO, respectively, was 27% (95% CI 20–36%) and 42% (95% CI 30–55%). When a LAMS of 3 was used in concert with speech abnormality, sensitivity improved to 36% (95% CI 28–45%) and 61% (95% CI 48–73%). Specificity of this model was 70%, (95% CI 64–75%). Most striking was the negative predictive value of this model for ELVO: 90% (95% CI 85–93%) The LAMS or LAMS plus speech can be used to decrease the number of missed large vessel occlusions and to route suspected large vessel occlusions to thrombectomy-capable centers. Other, more complicated scales may have little additional benefit. This derivation data set is the first to use paramedics and EMTs as examiners prospectively and supports prehospital protocol change underway in New York City.

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  1. 1.

    Hacein-Bey L, Heit JJ, Konstas AA (2018) Neuro-interventional management of acute ischemic stroke. Neuroimag Clin N Am 28:625–638

  2. 2.

    Saver JL (2005) Time is brain—quantified. Stroke 37:263–326

  3. 3.

    Brandler ES, Sharma M, Sinert RH, Levine SR (2014) Prehospital stroke scales in urban environments: a systematic review. Neurology 82(24):2241–2249

  4. 4.

    Smith EE, Kent DM, Bulsara KR, Leung LY, Lichtman JH, Reeves MJ, Towfighi A, Whiteley WN, Zahuranec DB, American Heart Association Stroke Council (2018) Accuracy of prediction instruments for diagnosing large vessel occlusion in individuals with suspected stroke: a systematic review for the 2018 guidelines for the early management of patients with acute ischemic stroke. Stroke 49:e111–e122

  5. 5.

    Pérez de la Ossa N, Carrera D, Gorchs M, Querol M, Millán M, Gomis M, Dorado L, López-Cancio E, Hernández-Pérez M, Chicharro V, Escalada X, Jiménez X, Dávalos A (2014) Design and validation of a prehospital stroke scale to predict large arterial occlusion, the Rapid Arterial Occlusion Evaluation Scale. Stroke 45:87–91

  6. 6.

    Carrera D, Gorchs M, Querol M, Abilleira S, Ribó M, Millán M, Ramos A, Cardona P, Urra X, Rodríguez-Campello A, Prats-Sánchez L, Purroy F, Serena J, Cánovas D, Zaragoza-Brunet J, Krupinski JA, Ustrell X, Saura J, García S, Mora MÀ, Jiménez X, Dávalos A, Pérez de la Ossa N, Catalan Stroke Code, and Reperfusion Consortium (Cat-SCR) (2019) Revalidation of the RACE scale after its regional implementation in Catalonia: a triage tool for large vessel occlusion. J NeuroIntervent Surg 11:751–756

  7. 7.

    Lima FO, Silva GS, Furie KL, Frankel MR, Lev MH, Camargo ÉC, Haussen DC, Singhal AB, Koroshetz WJ, Smith WS, Nogueira RG (2016) Field assessment stroke triage for emergency destination: a simple and accurate prehospital scale to detect large vessel occlusion strokes. Stroke 47:1997–2002

  8. 8.

    Llanes JN, Kidwell CS, Starkman S, Leary MC, Eckstein M, Saver JL (2004) The Los Angeles Motor Scale (LAMS): a new measure to characterize stroke severity in the field. Prehosp Emerg Care 8:46–50

  9. 9.

    Naziel B, Starkman S, Liebeskind DS, Ovbiagele B, Kim D, Sanossian N, Ali L, Buck B, Villablanca P, Vinuela F, Duckwiler G, Jahan R, Saver JL (2008) A brief prehospital stroke severity scale identifies ischemic stroke patients harboring persisting large arterial occlusions. Stroke 39:2264–2267

  10. 10.

    Smith WS, Lev MH, English JD, Camargo EC, Chou M, Johnston SC, Gonzalez G, Schaefer PW, Dillon WP, Koroshetz WJ, Furie KL (2009) Significance of large vessel intracranial occlusion causing acute ischemic stroke and TIA. Stroke 40:3834–3840

  11. 11.

    Dickson RL, Crowe RP, Patrick C, Crocker K, Aiken M, Adams A, Gleisberg GR, Nichols T, Mason C, Panchal AR (2019) Performance of the RACE Score for the prehospital identification of large vessel occlusion stroke in a suburban/rural EMS service. Prehosp Emerg Care.

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Correspondence to Ethan Samuel Brandler.

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Brandler, E.S., Thode, H. & Fiorella, D. The Los Angeles Motor Scale as a predictor of angiographically determined large vessel occlusion. Intern Emerg Med (2020) doi:10.1007/s11739-019-02272-4

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  • Stroke
  • Prehospital
  • Diagnosis
  • Large vessel occlusion