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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3590_Библиотеки_им_академика_М_И_Перельмана
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Fig. 3.4 Optimal TAVR implantation depth. Intraprocedural TEE images depict optimal implantation depth
of current-generation self-expanding (A) and balloon-expandable (B) TAVR valves. The red line depicts the
native aortic annulus, and the yellow line depicts the proximal edge of the valve stent in the LVOT. Notice the
prosthetic leaflets of the self-expanding valve (A) normally sit “supra-annular,” adjacent to the sinuses of
Valsalva, whereas in the balloon-expandable valve (B) the leaflets sit closer to the native aortic annulus. Ao,
Ascending aorta; LA, left atrium; LVOT, left ventricular outflow tract; TAV, transcatheter aortic valve.
valve function, and overhang of the calcified native aortic valve leaflets, which can interfere with
prosthetic valve function. Optimal initial positioning of an Edwards Sapien 3 balloon-expandable
valve is “50-50,” with 50% of the valve below the annulus and 50% above it. During balloon expansion, however, the Sapien 3 valve typically shortens from the distal end, and the final positioning is optimally 2 to 4 mm distal to the aortic annulus or 80/20 or 90/10 aortic/ventricular.
Normal positioning for the distal edge of the Medtronic CoreValve Evolut self-expanding valve
is 3 to 5 mm below the aortic annulus.
Stent expansion is best visualized in short-axis views of the prosthesis. In a true short-axis
view of the stent frame, it should appear round. An oval-appearing stent indicates underexpansion, and there is heightened risk of PVR (Fig. 3.5). For current-generation self-expanding valves,
the prosthetic leaflets sit supra-annular (superior to the native aortic annulus) and therefore underexpansion of the frame at the annular level does not typically affect prosthetic leaflet function.
However, with balloon-expandable valves, the prosthetic leaflets typically sit at the level of the
native aortic annulus, and underexpansion at this level can interfere with normal leaflet motion
and result in significant transprosthesis regurgitation.
In the absence of acute procedural complications, the next most important assessment is inter-
rogation for PVR, which is challenging and requires an integrated, multiparametric approach.
Published guidelines and recommendations largely agree on grading, but differ in recommending
a 3-point grading scheme (mild, moderate, severe) or a 6-point grading scheme (none/trace, mild,
mild-moderate, moderate, moderate-severe, severe).
3,4
At our institution we use a 6-point grad-
ing scheme largely in concordance with the noted published guidelines and recommendations.
The circumferential extent of PVR viewed in the short axis is an important component of this
assessment. Less than 10% circumference is considered mild, 10% to 20% is considered mildmoderate, 20% to 30% is considered moderate, and .30% is consistent with moderate-severe or
severe (Fig. 3.6). It is important to remember that acoustic shadowing from the valve stent and
native calcification commonly result in underestimation of PVR when viewed at the level of the
native annulus, and care must be taken to interrogate for PVR at the ventricular edge of the stent
(at the skirt level) (Fig. 3.7). Because of acoustic shadowing, one must also be cognizant that
posterior jets may be underappreciated by TTE from the parasternal window, and anterior jets
can potentially be missed with TEE from the midesophageal imaging window. Obtaining
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Fig. 3.5 Optimal TAVR stent expansion. Short-axis views of the TAV at the level of the aortic annulus depict
a fully expanded (A) vs. an incompletely expanded (B) TAV prosthesis. Fully expanded valves typically look
circular (A) in short-axis views, whereas underexpanded valves typically appear oval (B) and may be focally
underexpanded in regions of heavy calcification. LA, Left atrium; TAV, transcatheter aortic valve; RVOT, right
ventricular outflow tract.
Fig. 3.6 Circumferential extent of PVR. The circumferential extent of PVR is visualized in the short-axis view
with the imaging plane at the proximal or skirt level of the TAVR valve. The boundaries of the PVR are highlighted
by the red arrows in each panel. Images depict mild PVR with a circumferential extent ,10% (A), moderate PVR
with a circumferential extent of 20% to 30% (B), and severe PVR with a circumferential extent 30% (C).
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Fig. 3.7 Circumferential extent of PVR measured from the proximal stent. Care must be taken to image
the circumferential extent of PVR from the proximal edge of the TAV stent (A, depicted by the red line), which
in this case indicates moderate PVR (circumferential extent 20% to 30%). Imaging PVR at the level of the
native aortic annulus in the same patient (B, depicted by the red line) results in underestimation of PVR due
to acoustic shadowing from the TAV prosthesis.
