Is 5.5 cm Still the Optimal Size Threshold to Treat AAA in Men? A Contemporary Cost-utility Analysis

To determine the contemporary cost per quality-adjusted life year (QALY) gained for abdominal aortic aneurysm (AAA) repair in current practice and assess the optimal threshold for intervention.

The widely accepted 5.5 cm threshold for elective AAA repair in men remains largely consensus-based. However, contemporary evidence suggests that size-associated rupture risk may be lower than previously assumed, calling into question whether this threshold is cost-effective.

A Markov chain estimated the cost-utility of endovascular AAA repair (EVAR) and open surgical repair (OSR) compared with surveillance. Social Security Administration life tables informed survival, while Vascular Quality Initiative and Medicare data informed complication rates, reinterventions, and late rupture. Quality-adjusted life years (QALYs) were derived from published estimates. Two willingness-to-pay (WTP) thresholds were evaluated: $100,000/QALY (US) and $40,000/QALY (UK NICE equivalent). Given uncertainty in size-specific rupture risk, a range of annual rupture probabilities was modeled. The base-case analysis considered a 70-year-old man over a 10-year time horizon.

At a WTP threshold of $100,000/QALY, immediate EVAR became cost-effective when annual rupture risk was ≥2.2%, whereas OSR became cost-effective at ≥3.4%. At a $40,000/QALY threshold, the rupture risk thresholds were ≥5.0% for EVAR and ≥6.8% for OSR. Assuming an annual rupture risk of 0.4% (as reported in a contemporary study), the cost per QALY gained with EVAR was $1,233,000, while OSR was associated with a loss of QALYs.

The cost-effectiveness of AAA repair is highly dependent on rupture risk. Given that contemporary data suggest lower rupture rates than previously assumed, the current 5.5 cm repair threshold in men may not be optimally cost-effective from a population health perspective.