Echocardiographic Evaluation of Prosthetic Heart Valves

ECHOCARDIOGRAPHIC RECOGNITION,
FUNCTION AND DYSFUNCTION OF
PROSTHETICVALVES
DR.SOUMEN PRASAD BEHERA DM RESIDENT

JOSE VEGA (2010)
A surgical implant used to replace an
abnormal heart valve.

• Valvular heart disease affects >100 million people
worldwide and represents a growing problem
because of the increasing burden of degenerative
valve disease in the ageing population and of the still
high incidence of rheumatic heart disease in
developing countries.
• About 4 million prosthetic heart valve (PHV)
replacements have been performed over the past
50 years, and this remains the only definitive
treatment for most patients with severe valvular
heart disease.
• The total number of replacements is projected to
be 850 000 per year by 2050.

▪CLASSIFICATION OF PROSTHETIC HEART VALVES.
▪ECHOCARDIOGRAPHIC EVALUATION OF NORMAL
PROSTHETIC HEART VALVES
▪APPROACH TO AORTIC PROSTHETIC VALVES
▪APPROACH TO MITRAL PROSTHETIC VALVES
▪APPROACH TO PULMONARY AND TRICUSPID PHV
▪PROSTHETIC VALVE DYSFUNCTION
▪LIMITATIONS AND PITFALLS OF ECHO ASSESSMENT
OF PHV

CLASSIFICATION OF
PROSTHETIC HEART VALVES

PROSTHETIC
VALVES
MECHANICAL
VALVES
TISSUE VALVES
OR
BIOPROSTHESIS

MECHANICAL VALVE
Made of non biologic material
(pyrolitic carbon, polymeric
silicone substances, or titanium).
Caged ball
Tilting disk
BIOPROSTHETIC
VALVE
Human tissue
(homograft or
autograft)
Porcine tissue
Or bovine tissue
(heterograft)

TILTING
DISK
Single disk
prosthesis
Bileaflet
tilting disk

CAGED BALL VALVE
• The first artificial heart valve was the CAGED-
BALL, and the STARR-EDWARDS VALVE is by far
the most common (Fig.).
• It consists of a circular sewing ring on which is
mounted a U-shaped cage that contains a
silastic ball occluder.

caged-ball mechanical valves and their transesophageal echocardiographic
characteristics taken in the mitral position in diastole (UR) and in systole (LR).
The arrows in diastole point to the occluder mechanism of the valve and in
systole to the characteristic physiologic regurgitation observed with each valve.
DIASTOLE SYSTOLE

• When blood pressure in the chamber of the heart
(atrium) exceeds that of the pressure on the outside of
the chamber the ball is pushed against the cage and
allows blood to flow.
• At the completion of the heart's contraction, the
pressure inside the chamber drops and is lower than
beyond the valve, so the ball moves back against the
base of the valve forming a seal.
• To open, the ball moves forward into the cage, allowing
blood flow around the entire circumference.
• To occlude, the ball is driven back into the sewing ring
to prevent backflow.

• Edward lifesciences discontinued production of this
valve in 2007.
• Caged-ball mechanical prostheses have a small
amount of normal regurgitant flow (closing volume of
2–6 mL per beat).

SINGLE TILTING DISK
• The single tilting disk prosthesis consists of
✓ a round sewing ring
✓ a circular disk fixed eccentrically to the ring via a hinge.

• The disk moves through an arc of less than 90◦
(usually 55◦–85◦), thereby allowing antegrade flow in
the open position and seating within the sewing ring
to prevent backflow in the closed position.
• Because the hinge is eccentrically positioned within
the sewing ring and the disk opens less than 90◦,
major and minor orifices are created and some
stagnation of flow occurs behind the disk.

SINGLE TILTING DISK
transesophageal echocardiogram in mitral position
DIASTOLE (UR) SYSTOLE (LR).
The arrows in diastole point to the occluder mechanism of the
valve and in systole to the characteristic physiologic regurgitation
observed with each valve.

VALVE TYPE CHARACTERSTICS
BJORK–SHILEY VALVE • First type of single leaflet disc valve developed in 1969
• Approximately 600 reported cases of fractures in the
metal outlet struts holding the disc in place
MEDTRONIK HALL VALVE • Has a titanium housing, Teflon sewing ring and a carbon-
coated disc
• Thrombogenicity is low and mechanical performance is
excellent
OMNISCIENCE/
OMNICARBON VALVES
• Has a titanium housing, a polyester knit sewing ring in
which a pyrolytic carbon disc is suspended
• Omnicarbon valve is an all-pyrolytic carbon version of the
omniscience valve
MONOSTRUT VALVES • Both struts are machine connected to the housing to
reduce chances of strut fracture
ULTRACOR VALVES • Currently in use only outside the United States
• No significant hemolysis,
• Reported freedom from major systemic embolism was
99% for mitral and aortic valves
SUMMARY OF SINGLE DISC MECHANICAL VALVES

BILEAFLET TILTING DISK
• Bileaflet tilting disk valves consist of two semicircular
disks that open and close on a hinge mechanism
within the sewing ring.

• The opening angle is generally more vertical
(approximately 80◦) than the single disk
prosthesis.
• This results in three distinct orifices:
✓ two larger ones on either side and
✓ a smaller central rectangular-shaped orifice.

BILEAFLET TILTING DISK
transesophageal echocardiogram in mitral position
DIASTOLE (UR) SYSTOLE (LR).
The arrows in diastole point to the occluder mechanism of the
valve and in systole to the characteristic physiologic regurgitation
observed with each valve.

VALVE TYPE CHARACTERSTICS
ST. JUDE MEDICAL VALVE • Currently the most widely used valve that
consists of two semicircular leaflets functioning
in a unique hinge system
• Primarily made up of pyrolytic carbon, the valves
also contains tungsten for easy fluoroscopic
visualization after implantation
ST.JUDE REGENT VALVE • Is a modification of St. Jude medical valve in
supra annular cuff with carbon ring providing
greater orifice area for a given annular diameter.
CARBOMEDICS VALVE • Consists of titanium ring, pyrolytic carbon
housing and pyrolytic carbon coated leaflets.
SUMMARY OF BILEAFLET MECHANICAL VALVES

VALVE TYPES CHARACTERSTICS
MEDTRONIC
ADVANTAGE
VALVE
• Is a newer version bileaflet valve designed
to provide a large central flow area with
optimal blood flow through and across the
valve.
• The valve consists of cylindrical pyrolytic
carbon housing with two pyrolytic carbon
leaflets that open to 86*
Continued...
SORIN BIOCARBON VALVE EDWARD MIRA VALVE
OTHER EXAMPLES:

BIOLOGICAL (BIOPROSTHETIC) HEART VALVES
❑ Made up of human or animal tissue.
❑ Some valves may have some artificial parts to
help give the valve support and to aid
placement.
❑ Once the tissue is removed from the animal, it
is chemically treated to preserve the tissue and
prevent immunologic reaction once it is placed
in a patient.

