Cost analysis of cardiac MRI for cardiac transplant surveillance

Current heart transplant health surveillance relies on frequent cardiac catheterization with endomyocardial biopsy (cath-EMB) to detect acute rejection (AR). Cardiac magnetic resonance imaging (MRI) is an emerging diagnostic tool to detect signs of AR. Consistent with "Value MRI," we performed economic cost analysis modeling, if cardiac MRI is used for initial transplant surveillance rather than cath-EMB, while retaining the cath-EMB diagnostic "gold-standard."

With annual AR incidence of 2.5 - 5% (cath-EMB), clinical scenarios were modeled using pessimistic, realistic, and optimistic MRI positive test rate for parametric T1 and T2 mapping. Using probability theory, "expected cost" per patient and total Medicare savings per patient were calculated. Monte Carlo simulation was then performed 5000 times to estimate "per patient" cost with MRI as initial test. Longitudinal 20-year cost savings was modeled for 2 surveillance scenarios (lenient and intense), assuming 2.2% inflation rate and various discount rates.

Medicare cost savings were $689, $903, and $974 per patient (pessimistic, realistic, and optimistic MRI positivity) with confirmatory cath-EMB. Monte Carlo simulation median cost savings per patient was $795 (range $637 - $958). Inflation-adjusted, lifetime cost savings per patient (3% discount rate) ranged from $9,651 (pessimistic testing results/lenient surveillance plan) to $28,154 (optimistic/intense surveillance). Lifetime cost savings for 500 transplant recipients ranged from $4.8 million (M) (pessimistic/lenient) to $14.1M (optimistic/intense).

At even the most pessimistic MRI positive test rate, modeling suggests substantial Medicare cost savings when using MRI parametric mapping as surveillance for AR. Longitudinal cost savings are notable too.