Intro: Recent randomized clinical trials have demonstrated the benefit of endovascular mechanical thrombectomy in acute ischemic stroke patients with Emergent Large Vessel Occlusion (ELVO). Cincinnati Prehospital Stroke Scale is widely used tool by EMS but not specifically designed to predict ELVO. Previously reported prehospital stroke scales for ELVO have been limited, and not widely used. It is imperative to establish a simple and accurate tool for EMS to predict ELVO facilitating rapid patient transport to hospitals capable of endovascular intervention.
Hypothesis: Minnesota Prehospital Stroke Scale (MPSS) can predict the presence of ELVO with high accuracy comparable to NIHSS.
Methods: The MPSS assesses five parameters: Facial weakness, Arm weakness, Leg weakness, Speech difficulty and Eye deviation, with total score ranging 0-10 (See Table). We set MPSS 6 or above and NIHSS 7 or above as a cutoff for ELVO. We retrospectively analyzed all the stroke code patients seen in ED between January 2015 and April 2015 at a primary stroke center (n=120). We selected patients arriving in less than 6 hours with prehospital stroke alert activated by EMS. Hemorrhagic stroke patients were excluded. The following data were collected: 1) Presence of ELVO, 2) Initial NIHSS in ED, and 3) MPSS abstracted from initial ER NIHSS, then assessed the results using 2x2 table for ELVO and MPSS vs. NIHSS.
Results: Of 28 patients meeting criteria, 6 (21%) had ELVO (ICA, M1/M2): Mean MPSS was 7.5, whereas mean NIHSS was 15 for ELVO patients. Mean HPSS was 1.6, whereas mean NIHSS was 5.1 for non-ELVO patients. Sensitivity 83%, specificity 100%, PPV 100%, NPV 96%, and accuracy 96% for HPSS; sensitivity 83%, specificity 77%, PPV 50%, NPV 94% and accuracy 79% for NIHSS.
Conclusion: MPSS may be a useful tool for predicting ELVO. Further studies are necessary to validate the efficacy of the scale.