Economic evaluation. Comparative cost-effectiveness analyses of cardiac magnetic resonance imaging (CMR) and coronary angiography (CXA) combined with fractional flow reserve (FFR) test.
Comparative cost-effectiveness analyses of cardiac magnetic resonance imaging (CMR) andcoronary angiography (CXA) combined with fractional flow reserve (FFR) test K. Moschetti, D. Favre, C. Pinget, JB. Wasserfallen, J. Schwitter
The burden of coronary artery Distribution of deaths worlwide, WHO, 2011disease (CAD)Mortality burdenCardiovascular diseases are the most important killerof people Cardiovascular diseases 30% with 15% for CADThey are predicted to remain so for the next 20 yearsThe CAD with stroke are the most frequentIn Europe, the CAD accounts for between 15% and25% of all deathsHigh Cost burdenCAD is a leading cause of morbidity and loss of quality of lifeSince CAD is frequent, deadly and treatable, it is crucial to detect it (the myocardialischemia) prior to a heart attack
The coronary angiography test (CXA) and the fractionalflow reserve (FFR) measurement An X-ray machine is used to detect occlusions revealed by the dye. Performed during the CXA, the FFR - a guide wire-based procedure - measures blood pressure and detect myocardial ischemia
The Perfusion cardiac magneticresonance (P-CMR)- robust technique with high sensitivity and specificity- validated against other imaging modalities (SPECT, CT etc…)- increasingly used to test for inducible myocardial ischemia (a lack of blood flow)P-CMR can detect occlusions and flow-limiting CAD - as defined by the CXA + FFR
The Perfusion cardiac The CXA combinedmagnetic resonance with the FFR(P-CMR) - allow real-time estimation of the effects of a narrowed vessel,- not invasive, - allow simultaneous treatment with- none exposure to radiations angioplasty.=> can be used multiple times ButBut Invasive with radiation exposure,- can induce claustrophobia bleeding and complications- not safe for patients with certain type ofmedical devices
ObjectiveTo compare the cost-effectiveness ratio of 2 strategies used to diagnose hemodynamically significant CAD in relation to the pretest likelihood of CAD:• Strategy 1: perfusion-CMR to assess ischemia before referring positive patients to CXA (P-CMR+CXA),• Strategy 2: a CXA in all patients combined with a FFR test in patients with angiographically positive stenoses (CXA+FFR) Positive FFR Positive CXA P-CMR CXA Negative Negative Strategy 1 : (P-CMR+CXA) Strategy 2 : (CXA+FFR)
Material and Method Use of a mathematical model that submits to the 2 strategies, hypothetical patientcohorts with different pretest likelihood of CAD – PCAD Effectiveness criterion is the ability to accurately identify a patient with significant CAD The cost-effectiveness = total costs / number of patients correctly diagnosed ashaving CAD The costs evaluated from the third-party payer perspective and include - public prices of different tests (reimbursement fees), - costs of complications, - costs induced by diagnostic errors Clinical data from published literature
Decision tree for CAD diagnosis and outcomes for the 2 strategies SnCMR=0.88 CMR-MPR < 1.5 P-CMR to assess myocardial ischemiaPatient cohorts before referring positive patients to CXA.with different PCAD CXA confirms or refutes the P-CMR diagnosis. SpCMR=0.90 Non-diagnostic P-CMR (NDx) -> strategy 2 False-negative due to errors = at risk for complications Strategy 1 : (P-CMR+CXA) Stenosis Ø > 50% Patient cohorts with different PCAD a CXA to all patients and a FFR in patients with positive stenoses. FFR<=0.75 A positive stenosis is defined as a stenosis > 50% of luminal diameter A significant CAD is identified by a Strategy 2 is the reference with a 100% diagnostic accuracy stenosis > 50% and a FFR<=0.75 Strategy 2 : (CXA+FFR)
Results: Comparing the cost per effect (Cost effectiveness) 40,000 35,000 cost-eff. P-CMR+CXACost/CAD Dx (CHF) 30,000 cost-eff. CXA+FFR 25,000 20,000 Results in the Swiss context 15,000 64% 10,000 5,000 0 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 Prevalence of CAD (PCAD)
Results: Comparing the cost per effect (Cost effectiveness) 35,000 30,000 25,000 cost-eff. P-CMR+CXA Cost/CAD Dx ($) 20,000 cost-eff. CXA+FFR 15,000 Results in the US context 10,000 68% 5,000 0 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 Prevalence of CAD (PCAD)
Discussion /ConclusionThe study was designed to compare the relative costs per effect of 2 diagnosticstrategies for patients with suspected CAD.It shows that the pretest likelihood of CAD is a determinant of the ranking of thediagnostic tests in terms of cost-effectiveness.Compared to the gold standard of invasive CXA+FFR, the strategy involving a P-CMRwas found to be cost-effective up to a disease prevalence around 64% in the Swisscontext (resp. 68% in the US context).Above this value of the disease prevalence proceeding directly to the invasive tests wasmore cost-effective than P-CMR+CXA.
Discussion /ConclusionImplications for health professionals and patientsEven if the conclusions of the analysis should not be considered as clinicalguidelines, the results may help the decision making for clinical use of new generationsof (non-invasive) imaging procedures to detect ischemia.The results tend to show that the choice of cost-effective diagnostic strategies to detectrelevant CAD depends on the prevalence of the disease. THANK YOU
Clinical parameters and Costs for the different tests