Design and rationale of the RISC-Trial: Multicenter R CT to assess I mmediate discharge of S yncope patients admitted to the ( C ardiac) emergency room

Abstract Background Syncope is responsible for 1-3% of emergency department presentations. The European Society of Cardiology guidelines on syncope recommend a structured initial evaluation to diagnose syncope patients. If the cause for the syncopal event remains unexplained, risk-stratification is applied to distinguish between patients at high-risk of serious cardiovascular events and low-risk patients, who can be safely discharged. However, there is a group of patients in whom this risk can currently not be adequately determined, hereafter called intermediate-risk. In clinical practice, these patients are either immediately discharged or admitted for 24-hour in-hospital cardiac rhythm-monitoring. Due to the high cost of admission, immediate discharge could lower healthcare-costs, hospital bed utilization and patient burden. To our knowledge, there is not sufficient scientific basis for superiority of either. The RISC-trial aims to resolve this knowledge gap. Study Design The RISC-trial is an investigator-initiated multicenter prospective randomized controlled trial. A total of 640 pre-defined low- and intermediate-risk syncope patients are randomized to either immediate discharge or discharge after 24-hour in-hospital rhythm monitoring (1:1). The trial is powered to claim non-inferiority of immediate discharge with respect to (non-)fatal composite safety-endpoints which entail arrhythmic disorders, syncope recurrence and (cardiovascular)death. Furthermore, healthcare-costs and quality-of-life will be evaluated. Conclusion The RISC-trial is a multicenter RCT that aims to gather scientific evidence for immediate discharge of ESC-guideline based pre-defined low- and intermediate-risk syncope patients in the emergency department. Primary endpoints entail cardiovascular events such as arrhythmias, syncope and death. This trial is registered at ClinicalTrials.gov with trial-ID: NCT06472375.