WARRIORS is an international multicentre, open label, superiority RCT, randomly allocating consenting women with small AAA, morphologically suitable for EVAR in a 1:1 ratio to either early EVAR or routine ultrasonographic surveillance. This will be an international trial anchored in the UK, where there will be 15-18 recruiting sites, each aiming to randomise 10 patients. The trial is led by Colin Bicknell at Imperial College London. The named UK collaborators are Olivia McBride (Dundee), Rachel Bell (Newcastle), Matthew Bown and Rachel Evley (Leicester), Ian Loftus and Manuel Gomes from London (St George’s Hospital and University College London respectively). There will be a further ~100 recruiting sites from across the world, including North America, Europe and Australasia. This application seeks funding to allow 4 Irish vascular surgery centres to participate. In line with the UK centres, each Irish centre will aim to randomise 10 patients. In total the trial plans to randomise 1112 women in 1:1 ratio of either early EVAR or routine surveillance with delayed repair for either AAA rupture or reaching the threshold diameter of >5.4 cm. There will be a Vanguard phase, enrolling 250 patients internationally, of 250 patients to confirm both the feasibility of recruitment, and that the safety of the policy of early EVAR is within the range reported by observational studies from the USA. The primary composite outcome of aneurysm-related mortality and aneurysm rupture will be assessed by an independent outcome adjudication committee 5 years after randomisation. Secondary outcomes include QALYs and all-cause mortality at 5 years. Additional endpoints include operative mortality, anxiety, costs, cost-effectiveness, loss of eligibility for EVAR at the 5.5 cm diameter threshold and major adverse cardiovascular events (MACE), comprising myocardial infarction, stroke and lower limb amputation.
