BY Sruthi Meenaxshi

1. Echocardiographic evaluation of
Prosthetic Valves
Dr.Sruthi Meenaxshi, MBBS,MD,PDF

7. • Echocardiography is the key noninvasive modality for
evaluation of prosthetic valve structure and function
• Transthoracic echocardiography (TTE) is the mainstay for
monitoring prosthetic valves and can generally identify
normal function as well as evidence of valve dysfunction
(stenosis).
• Transesophageal echocardiography (TEE) is helpful
particularly for assessment of valve structure and
prosthetic valve regurgitation especially involving
mechanical mitral and tricuspid prostheses as well as
assessment of endocarditis for all valves
• This topic will review echocardiography of prosthetic heart
valves

10. Baseline transthoracic
echocardiogram
 American Heart Association/American College of Cardiology
(AHA/ACC) guideline recommendation to perform a transthoracic
echocardiogram (TTE) six weeks to three months after valve
implantation (when the hemoglobin has normalized) to evaluate
valve hemodynamics and to establish a baseline for future
comparison
 The TTE should include Doppler measurements of transvalvular
velocities as well as assessment of valvular and paravalvular
regurgitation.
 Adequate Doppler velocity recordings can generally be obtained
despite acoustic shadowing from valve prostheses.

11. • Transvalvular gradients for normally functioning prosthetic valves
are dependent upon
• valve type
• location
• size (as compiled in the 2009 American Society of
Echocardiography guidelines as well as patient-specific factors
• A higher than expected initial gradient is often due to a high
output state (eg, due to anemia) or patient-prosthetic mismatch
• It is only rarely due to early dysfunction of the prosthesis (eg,
thrombus formation or hemodynamically significant valvular
regurgitation)
• We suggest obtaining the postoperative baseline study after the
patient’s hemoglobin has returned to baseline to avoid recording a
gradient that is transiently higher than expected due to anemia.

12. Change in clinical status
The echocardiographer should be alert to the
range of complications that can occur with
prosthetic devices, including the following
Prosthetic obstruction due to
thrombus,
 pannus ingrowth,
leaflet thickening, or
calcification of biologic prostheses.

13. Prosthetic valve endocarditis

14. • Prosthetic regurgitation due to
 paravalvular leak,
prosthetic leaflet interference by thrombus,
 or vegetation or leaflet tear of a
bioprosthesis.

15. Prosthetic valve endocarditis
• findings including vegetations and abscess
formation
• ●Prosthetic valve dehiscence with valve ring
instability/"rocking."
• ●Mechanical structural failure (eg, strut
fracture and component escape), which is
rare with current valve types.

16. • A TTE is recommended as the initial test in patients with
prosthetic valves with a change in clinical status suggestive
of valve dysfunction and/or endocarditis
• Symptoms and signs of bioprosthetic valve degeneration,
• pannus formation, or
• endocarditis include new exertional dyspnea,
• a louder murmur, or a new murmur.
• Symptoms and signs of mechanical valve dysfunction due
to thrombosis, pannus formation, or endocarditis include a
new or louder murmur, new onset of dyspnea, and signs of
heart failure, thromboembolism, and hemolysis.

17. • For patients with a prosthetic valve, a TTE may also be useful since
it provides proper alignment for Doppler assessment of
transvalvular velocities, gradient, and valve area.
• In patients with aortic prostheses, valvular regurgitation can be
reliably detected on TTE.
• For all patients with a prosthetic valve, TTE may be useful for
assessment of biventricular cavity size and systolic function as
well as an estimate of pulmonary artery systolic pressure.

18. • Transesophageal echocardiography has much
higher sensitivity for detection of
• prosthetic valve thrombi
• vegetations
• extravalvular extension of infection as well as
prosthetic mitral regurgitation.

19. Surveillance of old bioprosthetic
valves
Since the incidence of bioprosthetic valve dysfunction
markedly increases 10 years after implantation, we agree
with the 2014 AHA/ACC valve guidelines, which state
that a TTE is reasonable in patients with a bioprosthetic
valve after the first 10 years, even in the absence of
change in clinical status
The guideline suggested annual TTE thereafter, but every
two to three years may be reasonable if valve function is
normal with annual echocardiograms when valvular
dysfunction presents.

