Computed Tomography Is More Cost-Effective Than Empiric Angiography in the Outpatient Evaluation of Chronic Limb-Threatening Ischemia

Abstract

INTRODUCTION: Vascular surgeons must frequently decide whether to perform invasive diagnostic angiography empirically or to first obtain noninvasive axial imaging such as computed tomographic angiography (CTA), when evaluating chronic limb-threatening ischemia (CLTI). However, there is a paucity of evidence guiding clinicians in this decision-making process between empiric conventional angiography and CTA, particularly from a cost-effectiveness perspective. METHODS: A Markov state-transition microsimulation model was constructed to compare empiric angiogram vs CTA-guided evaluation of CLTI patients. Parameters for mortality rates and clinical events were estimated using institutional data. Quality-of-life utility measures and healthcare system perspective costs were modelled using prior literature. Probabilistic sensitivity analysis (PSA) and one-way sensitivity analyses were performed using widely accepted parameter distributions. Costs and incremental cost-effectiveness ratios (ICERs) are reported in 2020 USD. RESULTS: The CTA-first strategy was more cost-effective than the empiric angiogram strategy in 54.9% of PSA simulations (Figure), at a willingness-to-pay (WTP) threshold of $150,000 per quality-adjusted life-year (QALY), with a representative ICER of $30,058/QALY. The CTA-first strategy was more often more cost-effective at all WTP thresholds. In one-way sensitivity analyses, empiric angiography became more cost-effective when reinterventions were more commonly endovascular, at lower angiographic costs and complication rates, and at higher surgical costs. The empiric CTA strategy demonstrated higher effectiveness than angiography with comparable costs. CONCLUSION: Empiric CT angiography appears more cost-effective than empiric angiogram in the outpatient evaluation of CLTI across a wide range of contemporary estimates for costs and effectiveness. Empiric CTA should be performed prior to angiography even in resource-constrained environments.Figure