Assessment of Diastolic function by echo

Dr Shreetal Rajan Nair

Diastolic function

• Physiology • Epidemiology of diastolic dysfunction• Diastolic heart failure – definitions• Etiology of diastolic dysfunction• Echo assessment of diastolic function - present guidelines - newer concepts

Diastolic dysfunction

defined as an inability of the left ventricle (LV)

to attain a normal end-diastolic volume without an inappropriate increase in LV end-diastolic pressure (LVEDP)

Epidemiology – Heart Failure with Preserved Ejection Fraction (HF-PEF)

• Accounts for 50% of cases of heart failure• older , more in females and more incidence in

obese• Associated with hypertension,T2DM,dyslipidemia,

and atrial fibrillation (AF).

Patients with HF-PEF have• a worse prognosis than those with Heart Failure

with Reduced Ejection Fraction (HF-REF)

HF- PEF - DIAGNOSIS

• 1. Symptoms typical of HF• 2. Signs typical of HF• 3. Normal or only mildly reduced LVEF and LV

not dilated• 4. Relevant structural heart disease (LV

hypertrophy/LA enlargement) and/or diastolic dysfunction

ESC 2012

ACCF/AHA 2013

a) clinical signs or symptoms of HF b) evidence of preserved or normal LVEF c) evidence of abnormal LV diastolic dysfunction

that can be determined by Doppler echocardiography or cardiac catheterization

Physiology

The ventricle has two alternating functions:1. systolic ejection 2. diastolic filling Diastole can be divided into four phases:

▪ Isovolumic relaxation ▪ The early rapid diastolic filling phase ▪ Diastasis ▪ Late diastolic filling due to atrial contraction

Left atrium functions as a RESERVOIR during systole, CONDUIT during early diastole and PUMP during late diastole

Atrial Pressures and Filling Curves

RA filling

• Right atrial filling is characterized by ▪ Small reversal of flow following atrial

contraction (a wave) ▪ Systolic phase : when blood flows from the superior and inferior vena cava into the atrium ▪ Small reversal of flow at end-systole (v wave) ▪ Diastolic filling phase when the atrium serves as a conduit for flow from the systemic venous return to the RV

LA fiiling

• LA filling from the pulmonary veins also is characterized by : ▪ Small reversal of flow following atrial contraction (a wave) ▪ Systolic filling phase ▪ Blunting of flow or brief reversal at end-systole (v wave) ▪ Diastolic filling phase

Determinants of diastolic function

• Ventricular relaxation and compliance• LA volume and function• Heart rate• Pericardium Derangement of any of the above will lead to

abnormal filling pressures and diastolic dysfunction

Factors affecting diastolic filling

• Early diastolic filling affected by

preloadtransmitral volume flow

rateatrial pressure

Late diastolic filling is affected by:

Cardiac rhythm Atrial contractile

function Ventricular end-diastolic

pressure

Etiology of diastolic dysfunction

Classification: diastolic dysfunction

Grade 1 (mild dysfunction) : impaired relaxation with normal filling pressure Grade 1a : impaired relaxation with increased filling pressure Grade 2 (moderate dysfunction): pseudonormalized mitral inflow pattern Grade 3 (severe reversible dysfunction): reversible restrictive (high filling pressure) Grade 4 (severe irreversible dysfunction): irreversible restrictive (high filling pressure)

Echo assessment of diastolic function

Echocardiographic assessment of diastolic filling pressure has been aptly described as “ noninvasive Swan-Ganz catheter ”

• 2D• Doppler – PW,CW and TDI• M mode • Newer modalities

Diastolic function assessment

Anatomic correlatesFunctional correlates

2D

• LV mass and dimensionsLV hypertrophy is the commonest cause of

diastolic dysfunctionRelative wall thickness :

• LA volume and LA volume index

LA volume and LA volume index

• LA volume index >34ml/m2 - independent predictor of death, heart failure, atrial fibrillation and ischemic stroke

• Limitations: dilated left atria – bradycardia,anemia and

other high-output states, atrial flutter or fibrillation and significant mitral valve disease

Ventricular Relaxation

• IVRT• the maximum rate of pressure decline(–dP/dt) • the time constant of relaxation (tau or τ)

Tau and ventricular relaxation

Tau and Weiss formula

• t corresponds to the time it takes for LVP to fall to 1/e (36%) of its initial value.

