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Prehospital identification of acute ischaemic stroke with large vessel occlusion: a retrospective study from western

Nedim Leto1,2, Conrad Arnfinn Bjørshol3,2, Martin Kurz2,4

  • 1The Regional Centre for Emergency Medical Research Western Norway, Stavanger University Hospital, Stavanger, Norway nedim.leto@sus.no.

Emergency Medicine Journal : EMJ
|November 15, 2023
PubMed

Insights

The G-FAST criteria, used by emergency medical services to detect acute ischemic stroke with large vessel occlusion, showed low sensitivity for direct transfer to a comprehensive stroke center. This indicates G-FAST is not currently suitable for selecting LVO patients for direct transfer.

Area of Science:

  • Neurology
  • Emergency Medicine
  • Radiology

Background:

  • Emergency medical services (EMS) in western Norway implemented the G-FAST (Gaze deviation, Facial palsy, Arm weakness, Visual loss, Speech disturbance) criteria to identify acute ischemic stroke (AIS) with large vessel occlusion (LVO).
  • The G-FAST criteria allow for bypassing primary stroke centers (PSCs) for direct transfer to comprehensive stroke centers (CSCs) for rapid endovascular treatment (EVT) evaluation in patients with gaze deviation and at least one other symptom.
  • The study aimed to evaluate the effectiveness of G-FAST criteria in selecting LVO patients for direct CSC transfer.

Purpose of the Study:

  • To investigate the efficacy of the G-FAST criteria for selecting patients with large vessel occlusion (LVO) stroke for direct transfer to a comprehensive stroke center (CSC).
  • To determine the sensitivity and specificity of the G-FAST criteria in identifying LVO patients eligible for direct transfer.

Main Methods:

  • A retrospective study analyzed data from emergency medical communication center (EMCC) dispatches and EMS records between August and December 2020.
  • Patients with at least one G-FAST symptom at EMS arrival were included, with stroke suspicion defined by these criteria.
  • Test characteristics of gaze deviation plus one other G-FAST symptom for LVO detection were calculated.

Main Results:

  • Out of 643 patients, 59 had LVO. Only seven patients met G-FAST criteria for direct CSC transfer, yielding a sensitivity of 12% (95% CI 5%–23%).
  • The specificity was high at 99.66% (95% CI 98.77%–99.96%), with a positive predictive value of 78% and negative predictive value of 92%.
  • Endovascular treatment (EVT) was administered to 64% of LVO cases, with a median time of 163 minutes from PSC arrival to EVT start at a CSC.

Conclusions:

  • The G-FAST prehospital criteria, as implemented by EMS, are not suitable for selecting patients with acute ischemic stroke and large vessel occlusion for direct transfer to a comprehensive stroke center.
  • The low sensitivity indicates that the G-FAST criteria miss a significant proportion of LVO patients who could benefit from direct transfer and rapid EVT.
Abstract

Keywords:
emergency ambulance systemspre-hospital carestroke

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