Objective: The evaluation of peripheral vascular disease in the primary care setting is routinely performed by contrast-enhanced magnetic resonance angiography (CE-MRA) and digital subtraction angiography (DSA). However, limited data are available on the relative costs and clinical outcomes following these diagnostic procedures. The objective of this study is to assess and compare costs associated with diagnostic imaging in peripheral vascular occlusive disease (PAOD).
Methods: US veterans (n = 19,209) with CE-MRA or DSA for the assessment of PAOD from fiscal year (FY) 1999 to FY 2004. Main outcome measure(s) using the Department of Veterans Affairs' (VA) costing algorithms, cost, and log-cost of interventions (e.g., revascularization, stent, angioplasty), amputations or mortality rates within 30/90 days and 1 year of DSA or CE-MRA were compared, and adjusted for patient characteristics and disease severity using multivariate regression. Imaging modality selection bias was evaluated with propensity score, instrumental variables, and Heckman methods using untransformed costs and log-costs with smearing retransformation.
Results: Initial CE-MRA imaging was significantly more likely among patients with prior renal disease or bypass surgery [odds ratio (OR) > 2; P < 0.001], and less likely among patients with prior amputation, peripheral vascular disease (PVD), claudication, or other cardiovascular disease (OR < 0.7; P < 0.001). After adjusting for endogenous choice of initial imaging modality, 30-day treatment costs were US$3500-$4300 lower (P < 0.001) for patients with initial CE-MRA. Eighty-two percent of DSA imaging patients had no additional procedures or events within 30 days, and 65% at 90 days. Less than 3.2% (3.6%) of patients had any repeat imaging within 30 (90) days of initial imaging.
Conclusions: Relative to DSA, CE-MRA imaging was associated with substantial treatment episode savings, beyond the US$950 direct savings in imaging cost per procedure. Substituting CE-MRA for DSA among those not planning or requiring any follow-up procedures within 30 days, could have reduced outpatient imaging costs by up to 55%, and reduced VA system costs by US$13.2 million over the six-year period.