BACKGROUND: Aortic valve stenosis (AVS) represents the most prevalent primary valvular lesion necessitating surgical intervention or transcatheter intervention in Europe and North America. Its prevalence is increasing at a rapid rate as a consequence of the ageing population. A variety of mechanical interventions are available to determine the management of AVS; however, there is currently a paucity of robust data with which to perform a comparative analysis of the efficacy of surgical aortic valve replacement (SAVR) and that of conventional stented xenograft bioprostheses (BP) or sutureless aortic valves (SAV) and transcatheter aortic valve implantation (TAVI). The present study aims to compare the effectiveness and clinical outcomes of SAVR using BP or SAV technique and TAVI in patients with severe AVS. METHODS AND ANALYSIS: A collaboration between three cardiac surgery centres across two European countries has resulted in the conception of the Transcatheter Aortic Valve Implantation vs Surgical Aortic Valve Replacement trial. This prospective non-randomised trial is designed to evaluate the long-term outcomes of TAVI in comparison to SAVR for AVS in patients at risk of severe valve obstruction. The registry will enrol successive patients who have undergone mechanical intervention for AVS between January 2015 and December 2025. Investigators will assess the difference between replacement procedures for both the standard surgical approach and the transcatheter procedure. The principal clinical outcome under consideration will be the composite degree of all-cause mortality, ischaemic stroke or rehospitalisation at 10 years. The present study will also have a number of secondary endpoints, including all-cause mortality, followed by functional status, hospitalisation, neurocognition, physiological measures (echocardiographic assessment), adverse events and reoperation. ETHICS AND DISSEMINATION: It is hypothesised that the nature of the trials will serve to minimise bias related to institutional volume and surgical experience. Each participating centre is required to have an aortic valve programme that enables proper follow-up and management of any late aortic events following replacement surgery for the AVS. The data collected will provide valuable insight into the comparative effectiveness of various surgical approaches, both standardised and advanced, in aortic valve surgery and TAVI. This comprehensive analysis will contribute significantly to the development of robust international guidelines. TRIAL REGISTRATION NUMBER: Clinical Trial Gov.Com. ID: NCT05261204 IRB. ID: 2022011057.