BIOPROSTHETIC
VALVES
XENOGRAFT
(HETEROGRAFT)
HOMOGRAFT AUTOGRAFT

STENTED
PORCINE
XENOGRAFT
PERICARDIAL
XENOGRAFT
STENTLESS
PORCINE
XENOGRAFT
PERICARDIAL
XENOGRAFT

PORCINE STENTED VALVES
 The porcine stented valve was the first generation of
porcine tissue valves.
 They have been available for more than 30 years.
 The valves are made from natural porcine aortic
valves, but may be used for aortic or mitral valve
replacement.
 They are preserved and fixed within a polypropylene
mount attached to a Dacron sewing ring.
 Because the tissue has been preserved, it is less
pliable than native valve tissue.
 The leaflets themselves are supported by stents,
which vary in number and design and arise vertically
from the sewing ring.

• Carpenter-Edwards
• Hancock II

ECHOCARDIOGRAPHIC FEATURES IN DIASTOLE (LEFT)
AND IN SYSTOLE (RIGHT) AS SEEN BY TEE.

VALVE CHARACTERSTICS
Hancock
standard
mitral
bioprosthesis
• First commercial tissue-treated porcine valve
introduced in 1970
• Freedom from structural valve deterioration at
10 years after mitral valve replacement ranges
from 74% to 94%, and at 15 years is around
38% for the age group 50–59 years and around
62% for above 70 years of age
Hancock
modified
orifice aortic
bioprosthesis
• Fabricated trileaflet porcine valve with a
composite design where the right coronary cusp
and its flow impeding muscle shelf is replaced
with a noncoronary cusp from a second valve
• All three flexible leaflets open completely and
symmetrically allowing maximal blood flow
STENTED PORCINE BIOPROSTHETIC VALVES

Hancock II aortic
and
Mitral bioprostheses
• Incorporated several design modifications
(such as thinner stent wall, reduced
muscular shelf, reduced sewing cuff )
with the aim of improving hemodynamics,
facilitate implantation, and increase
durability
Hancock modified
orifice II
aortic bioprosthesis
• Combines the features of modified orifice
and Hancock II valve to improve the valve
area and the hemodynamics

Mosaic aortic and mitral
bioprostheses
• Has anticalcification treatment with alpha amino oleic acid
• suitable for supra-annular positioning
Carpentier–Edwards
tissue valves
• Consists of natural porcine aortic valves with wire stent
covered with polytetrafluoroethylene cloth to enhance the
tissue in growth
• Their supra-annular designs are intended to permit an orifice
area comparable to the patient’s annulus, thus improving
hemodynamics
Biocor St Jude Medical
tissue valve
• Has a zero-pressure fixation and a supra-annular
configuration with a low incidence of valve-related
complications
Epic valve • Combines the features of the Biocor valve with
anticalcification treatment, and silver coating of the sewing
ring and stent cloth covering to prevent infective endocarditis
CONTINUED. . .

PORCINE STENTLESS VALVE
▪ The porcine stentless valve is used for aortic valve
replacement.
▪ The valve is made from a natural porcine aortic valve and is
fixed in buffered glutaraldehyde solution at a low pressure.
▪ No stents or synthetic sewing rings are used.
▪ Therefore, these valves are very similar to the homograft valve.
▪ These valves are technically more difficult to implant but are
useful in patients with small hypertrophied hearts.

ECHOCARDIOGRAPHIC FEATURES IN DIASTOLE (LEFT) AND IN
SYSTOLE (RIGHT) AS SEEN BY TEE.

Medtronic
freestyle
aortic root
bioprosthesis
• Stentless design that allows full-root, root-inclusion, and subcoronary
(complete and modified) implantation.
• An 8-year follow-up study showed survival after
✓ implantation was 59%,
✓ freedom from thromboembolic complications was 83%,
✓ freedom from postoperative endocarditis was 96%, and
✓ freedom from reoperation was 100% and there was no change in the
mean systolic gradients across the valve
Toronto
stentless
porcine valve
• Allows for subcoronary implantation; has a cloth covering that
separates the valve from the host aorta wall to facilitate suturing and
to promote tissue in growth.
• Achieves transvalvular gradients comparable to that of native valves
and provides 31% more orifice area than stented bioprostheses

Biocor
stentless
valve
• Has an anticalcification treatment for durability.
• Freedom from structure valve deterioration was
92% at aortic position at an 8-year follow-up
Cryolife–
Ross valve
• Low-pressure fixation with glutaraldehyde.
• Highly symmetric design where three
noncoronary cusps are sewn together
Continued. . .

PERICARDIAL VALVES
The Carpentier-Edwards PERIMOUNT
Pericardial Bio prosthesis
• Pericardial valves include the Perimount series
valves (Edwards Life Sciences).
• Ionescu-Shiley pericardial valves have been
discontinued.
• They offer improved hemodynamics with a
decreased transvalvular pressure gradient when
compared with older stented models.

A NORMALLY FUNCTIONING PORCINE AORTIC PROSTHESIS
• Leaflet opening during systole resembles that of a normal native valve.
• The overall appearance is so similar, in fact, that normally functioning
aortic bioprostheses are occasionally mistaken for “normal” aortic valves
when historical information is not available.
• When examined carefully, however, the sewing ring and struts are more
echogenic than normal and tend to shadow the leaflets, a clue to the
presence of prosthetic material.

▪ HOMOGRAFTS, OR ALLOGRAFTS
(I.E, HUMAN VALVES)
• Obtained from cadaver tissue donations.
• The aortic valve and a portion of the aorta
or the pulmonic valve and a portion of the
pulmonary artery are harvested and
stored cryogenically.
• Homografts are not always available and
are very expensive.

