K. Moschetti, D. Favre, C. Pinget, JB. Wasserfallen, J. Schwitter

Comparative cost-effectiveness analyses of

cardiac magnetic resonance imaging (CMR) and

coronary angiography (CXA) combined with fractional

flow reserve (FFR) test

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

Mortality burden

Cardiovascular diseases are the most important killer

of people

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

Cardiovascular diseases 30% with 15% for CAD

The burden of coronary artery disease (CAD)

Distribution of deaths worlwide, WHO, 2011

The coronary angiography test (CXA) and the fractional flow reserve (FFR) measurement

Performed during the CXA, the FFR - a guide wire-based procedure - measures blood pressure and detect myocardial ischemia

An X-ray machine is used to detect occlusions revealed by the dye.

P-CMR can detect occlusions and flow-limiting CAD - as defined by the CXA + FFR

- 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)

The Perfusion cardiac magnetic resonance (P-CMR)

- not invasive, - none exposure to radiations

=> can be used multiple times

But

- can induce claustrophobia- not safe for patients with certain type of

medical devices

The Perfusion cardiac magnetic resonance (P-CMR)

The CXA combined with the FFR

- allow real-time estimation of the effects of a narrowed vessel,

- allow simultaneous treatment with angioplasty.

But

Invasive with radiation exposure, bleeding and complications

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)

Objective

P-CMR

Positive CXA

Negative

CXA

Positive FFR

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 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

Decision tree for CAD diagnosis and outcomes for the 2 strategies

Patient cohorts with different PCAD

CMR-MPR < 1.5

SnCMR=0.88

SpCMR=0.90

Strategy 1 : (P-CMR+CXA)

Non-diagnostic P-CMR (NDx) -> strategy 2

False-negative due to errors = at risk for complications

Patient cohorts with different PCAD

Stenosis Ø > 50%

FFR<=0.75

Strategy 2 is the reference with a 100% diagnostic accuracy

Strategy 2 : (CXA+FFR)

a CXA to all patients and a FFR in patients with positive stenoses.

A positive stenosis is defined as a stenosis > 50% of luminal diameter

A significant CAD is identified by a stenosis > 50% and a FFR<=0.75

P-CMR to assess myocardial ischemia before referring positive patients to CXA.

CXA confirms or refutes the P-CMR diagnosis.

Results: Comparing the cost per effect (Cost effectiveness)

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

cost-eff. P-CMR+CXA

cost-eff. CXA+FFR

Prevalence of CAD

Co

st/

CA

D D

x (

CH

F)

Results in the Swiss context

(PCAD)

64%

Results: Comparing the cost per effect (Cost effectiveness)

Results in the US context

0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.000

5,000

10,000

15,000

20,000

25,000

30,000

35,000

cost-eff. P-CMR+CXA

cost-eff. CXA+FFR

Prevalence of CAD

Co

st/

CA

D D

x (

$)

68%

(PCAD)

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.

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

Clinical parameters and Costs for the different tests