Low Output Low Gradient AS

Natesa G. Pandian

Disclosure: Speakers Bureau Lantheus Inc

AS Pressure Gradient

4 V 2

AS Pressure Gradient Max Instantaneous

Gradient Mean

Gradient Apical Suprasternal

How severe is AS? It it really low gradient?

Discrepancy between

Echo and Cath

Aortic Stenosis

Mean Peak to Peak MIG

Pressure Recovery Phenomenon

Total E = kinetic E + P Total E = kinetic E, P

Pressure Recovery Phenomenon

Catheter

Doppler Total E = kinetic E + P Total E = kinetic E, P

Catheter

Doppler

Issue in Small aortas Mod to severe AS

Pressure Recovery Phenomenon

Catheter

Doppler

Issue in Small aortas Mod to severe AS Correction:

Energy Loss Coef =

EOA x Aa/Aa-EOA

Pressure Recovery Phenomenon Aortic Valve Area Calculation

Continuity Equation “What goes in must come out”

Ao Valve Area by Continuity Equation

V1 V2

V1 A1 x V1 = A2 x V2

V2

Ao Valve Area by Continuity Equation

V1 V2

V1

Ao Valve Area = LVOF area x TVI1

TVI2

A1 x V1 = A2 x V2

V2

Aortic Valve Area by TEE

Surgical AVA

TEE AVA

Kasliwal/Trehan/Pandian

Echocardiography

Potential Errors

• LV outflow measurement

• Proximal flow velocity recording

• Maximum velocity recording

• Inaccuracy related to flow

Mild

Moderate Severe

Velocity (m/s) < 3.0 3.0 - 4.0 > 4.0

Mean Grad (mm Hg) < 25 25 - 40 > 40

Valve area (cm2) > 1.5 1.0 - 1.5 < 1.0

AVA index (cm2/m2) < 0.6

Echo Criteria for Severity of AS

Mild

Moderate Severe

Velocity (m/s) < 3.0 3.0 - 4.0 > 4.0

Mean Grad (mm Hg) < 25 25 - 40 > 40

Valve area (cm2) > 1.5 1.0 - 1.5 < 1.0

AVA index (cm2/m2) < 0.6

Echo Criteria for Severity of AS

“If the mean gradient is less than 40,

it can not be severe AS”

“If the mean gradient is less than 40,

it can not be severe AS” X Calculated relation of aortic valve area

to mean pressure gradient by cath

Carabello BA et al N Engl J Med 2002

Valve area and mean pressure gradient (dPm) with relationship to criteria for severe aortic stenosis.

Jander N Eur Heart J Suppl 2008;10:E11-E15

The issue of LVOT diameter

•Major cause for low output

•Underestimation of SV

•TEE if TTE is not good

Severe AS and Low Gradient

Does exist

Severe AS and Low Gradient

What are the mechanisms ?

Severe AS and Low Gradient

Systolic LV dysfunction,

Low Stroke Volume

1

73 Male Severe AS, EF 32, Severe HF, No CAD LV dysfunction

Low cardiac output

Low Velocity, Low Gradient

Mild AS

Severe AS Low SV

LV dysfunction

Low cardiac output

Low Velocity, Low Gradient

2 solutions for diagnosis

Low Velocity, Low Gradient

TEE planimetry

Of AVA

Dobutamine

Stress testing

Low EF, Low Gradient Severe AS

Management

Dobutamine Stress in Low Gradient AS in HF Patient

Optimal surgical candidate:

With Dobutamine, Mean gradient > 30 mm Hg AVA increase < 0.3 sqcm Stroke volume > 20%

If severe LV dysfunction with no reserve, then medical therapy

Low-gradient aortic stenosis: operative risk stratification and predictors for long-term outcome: a multicenter study

using dobutamine stress hemodynamics Monin JL, et al. Circulation 2003 ;108:319-24 Severe AS and Low Gradient

Increased Vascular Afterload

2

Systemic Hypertension in 30 – 50% of AS patients

Little SH, Chan KL, Burwash IG. Heart. 2007; 93(7):848-5

Impact of increasing arterial blood pressure in aortic stenosis

Normal arterial BP does not exclude increased vascular load because of pseudonormalization (30% of pts)

Aging

Hypertension

Atherosclerosis

Decreased compliance

Increased impedance

Normal arterial BP does not exclude increased vascular load because of pseudonormalization (30% of pts)

Aging

Hypertension

Atherosclerosis

Decreased compliance

Increased impedance

Normal arterial BP does not exclude increased vascular load because of pseudonormalization (30% of pts)

Aging

Hypertension

Atherosclerosis

Decreased compliance

Increased impedance

Normal arterial BP does not exclude increased vascular load because of pseudonormalization (30% of pts)

Aging

Hypertension

Atherosclerosis

Global hemodynamic

load (Valvuloarterial

impedance, Zva)

Valvuloarterial Impedance (Zva)

Systolic BP + Mean gradient

Stroke volume/Height

AS + Increased Vascular Load

Management

Severe AS Surgery

Moderate AS ?

Severe AS and Low Gradient

Small Left Ventricle

Normal EF but decreased SV

3

Normal Flow AS

ED

ES

Normal Flow AS

Paradoxical Low Flow AS

Pibarot & Dumesnil JACC 2009

ED

ES

Circulation. 2007;115:2856-2864

n = 381 SV > 35 cc

n = 181 SV < 35 cc

Low Gradient, Normal EF Severe AS

Management

Aggressive Rx of underlying disease

Intervention issues not resolved

Severe AS and Low Gradient

Filling dysfunction

Restrictive physiology

Low stroke volume

4

March 2009

•80 year old male, Active

•A Fib on Coumadin, Rate Control

•Soft A2, 4/6 SEM

•Active, No Symptoms

Case

March 2009 Mean Grad 10 mm Hg AVA 1.4 sqcm

May 2011

•80 year old male, Active

•A Fib on Coumadin, Rate Control

•Exertional Dyspnea

May 2011 EF 50% Maximum Grad 68 Mean Grad 35 mm Hg AVA 0.9 sqcm Elevated Filling Pressures Cath: 2V CAD

•Had AVR, CABG, Maze Procedure

•LA appendage pathology: Amyloidosis

•Heart Failure

•Prolonged hospitalization

•QOL worse than pre-op

Filling dysfunction

Restrictive physiology

Low stroke volume

Many causes

AS + Restrictive CMP

Management

Severe AS Surgery

Anticipate increased events

Severe AS and Low Gradient

Coexisting

Moderate or severe MR

5

Coexisting MR Coexisting MR

Coexisting MR

SV 46 ml Forward CO 2.6 l/min

AS + Co-existing MV disease

Management

Severe AS Surgery for Ao V and MV

Anticipate increased events

Severe AS but Low Gradient

Low EF Low Stroke

Volume Small LV

Normal EF Low SV

Normal EF Mod-Severe

MR

Normal EF Restrictive

Filling

Increased Vascular

Load

Low Gradient, Severe AS

Management

Surgery, TAVI

Case by case judgement

Thank you !