TAVR Hemodynamics Post Implantation:
Is Echo Enough?Amr E Abbas, MD, FACC, FSCAI, FASE, FSVM, RPVI
Director, Cardiovascular Research
Beaumont Health, Royal Oak, MI
Professor of Medicine
OUWB School of Medicine
DisclosuresEdwards Life Sciences:Speaker BureauResearch Grants
Case 1
• 83 year old female with H/O bio-prosthetic aortic valve
• Presented with NYHA Class III
• TEE suggestive of severe AR
• Underwent successful TF-TAVR ViV with 23 mm Evolut R
• Simultaneous CATH ECHO MG obtained
• Discharged with no complications5/23/2019 3
Simultaneous Post TAVR ECHO/CATH
5/23/2019 4
ECHO MG 6 mmHg CATH MG 0 mmHg
Case 2• 79 year old man with H/O bio-prosthetic aortic valve• Presented with acute congestive heart failure requiring
intubation• TEE suggestive of severe AS with MG 40 mmHg, AVA 0.71
and severe AI• Underwent successful TF-TAVR ViV with 20mm SAPIEN 3
valve• Simultaneous CATH ECHO MG obtained5/23/2019 5
5/23/2019 6
ECHO MG 40 mmHg CATH MG 11 mmHgSimultaneous Post TAVR ECHO/CATH
Topics of Discussion• Why was there a CATH ECHO discordance?
• Is the Bernoulli equation valid post implant in normal valves?• Clinical Data• Bench Data• Physics: Bernoulli assumptions and Pressure Recovery• Sequel and Clinical implications
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Post TAVR: CATH Vs. ECHO• Post TAVR ECHO and CATH MG were obtained simultaneously • 314 TAVR
• 278 Native & 36 ViV• 278 Native
• 217 BE• 77 small: < 26 mm & 140 large: > 26 mm
• 61 SE• 21 small: < 26 mm & 40 large: > 26 mm
• 36 ViV• 29 BE & 7 SE5/23/2019 8
5/23/2019 9
MEAN 0.96 +/- 3.3MEDIAN 0
RANGE 0 - 37
MEAN 6.2 +/- 4.7MEDIAN 5
RANGE 1 - 40
Simultaneous Immediate Post TAVR ECHO/CATH Gradients
CATH MG ECHO MG
Abbas et al. Invasive vs. Echocardiographic Evaluation of Transvalvular Gradients Immediately Post TAVR: Demonstration of Significant Echocardiography-Catheterization Discordance. Circ Int in Press
5/23/2019 10
MEAN 4.8+/- 7.5MEDIAN 0.5RANGE 0 - 37
MEAN 5.2 +/- 3.4MEDIAN 5
RANGE 1-30
MEAN 0.45 +/- 1.6MEDIAN 0
RANGE 0 - 14
MEAN 11.3 +/- 8.5MEDIAN 9.5RANGE 1-40
Native Vs. ViV: CATH Vs. ECHO MG
VIV CATH VIV ECHO
NV CATH NV ECHO
Mando R, Abbas AE, et al. ECHO Overestimates Trans-Aortic Valve Gradients Immediately Post TAVR: A Pressure Recovery
Phenomenon in a Simultaneous CATH and ECHO Study. J Am Coll Cardiol 2019;73:1251.
5/23/2019 11
MEAN 0.46+/- 1.7MEDIAN 0
RANGE 0 - 14
MEAN 5.3 +/- 3.3MEDIAN 4
RANGE 2-20
MEAN 0.75 +/- 3.24MEDIAN 0
RANGE 0 - 24
MEAN 5.58 +/- 3.4MEDIAN 5
RANGE 1-30
Native BE Vs. SE: CATH Vs. ECHO MG
BE CATH BE ECHO
SE CATHSE ECHO
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Native Large Vs. Small BE/SE CATH vs. ECHO MG
CATH MG
ECHO MG
CATH MG
ECHO MG
0 mmHg 6 4 5 4
0 mmHg
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Native Large vs. Small BE/SE CATH vs. ECHO MG
5/23/2019 14ViV ECHO MG > Day 1 compared to Post TAVR ECHO
P < 0.0001
P NS P NS
11 mmHg
18 mmHg
P1-P2 = 1/2ρ(V22-V1
2)
P1&V1= proximal to obstruction
P2&V2= distal to obstruction
ρ=mass density of blood
R=viscous resistance
μ = viscosity
Convective acceleration
Decreased AVA+ρ ∫max (dv/dt) * ds Flow acceleration
Systole+R(μ) Viscous/Friction
Losses
V1 P1
Bernoulli Equation
P1-P2 = 4(V22) - 4(V1
2)
• Convective Acceleration: River flow when narrows• With steady non-pulsatile flow, a decrease in area leads to an increase in velocity of
blood flow
• Steady Flow = Area x velocity
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Bernoulli Components
Q
V2V1
A1A2A3 P2P1
D
P3
AS
• Flow Acceleration: Intermittent water pump• Change in flow velocity with systole: at a constant area, an increase in flow leads to
increased velocity
• Pulsatile Flow = Constant Area x velocity
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Bernoulli Components
Q
V2V1
A1A2A3 P2P1
D
P3
AS
• Viscous Forces R (μ): Movement of molasses • Viscous R: Energy losses due to friction between fluid layers and adjacent wall
• Viscosity: (μ) lower viscosity leads to higher gradients (anemia)
5/23/2019 18
Bernoulli Components
Q
V2V1
A1A2A3 P2P1
D
P3
AS
• Energy dissipation: Rubbing your hands together • Heat generation
• Viscous R: • Energy losses due to friction between fluid layers and adjacent wall
• Valve inertia: energy absorbed to open the valve
5/23/2019 19
Bernoulli Components
Q
V2V1
A1A2A3 P2P1
D
P3
AS
Pressure Recovery
VentriclePressure Energy (200 mmHg)
Aortic Valve: CentralPressure ➔Kinetic Energy
Pressure (140 mmHg)
AortaPressure Energy (160 mmHg)
Turbulence & VorticesLateral
(20 mmHg)
Heat & Friction (40mmHg)
Lost 40Pressure Recovery 20 mmHg
ECHO MG: 60 mmHg ΔPmax
CATH MG: 40 mmHg ΔPnet
Net energy loss
Doppler/ Catheter Discordance:
20 mmHg
Eddy Currents
CentralFlow
CombinedFlow
Why ECHO CATH DISCORDANCE?• We did not adjust for LVOT MG
• We did not adjust for pressure recovery
• ECHO MG x 2 x AVA/AsAoA x (1-AVA/AsAoA ).