20. • However, in individuals at increased risk of early
valvular degeneration such as those with chronic
renal failure and young age at implantation, it is
reasonable to repeat echocardiography at five
years post-implantation and yearly thereafter
• Routine annual echocardiographic evaluation is
not indicated in patients with mechanical valve
prostheses with normal postoperative baseline
examination and no signs or symptoms of valve
dysfunction

21. KEY COMPONENTS OF THE
ECHOCARDIOGRAM
Echocardiographic evaluation of patients with prosthetic
valves includes
imaging of the valve and its seating;
assessment of valve hemodynamics
 transvalvular velocities
 identification and quantification of valve regurgitation
(intravalvular and paravalvular);
 measurement of cardiac chamber sizes
 left ventricular wall thicknesses
 assessment of left ventricular systolic and diastolic
function

22. • Prosthetic valves are generally inherently
stenotic, so Doppler velocity recordings across
normally functioning valves are similar to those
of mild native valve stenosis
• Normal function of the valve is confirmed by
• evaluation of the contour of the jet velocity
• acceleration time (the time from onset of flow to
maximal velocity),
• the effective orifice area (EOA)
• Doppler velocity index (DVI).

23. • An increase in the transprosthetic velocity could be due to
• valvular obstruction,
• regurgitation, or an
• increase in cardiac output,
• Decrease in either the EOA or the DVI is more specific for
prosthetic obstruction.
A Doppler velocity pattern demonstrating normal transprosthetic flow
gradient and flow duration is usually sufficient to exclude a stenotic
valve
However, the gradient may not be elevated in the setting of
obstruction with low stroke volume.
• The EOA is calculated using the continuity equation:
• EOA = stroke volume/VTIPrV

24. • where VTIPrV is the velocity time integral through the prosthesis
determined by continuous wave Doppler.
• The stroke volume is generally derived from an adjacent site as
cross-sectional area (estimated from the associated diameter and
assuming a circular area) multiplied by the VTI of flow measured by
pulsed wave Doppler at that site.
• For prosthetic aortic and pulmonic valves, site for calculation of
stroke volume is at the site of flow just proximal to the valve.
• For prosthetic mitral valves, stroke volume may be calculated at
the aortic or pulmonary annulus if no significant regurgitation is
present.

25. Doppler velocity index or dimension
less index
• The DVI is a simplified method for evaluating
aortic valve obstruction.
• The DVI is the ratio of the velocity proximal to the
valve by pulsed wave Doppler to the velocity
through the valve by continuous wave Doppler.
• Use of this index avoids the need to measure
stroke volume
• A DVI <0.25 suggests significant valve
obstruction.

26. • Prosthetic aortic regurgitation (intravalvular or
paravalvular) can generally be identified by
transthoracic echocardiography (TTE).
• Prosthetic mitral regurgitation and tricuspid
regurgitation are usually difficult to assess on
TTE due to acoustic shadowing and thus
transesophageal echocardiography (TEE) is
preferred.

27. Role of TTE and TEE
TTE and TEE are complementary in the evaluation of prosthetic valves.
As mentioned, acoustic shadowing caused by prosthetic material may limit
TTE visualization of
prosthetic discs/leaflets,
vegetations, abscesses
and thrombi.
In addition, while prosthetic aortic valve regurgitation is usually well
visualized on TTE color Doppler imaging, prosthetic mitral regurgitation is
frequently undetectable
As a result, TEE is the imaging method of choice when the TTE is technically
inadequate or when there are borderline findings on the TTE in a patient in
whom there is a strong clinical suspicion of prosthetic malfunction

28. Complications of prosthetic valve
• Paravalvular leak
• Endocarditis
• Extrinsic interference of function (pannus, thrombus,
vegetation) resulting in obstruction and/or
regurgitation
• Leaflet tears of bioprosthesis
• Leaflet calcification/stenosis of bioprosthesis
• Ball variance, now rare as ball in cage valves are no
longer implanted
• Strut fracture and component escape, also now rare
with newer-generation valves

29. • It is worth mentioning the finding of
microbubbles, which can be seen in an
otherwise normally functioning mechanical
prosthesis and are not associated with valve
pathology.
• They are usually seen with mitral prostheses
within the left ventricular inflow and are likely
due to degassing of carbon dioxide

30. FEATURES OF VALVE DYSFUNCTION
• Prosthetic valve obstruction —
• Prosthetic valve obstruction should be
suspected in a newly symptomatic patient
with a rise in transprosthetic gradient from a
baseline determination or from established
normal values for valves of that type and size.
• The expected range of Doppler gradients and
effective orifice area encountered in properly
functioning valves.

