Comparative cost-effectiveness analyses of cardiac magnetic resonance imaging (CMR) and coronary angiography (CXA) combined with fractional flow reserve (FFR) test.

1. Comparative cost-effectiveness analyses of
cardiac magnetic resonance imaging (CMR) and
coronary angiography (CXA) combined with fractional
flow reserve (FFR) test
K. Moschetti, D. Favre, C. Pinget, JB. Wasserfallen, J. Schwitter

2. The burden of coronary artery Distribution of deaths worlwide, WHO, 2011
disease (CAD)
Mortality burden
Cardiovascular diseases are the most important killer
of people
Cardiovascular diseases
30% with 15% for CAD
They are predicted to remain so for the next 20 years
The CAD with stroke are the most frequent
In Europe, the CAD accounts for between 15% and
25% of all deaths
High Cost burden
CAD is a leading cause of morbidity and loss of quality of life
Since CAD is frequent, deadly and treatable, it is crucial to detect it (the myocardial
ischemia) prior to a heart attack

3. The coronary angiography test (CXA) and the fractional
flow 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

4. The Perfusion cardiac magnetic
resonance (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

5. The Perfusion cardiac The CXA combined
magnetic 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
But
But
Invasive with radiation exposure,
- can induce claustrophobia bleeding and complications
- not safe for patients with certain type of
medical devices

6. Objective
To 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)

7. Material and Method
 Use of a mathematical model that submits to the 2 strategies, hypothetical patient
cohorts 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 as
having 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

8. Decision tree for CAD diagnosis and outcomes for the 2 strategies
SnCMR=0.88
CMR-MPR < 1.5
P-CMR to assess myocardial ischemia
Patient 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)

9. Results: Comparing the cost per effect (Cost effectiveness)
40,000
35,000
cost-eff. P-CMR+CXA
Cost/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)

10. 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)

11. Discussion /Conclusion
The study was designed to compare the relative costs per effect of 2 diagnostic
strategies for patients with suspected CAD.
It shows that the pretest likelihood of CAD is a determinant of the ranking of the
diagnostic tests in terms of cost-effectiveness.
Compared to the gold standard of invasive CXA+FFR, the strategy involving a P-CMR
was found to be cost-effective up to a disease prevalence around 64% in the Swiss
context (resp. 68% in the US context).
Above this value of the disease prevalence proceeding directly to the invasive tests was
more cost-effective than P-CMR+CXA.

12. Discussion /Conclusion
Implications for health professionals and patients
Even if the conclusions of the analysis should not be considered as clinical
guidelines, the results may help the decision making for clinical use of new generations
of (non-invasive) imaging procedures to detect ischemia.
The results tend to show that the choice of cost-effective diagnostic strategies to detect
relevant CAD depends on the prevalence of the disease.
THANK YOU

13. Clinical parameters and Costs for the different tests