“sweeps” through multiple echocardiographic imaging planes can be helpful to be sure occult
PVR is not missed. Correlation with invasive hemodynamics (measurement of left ventricular
end diastolic pressure [LVEDP] and diastolic aortic pressure) will also guide the procedural team
as to whether there is undetected PVR that needs more careful echocardiographic assessment. To
avoid acoustic shadowing, it is also critically important that PVR be interrogated from multiple
imaging windows, including the parasternal, apical, and subcostal windows, by TTE and both the
midesophageal and transgastric views by TEE.
In addition to circumferential extent of PVR, there are a number of other important echo-
cardiographic findings that correlate with the severity of aortic regurgitation (AR). A dense AR
continuous wave Doppler signal generally correlates with moderate or greater regurgitation,
whereas a short pressure half-time, ,200 msec, is thought to generally indicate severe regurgitation, although these parameters lack thorough validation in the TAVR setting (Fig. 3.8).
Holodiastolic reversals in the descending thoracic aorta by pulse wave Doppler assessment,
particularly when the end-diastolic velocity is .20 cm/sec, also indicate significant AR (see
Fig. 3.8). Additionally, multiple other qualitative or semiquantitative parameters may indicate
significant PVR; a jet path that is visible along the stent frame, or a jet origin diameter .30%
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Fig. 3.8 Spectral Doppler parameters of paravalvular regurgitation. Continuous wave Doppler of the TAVR
PVR jet can be helpful to determine severity and hemodynamic significance (A, red arrow). Generally, a pressure
half-time ,200 msec is supportive of severe PVR. Similarly, spectral wave Doppler flow reversals in the descending thoracic aorta can be helpful to define the severity of aortic regurgitation (B, yellow arrow). Holodiastolic reversals, particularly when the end-diastolic velocity is .0.20 cm/sec, is supportive of severe regurgitation.
Fig. 3.9 TAVR valve thrombosis. TAVR and surgical bioprosthetic valve thrombosis is an increasingly rec-
ognized entity of unclear clinical significance. A typical example of TAVR valve thrombosis is shown in diastole
(A, red arrow) and systole (B, red arrow). Typically, the leaflets appear thickened with increased echogenicity
and a “filled-in” appearance on the aortic surface of the prosthetic leaflet, and this is typically associated with
leaflet dysfunction/reduced mobility.
the diameter of the LVOT, and a visible flow convergence on the aortic side of the valve are all
suggestive of moderate or greater PVR.
Next, attention should be turned to assessment of the prosthesis mean systolic gradient. Compared with surgically implanted valves, TAVR prostheses generally have a favorable hemodynamic
profile, and significant patient–prosthesis mismatch is uncommon. However, recent literature has
highlighted the incidence of bioprosthetic valve thrombosis in both transcatheter and surgically
implanted valves.
5
Importantly, valve thrombosis with abnormal prosthetic leaflet motion has been
documented with little or no increase in transvalvular mean gradient. When possible, direct visualization of the prosthetic leaflets is therefore helpful to screen for subclinical prosthetic valve
thrombosis, although the clinical significance of this entity is uncertain (Fig. 3.9).
3
6
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TEE Guidance for Transseptal Puncture
Transseptal puncture (TSP) is a common preliminary step for a growing list of structural heart
procedures. Importantly, it provides transvenous access to the left atrium, the mitral valve, and other
left-sided cardiac structures. TEE is critically important for precise localization of the TSP site to
increase the likelihood of procedural success and improve the safety of this important step. Punctures that are too posterior can risk perforation of the left atrial free wall and subsequent cardiac
tamponade, and punctures that are too anterior risk puncture of the coronary sinus of Valsalva.
We typically guide the majority of TSP for structural heart procedures with biplane TEE. The
standard bicaval view (100 to 120 degrees) serves as the primary view, and the orthogonal view
(10 to 30 degrees) typically shows the atrial septum with the aortic valve roughly in a short-axis
view (Fig. 3.10). The bicaval view provides superior-inferior localization of the transseptal needle,
and the orthogonal view (10 to 30 degrees) provides anterior-posterior localization. The transseptal needle is typically advanced from the inferior vena cava to the superior vena cava and slowly
withdrawn toward the atrial septum. The echo transducer is typically held stationary, and the
operator withdraws the needle until it is visualized on echocardiography. Small stepwise adjustments are then made until the needle is at the optimal location.
