tavr hemodynamics post implantation: is echo enough?mean 5.2 +/- 3.4 median 5 range 1-30 mean 0.45...

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

5/23/2019 7

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


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


RANGE 1-30


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


RANGE 2-20

MEAN 0.75 +/- 3.24MEDIAN 0

RANGE 0 - 24


RANGE 1-30

Native BE Vs. SE: CATH Vs. ECHO MG

BE CATH BE ECHO

SE CATHSE ECHO

5/23/2019 12

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

5/23/2019 16

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

5/23/2019 17


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


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


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


ECHO vs. CATH: LVOT and PRViV TAVR

5/23/2019 23


CATH/ECHO Discordance Before & After Adjusting for LVOT Gradient and “Pressure

Recovery”

5/23/2019 24


Simplified Bernoulli Assumptions• Laminar/steady flow: • Negligible Flow Acceleration

• Short tube: • Negligible viscous loss

•No Pressure Recovery

•Neglect 4V12 (In AS: V2 >>> V1)

5/23/2019 25

ECHO Underestimates

ECHO Overestimates

Bernoulli: Laminar vs. Turbulent Flow

5/23/2019 26

Evolut R SAPIEN 3 Valve

Hatoum, et al. J Thorac Cardiovasc Surg 2018

5/23/2019

27

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

5/23/2019 28

CATH MG

Bernoulli Equation

45 mmHg


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


Modified

47 - 4 – 41 = 2 mmHg


Simplified

47 – 41 = 6 mmHg

5/23/2019 29

CATH MG

Bernoulli Equation

14 mmHg


4V22

14 mmHg

ECHO MG


Flow Acceleration

1 mmHg

Viscous

3 mmHg

Pressure Recovery

10 mmHg

+

+-

-

=

=

CATH MG

14 – 10 = 4 mmHg

LVOT Pressure

4V12

4 mmHg


Simplified

14 – 4 = 10 mmHg

Post TAVR Laminar

Pressure Recovery

5/23/2019 30

CATH MG

Bernoulli Equation

14 mmHg


4V22

11 mmHg

ECHO MG


Flow Acceleration

5 mmHg

Viscous

1 mmHg

Pressure Recovery

8 mmHg

+

+-

-

=

=

CATH MG

14 – 8 = 6 mmHg

LVOT Pressure

4V12

3 mmHg


Modified

11 - 3 – 6 = 2 mmHg


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

5/23/2019 31

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

5/23/2019 33

Prosthesis Patient Mismatch

5 mmHg difference between severe and no PPM

5/23/2019 34

“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

5/23/2019 36

tavr hemodynamics post implantation: is echo enough?mean 5.2 +/- 3.4 median 5 range 1-30 mean 0.45...

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