The aim of this review is to supplement Evidence review K, which assesses the comparative safety and effectiveness of endovascular aneurysm repair (EVAR) and open surgical repair (OSR) for the treatment of unruptured abdominal aortic aneurysms (AAAs).

While Evidence review K was confined to randomised evidence addressing this question, this additional review identifies, appraises and synthesises evidence from published observational studies that attempt to estimate the relative benefits and harms of EVAR and OSR while accounting for imbalances in potentially confounding factors. The particular focus of the review is to investigate the proposition that, as the RCTs recruited participants up to 20 years ago, the balance of benefits and harms has become more favourable to EVAR in more recent practice.

Details of the committee’s consideration of this evidence in conjunction with the original review of randomised trials can be found in Evidence review K.