▪ AUTOGRAFTS (I.E, AUTOLOGOUS VALVES)
▪ Obtained by excising the patient’s own pulmonic valve
and a portion of the pulmonary artery for use as the
aortic valve.(Ross procedure)
▪ Anticoagulation is unnecessary because the valve is the
patient’s own tissue and is not thrombogenic.
▪ The autograft is an alternative for :
children (it may grow as the child grows),
women of childbearing age,
young adults,
patients with a history of peptic ulcer disease,
those who cannot tolerate anticoagulation.

CHOICE OF PROSTHETIC VALVE
2017 AHA/ACC Focused Update of the 2014
AHA/ACC Guidelines
NISHIMURA ET AL. 2017 VHD FOCUSED UPDATE

COR LOE RECOMMENDATION
I C-LD
(LIMITED
DATA)
The choice of type of prosthetic heart valve should be a shared
decision-making process that accounts for the patient’s values and
preferences and includes discussion of the indications for and risks of
anticoagulant therapy and the potential need for and risk associated
with reintervention
C A bioprosthesis is recommended in patients of any age for whom
anticoagulant therapy is contraindicated, cannot be managed
appropriately, or is not desired.
II-a B-NR An aortic or mitral mechanical prosthesis is reasonable for patients
less than 50 years of age who do not have a contraindication to
anticoagulation
B-NR For patients between 50 and 70 years of age, it is reasonable to
individualize the choice of either a mechanical or bioprosthetic valve
prosthesis on the basis of individual patient factors and preferences,
after full discussion of the tradeoffs involved.
B A bioprosthesis is reasonable for patients more than 70 years of age
IIb C Replacement of the aortic valve by a pulmonary autograft (the Ross
procedure), when performed by an experienced surgeon, may be
considered for young patients when VKA anticoagulation is
contraindicated or undesirable

FAVOR MECHANICAL PROSTHESIS FAVOR BIOPROSTHESIS
Age <50 yrs
• Increased incidence of structural deterioration
with bioprosthesis (15-y risk: 30% for age 40 y,
50% for age 20 y)
• Lower risk of anticoagulation complications
Age >70 yrs
• Low incidence of structural
deterioration (15-y risk: <10% for age
>70 yr)
• Higher risk of anticoagulation
complications
Patient preference (avoid risk of
reintervention)
Patient preference (avoid risk and
inconvenience of anticoagulation
and absence of valve sounds)
Low risk of long-term anticoagulation High risk of long-term anticoagulation
Compliant patient with either home monitoring or
close access to INR monitoring
Limited access to medical care or
inability to regulate VKA
Other indication for long-term anticoagulation
(e.g., AF)
Access to surgical centers with low
reoperation mortality rate.
High-risk reintervention (e.g., porcelain aorta,
prior radiation therapy)
Small aortic root size for AVR (may preclude valve-
in-valve procedure in future).
FACTORS USED FOR SHARED DECISION MAKING ABOUT TYPE OF VALVE PROSTHESIS

ECHOCARDIOGRAPHIC EVALUATION
OF PROSTHETIC HEART VALVES

▪2D TTE is recommended as first-line imaging
in PHV.
▪TTE is also the method of choice for Doppler
signal recordings.
▪Both TTE and TOE are needed for complete
evaluation in a patient with suspected PHV
dysfunction.
▪3D echocardiography, especially with TOE,
can provide additional information and is
increasingly used.

❑ For both TTE and TOE, it is essential to obtain
images in multiple views and multiple planes to
ensure complete visualization of the valvular and
paravalvular region.
❑ Liberal use of zoom and focused imaging is
highly recommended.
❑ TTE/TOE has higher sensitivity in mitral than
aortic position for examining disc valve motion.
❑ For the evaluation of PHV regurgitation, TOE is
superior in mitral/tricuspid position while TTE is
better in aortic position.

❑ TOE, especially when completed by 3D
evaluation, remains superior for assessing
paravalvular regurgitation.
❑ A comprehensive echocardiographic study
is indicated in case of new murmur or any
symptoms possibly related to PHV.
❑ When obtained early after hospital
discharge, it can serve to define baseline
PHV characteristics (‘fingerprint’).

PHV
essential
information
CLINICAL
INFORMATION
DOPPLERIMAGING
PROSTHETIC HEART VALVE EVALUATION

CLINICAL INFORMATION NEEDED TO
EVALUATE PROSTHETIC VALVES

IMAGING
▪MORPHOLOGICAL
CHARACTERSTICS.
▪HEMODYNAMIC
CHARACTERSTICS.

DOPPLER
CONTOUR OF JET VELOCITY
PEAK VELOCITY
PEAK/MEAN PRESSURE GRADIENT
VTI OF THE JET
DOPPLER VELOCITY INDEX
PRESSURE HALF TIME
EFFECTIVE ORIFICE AREA
PRESENCE,LOCATION AND SEVERITY OF
REGURGITATION

ECHOCARDIOGRAPHIC IMAGING OF PROSTHETIC
HEART VALVES
(MORPHOLOGICAL CHARACTERSTICS)
• LEAFLET/DISC MORPHOLOGY
• LEAFLET/DISC MOBILITY
• SEWING RING: SEPARATION, ROCKING, ABSCESS,
FISTULA
• PRESENCE OF ABNORMAL MASSES, SUCH AS THROMBI
OR VEGETATIONS
• COLOR FLOW FOR CENTRAL OR PARAVALVULAR
REGURGITATION
• ABNORMAL ECHOES

• M-mode echocardiogram of a St. Jude mitral prosthetic
valve.
• M-mode echocardiography is ideal to record the brisk
opening and closing of the disks (arrows). IVS,
interventricular septum; MV, mitral valve.

2D and 3D as well as 2D and 3D colour flow appearance of a bileaflet
mechanical valve in the closed position from the atrial perspective

2D and 3D as well as 2D and 3D color flow appearance of a bileaflet
mechanical valve in the opened position from the atrial perspective

(D) 3D perspective. Of a bioprosthetic valve
(E) The atrial aspect of a normal bioprosthetic valve in mitral
position in diastole from a 3D perspective. The ring of the
prosthesis as well as the atrial surface of the three leaflets in
systole are seen.

