Henry Zhao1,2, Karen Smith1,3,4, Stephen Bernard1,4, Michael Stephenson2, Henry Ma5, Ronil V Chandra5, Thanh Phan5, Christopher F Bladin2,6, Leonid Churilov1,7, Douglas Crompton8, Helen M Dewey6, Tissa Wijeratne9, Geoffrey Cloud10, Vincent Thijs11, Timothy J Kleinig12, Jo Lyn Ng1, Cameron Williams1, Fana Alemseged1, Felix Ng1,8,2,11, Peter J Mitchell1,13, Mark W Parsons1, Nawaf Yassi1,2,4,14, Stephen M Davis1, Bruce C V Campbell1,2. 1. Departments of Medicine and Neurology, Melbourne Brain Centre at The Royal Melbourne Hospital (H.Z., L.C., J.L.N., C.W., F.A., F.N., P.J.M., M.W.P., N.Y., S.M.D., B.C.V.C.), University of Melbourne, Australia. 2. Ambulance Victoria, Melbourne, Australia (H.Z., K.S., S.B., M.S., C.F.B., F.N., N.Y., B.C.V.C.). 3. Department of Epidemiology and Preventive Medicine, Department of Community Emergency Health and Paramedic Practice (K.S.), Monash University, Melbourne, Australia. 4. Discipline of Emergency Medicine, University of Western Australia (K.S., S.B.). 5. Monash Health and Department of Medicine, School of Clinical Science (H.M., R.V.C., T.P.), Monash University, Melbourne, Australia. 6. Department of Neurology, Eastern Health and Eastern Health Clinical School, Faculty of Medicine, Nursing and Health Sciences (C.F.B., H.M.D.), Monash University, Melbourne, Australia. 7. Department of Medicine, Austin Health, Melbourne Medical School (L.C.), University of Melbourne, Australia. 8. Department of Neurology, Northern Health, Faculty of Medicine, Dentistry and Health Sciences (D.C., F.N.), University of Melbourne, Australia. 9. Department of Neurology, Western Health, Faculty of Medicine, Dentistry and Health Sciences (T.W.), University of Melbourne, Australia. 10. Department of Neurology, Alfred Health, Department of Clinical Neurosciences, Central Clinical School (G.C.), Monash University, Melbourne, Australia. 11. Department of Neurology, Austin Health, Australia (V.T., F.N.). 12. Department of Neurology, Royal Adelaide Hospital, Australia (T.J.K.). 13. Department of Radiology, Royal Melbourne Hospital (P.J.M.), University of Melbourne, Australia. 14. Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia (N.Y.).
Abstract
BACKGROUND AND PURPOSE: Severity-based assessment tools may assist in prehospital triage of patients to comprehensive stroke centers (CSCs) for endovascular thrombectomy (EVT), but criticisms regarding diagnostic inaccuracy have not been adequately addressed. This study aimed to quantify the benefits and disadvantages of severity-based triage in a large real-world paramedic validation of the Ambulance Clinical Triage for Acute Stroke Treatment (ACT-FAST) algorithm. METHODS: Ambulance Victoria paramedics assessed the prehospital ACT-FAST algorithm in patients with suspected stroke from November 2017 to July 2019 following an 8-minute training video. All patients were transported to the nearest stroke center as per current guidelines. ACT-FAST diagnostic accuracy was compared with hospital imaging for the presence of large vessel occlusion (LVO) and need for CSC-level care (LVO, intracranial hemorrhage, and tumor). Patient-level time saving to EVT was modeled using a validated Google Maps algorithm. Disadvantages of CSC bypass examined potential thrombolysis delays in non-LVO infarcts, proportion of patients with false-negative EVT, and CSC overburdening. RESULTS: Of 517 prehospital assessments, 168/517 (32.5%) were ACT-FAST positive and 132/517 (25.5%) had LVO. ACT-FAST sensitivity and specificity for LVO was 75.8% and 81.8%, respectively. Positive predictive value was 58.8% for LVO and 80.0% when intracranial hemorrhage and tumor (CSC-level care) were included. Within the metropolitan region, 29/55 (52.7%) of ACT-FAST-positive patients requiring EVT underwent a secondary interhospital transfer. Prehospital bypass with avoidance of secondary transfers was modeled to save 52 minutes (95% CI, 40.0-61.5) to EVT commencement. ACT-FAST was false-positive in 8 patients receiving thrombolysis (8.1% of 99 non-LVO infarcts) and false-negative in 4 patients with EVT requiring secondary transfer (5.4% of 74 EVT cases). CSC bypass was estimated to over-triage 1.1 patients-per-CSC-per-week in our region. CONCLUSIONS: The overall benefits of an ACT-FAST algorithm bypass strategy in expediting EVT and avoiding secondary transfers are estimated to substantially outweigh the disadvantages of potentially delayed thrombolysis and over-triage, with only a small proportion of EVT patients missed.
BACKGROUND AND PURPOSE: Severity-based assessment tools may assist in prehospital triage of patients to comprehensive stroke centers (CSCs) for endovascular thrombectomy (EVT), but criticisms regarding diagnostic inaccuracy have not been adequately addressed. This study aimed to quantify the benefits and disadvantages of severity-based triage in a large real-world paramedic validation of the Ambulance Clinical Triage for Acute Stroke Treatment (ACT-FAST) algorithm. METHODS: Ambulance Victoria paramedics assessed the prehospital ACT-FAST algorithm in patients with suspected stroke from November 2017 to July 2019 following an 8-minute training video. All patients were transported to the nearest stroke center as per current guidelines. ACT-FAST diagnostic accuracy was compared with hospital imaging for the presence of large vessel occlusion (LVO) and need for CSC-level care (LVO, intracranial hemorrhage, and tumor). Patient-level time saving to EVT was modeled using a validated Google Maps algorithm. Disadvantages of CSC bypass examined potential thrombolysis delays in non-LVO infarcts, proportion of patients with false-negative EVT, and CSC overburdening. RESULTS: Of 517 prehospital assessments, 168/517 (32.5%) were ACT-FAST positive and 132/517 (25.5%) had LVO. ACT-FAST sensitivity and specificity for LVO was 75.8% and 81.8%, respectively. Positive predictive value was 58.8% for LVO and 80.0% when intracranial hemorrhage and tumor (CSC-level care) were included. Within the metropolitan region, 29/55 (52.7%) of ACT-FAST-positive patients requiring EVT underwent a secondary interhospital transfer. Prehospital bypass with avoidance of secondary transfers was modeled to save 52 minutes (95% CI, 40.0-61.5) to EVT commencement. ACT-FAST was false-positive in 8 patients receiving thrombolysis (8.1% of 99 non-LVO infarcts) and false-negative in 4 patients with EVT requiring secondary transfer (5.4% of 74 EVT cases). CSC bypass was estimated to over-triage 1.1 patients-per-CSC-per-week in our region. CONCLUSIONS: The overall benefits of an ACT-FAST algorithm bypass strategy in expediting EVT and avoiding secondary transfers are estimated to substantially outweigh the disadvantages of potentially delayed thrombolysis and over-triage, with only a small proportion of EVTpatients missed.
Authors: Lan Gao; Marj Moodie; Nawaf Yassi; Stephen M Davis; Christopher F Bladin; Karen Smith; Stephen Bernard; Michael Stephenson; Leonid Churilov; Bruce C V Campbell; Henry Zhao Journal: Front Neurol Date: 2022-05-13 Impact factor: 4.086