Abstract
BackgroundPrehospital stroke trials will inevitably recruit patients with non-stroke conditions, so called stroke mimics. We undertook a pre-specified analysis to determine outcomes in patients with mimics in the second Rapid Intervention with Glyceryl trinitrate in Hypertensive stroke Trial (RIGHT-2).MethodsRIGHT-2 was a prospective, multicentre, paramedic-delivered, ambulance-based, sham-controlled, participant-and outcome-blinded, randomised-controlled trial of transdermal glyceryl trinitrate (GTN) in adults with ultra-acute presumed stroke in the UK. Final diagnosis (intracerebral haemorrhage, ischaemic stroke, transient ischaemic attack, mimic) was determined by the hospital investigator. This pre-specified subgroup analysis assessed the safety and efficacy of transdermal GTN (5 mg daily for 4 days) versus sham patch among stroke mimic patients. The primary outcome was the 7-level modified Rankin Scale (mRS) at 90 days.ResultsAmong 1149 participants in RIGHT-2, 297 (26%) had a final diagnosis of mimic (GTN 134, sham 163). The mimic group were younger, mean age 67 (SD: 18) vs 75 (SD: 13) years, had a longer interval from symptom onset to randomisation, median 75 [95% CI: 47,126] vs 70 [95% CI:45,108] minutes, less atrial fibrillation and a lower systolic blood pressure and Face-Arm-Speech-Time tool score than the stroke group. The three most common mimic diagnoses were seizure (17%), migraine or primary headache disorder (17%) and functional disorders (14%). At 90 days, the GTN group had a better mRS score as compared to the sham group (adjusted common odds ratio 0.54; 95% confidence intervals 0.34, 0.85; p = 0.008), a difference that persisted at 365 days. There was no difference in the proportion of patients who died in hospital, were discharged to a residential care facility, or suffered a serious adverse event.ConclusionsOne-quarter of patients suspected by paramedics to have an ultra-acute stroke were subsequently diagnosed with a non-stroke condition. GTN was associated with unexplained improved functional outcome observed at 90 days and one year, a finding that may represent an undetected baseline imbalance, chance, or real efficacy. GTN was not associated with harm.Trial registrationThis trial is registered with International Standard Randomised Controlled Trials Number ISRCTN 26986053.
Highlights
Prehospital stroke trials will inevitably recruit patients with non-stroke conditions, so called stroke mimics
One-quarter of patients suspected by paramedics to have an ultra-acute stroke were subsequently diagnosed with a non-stroke condition
Summary of results and comparison with other studies In our further analysis of the RIGHT-2 study, we found that 26% of the 1149 cases suspected by paramedics to be a stroke had a non-stroke final diagnosis
Summary
Prehospital stroke trials will inevitably recruit patients with non-stroke conditions, so called stroke mimics. Stroke can be difficult to diagnose in the prehospital setting as there is no perfect or readily available diagnostic test. Conditions such as seizures, migraine and functional disorders can present with symptoms suggestive of a stroke, use of the term ‘stroke mimics’ [3]. Numerous factors have been reported to be associated with a greater probability of an event being a mimic rather than stroke, including younger age, female sex, fewer vascular risk factors, history of seizures and less severe presenting symptoms including a lower likelihood of facial or limb weakness, speech difficulty or acute hypertension [5, 6]. As it is limited to examining the patient for facial palsy, altered motor functioning of the arm and abnormal speech, FAST is less likely to identify mild or severe strokes and those affecting only the posterior circulation [8, 9]
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