Analysis of the differences between the European Society for Vascular Surgery 2019 and National Institute for Health and Care Excellence 2020 guidelines for abdominal aortic aneurysm

Objective The aim was to understand why two recently published guidelines for the diagnosis and management of patients with abdominal aortic aneurysm, the National Institute for Health and Care Excellence (NICE) 2020 guidelines and the European Society for Vascular Surgery (ESVS) 2019 guidelines, have discordant recommendations in several important areas. Methods A review of the approach, methodology, and evidence used by the two guideline committees was carried out to understand potential reasons for their differing recommendations in their two final published guidelines. Results NICE guidelines use a multidisciplinary committee to address a limited number of prospectively identified questions, using rigorous methods heavily reliant on evidence from randomised controlled trials (RCTs) supported by in house economic modelling, with the purpose of providing the best, cost-effective health care in the UK in 46 main recommendations. The ESVS guidelines use an expert committee to encourage clinical effectiveness across a range of European health economies. ESVS guideline topics, but not questions, are prospectively identified, assessment of evidence was less rigorous, and 125 recommendations were made. More up to date evidence searches by the ESVS committee partially underscore the differences in recommendations for screening women. The NICE committee did not consider sex specific analysis or evidence for thresholds for intervention but relied on sex specific modelling to support their advice to use endovascular repair (EVAR) for ruptures in women. Their recommendation to use open repair for ruptured abdominal aortic aneurysms (AAAs) in men aged < 71 years was based on in house economic modelling. NICE recommends an open first strategy for non-ruptured AAA mainly based on earlier RCTs and UK specific economic modelling, while the ESVS guidelines recommend an EVAR first strategy after consideration of modern, but lower quality, evidence from observational studies. Similar reasons explain differences in the recommended treatments of juxtarenal aneurysms. Conclusion Differences between the NICE and ESVS guidelines can be explained, at least in part, by their differing perspectives, methodologies, and quality assurance. Future ESVS guidelines may benefit from more multidisciplinary input and prospectively identified questions.