ACOUSTIC SHADOWING
• Prosthetic materials, particularly in mechanical models, cause
numerous ultrasound artefacts, including
✓ acoustic shadowing,
✓ reverberations,
✓ refraction, and
✓ mirror artefacts
• This often affects imaging quality and is even more
pronounced in case of double PHVs.
• Multiple and sometimes off-axis views must be used to
overcome these problems and interrogate areas around the
prostheses.
• At lower gain settings, the valves are generally better
visualized.

The presence of a St. Jude aortic prosthesis (arrows) creates a pattern of
reverberations that extends into the left atrium.
This creates a shadowing effect and can obscure the presence of mitral regurgitation

• Generally, the left/right atrial (LA/RA) side of a
prosthetic mitral/ tricuspid valve is obscured by
acoustic shadowing from the TTE approach, resulting
in a low sensitivity for detection of prosthetic mitral
or tricuspid regurgitation (MR, TR), thrombus,
pannus, or vegetation.
• TOE provides superior images of the LA/RA side of
the mitral/tricuspid prosthesis.
• For stented valves, the ultrasound beam should be
carefully aligned parallel to the flow to avoid
shadowing effects of the stents and sewing ring.

Acoustic shadowing and reverberations seen with 2D transthoracic and transesophageal
echocardiography when imaging a mechanical valve in mitral position depending on the
acoustic view used (A and B, acoustic shadowing and reverberations on the atrial side
(LA) vs. C and D on the ventricular (LV) side.

Mechanical valve in mitral position: cavitation and strands.
(A) Cavitation (yellow arrow) inside the left ventricular cavity related to the
presence of a mechanical valve in mitral position, as seen from the apical
transthoracic approach.
(B) Fibrin strands (orange arrow) seen as fine filamentous masses attached to
the atrial side of a mechanical valve in mitral position as seen from the
transoesophageal approach.

HEMODYNAMIC CHARACTERSTICS
OF PROSTHETIC HEARTVALVES
a) BLOOD FLOW THROUGH NORMALLY
FUNCTIONING PROSTHETICVALVES
b) SHAPE AND NUMBER OF ORIFICES THROUGH
WHICH FORWARD FLOW OCCURS
c) PRESSURE RECOVERY
d) NORMAL, OR PHYSIOLOGIC, REGURGITATION

BLOOD FLOW THROUGH NORMALLY
FUNCTIONING PROSTHETIC VALVES
Blood flow through normally functioning prosthetic valves
differs from flow through native valves in several
important ways.
❑ Artificial heart valves are inherently stenotic.
❑ There is a variety of explanations for this consistent
observation.
❑ The sewing ring of the valve may be too small relative to
the flow.
❑ In young patients, what passes for an adequately sized
valve in childhood may become functionally stenotic as
the patient grows.

❑ More importantly, the effective orifice area is
significantly smaller than the area of the sewing ring
because the valve assembly (i.e., the occluder
mechanism) occupies some of the central space.
❑ Leaflets of bioprostheses, by virtue of the preservation
process, are stiffer and therefore these valves have a
higher resistance to forward flow compared with
equivalently sized native valves.
❑ Thus, flow velocity through a normally functioning
artificial valve is generally higher than would occur
through a normal native valve.
❑ However, the range of velocities through a normally
functioning bioprosthesis is considerable.
❑ Both valve size and type determine the pressure
gradient that one can expect in the absence of
dysfunction.

Stented bioprosthetic valves
(high gradient flow)
Mechanical valves
Stentless
bioprosthetic
valves
For all these reasons, the range of velocities that must be
considered normal varies widely among prosthetic valves.

SHAPE AND NUMBER OF ORIFICES THROUGH
WHICH FORWARD FLOW OCCURS
▪ It is an important difference between native and
prosthetic valves.
▪ A bileaflet tilting disk valve has three separate orifices,
a rectangular-shaped central orifice surrounded by two
larger semicircular orifices.
▪ Flow velocity is highest through the central orifice, and
if this flow is sampled with continuous wave Doppler
imaging, an overestimation of the true gradient can
occur.
▪ This is because flow through all three orifices
contributes to net gradient.

▪ By only sampling the highest velocity through the
central orifice and ignoring lower velocity flow through
the other two, an overestimation of true gradient
occurs.
▪ Flow through a caged ball valve does not go through a
well-defined orifice but rather goes around the
periphery of the spherical occluder .
▪ The variability and orientation of the flow complicate
the Doppler interrogation of these valves.
▪ Flow through bioprostheses is often triangular in shape
and may occur through an area that is significantly
smaller than the sewing ring itself.
▪ All these factors contribute to the challenges inherent to
assessing prosthetic valve function by any technique.

PRESSURE RECOVERY
 A potentially important phenomenon affecting
flow through prosthetic valves.
 When evaluating the peak velocity and pressure
gradient across the PHVs, the CW doppler picks
up the maximum velocity just at the tips of the
prosthesis leaflets/occluders, which is where the
maximum drop would occur.
 As the velocity of blood flow decreases towards
ascending aorta, a part of this kinetic energy
gets converted into static energy or pressure.
 This phenomenon is called pressure recovery.

 If an invasive catheter is placed at ascending
aorta about 2-3 cm beyond the valve, then this
area of ascending aorta will record a higher
pressure due to pressure recovery.
 Thus the net difference of pressure between LV
and this point will be lower as compared to
that derived from the instantaneous peak
gradient picked by CW doppler .
 The pressure recovery is negligible for mitral
valves because the downstream chamber or the
LV is large.

The concept of pressure recovery.
A: Flow through a tapered stenosis results in significant pressure recovery
downstream from the obstruction. In this case, sampling within the
obstruction (SV1) yields a higher velocity compared with a sample site
downstream (SV2) where pressure recovery has occurred. At this site, the
recovery of pressure is associated with a lower velocity.
B: In the absence of pressure recovery, different locations for sample
volume (SV) measurement yield fairly similar velocities.

NORMAL, OR PHYSIOLOGIC, REGURGITATION
• Another unique aspect of prosthetic valve
function.
• This occurs with virtually all types of
mechanical prostheses and is actually part of
the design of the valve.
• Physiologic regurgitation can be divided into
two types:
closure backflow and
leakage.

• Closure backflow occurs because of the flow
reversal required to close the occluding
mechanism.
• This results in a small amount of regurgitation
that ends once the occluder mechanism is
seated in the sewing ring.
• Leakage backflow occurs after the prosthesis
has closed and is the result of a small amount
of retrograde flow between and around the
occluding mechanism.
• It is often part of the design of the prosthesis
to provide a washing mechanism and prevent
thrombus formation on its upstream side.