31. Pannus formation in a st judes valve

32. Thrombus formation in St judes
mechanical Prosthetic valve . After
successful thrombolysis mean gradient
hasd significantly reduced

34. • Causes of obstruction include pannus ingrowth,
thrombus, and vegetation
• Clinical clues to this possibility include the age of
the valve and the adequacy of anticoagulation. In
a bioprosthesis or heterograft, the leaflets
themselves may become calcified and immobile.
• There has been an increasing recognition of
subclinical thrombus formation on bioprosthetic
valves, which appears to be more common in
percutaneous valves than in surgically placed
valves as discussed separately

35. • Once there is a high suspicion of obstruction, transesophageal
echocardiography (TEE) should be performed for etiologic definition
with both mechanical and bioprosthetic valves, especially for mitral
prostheses.
• Doppler transthoracic echocardiography (TTE) is the primary
means to diagnose prosthetic valve obstruction; hemodynamic
cardiac catheterization is not routinely needed
• 3D-TEE may be helpful in identifying pannus, although its utility has
not been well defined
• Computed tomography (CT) scan is an important adjunctive imaging
modality.

36. • In the case of suspected aortic pannus, the
distal end of the left ventricular outflow tract
should be examined both with imaging and
with color flow Doppler.
• Pannus tends to lie close to the valve ring and
can be easily overlooked.

37. • In the mitral position, the same procedure should be followed.
• Finding a high grade of spontaneous contrast in the left atrium,
with or without thrombi, or finding thrombus around the sewing
ring in the setting of adequate anticoagulation should heighten
suspicion of pannus formation.
• Thin fibrillar strands may also be encountered adjacent to the
mitral annulus and on the sewing ring of the valve.
• These structures are brightly reflective and highly mobile and may
or may not be associated with a pathologic process.

38. Distinction between thrombus and
pannus
• The most common etiology for prosthetic
valve obstruction is thrombus formation;
pannus formation due to fibrous tissue
ingrowth is far less common.
• Since treatment options for thrombus and
pannus differ, it is important to distinguish
between these two causes.

39. • Echocardiographic differentiation of pannus and
thrombus may be difficult. In general:
• ●Thrombus tends to be larger, mobile, be
somewhat less echo-dense, and more commonly
associated with spontaneous echo contrast.
• ●Pannus is highly echogenic, consistent with its
fibrous composition; is usually firmly fixed
(minimal mobility) to the valve apparatus; and
mostly involves the sewing ring, which may
make it difficult to distinguish from the ring

40. • In order to establish factors associated with the
presence of thrombus, one study evaluated the
findings on a preoperative TEE in 53 patients with an
intraoperative diagnosis of pannus or thrombus
• Predictors of thrombus or a mixed presentation
(pannus and thrombus) included:
Mobile mass
Attachment of mass to valve occluder
Elevated gradients
An international normalized ratio ≤2.5

41. Prosthetic valve regurgitation
• Physiologic regurgitation, the so-called "seating
puff" of angiography, is universally encountered
with mechanical valves and dependent in degree
on the type of prosthesis used.
• However, severe regurgitation may result from
bioprosthetic valve leaflet degeneration or
destruction from endocarditis, mechanical valve
pannus, thrombus, or vegetation that interferes
with mechanical leaflet function.

42. Physiologic regurgitation
All mechanical valves exhibit some degree of obligatory
regurgitation of up to 15 mL of blood
The physiologic regurgitation associated with prosthetic
valves appears only briefly and is due to retrograde
volume displacement as the valve leaflets close
. This type of regurgitation is detected by highly sensitive
color flow Doppler imaging on TEE.
In addition, a certain amount of more prolonged
"leakage backflow" regurgitation occurs after the valve
closes .
These are often referred to as "washing jets," believed
to inhibit the formation of thrombi.