• The formula also indicates that LVP fall, and therefore relaxation, will be 97% complete 3.5*t after dP/dt

• Diastolic dysfunction is present when tau is >48 ms

• Pt=(P0-P‘)e-t/t+P‘• where Pt is LVP at time t; P0 is LVP at dP/dt min (time

0); P‘ is the asymptotic pressure, to which relaxation would lead if completed without LV filling.

• P‘ is negative in normal ventricles, which means that the non-filling ventricle develops diastolic suction.

Ventricular Compliance and stiffness

• Compliance is the ratio of change in volume to change in pressure (dV/dP).

• Stiffness is the inverse of compliance: the ratio of change in pressure to change in volume (dP/dV)

SURROGATE MESUREMENTS of ventricular stiffness

• DT of mitral velocityStiffness [in millimeters of mercury per ml] is calculated

as K = [70ms/(DT- 20ms)A wave transit time

The slope (Kc) of this line is the chamber stiffness constant and can be used to quantify chamber stiffness.

Acquisition of mitral inflow

• apical 4 chamber, PW• 1 mm – 3mm sample volume between mitral

valve tips• initially obtained at sweep speeds of 25 to 50

mm/s for the evaluation of respiratory variation of flow velocities

• If variation is not present, the sweep speed is increased to 100 mm/s, at end-expiration, averaged over 3 consecutive cardiac cycles

Mitral inflow

Primary measurements • the peak early filling (E-wave) • late diastolic filling (A-wave) velocities• the E/A ratio• deceleration time (DT) of early filling velocity • the IVRT

derived by placing the cursor of CW Doppler in the LV outflow tract to simultaneously display the end of aortic ejection and the onset of mitral inflow

Mitral inflow

Secondary measurements • mitral A-wave duration (obtained at the level of the

mitral annulus) diastolic filling time• the A-wave velocity-time integral and the total mitral

inflow velocity-time integral (and thus the atrial filling fraction)

• Mid diastolic flow is an important signal to recognize. Low velocities can occur in normal subjects but when increased (>20 cm/s)- represent markedly delayed LV relaxation and elevated filling pressures

The mitral L wave

• distinct forward flow velocity after the E wave with a peak velocity >20cm/s

• Marker of advanced diastolic dysfunction• Delayed and prolonged LV relaxation • Increased LA pressure• Effect of valsalva and leg elevation• More frequently seen in AF patients

Eur J Echocardiography (2006) 7, 16-21; Ha et alCirc J 2007; 71: 1244–1249; Nakai et al

The mitral L wave

IVRT

• time interval between aortic valve closure and mitral valve opening

• normal IVRT is approximately 80 to 100 ms• Impaired relaxation associated with prolonged

IVRT• Decreased compliance and elevated filling

pressures associated with shortened IVRTUseful in determining the severity of diastolic dysfunction particularly in serial studies of patients on medical therapy or with disease progression

IVRT

CW Doppler in the LV outflow tract to simultaneously display the end of aortic ejection and the onset of mitral inflow.

Limitations of mitral inflow measurement

• sinus tachycardia• conduction system disease• Arrhythmias

Sinus tachycardia and first-degree AV block can result in partial or complete fusion of the mitral E and A waves (mitral DT cannot be measurable; IVRT can be measured

Limitations of mitral inflow measurement

In atrial flutter• Unable to measure E velocity, E/A ratio or DTIn AV blocks• multiple atrial filling waves are seen, with

diastolic mitral regurgitation (MR) interspersed between non conducted atrial beats

• PA pressures calculated from Doppler TR and PR

Valsalva maneuver

Clinical applications

• A pseudo normal mitral inflow pattern is caused by a mild to moderate increase in LA pressure in the setting of delayed myocardial relaxation

• Because the Valsalva maneuver decreases preload during the strain phase, pseudo normal mitral inflow changes to a pattern of impaired relaxation

• In cardiac patients, a decrease of >/= 50% in the E/A ratio is highly specific for increased LV filling pressures, but a smaller magnitude of change does not always indicate normal diastolic function.

QUANTITATIVE ANALYSIS

• 1 . MAXIMUM VELOCITIES• 2 . VELOCITY TIME INTEGRALS• 3 . TIME INTERVALS• 4 . ACCELERATION AND DECELERATION

TDI - acquisition• PW apical view• The sample volume should be positioned at or 1 cm within the septal and

lateral insertion sites of the mitral leaflets.• sweep speed of 50 to 100 mm/s at end-expiration ; average of >/= 3

consecutive cardiac cycles.• For the assessment of global LV diastolic function, it is recommended to

acquire and measure tissue Doppler signals at least at the septal and lateral sides of the mitral annulus and their average.