• Because leakage backflow may be
holosystolic (or holodiastolic, depending
on valve location), it must be
distinguished from pathologic
regurgitation.
• This depends on the severity and the
pattern of regurgitation.
• For example, leakage through a bileaflet
valve often results in two symmetric
narrow jets directed obliquely from the
edges of the valve.

PHYSIOLOGICAL PROSTHETIC
REGURGITATION
JET AREA < 2 CM2 JET LENGTH < 2.5 CM

PHYSIOLOGIC REGURGITATION through a
normally functioning St. Jude mitral prosthesis
(arrows)

• Normal bio prosthetic valves may also exhibit mild
regurgitation.
PHYSIOLOGIC REGURGITATION through a
porcine aortic prosthesis (arrow)
• Some pericardial valves demonstrate mild central
regurgitation that resolves 4 to 6 weeks after
implantation.

Physiologic regurgitation through a St. Jude aortic valve.
The jets originate at the periphery and appear to cross just
below the valve (arrow).
The occurrence of this type of regurgitation is part of the design
of many prosthetic valves.

DOPPLER EVALUATION OF
PROSTHETIC HEARTVALVES
•The principles of interrogation and recording of flow
velocity through prosthetic valves are similar to those
used in evaluating native valve stenosis or regurgitation.
•This includes
✓pulsed-wave (PW)
✓continuous-wave (CW) Doppler
✓color Doppler
using several windows for optimal recording and
minimizing angulation between the Doppler beam and
flow direction.

DOPPLER
CONTOUR OF JETVELOCITY
PEAKVELOCITY
PEAK/MEAN PRESSURE GRADIENT
VTI OFTHE JET
DOPPLERVELOCITY INDEX
PRESSURE HALFTIME
EFFECTIVE ORIFICE AREA
PRESENCE,LOCATION AND SEVERITY OF
REGURGITATION

VELOCITY CONTOUR AND
ACCELERATION TIME
 The shape of the velocity trace gives important
clues to the presence or absence of significant
stenosis of the prosthesis.
 Normal contour is triangular with early peaking
and short acceleration time or AT while with
increasing severity of the stenosis the contour
becomes more and more rounded with late peaking
shape and increased AT (>100 ms).

• A ratio of AT to ejection time (ET) > 0.4 is also
suggestive of stenotic PHV.
• However, severe LV dysfunction or severe PPM may
also increase AT and confound the interpretation.

The following Figure illustrates flow through different types of mitral
prostheses.
There is variability in the contour and velocity among the four examples.
Gradients across “normal” prosthetic valves vary across a wider range
compared with native valves.

• Despite differences in flow characteristics, the basic
Doppler principles applied to native valves are also
relevant to the study of prosthetic valves.
• For example, Doppler imaging can be used to measure
both the maximal and mean pressure gradient across
prostheses (Fig.).

DETERMINATION OF GRADIENTS
ACROSS PROSTHETIC VALVES.
• Blood velocity across a prosthetic valve is
dependent on several factors, including flow
and valve size and type.
• The simplified Bernoulli equation has been
the key to the noninvasive calculation of
pressure gradients across all cardiac valves,
including prosthetic valves,
whereby pressure gradient is
derived as 4 V2 , where V is the velocity of the jet
in meters per second.

• In patients with aortic prostheses and high
cardiac output or narrow LV outflow (LVO),
the velocity proximal to the prosthesis may be
elevated and therefore not negligible
(proximal velocity > 1.5 m/s).
• In these situations, estimation of the pressure
gradient is more accurately determined by
considering the velocity proximal to the
prosthesis as
PG = 4(V22-V12)

• Pressure gradients derived with the simplified
Bernoulli equation have correlated well with
hemodynamically measured gradients.
• In bileaflet prostheses and caged-ball valves, however,
overestimation of the gradient may occur, particularly
with smaller valves and high cardiac output.
• Usually, a mean gradient of >20 mm Hg for aortic PHV
and >5 mm Hg for mitral prosthesis should prompt a
thorough evaluation for stenosis of PHV.

• However, because of the existence of multiple
jets through many types of prosthetic valves,
more than one velocity pattern can often be
recorded.
• The phenomenon of pressure recovery may
also lead to overestimation of the pressure
gradient.

Examples of flow through two different St. Jude aortic prosthetic
valves.
A: Flow velocity is normal and crisp valve clicks are present.
B: Jet velocity is increased, indicating a peak pressure gradient of
approximately 77 mm Hg. Valve clicks, especially at the time of valve
opening, are diminished

• For this reason, it is often helpful to obtain a
baseline Doppler imaging study in all patients
at a time when the valve is known to be
functioning normally, such as during the first
postoperative clinic visit.
• This can then be used as a reference for future
evaluations to help determine whether a given
pressure gradient is normal or abnormal for the
individual.
• In addition, tables have been published
providing a range of normal values for different
types of valves in the various positions.

 The continuity equation is invalid or inaccurate when
there is concomitant moderate or severe aortic or mitral
regurgitation.
 It is always preferable to calculate the EOA of the
implanted PHV by continuity equation and compare it
with the reference EOA for the model and size of the
PHV implanted.
 Fixed cut-offs are misleading especially for the small
diameter PHVs.

DOPPLER VELOCITY INDEX
• The Doppler velocity index is a dimensionless
ratio of LVOT velocity by PW Doppler to the
velocity by CW Doppler across the aortic
prosthesis.
• VTI may also be used instead.
• A ratio of 0.30 or less is abnormal, while a value
less than 0.25 is suggestive of significant PHV
stenosis at aortic position.
DVI = (LVOT )VTI
(AOV )VTI

• In case of mitral PHV, VTI across the mitral PHV by CW
Doppler divided by LVOT VTI.
DVI = VTI (MV)
VTI (LVOT)
• A ratio of 2.5 or more is suggestive of significant PHV
stenosis at mitral position.
• DVI is a reliable and quick method to assess PHV
stenosis especially when the CSA of the LVOT is
unreliable or difficult to obtain.
• This also eliminates the errors, which are common
with LVOT-VTI assessments.

