WARRIORS Trial and Registry

Design

WARRIORS (Women's Aneurysm Research: Repair Immediately Or Routine Surveillance) is an international, multicenter, open label, superiority RCT, randomly allocating consenting with small abdominal aortic aneirysm (AAA), morphologically eligible for endovascular repair (EVAR), in a 1:1 ratio to either early AAA repair by EVAR or to routine ultrasonographic surveillance. It will have a Vanguard phase with adjudicated endpoints. Each participant will be followed up for 5-years.

It is planned that the UK will provide13.5%of total target recruitment. The remaining patients will be recruited in mainland Europe (32.5% North America and Australasia (4.5%)

The trial will start with an international Vanguard phase of 250 patients,, to optimise and confirm randomization rates and patient safety (operative mortality rate) and ensure inclusivity of underserved groups. In both the UK and other countries, the Vanguard phase is scheduled to start in April 2025. Women will be recruited over 12 months during which period there will be an ongoing programme of qualitative research to optimise recruitment and ensure representation of minority and underserved groups. The Vanguard trial will run for a further 6 months, to allow completion of interventions and post-operative follow up and analysis of the results. The international Vanguard trial is scheduled to run for one year following the opening of >25% of target sites per participating country to assess and feasibility (recruitment) and safety (operative mortality, aneurysm exclusion and complications). support recruitment rates. The Vanguard phase should be completed within the first 30- months of the trial and include a total of 250 women (including 50 from the UK) and with total accrual of 35 patients/month between months 6-12. The qualitative work to optimise recruitment will use the Quintet Recruitment Intervention (QRI) [12], to identify recruitment obstacles and facilitate improvements to the recruitment process, and the SEAR framework [13], to capture ethnic and diversity characteristics and highlight any discrepancies in the recruitment process, which may negatively impact underserved groups participating (details given below). If only 150-249 have been recruited, improvement measures/additional centres will be introduced to achieve the target accrual of 35/month, with re-evaluation (after a further 6 months). Remedial measures could include visiting and motivating centers, implementation of actions arising from the qualitative work (including improving patient-facing material), running focus groups with those identifying patients including vascular nurses and sonographers, the opening of reserve sites, and an incentive programme (e.g. rewards for recruiting every 50th or 1100th woman). If <150 patients have been randomised and current monthly recruitment is <35/month for months 10-12, the trial should be stopped.

The results of the Vanguard trial should enable the Data Monitoring and Ethical Committee (DMEC) to set stopping rules for the rest of the trial, based on operative mortality and major complications. In the Vanguard phase, we propose that 30-day mortality for early elective EVAR group should not exceed 3%, but this will need the agreement of the DMEC.