43. • Normally functioning mechanical valves, such as the
bileaflet St. Jude prosthesis, usually have two to four
centrally directed regurgitant jets.
• Features associated with these jets include a low
intensity and only minimal penetration into the
atrium, generally less than 3 cm
• The monodisc Medtronic-Hall valve has two jets, one
of which is prominent and longer
• Normally functioning bioprosthetic and heterografts
are less likely to have these small regurgitant signals;
when mild regurgitation is present, there is usually one
central jet

44. Pathologic regurgitation
• Most pathologic regurgitation associated with
mechanical valves is perivalvular.
• However, occasionally, disc closure may be
impeded by a vegetation or thrombus leading to
combined stenosis and regurgitation.
• If TTE does not reveal the offending mass or
tissue, TEE should be performed.
• Bioprostheses with leaflet degeneration may
exhibit central pathologic regurgitation that is
broad-based when severe.

45. Paravalvular regurgitation
• — Trace or mild paravalvular regurgitation immediately following
valve replacement is common with both mechanical and
bioprosthetic prostheses and generally not progressive.
• Paravalvular regurgitation can develop late after valve replacement
due to suture dehiscence, from a poorly seated ring, or from
endocarditis leading to valve dehiscence.
• Hemolysis is a common complication of these leaks, especially
when they occur with a mitral valve prosthesis
• Paravalvular regurgitation should be suspected when a patient
with a prosthetic valve presents with hemolytic anemia.

46. • To recognize a paravalvular leak, TEE must be performed with a high
color frame rate in several views from several angles outside the
sewing ring
• There should be a careful search for periprosthetic leaks around as
much of the valve circumference as possible and an attempt made
to define the extent of the regurgitation once it is identified.
• The origin of a periprosthetic leak may appear deceptively narrow
when caused by disruption of a limited number of sutures.
• Three-dimensional echocardiography is helpful in mapping the
extent of the paravalvular leak and has proven efficacious for
guiding percutaneous device closure of these leaks.

47. Prosthetic valve dehiscence
• Prosthetic valve dehiscence is identified on echocardiography as a
separation of the prosthetic ring from the native valvular annulus and is
usually accompanied by paravalvular regurgitation.
• Valve dehiscence is most frequently caused by endocarditis.
• Rocking of a prosthetic valve is a sign of dehiscence, particularly in the
aortic position.
• Rocking of a prosthetic mitral valve can be caused by dehiscence or by
retained native posterior leaflet or posterior and anterior leaflets, with the
latter generally not accompanied by paravalvular regurgitation
• Prosthetic valve dehiscence may be identified by TTE but is frequently
better visualized with TEE

48. Thromboembolism
• In patients with a suspected cardiac cause for
embolism, the source may be a thrombus
from a nonobstructed or obstructed
prosthetic heart valve.

49. SPECIFIC PROSTHETIC VALVE
DISORDERS
• Prosthetic aortic stenosis — Aortic prosthetic
obstruction may be due to thrombus or
vegetation, pannus ingrowth, or progressive
leaflet degeneration in the case of a
bioprosthetic valve.

51. • we agree with the American Society of
Echocardiography algorithm for diagnosis of
prosthetic aortic stenosis
• ●If the peak velocity across the aortic
prosthesis is greater than 3 m/sec or if there is
a significant increase over baseline, the
Doppler velocity index (DVI) should be
calculated.

52. Doppler velocity index or
dimensionless index

53. Algorithm of prosthetic valve
assessment in aortic valve

54. • Further analysis should include measurement of
the acceleration time (AT), which is the time from
transvalvular flow onset to maximal velocity
• An AT <100 msec is consistent with normal
function, whereas an AT >100 msec is concerning
for obstruction and further evaluation is
warranted.
• A DVI <0.25 suggests prosthetic aortic valve
stenosis if accompanied by an AT >100 msec.

55. • Finally, the effective orifice area (EOA) indexed by
body surface area can provide evidence of
patient-prosthetic mismatch when the
transprosthetic velocity is high but the DVI is
>0.25 and the AT is <100 msec.
• Patient-prosthetic mismatch is suggested by an
EOA index of <0.8 cm2/m2 and is considered
severe when the EOA index is <0.65 cm2/m2

56. • When prosthetic aortic valve stenosis is
suspected, the transthoracic
echocardiography (TTE) is usually not
adequate for visualization of the leaflet
motion or presence of thrombus and thus
warrants further investigation with
fluoroscopy of a mechanical valve and/or
transesophageal echocardiography (TEE)

57. Prosthetic aortic regurgitation
Mechanical prosthetic valves displace blood
when the occluder disc closes and may also have
small holes in the occluders and at hinge points;
the pattern is characteristic for the valve type
• Biologic valves may have minor degrees of
central regurgitation, which are detectable
due to the high sensitivity of color flow
Doppler.