PRESSURE HALF TIME
• Not appropriate to calculate the PHT formula to
estimate orifice area in case of PHVs.
• For large valve areas, PHT reflects atrial and LV
compliance characteristics and loading
conditions and has no relation to valve area.

• However, pressure half-time generally
overestimates the valve area in the presence of
a mitral prosthesis.
• Hence having a baseline study and using the
patient as his or her own control is essential for
future management.
• Also, unlike native valves the concept of pressure half
time (PHT) has not been validated for EOA calculation
of a mitral PHV.
• However, significantly prolonged PHT (>200 msec)
may be suggestive of stenotic mitral PHV.

• Doppler recordings should be performed at a sweep
speed of 100 mm/s.
• Measurements should be taken over 1 to 3 cycles in
sinus rhythm.
• In atrial fibrillation, Doppler measurements should
be performed when possible during periods of
physiologic heart rate (65-85 beats/min). Averaging
from 5 to 15 beats in atrial fibrillation has been
suggested but is cumbersome and may still give an
unrepresentative result, because cycle lengths may
vary substantially.

• In cases in which the derivation of a parameter
requires measurements from different cardiac
cycles (eg, EOA by the continuity equation, DVI),
matching of the respective cycle lengths to within
10% is advised.

A: A porcine mitral prosthesis is visualized using
transesophageal echocardiography.
B: Color Doppler imaging demonstrates both
transvalvular and perivalvular (arrow) mitral
regurgitation

APPROACH TO MITRAL
PROSTHETIC VALVE

MITRAL PHV DOPPLER PARAMETERS
PARAMETER NORMAL POSSIBLE
STENOSIS
SUGGESTIVE OF
STENOSIS
PEAK
VELOCITY(m/s)
<1.9 1.9-2.5 >2.5
MEAN
GRADIENT(mm Hg)
≤5 6-10 >10
EOA(cm2) >2.2 1-2 <1
DVI <2.2 2.2-2.5 >2.5
PHT <130 130-200 >300

ECHO GRADING OF SEVERITY OF
PROSTHETIC MITRAL VALVE
REGURGITATION

PARAMETER MILD MODERATE SEVERE
LV SIZE NORMAL NORMAL OR
DILATED
DILATED
PROSTETIC VALVE USUALLY
NORMAL
ABNORMAL ABNORMAL
COLOR FLOW JET
AREA
SMALL,CENTRAL
JET(USUALLY < 4
cm2,< 20% OF
LA AREA)
VARIABLE LARGE CENTRAL
JET(USUALLY > 8
cm2 OR > 40%
OF LA AREA)
REGURITANT
VOLUME(ML/BEAT)
<30 30-59 >60
REGURGITANT
FRACTION(%)
<30 30-49 >50

INCOMPLETE OR
FAINT
DENSE DENSE
PARABOLIC USUALLY PARABOLIC EARLY PEAKING,
TRIANGULAR

SYSTOLIC
DOMINANCE
SYSTOLIC
BLUNTING
SYSTOLIC FLOW
REVERSAL

APPROACH TO AORTIC
PROSTHETIC VALVE

AORTIC PHV DOPPLER PARAMETERS
PARAMETER NORMAL POSSIBLE STENOSIS SUGGESTIVE OF
STENOSIS
JET CONTOUR TRIANGULAR,
EARLY PEAKING
INTERMEDIATE ROUNDED,
SYMMETRICAL
PEAK VELOCITY(m/s) <3 3-4 >4
MEAN
GRADIENT(mm Hg)
<20 20-35 >35
EOA(cm2) >1.2 0.8-1.2 <0.8
DVI >0.30 0.25-0.29 <0.25
ACCELERATION
TIME(AT)(msec)
<80 80-100 >100

ECHO GRADING OF SEVERITY OF
PROSTHETIC AORTIC VALVE
REGURGITATION

MECHANICAL OR
BIOPROSTHETIC
USUALLY
NORMAL
ABNORMAL ABNORMAL
LV SIZE NORMAL NORMAL OR
MILDLY DILATED
DILATED
JET/LVOT I CENTRAL
JETS
<25% 25-65 % >65%
JET DENSITY
CW DOPPLER
INCOMPLETE OR
FAINT
DENSE DENSE
JET DECELERATION
TIME(PHT)
> 500 200-500 <200
DIASTOLIC FLOW
REVERSAL IN
DESCENDING AORTA
ABSENT OR
EARLY DIASTOLIC
INTERMEDIATE PROMINENT OR
HOLODIASTOLIC
REGURITANT
VOLUME(ML/BEAT)
<30 30-59 >60
REGURGITANT
FRACTION(%)
<30 30-50 >50

APPROACH TO PULMONARY
PROSTHETIC VALVE

FINDINGS SUSPICIOUS OF PROSTHETIC
PULMONARY VALVE STENOSIS
 Cusp or leaflet thickening or immobility.
 Peak velocity through the prosthesis > 3 m/s or > 2
m/s through a homograft.
 Increase in peak velocity on serial studies.
(more reliable parameter)
 Impaired RV function or elevated RV systolic pressure.

EVALUATION OF PROSTHETIC
PULMONARY VALVE
REGURGITATION

VALVE STRUCTURE USUALLY NORMAL ABNORMAL OR
VALVE
DEHUSCENCE
ABNORMAL OR
VALVE
DEHUSCENCE
RV SIZE NORMAL NORMAL OR
DILATED
DILATED
JET SIZE (CENTRAL
JETS)
THIN WITH A
NARROW ORIGIN,
JET WIDTH < 25% OF
PULMONARY
ANNULUS
50% OF
PULMONARY
ANNULUS
> 50% OF
PULMONARY
ANNULUS
JET DENSITY,CW INCOMPLETE OR
FAINT
DENSE DENSE
JET DECELERATION
RATE ,CW
SLOW
DECELERATION
VARIABLE STEEP,EARLY
TERMINATION OF
DIASTOLIC FLOW
DIASTOLIC FLOW
REVERSAL IN THE
PULMONARY
ARTERY
NONE PRESENT PRESENT

Examples of a normal prosthetic pulmonary valve and that of an obstructed
pulmonary homograft showing dilatation of the right ventricle and a
deformed septum.
The obstructed homograft had a maximal gradient of 64 mm Hg.

