Pretreatment imaging workup for patients with intermittent claudication: A cost-effectiveness analysis

PURPOSE: To determine the optimal imaging strategy in pretreatment workup of patients with intermittent claudication with use of noninvasive imaging modalities and intraarterial digital subtraction angiography (DSA). MATERIALS AND METHODS: A decision-analytic model that considered test characteristics such as sensitivity, complications induced by the test, implications of missing lesions, and the consequences of overtreating patients, was developed to evaluate the societal cost-effectiveness (CE) of magnetic resonance (MR) angiography, duplex ultrasonography (US), and DSA. Our main outcome measures were quality-adjusted life years (QALYs), lifetime costs (in dollars), and incremental CE ratios. The base-case analysis considered a cohort of 60-year old male patients without a history of coronary artery disease who presented with severe claudication to undergo pretreatment imaging workup. RESULTS: The range in effectiveness and lifetime costs among different diagnostic workup strategies was small (largest difference in effectiveness: 0.025 QALYs; largest difference in lifetime costs: $1,800). If treatment was limited to angioplasty in patients with suitable lesions, MR angiography had an incremental CE ratio of $35,000 per QALY compared with no diagnostic workup, and DSA had an incremental CE ratio of $471,000 per QALY compared with MR angiography. If treatment options included both angioplasty and bypass surgery, DSA had an incremental CE ratio of $179,000 per QALY compared with no diagnostic workup, and MR angiography and duplex US were less effective and more costly. CONCLUSIONS: The differences in costs and effectiveness among diagnostic imaging strategies for patients with intermittent claudication are slight and MR angiography or duplex US can replace DSA without substantial loss in effectiveness and with a slight cost reduction.