The optimal location of the TSP site depends on the procedure being performed. Generally,
LAAO requires an inferior and posterior TSP, whereas TMVR requires a posterior and superior TSP. TSP before TMVR generally requires that the TSP site in the four-chamber
horizontal midesophageal plane is at least 4.0 to 4.5 cm posterior to the plane of the mitral
annulus for adequate maneuvering of the device within the left atrium. Careful attention must
be paid to optimizing the TSP location, because this can significantly facilitate subsequent
procedural success.
Fig. 3.10 TEE biplane imaging for TSP. Two orthogonal biplane images are used to guide TSP before a
planned transcatheter procedure requiring left atrial access. The left panel (multiplane angle 105 degrees)
depicts a typical bicaval view and localizes the TSP needle in the superior-inferior axis. Movement toward the
SVC (rightward in the image) depicts superior movement, whereas movement away from the SVC (leftward
in the image) depicts inferior movement. An orthogonal view of the atrial septum is shown in the right panel
and indicates movement in the anterior-posterior dimension. Movement toward the AV (rightward) indicates
anterior movement, whereas movement away from the AV indicates posterior movement (leftward). AV , Aortic
valve; FO, fossa ovalis; LA, left atrium; RA, right atrium; SVC, superior vena cava.
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Percutaneous Left Atrial Appendage Occlusion
Recently, minimally invasive devices have been developed to occlude the left atrial appendage
(LAA), a common source of systemic embolism in atrial fibrillation (AF), as an alternative to
systemic anticoagulation.
approach (Watchman device, Boston Scientific, Maple Grove, MN). The bulk of the clinical
experience with LAAO involves the Watchman device, which is clinically approved for patients
with AF who are at high risk of stroke but are unable to take long-term anticoagulants.
PREPROCEDURE ASSESSMENT
LAAO is generally performed under TEE guidance. TEE remains the modality of choice for
excluding intracardiac mass or thrombus, evaluating the atrial septum before TSP, sizing the
LAA before implantation, and evaluating for baseline pericardial effusion preprocedure.
Sizing for LAA devices at our institution is driven primarily by TEE measurements. The
ostial LAA measurements are derived at the level of the circumflex coronary artery to a position
1 to 2 cm below the warfarin ridge (Fig. 3.11). The timing of the ostial measurement is generally
at the point in the cardiac cycle when the ostial diameter is the largest. The appendage length or
depth is measured from the plane of the ostial measurement to the tip of the LAA in each view.
7,8
Generally, these devices occlude the LAA via an endovascular
Fig. 3.11 LAA TEE sizing before LAAO. LAA (*) ostial diameter measurements are performed at TEE mul-
tiplane angles of approximately 0, 45, 90, and 135 degrees (panels A, B, C, and D). The diameter is measured
from the level of the circumflex coronary artery (red arrows) to the opposite wall at a level approximately
1.5 cm from the tip of the warfarin ridge while being careful to be sure that all pectinate muscles and LAA
lobes are distal to the measured ostium. The LAA depth is measured from the plane of the LAA measured
ostium to the distal tip of the LAA in each view. LA, Left atrium.
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Fig. 3.12 LAA sizing by 3D TEE sizing before LAAO. LAA (*) ostial dimensions can be measured with 3D
TEE and multiplanar reconstruction. Alignment with the LAA ostium is performed in two orthogonal long-axis
views (A and B, blue lines), creating a short-axis view of the LAA ostium (C, *). The short-axis view is used
for measurement of ostial area, circumference, and minimum/maximum diameters. The unedited 3D volumetric dataset of the LAA is shown in panel D. LA, Left atrium.
Measurements are obtained between 0 and 135 degrees in 45-degree increments, and the largest
values are used for device sizing. 3D TEE with multiplanar reconstruction is also useful for more
precise measurement of minimum and maximum ostial diameter and also measurement of ostial
area and circumference (Fig. 3.12).
It is generally recommended that the device diameter size be 8% to 20% larger than the larg-
est LAA ostial diameter. Exclusion criteria for the currently available Watchman device include
an ostial diameter ,16.8 mm, ostial diameter .30.4 mm, or LAA depth that is less than the
maximal ostial diameter. When the appendage depth is less than the maximal ostial diameter, the
appendage is considered too shallow for implantation. Also, an accessory lobe that is too close to
the ostium (,1 cm) may not be adequately covered by the device, and this is considered a relative
contraindication due to the persistent source of thromboembolism. Alternative LAA occlusion
devices, such as the Amulet, may be suitable for shallow LAA but are not yet approved for clinical use outside of clinical trials in the United States.