APPROACH TO TRICUSPID
PROSTHETIC VALVE

ECHO GRADING OF SEVERITY OF PROSTHETIC TRICUSPID VALVE
REGURGITATION
VALVE STRUCTURE USUALLY NORMAL ABNORMAL OR
VALVE
DEHISCENCE
ABNORMAL OR
VALVE
DEHISCENCE
JET AREA (cm2) <5 5-10 >10
VC WIDTH (cm) N.D <0.7 >0.7
JET DENSITY AND
CONTOUR BY CW
DOPPLER
FAINT,
PARABOLIC
DENSE,VARIABLE
CONTOUR
DENSE WITH
EARLY PEAKING
DOPPLER
SYSTOLIC HEPATIC
FLOW
NORMAL OR
BLUNTED
BLUNTED HOLOSYSTOLIC
REVERSAL
RA,RV,IVC NORMAL DILATED MARKEDLY
DILATED

• Transthoracic echocardiographic and Doppler images in a patient with normal prosthetic tricuspid
valve and another with prosthetic stenosis.
• The case with normal prosthetic valve function had mildTR and a large central inflow jet in diastole.
• The patient with tricuspid valve stenosis had an eccentric narrow jet with an elevated velocity and
mean gradient

SPECIFIC CAUSES OF DYSFUNCTION
Obstruction:
A common cause of obstruction results from a mismatch
between the valve and the patient.
(PATIENT-PROSTHESIS MISMATCH)
▪ In this situation, the prosthesis functions as intended but
is too small to accommodate the necessary flow.
▪ When the effective orifice area is small relative to the
patient’s body surface area, hemodynamic abnormalities
occur.
▪ This results in the generation of a significant pressure
gradient across the valve.

• A common reason for prosthesis-patient mismatch
occurs in young patients who outgrow their prosthetic
valve.
• Small patients, especially women, are prone to this
condition because of the necessity to implant small
prostheses that result in suboptimal hemodynamics.
• A form of prosthesis-patient mismatch often involves a
prosthetic valve that functions adequately at rest but
is unable to accommodate the hemodynamic demands
of exercise.
• It should be known that a high flow velocity alone is
not proof of an obstructed prosthesis.
• A high cardiac output and/or severe regurgitation are
additional causes of increased velocity without
obstruction.

GRADINGTHE SEVERITY OF PPM
AORTICVALVE MITRALVALVE
PPM iEOA
INSIGNIFICANT >0.85 cm2/m2
MODERATE 0.65-0.85
cm2/m2
SEVERE < 0.65 cm2/m2
PPM iEOA
INSIGNIFICANT >1.2 cm2/m2
MODERATE 0.9-1.2 cm2/m2
SEVERE < 0.9 cm2/m2

• OTHER CAUSES OF OBSTRUCTION:
• Obstruction can occur as a result of technical
difficulties encountered while implanting the
prosthesis.
• INTRAOPERATIVE STUCKING OF PROSTHETIC
VALVE LEAFLET that results in immobility of one
hemidisk ,resulting in both stenosis and regurgitation.
• THROMBUS AND PANNUS FORMATION
i. Thrombotic interference is the most common cause of
obstruction of mechanical prostheses.
ii. It may develop gradually over time or occur suddenly
with catastrophic consequences.

THROMBUS
• MORE MOBILE.
• LESS ECHOGENIC
PANNUS
• LESS MOBILE.
• MORE DENSE AND
ECHOGENIC.
• Pannus is the result of ingrowth
of fibrous tissue at the interface
between prosthetic material and
native tissue.
• It is usually confined to the area
around the sewing ring.

Pannus formation on a St Jude Medical valve prosthesis in the aortic position
as depicted by TEE.
The mass is highly echogenic and corresponds to the pathology of the pannus
at surgery. The pannus is depicted by the arrows. LA, Left atrium; LV, left
ventricle

A large thrombus is visualized on transthoracic (A) and transesophageal (B) imaging.
The thrombus can be seen on the left atrial aspect of the mitral prosthesis (arrows).
B: Multiple thrombi were demonstrated (arrows) adjacent to the sewing

• A relatively small thrombus in a location that interferes
with opening of the ball or disk can result in a
substantial increase in the pressure gradient across the
prosthetic valve.
• The abnormality may be either permanent or
intermittent and may or may not be associated with
regurgitation.
• Transthoracic echocardiography has low sensitivity for
visualizing obstructive thrombi affecting mechanical
prostheses.
• Most often, prosthesis dysfunction is suspected when
transthoracic Doppler imaging reveals evidence of an
increased pressure gradient.
• Then, the precise cause of the gradient is determined
with transesophageal imaging.

The most common cause of prosthesis obstruction is the presence
of a thrombus.
In this example,
A : a small thrombus was barely visible on transesophageal imaging
B: Color Doppler imaging demonstrates increased turbulence but
no significant mitral regurgitation.
C: Doppler imaging confirms obstruction by demonstrating a very
high mean pressure gradient of 29 mm Hg.

• Occasionally, a larger thrombus can be
seen with the transthoracic approach.
• Careful scrutiny of the motion of the
occluder is a key to diagnosis.
• The range of occluder motion should be
assessed from multiple planes.
• M-mode echocardiography can be helpful
in this setting.

• Bioprosthetic valves may become obstructed
through the process of FIBROCALCIFIC
DEGENERATION, a primary degenerative
process that occurs slowly and leads to
prosthesis obstruction, almost always with a
component of regurgitation.
• Up to 35% of porcine prostheses fail within 10
to 15 years of implantation, most with a
component of primary tissue degeneration.
• Pericardial valves appear somewhat more
durable.

• The risk of significant fibrocalcific
degeneration is greater for valves in the mitral
position and much higher in younger versus
older patients.
• Two-dimensional imaging demonstrates
increased echogenicity and decreased mobility
of the leaflets and Doppler imaging can be
used to confirm an abnormally high pressure
gradient across the valve.
• The fibrocalcific changes may mimic
endocarditis and distinguishing vegetation
from degeneration may be impossible on the
basis of appearance alone.

A, severe fibrocalcific degeneration is
demonstrated by the arrows.
B, color Doppler imaging indicates
turbulent antegrade flow through the
calcified leaflets.
C, continuous wave Doppler confirms
obstruction with a high mean
transmitral pressure gradient. This is the
result of primary tissue degeneration of
the prosthetic valve.

