Is adenosine administration necessary for the invasive functional assessment of coronary artery stenoses?

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1 Is adenosine administration necessary for the invasive functional assessment of coronary artery stenoses? Sayan Sen MRC Clinical Research Training Fellow Coronary Flow Trust

2 Background Pressure derived indices (FFR) are favoured over flow based indices Ease of use Reproducibility Clear cut off value When used to guide angioplasty FFR: improves clinical outcomes reduces procedural costs...class (1a) recommendation in European guidelines Clinical adoption is limited...

3 Background One reason: Adenosine administration Adds time and cost Cannot be given to all patients Disliked by patients Risk

4 Background Why do we need vasodilators...? Development of FFR Pa Pd Pressure wire fidelity was poor phasic analysis of pressure not possible De Bruyne et al. JACC 1993;22; Pressure and flow are proportional when resistance is constant Vasodilators administered to make resistance constant Pijls et al Circulation 1993;87;

5 Phasic resistance during the cardiac cycle Velocity (m/s) Velocity (M -2 ) Pressure (mm Hg) Pressure (mmhg) Resistance (mmhg M -2 ) Resistance (mm Hg s/m) Time (s)

6 Phasic resistance during the cardiac cycle Velocity (m/s) Velocity (M -2 ) Pressure (mm Hg) Pressure (mmhg) Resistance (mmhg M -2 ) Resistance (mm Hg s/m) Time (s)

7 Identification of wave- free period Wave- free period Wave- free period Blood flow is passive 75% of diastole Resistance is constant Suitable for a new pressure only index? Sen S, Davies JE et al. JACC (Epub ahead of print Dec 5, 211) Davies JE et al. Circulation 26;113: Davies JE et al. Circulation 211;124:

8 Pressure (mm Hg) Hypothesis Hypothesis 1: During the wave- free period intra- coronary resistance is similar to mean resistance under adenosine hyperaemia 12 Hypothesis 2: Mean Pd/Pa ratio over the wave- free period (instantaneous wave- free ratio, ifr) is comparable to FFR Time (ms)

9 ADVISE Study ADenosine Vasodilation Independent Stenosis Evaluation Study Part 1 Proof of concept Resting wave- free resistance vs. mean hyperaemic resistance n=39 Intra- coronary pressure and flow velocity measurements Part 2 Validation study ifr vs. FFR n=157 Intra- coronary pressure measurements Baseline resistance assessment ifr & FFR assessment Resistance assessment under pharmacological vasodilatation

10 1 8 6 Results Patient characteristics 83% 56% 96% Stenoses: 156 Age: 63 years % 22% 8% 5 4 Vessel characteristics 44% Male DM Smoker BP EF<3% Stable 3 31% 27% 29% 2 1 MV LAD Cx RCA

11 Results - Hypothesis 1 Test stability and magnitude of resistance during wave- free period in comparison to during adenosine hyperaemia

12 Stability of resistance 16 Co- efficient of variation Wave- free resistance Hyperaemic resistance

13 Stability of resistance is similar over the wave- free period and during hyperaemia 16 Co- efficient of variation p=.96 Wave- free resistance Hyperaemic resistance

14 Magnitude of resistance 7 6 Resistance (mmhg s/m) Resting mean resistance Hyperaemic mean resistance Resting wave- free resistance

15 Magnitude of resistance is similar over the wave- free period and during hyperaemia p<.1 7 p<.1 Resistance (mmhg s/m) p=.7 Resting mean resistance Hyperaemic mean resistance Resting wave- free resistance

16 Summary Stability of resistance is similar over the wave- free period and during hyperaemia Magnitude of resistance is similar over the wave- free period and during hyperaemia

17 Is the duration of the wave- free period consistent?

18 Duration of wave- free period independent of Blood Pressure, heart rate, type of vessel 1 Duration of wave- free period BP (mmhg)

19 Duration of wave- free period independent of Blood Pressure, heart rate, type of vessel 1 Duration of wave- free period Heart rate(/min)

20 Duration of wave- free period independent of Blood Pressure, heart rate, type of vessel Right vs left coronary artery Diabetes Hypertension p=ns Multi- vessel

21 The duration of the wave- free period is independent of haemodynamics and anatomy

22 Hypothesis 2: Mean Pd/Pa ratio over the wave- free period (ifr) is comparable to FFR

23 ifr vs. FFR 1. r = ifr FFR

24 ifr vs. FFR 1. r =.9 RCA LCA.8.6 ifr FFR

25 ifr vs. FFR - diagnostic characteristics 1. Diagnostic accuracy, 88% False (+) (+) predictive value, 91%.8 False (-) (- ) predictive value, 85%.6 Sensitivity, 85% FFR Specificity, 91%.4.2 Positive ifr Negative ifr RCA LCA

26 ifrvs. FFR - disagreements 1.8 Magnitude of resistance.6 ΔFFR - ifr R² = Δ Abs Hyperaemic wave- free resistance (mmhg s/m)

27 Conclusion During the wave- free period... Resistance is similar in magnitude and variability to adenosine mediated hyperaemia The instantaneous wave- Free Ratio (ifr) Adenosine- free pressure only index Comparable to FFR Sen S, Davies JE et al. JACC (Epub ahead of print Dec 5, 211)

28 Clinical implications of ifr Promote physiologically guided revascularisation Applicable to a wider patient population Improved work- flow in catheter lab Improves patient experience further validation

29 ADVISE team Hospital Clínico San Carlos Javier Escaned, Rafael Mila Royal Brompton Hospital Carlo Di Mario Imperial College Justin Davies Iqbal Malik, Jamil Mayet, Alun Hughes, Darrel Francis, Ghada W Mikhail, Rodney A Foale, Jason Tarkin, Ricardo Petraco, Christopher Broyd, Richard Jabbour, Amarjit Sethi, Christopher Baker, Michael Bellamy, Mahmud Al- Bustami, David Hackett, Masood Khan, David Lefroy, and Kim H Parker.

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31 Hypothesis 1 (1) Test stability and magnitude of resistance during wave- free period in comparison to during adenosine hyperaemia (2) Test the stability of the wave- free period as consistent easily identifiable period in the cardiac cycle

32 ifrvs. FFR - disagreements False negative ifr or False positive FFR? ifr.6 HSR FFR

33 ifrvs. FFR - disagreements False negative ifr or False positive FFR? ifr.6 Negative HSR = false (+) FFR FFR