PROCEDURAL GUIDANCE
TEE has an important role during LAAO for procedural guidance; assessment of device position,
compression, and sealing; and assessment of potential procedure-related complications.
The process of guiding the TSP was discussed previously. Typically, a posterior and inferior TSP
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site facilitates cannulation of the LAA and coaxial alignment of the device with the long axis of
the LAA. Precise localization of the TSP site is a critical component of procedural success.
After the TSP, echocardiography is helpful to guide cannulation of the LAA. At our institution, device position is fine-tuned within the LAA using a combination of TEE and angiography.
A multiplane transducer angle of approximately 135 degrees is preferred at the time of device
deployment because this angle typically matches the fluoroscopic right anterior oblique view that
is also used at the time of deployment. Ideally, the proximal edge of the device should be situated
at the level of the measured ostium of the left atrial appendage, and all lobes of the appendage
and pectinate muscles should be excluded from the intravascular space by the device.
The first step in assessing the device postdeployment is to evaluate the device position and
compression. Ideally, the device should be well seated within the LAA. Care must be taken to
interrogate from all multiplane angles to be sure that the shoulders of the device are situated
within the ostium and not overhanging into the left atrium. If a shoulder of the device is positioned significantly outside the ostium of the appendage, this may prompt device retrieval and
repositioning to minimize the risk of device embolization (Fig. 3.13). Similar to the initial ostial
sizing measurements, device compression is measured between 0 and 135 degrees at 45-degree
increments. The device diameter is measured from shoulder to shoulder in the four standard
views, and the central “threaded insert” portion of the device should be visible at the time of
measurement (see Fig. 3.13). Optimal device compression, the percentage difference between the
original device size and the postdeployment diameter, is 8% to 20%.
The next component of the postprocedure assessment involves interrogation for any residual
communication between the LAA and the left atrium. Residual communication between the appendage and the intravascular space may result in a persistent risk of cardioembolism, although a
communication ,5 mm in diameter is generally not associated with increased risk and is felt to
be an acceptable result. Color Doppler imaging with the Nyquist limits set at 35 to 40 cm/sec is
used to interrogate for any residual para-device flow. Care must be taken to interrogate the entire
circumference of the device using all multiplane transducer angles. If there is adequate compression
and no significant para-device leak, a “tug test” is performed by applying backward traction to the
device catheter to ensure device stability. The presence of pericardial effusion and severity of atriallevel shunting at the site of the TSP should be checked before withdrawing the TEE probe.
Fig. 3.13 LAAO postdeployment device size and position. Panel A shows one shoulder of a Watchman
device protruding from the ostium of the LAA (red arrow) into the LA. Excessive protrusion of a device shoulder may reduce device stability and necessitate recapture and redeployment. Panel B shows excellent device
position with both shoulders sitting within the LAA. Measurement of the device diameter (dashed lines) is
performed from shoulder to shoulder, and the central device threaded insert (yellow arrow) should be visible
at the time of measurement. LA, Left atrium.
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Transcatheter Closure of Paravalvular Regurgitation
Patients with significant PVR may present with heart failure or hemolysis. Reoperation for surgical closure of PVR may be associated with high surgical risk in some patients, and transcatheter
closure of PVR has evolved as an alternative approach in these patients.
to closure of PVR varies by institution, we generally take an antegrade (transseptal) approach for
closure of mitral PVR and a retrograde (aortic) approach to closure of aortic PVR. The most common devices used to close PVR are from the Amplatz family of septal, ductal, and vascular occluders (St. Jude Medical, St. Paul, MN).
PREPROCEDURE IMAGING
Critical components of baseline PVR assessment include confirming the origin of the regurgitant
jet is paravalvular as opposed to valvular, assessing the severity of regurgitation, identifying the
number of regurgitant jets and assessing their size and location, excluding significant valve dehiscence (which would preclude percutaneous closure), and identifying any adjacent structures that
may increase the risk of procedural complications. In our laboratory, TEE is used to guide closure
of mitral PVR. It offers definitive assessment of the entire mitral annular sewing ring in high
resolution, whereas TTE is significantly limited by acoustic shadowing (Fig. 3.14). For aortic
PVR, we generally prefer TEE for posterior regurgitant lesions and TTE for anterior regurgitant
lesions to avoid acoustic shadowing from the prosthesis.