• Acute rupture or fracture of a calcified leaflet can lead to sudden
and severe regurgitation, often a medical emergency requiring
urgent surgery.
• This can often be visualized with two dimensional imaging from a
window that records the bioprosthesis from the upstream side.
• Typically, this results in an unusual flow pattern on pulsed Doppler
interrogation,
• This striated signal generally indicates the presence of a torn or
perforated leaflet.

INFECTIVE ENDOCARDITIS
• A potentially catastrophic complication of
prosthetic valves.
• As with native valves, an early and accurate
diagnosis is essential to a favorable outcome.
• In contrast to native valve endocarditis, infection
involving prostheses is more variable and more
difficult to diagnose.
• Because of the reflectance of the prosthetic
material, as well as its shadowing effect, detecting
vegetations is challenging.
• Like thrombi, they are easily obscured and require
imaging from multiple windows to detect. The most
common site for attachment of a vegetation is at
the base or sewing ring of the prosthetic valve.

A large vegetation can be seen in the left
atrium (arrow), attached to the sewing
ring of a St. Jude mitral prosthesis.
A large vegetation is demonstrated in a
patient with a repaired mitral valve and
mitral ring. The vegetation can be seen
filling the mitral orifice (arrows)

An atypical location for a vegetation. The vegetation is attached to
the distal edge of the stents of a bioprosthetic mitral valve.
The valve leaflets (small arrows) and the vegetation (large arrow)
are shown. The leaflets themselves appeared free of infection

In this example, transthoracic echocardiography (TTE)
(A) is unable to identify the large vegetation present on this St. Jude mitral
prosthesis.
B: The large mass (arrows) is recorded in the left atrium using
transesophageal echocardiography (TEE).

• Small vegetations can be missed.
• Pannus or loose suture material can be confused
with small vegetations and are sources of false-
positive findings.
• Distinguishing vegetation from thrombus is nearly
impossible from echocardiographic criteria alone.
• The distinction relies heavily on the clinical
situation, that is, the presence of fever and the
results of blood cultures.

An ominous complication of prosthetic valve
endocarditis is the development of an abscess.
As is the case with native valves, transesophageal
echocardiography is significantly more sensitive for
detecting abscesses.
However, because of the reflectance of the sewing ring
and the tissue changes that occur after valve surgery, this
diagnosis can be difficult even when transesophageal
imaging is performed.
Abscesses may be either echo dense or echo lucent, and
color flow imaging may reveal evidence of flow within
the abscess cavity (Figs.)

This patient developed fever approximately 1 month after aortic valve
replacement.
A: A mycotic aneurysm (arrows) developed as the result of abscess formation
adjacent to the sewing ring.
B:The aneurysm (arrows) is further demonstrated from the short-axis view

C: Flow through
the aneurysm
which has
ruptured into the
right ventricle
(arrow) is shown

A transesophageal echocardiogram was performed on a patient who presented
with evidence of endocarditis.
In panel A, a large, echo-free space (∗) is noted between the aortic root and the left
atrium. The arrow identifies an area of communication between the left ventricular
outflow tract and this echo-free space.
In panel B, color Doppler imaging confirms flow through this space. This represents
a large abscess, an ominous complication of bacterial endocarditis

DEHISCENCE:
• If the degree of destabilization of the sewing
ring reaches a certain point, dehiscence of the
prosthesis may occur.
• This leads to a characteristic rocking of the
sewing ring within the implantation site.
• Dehiscence is a serious complication of
prosthetic valve endocarditis and is almost
always associated with significant perivalvular
regurgitation.

• Establishing the diagnosis of dehiscence is
relatively straightforward in the mitral position
where rocking of the prosthesis relative to the
mitral annulus is easy to detect.
• Dehiscence of an aortic prosthesis may be more
difficult to establish because of the shadowing
effect of the aortic root.
• More often, transesophageal imaging is required
to confirm this diagnosis.

Severe dehiscence of a porcine aortic prosthesis.
A: Prosthesis motion is evident, independent of motion of
the aortic root.
B: Significant perivalvular regurgitation (arrow)

MECHANICAL FAILURE:
• Primary mechanical failure or defects in manufacturing are
increasingly rare causes of prosthesis dysfunction.
• In the past, several recognized defects occasionally developed
in some specific types of prostheses.
• For example, a gradual change in the shape of the occluder of
Starr-Edwards prosthesis, termed ball variance, sometimes
resulted in dysfunction as the ball intermittently became stuck
within the cage.

• Older models of the Bj ¨ ok-Shiley valve occasionally
developed fractured struts that resulted in embolization of the
disk.
• Disk fracture has also been reported, although it is quite rare.
• Each of these types of abnormality can be assessed with
echocardiography.
• Fortunately, improvements in design and manufacture have
made such catastrophic failures exceedingly uncommon.

LIMITATIONS AND PITFALLS OF
ECHOCARDIOGRAPHY IN ASSESSING
PHV

• REVERBERATIONS:
✓This is the phenomenon of entrapment of the ultrasonic waves in
an enclosed tissue interface leading to repeated secondary
reflections due to bouncing of waves between the tissue and
another highly reflecting surface.
✓These signals are interpreted or imaged as if the same object at
twice the distance from the actual structure being imaged.
✓Calcified structures and metallic objects produce strong
reverberations
✓Sometimes, reverberations merge and give an appearance of a
echogenic linear structure, also called comet-tail or ring down
artefact.

• ACOUSTIC SHADOWING
• MICROBUBBLES
• IMPROPER ORIENTATION OR ALIGNMENT:
✓Failure to detect maximal velocity through the valves
due to unique orientation of the valves in the heart,
which usually requires multiple modified windows to
orient and align the structures with the ultrasound
beam for derivation of maximal pressure gradients.

• NORMAL BUT EXCESSIVE MOVEMENT:
✓When attempts are made for reservation of
both anterior or posterior mitral leaflets during
mitral PV insertion, an enhanced but
physiologically normal mobility of prosthesis
may be observed.
✓Absence of pathological regurgitant jet
differentiates from dehiscence in such cases.

• MIMICKING OF AORTIC ROOT ABSCESS:
✓Area around the aortic root may appear echogenic,
thickened in the immediate postoperative period up
to few days due to oedema or hematoma, especially
after implantation of stentless valve mimicking and
aortic root abscess.
✓This may resolve over 3-6 months.

Echocardiographic Evaluation of Prosthetic Heart Valves

Echocardiographic Evaluation of Prosthetic Heart Valves

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