• Or
• Should we even use the Simplified Bernoulli Equation? It was designed for stenotic valves. ? Misleading when used to determine post TAVR Echo MGs in normal functioning valves
• Is there a difference between valves?5/23/2019 21
ECHO vs. CATH: LVOT and PR Native TAVR
5/23/2019 22
Abbas et al. Invasive vs. Echocardiographic Evaluation of Transvalvular Gradients Immediately Post TAVR: Demonstration of Significant Echocardiography-Catheterization Discordance. Circ Int in Press
ECHO vs. CATH: LVOT and PRViV TAVR
5/23/2019 23
Abbas et al. Invasive vs. Echocardiographic Evaluation of Transvalvular Gradients Immediately Post TAVR: Demonstration of Significant Echocardiography-Catheterization Discordance. Circ Int in Press
CATH/ECHO Discordance Before & After Adjusting for LVOT Gradient and “Pressure
Recovery”
5/23/2019 24
Abbas et al. Invasive vs. Echocardiographic Evaluation of Transvalvular Gradients Immediately Post TAVR: Demonstration of Significant Echocardiography-Catheterization Discordance. Circ Int in Press
Simplified Bernoulli Assumptions• Laminar/steady flow: • Negligible Flow Acceleration
• Short tube: • Negligible viscous loss
•No Pressure Recovery
•Neglect 4V12 (In AS: V2 >>> V1)
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ECHO Underestimates
ECHO Overestimates
Bernoulli: Laminar vs. Turbulent Flow
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Evolut R SAPIEN 3 Valve
Hatoum, et al. J Thorac Cardiovasc Surg 2018
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CATH MG
Bernoulli Equation
Convective Acceleration
4V22
ECHO MGSimplified Bernoulli
Flow Acceleration
ViscousPressure Recovery
+
+-
-
=
=
CATH MG
LVOT Pressure
4V12
ECHO CATH DISCORDANCE
Simplified
4V22 – CATH
CATH Vs. ECHO MGCATH MGECHO MG
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CATH MG
Bernoulli Equation
45 mmHg
Convective Acceleration
4V22
47 mmHg
ECHO MG
47 mmHgSimplified Bernoulli
Flow Acceleration
1 mmHg
Viscous
1 mmHg
Pressure Recovery
4 mmHg
+
+-
-
=
=
Aortic Stenosis
CATH MG
45 - 4 = 41 mmHg
LVOT Pressure
4V12
4 mmHg
ECHO CATH DISCORDANCE
Modified
47 - 4 – 41 = 2 mmHg
ECHO CATH DISCORDANCE
Simplified
47 – 41 = 6 mmHg
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CATH MG
Bernoulli Equation
14 mmHg
Convective Acceleration
4V22
14 mmHg
ECHO MG
14 mmHgSimplified Bernoulli
Flow Acceleration
1 mmHg
Viscous
3 mmHg
Pressure Recovery
10 mmHg
+
+-
-
=
=
CATH MG
14 – 10 = 4 mmHg
LVOT Pressure
4V12
4 mmHg
ECHO CATH DISCORDANCE
Simplified
14 – 4 = 10 mmHg
Post TAVR Laminar
Pressure Recovery
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CATH MG
Bernoulli Equation
14 mmHg
Convective Acceleration
4V22
11 mmHg
ECHO MG
11 mmHgSimplified Bernoulli
Flow Acceleration
5 mmHg
Viscous
1 mmHg
Pressure Recovery
8 mmHg
+
+-
-
=
=
CATH MG
14 – 8 = 6 mmHg
LVOT Pressure
4V12
3 mmHg
ECHO CATH DISCORDANCE
Modified
11 - 3 – 6 = 2 mmHg
ECHO CATH DISCORDANCE
Simplified
11 – 6 = 5 mmHg
POST TAVR Turbulent Less
Pressure Recovery
ECHO CATH DISCORDANCE •A result of•Bernoulli Assumptions•Pressure Recovery
• Lead to•Prosthesis patient mismatch• TAVR valve choice•Valve fractures
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How Gradient and Area Interact
AV VELOCITY
Continuity Equation
Aortic valve areaAREA LVOT x Velocity LVOT /Velocity AV
Bernoulli Equation
Gradient4 (AV Velocity)2
32
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Prosthesis Patient Mismatch
5 mmHg difference between severe and no PPM
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“CHOICE OF VALVE”
Conclusions
• Post TAVR ECHO-CATH discordant MGs caused by• Bernoulli simplification and assumptions
• Pressure recovery
• What does a high ECHO MG mean? CATH in All?
• How frequent is prosthesis patients mismatch (PPM)? CONFLICTING OUTCOME?
• Compare TAVR valves by ECHO MG ONLY?
• Should we fracture valves just by ECHO MG ONLY?
• Does this happen with surgical valves as well?5/23/2019 35
THANK YOU
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