59. • Grading the severity of pathological prosthetic aortic
regurgitation can be challenging and an integrative
approach is recommended
• When there is significant dehiscence of the valve (more
than 40 percent), a rocking motion is detected, which is
usually associated with severe regurgitation.
• The following features suggest severe regurgitation: jet
width >65 percent, pressure half-time <200 msec,
holodiastolic flow reversal in the descending aorta,
regurgitant volume >60 mL, and a regurgitant fraction >50
percent
• In addition, chronic severe aortic regurgitation is a cause of
left ventricular dilation.

60. • While TTE can detect and often grade
prosthetic aortic regurgitation, the cause is
often not apparent.
• TEE should be performed in order to diagnose
endocarditis with or without abscess,
thrombus interfering with disc closure, and
bioprosthetic leaflet tears.

61. Prosthetic mitral stenosis
• Prosthetic mitral valve obstruction can also
occur because of thrombus, pannus,
vegetation, and bioprosthetic leaflet
thickening or calcification.
• The peak transmitral velocity, the mean
gradient, and pressure half-time should all be
considered in the context of the heart rate
and compared with previous
echocardiographic studies.

62. Prosthetic mitral regurgitation
• Since the color Doppler jet is usually obscured because of
acoustic shadowing caused by the prosthesis, other clues to
regurgitation must be heeded
• There may be increased rocking of the prosthesis
associated with dehiscence of the sewing ring.
• The peak transmitral E wave velocity is increased as is the
mean gradient, although the pressure half-time remains
within normal range.
• The left ventricular volume may be increased and the
ejection fraction is usually preserved.
• However, in the presence of significant mitral regurgitation,
the forward stroke volume falls, which can be inferred by a
decrease in the left ventricular outflow tract VTI.

64. Prosthetic tricuspid valve dysfunction
• The principles for evaluating the prosthetic
tricuspid valve are similar to that of the mitral
valve.
• Bioprostheses are more commonly used than
mechanical prostheses in the tricuspid
position due to issues of valve thrombosis.
• Because of the respirophasic variation in
transtricuspid velocities, at least five beats
should be measured.

65. summary
• Transthoracic echocardiography (TTE) is helpful in
evaluating prosthetic valve function, particularly valve
gradients, but views are frequently limited for assessment
of vegetations, thrombus, and regurgitation, especially for
mitral and tricuspid prostheses.
• ●Transesophageal echocardiography (TEE) is particularly
helpful in detecting paravalvular leak, prosthetic mitral and
tricuspid regurgitation, vegetation, abscess, valve
obstruction, ball variance, strut fracture and component
escape, bioprosthetic leaflet tears, and bioprosthetic
calcification/stenosis.
• As a result, initial TEE is often preferred. A TTE may be
more useful to assess chamber sizes and ventricular
function.

66. • ●A TTE with Doppler measurements of transvalvular velocities
obtained six weeks to three months after prosthetic valve
implantation (when the hemoglobin has normalized) is helpful to
establish a baseline for future comparison.
• ●Complications of prosthetic valves include prosthetic valve
obstruction, regurgitation, endocarditis, dehiscence, and
mechanical structural failure (rare with current valve types).
• ●We suggest monitoring by TTE starting 10 years after implantation
of a bioprosthetic valve due to the risk of valve degeneration.
• However, in patients with risk factors for early deterioration such
as those with renal failure and implantation at younger ages, it is
reasonable to start monitoring at five years.

67. • Trace or mild paravalvular regurgitation immediately following valve
replacement is common and generally not progressive. Paravalvular
regurgitation can develop late after valve replacement due to broken or
dehisced sutures, from a poorly seated ring, or from endocarditis
(dehiscence
• ●Prosthetic valve obstruction should be suspected when a patient
develops symptoms of heart failure and increased transprosthetic
gradient. TEE is the primary means to confirm prosthetic valve obstruction
and investigate its causes (pannus, thrombus, or vegetation).
• ●Pathologic, intense prosthetic valve regurgitation can result from
bioprosthetic valve degeneration, mechanical valve pannus, thrombus, or
vegetation
• ●Systemic emboli can arise from nonobstructive or obstructive valve
thrombosis.