A Cost-Effectiveness Model Comparing Endovascular Repair to Open Surgical Repair of Abdominal Aortic Aneurysms in Canada

The primary risk of abdominal aortic aneurysms (AAAs) is rupture, which is associated with a high mortality rate. Elective surgical options for AAA include open repair (OR) and endovascular aneurysm repair (EVAR). EVAR is less invasive than OR, and therefore may have less surgical risk than OR. However, the graft used for EVAR is much more expensive then the graft used for OR. A decision model with a 10-year time horizon was used to assess the cost-effectiveness of EVAR versus OR. The primary outcome measure was quality-adjusted life-years (QALYs). The model incorporated the costs and benefits of both perioperative outcomes and postoperative outcomes. A systematic review was conducted to derive clinical outcome rates. Cost and utility model variables were based on various literature sources and data from a recent Canadian observational study. Parameter uncertainty was assessed using probabilistic sensitivity analysis. In the base-case model, the incremental cost per QALY of EVAR was estimated to be $268,337, whereas the incremental cost per life-year was found to be $444,129. The incremental cost per QALY of EVAR remained above $295,715 under different assumptions of cohort age and model time horizon. Based on commonly quoted willingness-to-pay thresholds, EVAR was not found to be cost-effective compared to OR.