Pd/Pa and iFR: new concept or more of the same? - Niels van Royen

1. Pd/Pa and iFR:
new concept or more of the same?
Aim Radial
September 20 2017, Stuttgart
Niels van Royen, MD, PhD
Head of Department of Cardiology
Radboud University Medical Center
Nijmegen, the Netherlands

2. Disclosures
 I have no financial conflicts of interest related to this
presentation

3. Fractional flow reserve (FFR)
FFR = distal coronary pressure / aortic pressure
maximal hyperemia
Wilson , NEJM, 1996

4. Tonino et al, NEJM 2009
P=0.02
FAME-studies

5. Instantaneous wave free ratio (iFR)
iFR also ratio between Pd and Pa but:
1. measured during resting conditions
2. measured during wave-free period

6. Hemodynamics during wave free period

7. Jeremias et al; JACC 2013
Strong, but not optimal correlation between FFR and iFR
Suboptimal correlation a priori when comparing a novel to an established index
iFR versus FFR, RESOLVE study

8. iFR and FFR versus H2O PET-perfusion
de Waard et al, ACC 2014

9. 0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
12 misclassifications
rho=0.56; P<0.001
FFR
PETMBF(mL·min-1
·g-1
)
12 misclassifications
rho=0.63; P<0.001
iFR
4.0
4.5
12 misclassifications
rho=0.62; P<0.001
)
13 misclassifications
rho=0.57; P<0.001
0.0
0.5
1.0
FFR
PET
iFR
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
12 misclassifications
rho=0.62; P<0.001
Pd/Pa
PETMBF(mL·min-1
·g-1
)
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
13 misclassifications
rho=0.57; P<0.001
iFRa
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
12 misclassifications
rho=0.56; P<0.001
FFR
PETMBF(mL·min-1
·g-1
)
12 misclassifications
rho=0.63; P<0.001
iFR
4.0
4.5
12 misclassifications 13 misclassifications
iFR and FFR versus PET-perfusion
de Waard et al, ACC 2014

10. 1. Van de Hoef et al. Circ Cardiovasc Interv. 2012;5(4):508-14
2. Sen et al. J Am Coll Cardiol. 2013;61(13):1409-20
5. Petraco et al. Circ. Int. 2014 Aug;7(4)
6. de Waard et al. (ACC 2014)
3. Van de Hoef Euroint. 2015 Dec;11(8):914-25
4. Sen et al. J Am Coll Cardiol. 2013;62(6):566
0
20
40
60
80
100
HSR HSR SPECT PET CFR
Accuracy(%)orROC(%)
FFR
iFR
p=ns
p<0.01
p=ns p=ns
p<0.01
iFR and FFR versus other modalities

11. Davies et al, NEJM 2017 Gottberg et al, NEJM 2017
DEFINE-FLAIR and iFR SWEDEHEART

12. Hyperemia during wave free period;
only explanation?
Another mechanism: coronary autoregulation
Gould et al, Circulation, 1975!

13. Nijer et al, EHJ, 2016

14. • 567 vessels in 301 patients
• Combined intracoronary pressure and flow measurements
• Permitted to relate stenosis to pressure, flow and resistance
IDEAL study

15. Nijjer, de Waard et al, EHJ, 2016
Relation between stenosis severity and
pressure, flow and resistance at rest
Coronary autoregulation at rest

16. Direct proof of coronary autoregulation in humans
SPECT-PET: hyperemia required
Flow is maintained at rest

17. Direct proof of coronary autoregulation in humans
SPECT-PET: hyperemia required
Flow is maintained at rest

18. iFR: hyperemia not required
Resting pressure gradient rises

19. Rest vs adenosin: similar pressure gradients

20. Jeremias et al; JACC 2013
Pd/Pa as an alternative to iFR?
de Waard et al, ACC 2014

21. Jeremias et al; JACC 2013
Pd/Pa as an alternative to iFR?
de Waard et al, ACC 2014
No clinical outcome data Pd/Pa

22. Van der Hoeven et al. 2017 TCT
FFR/iFR in non-culprit vessels
during STEMI?
iFR

23. Van der Hoeven et al. 2017 TCT
FFRiFR
FFR/iFR in non-culprit vessels
during STEMI?

24. instantaneous wave-free ratio guided Multi vessel
revascularizatiOn During percutaneous coronary
intervEntion for acute myocaRdial iNfarction
the iMODERN trial
Radboud university medical center (Nijmegen, the Netherlands)
Robin Nijveldt, Niels van Royen
Centro Hospitalar de Lisboa Ocidental (Lisbon, Portugal)/
Fernando Fonseca Hospital (Amadora, Portugal)
Luís Raposo, Sérgio Baptista
Aarhus University Hospital (Skelby, Denmark)/
Lund university (Lund, Sweden)
Michael Maeng, Matthias Götberg
Hospital Clínico San Carlos/ CNIC (Madrid, Spain)
Javier Escaned, Borja Ibáñez
Imperial College London (London, UK)
Justin Davies

25. Conclusion
• iFR performs equally to FFR
• Coronary autoregulation permits non-hyperemic stenosis
interrogation
• Pd/Pa probably good alternative, no clinical outcome data

26. Take home message
• use iFR or FFR, as long as you don’t use eye-FR!