• In patients with cardiac disease, e’ can be used to correct for the effect of LV relaxation on mitral E velocity, and the E/e’ ratio can be applied for the prediction of LV filling pressures.

• The E/e’ ratio is not accurate as an index of filling pressures in normal subjects or in patients with heavy annular calcification, mitral valve disease and constrictive pericarditis

TDI

• Early diastolic filling velocity (e )′• Filling velocity after atrial contraction (A )′• Ratio of early to atrial diastolic myocardial

velocity (e /′ A )′• Ratio of transmitral blood flow velocity to

tissue Doppler velocity (E/e )′

Medial vs lateral annular velocities

• use the average (septal and lateral) e´ velocity in the presence of regional dysfunction

• septal E/e´ ratio <8 is usually associated with normal LV filling pressures a ratio >15 is associated with increased filling pressures• between 8 and 15, other echocardiographic indices should be used.• In normal EFs, lateral tissue Doppler signals(E/e ánd e´/a´)

have the best correlations with LV filling pressures and invasive indices of LV stiffness.

• TE-e´is particularly useful in situations in which the peak e´velocity has its limitations

the E/e´ ratio is 8 to 15.

• an IVRT/TE-e´ratio ,2 has reasonable accuracy in identifying patients with increased LV filling pressures

PCWP and E/e’

PCWP and E/e’

PCWP and E/e’

• pulmonary capillary wedge pressure usually is >20 mm Hg when E/e’ is >15 (e’from the medial annulus) or >12 (e’ from lateral annulus)

E/e’ ratio

• E/e’ is highly predictive of adverse events in acute myocardial infarction,hypertensive heart disease, severe secondary MR, end-stage renal disease, atrial fibrillation and cardiomyopathy

• The E/e’ ratio is among the most reproducible echocardiographic parameters to estimate PCWP and is the preferred prognostic parameter in many cardiac conditions.

Pulmonary venous flow - acquisition

• Apical 4 chamber• PW• Sample volume 2mm-3mm > 0.5 cm into the

pulmonary vein• Wall filter settings must be low enough to display

the onset and cessation of the atrial reversal (Ar) velocity waveform

• sweep speed of 50 to 100 mm/s at end expiration; average of >/=3 consecutive cardiac cycles.

PULMONARY VENOUS WAVE FORM

• peak systolic (S) velocity, peak anterograde diastolic (D) velocity , the S/D ratio

systolic filling fraction (Stime-velocity integral/[Stime-velocity integral?

• D time-velocity integral]) and the peak Ar velocity in late diastole.

• Other measurements are the duration of the Ar velocity, the time difference between it and mitral A-wave duration (Ar ? A)

• and D velocity DT. • There are two systolic velocities (S1 and S2

Acquisition – color M mode flow propagation velocity

• apical 4-chamber view• color flow imaging .• M-mode scan line is placed through the center of the LV inflow

blood column from the mitral valve to the apex. • color flow baseline is shifted to lower the Nyquist limit so that

the central highest velocity jet is blue.• Flow propagation velocity (Vp) is measured as the slope of the

first aliasing velocity during early filling, measured from the mitral valve plane to 4 cm distally into the LV cavity.

• Alternatively, the slope of the transition from no color to color is measured.

• Vp >50 cm/s is considered normal

Diastolic stress test

• supine bicycle or treadmill protocol.• E ; e’• TR jet assessed before and after exercise• Diastolic heart failure : E/e’ ratio increases and

pulmonary systolic pressure increases• In normal heart the ratio is maintained• Role of dobutamine ???

Estimation of LV filling in special populations

• Atrial fibrillation : measurements of average of 10 cycles

• Sinus tachycardia: E – A fusion occurs• Restrictive cardiomyopathy• Hypertrophic cardiomyopathy - Ar - A duration

(>30 ms) used to predict LVEDP• Pulmonary hypertension

Predictors of raised LVEDP

PCWP and various parameters

• Mean PCWP= 17+ (5XE/A)- (0.11 X IVRT)• E/Vp > 2.5 predicts PCWP > 15 mm Hg • T (E-e’) delayed in impaired relaxation• IVRT/ T (E-e’) < 2 predicts PCWP > 15 mm Hg• Ar velocity – mitral A >/= 30 ms – marker of

raised PCWP

Recent indices of diastolic function

Summary- diastolic parameters

Thank you