Pre-hospital stroke scales detect anterior circulation large vessel occlusion (aLVO) with acceptable-to-good accuracy, according to PRESTO, a large prospective observational study, the results of which were published in January 2021 in the Lancet.
PRESTO compared eight different pre-hospital stroke scales which were developed to identify patients that are likely to have aLVO and thus could allow for direct transportation of thrombectomy-eligible patients to an endovascular-capable centre without delaying intravenous treatment for other patients.
The findings, which were published in the Lancet by Martijne Duvekot (Albert Schweitzer Hospital, Dordrecht and Erasmus MC, Rotterdam, Netherlands) et al, showed that RACE, G-FAST, and CG-FAST are the best performing pre-hospital stroke scales out of the eight tested, and approach the performance of the clinician-assessed National Institutes of Health Stroke Scale (NIHSS).
Speaking to NeuroNews, Martijne Duvekot states: “To improve clinical outcomes of patients with ischaemic stroke due to large vessel occlusion, it is important to consider tailored regional implementation of transportation strategies.
“The PRESTO study provides reliable knowledge about the performance of pre-hospital stroke scales, as PRESTO was performed in a large, unselected cohort of suspected stroke patients that were transported in the ambulance.
“Health care professionals and policy makers can use the information generated by PRESTO to decide on the optimal pre-hospital stroke scale and threshold to customise pre-hospital triage in their region.”
Due to the time-sensitive effect of endovascular treatment, rapid pre-hospital identification of aLVO in individuals with suspected stroke is essential, especially as inter-hospital transfers are an important cause of delay of endovascular treatment.
The multicentre, prospective, observational cohort study included adults with suspected stroke who were transported by ambulance to one of eight hospitals in southwest Netherlands. Suspected stroke was defined by a positive Face-Arm-Speech-Time (FAST) test. Individuals with blood glucose of at least 2.5 mmol/L were included, while those who presented more than six hours after symptom onset were excluded from the analysis.
After structured training, paramedics used a mobile app to assess items from eight pre-hospital stroke scales: Rapid Arterial oCclusion Evaluation (RACE), Los Angeles Motor Scale (LAMS), Cincinnati Stroke Triage Assessment Tool (C-STAT), Gaze-Face-Arm-Speech-Time (G-FAST), Prehospital Acute Stroke Severity (PASS), Cincinnati Prehospital Stroke Scale (CPSS), Conveniently-Grasped Field Assessment Stroke Triage (CG-FAST), and the FAST-PLUS (Face-Arm-Speech-Time plus severe arm or leg motor deficit) test.
The primary outcome was the clinical diagnosis of ischaemic stroke with a proximal intracranial LVO in the anterior circulation (aLVO) on CT angiography. Baseline neuroimaging was centrally assessed by neuroradiologists to validate the true occlusion status. Pre-hospital stroke scale performance was expressed as the area under the receiver operating characteristic curve (AUC) and was compared with NIHSS scores assessed by clinicians at the emergency department.
Between August 2018, and September 2019, 1,039 people (median age 72 years) with suspected stroke were identified by paramedics, of whom 120 (12%) were diagnosed with aLVO.
Of all prehospital stroke scales, the AUC for RACE was highest (0.83, 95% CI: 0.79–0.86), followed by the AUC for G-FAST (0.80, 0.76–0.84), CG-FAST (0.80, 0.76–0.84), LAMS (0.79, 0.75–0.83), CPSS (0.79, 0.75–0.83), PASS (0.76, 0.72–0.80), C-STAT (0.75, 0.71–0.80), and FAST-PLUS (0.72, 0.67–0.76).
The NIHSS as assessed by a clinician in the emergency department did somewhat better than the pre-hospital stroke scales with an AUC of 0.86 (95% CI: 0.83–0.89).