9,10
Although the approach
Fig. 3.14 Preprocedure assessment of mitral paravalvular regurgitation. 2D TEE with color Doppler
imaging reveals a complex jet of mitral regurgitation (*) near the anterolateral sewing ring and the LAA ostium
(A). The PVR defect is not well seen on non-color 3D imaging (B), but 3D color Doppler imaging reveals an
anterolateral crescentic arc of PVR adjacent to the LAA (C). Systolic flow reversals (D, red arrow) in the left
upper pulmonary vein support hemodynamically significant PVR. LA, Left atrium; LAA, left atrial appendage.
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However, it is important to remember that the circumferential extent of regurgitation around
the valve is not the actual extent, because frequently these funnel down to a narrow egress in the
LVOT. The “garden hose” or spraying of the jet in the LVOT can easily cause it to be overestimated. Assessment of PVR should therefore be performed through integration of clinical and all
imaging findings.
Multiple echocardiographic parameters are used to assess mitral paravalvular regurgitation. In
some circumstances the regurgitant orifice area can also be measured by planimetry using 3D
TEE with color Doppler imaging with multiplanar reconstruction, but care must be taken during
image acquisition to avoid acoustic shadowing from the prosthesis ring. The regurgitant jet density and contour by continuous wave Doppler can also be helpful to assess severity. Generally,
severe regurgitant jets are denser and tend to have an early, dagger-shaped peak signal, whereas
moderate or less regurgitant jets tend to be less dense and the spectral envelope tends to be more
parabolic in shape. Pulmonary vein flow is also very helpful in determining the hemodynamic
significance of MR. Generally, systolic predominant pulmonary vein flow is consistent with mild
MR, systolic blunting is more typical of moderate or moderate-severe MR, and systolic reversals
is a specific sign for severe MR.
Similarly, aortic PVR requires a multiparametric approach for definitive assessment. It is often
feasible to define the severity of aortic PVR based on TTE. However, in select cases TEE may
be helpful for more definitive assessment. Although the circumferential extent of regurgitation is
better validated in TAVR patients, additional measures of AR severity are similar to those used
for the post-TAVR assessment and were discussed previously.
In addition to defining the severity of PVR, it is critical to identify the number and location
of regurgitant jets. For mitral PVR, multiplane 2D TEE can be used to interrogate the entire
sewing ring of the prosthetic valve. However, 3D TEE is superior in identifying the number of
jets present, as well as characterizing their size and circumferential extent (see Fig. 3.14). It is also
critical to evaluate the location of regurgitant lesions with respect to other structures, which could
interfere with device deployment or result in complications. For example, plugs placed in defects
near the free margin of tilting disks on a mechanical prosthesis are more likely to interfere with
disk motion as opposed to plugs placed near the posts of the mechanical prosthesis. For aortic
PVR one must also consider the proximity of the defect to the ostia of the coronary arteries and
whether probing around the defect with a wire could result in iatrogenic trauma to a coronary
artery or whether there is risk of coronary obstruction after implantation of a device.
Communication between the interventional cardiologist and the echocardiographer is an
important component of the procedure. In our practice we have found it helpful to describe lesions using standard spatial coordinates (e.g., anterior vs. posterior) and in relationship to anatomic landmarks (e.g., adjacent to the LAA). Using 2D TEE, the anteroposterior dimension can
be described in the standard long-axis view (120 to 140 degrees), medial vs. lateral can be described in the standard 0-degree view, and the LAA is a helpful anterolateral landmark that is
typically seen at a multiplane angle of 60 to 90 degrees (Fig. 3.15). Using a 3D TEE “surgeon’s
view” of the mitral valve, from the perspective of the left atrium, the aortic valve is situated anterior, the LAA is anterolateral, and the atrial septum is medial (see Fig. 3.15). Additionally, describing defects seen on echocardiography with respect to landmarks also visible on fluoroscopy
is helpful to guide the interventional cardiologist (e.g., PVR jet is adjacent to the posterior posts
of the mechanical prosthesis).
PROCEDURAL GUIDANCE
At our institution, closure of mitral PVR most commonly involves an antegrade approach, with
femoral venous access followed by TSP to gain access to the left atrium. Once the catheters have
safely gained entry to the left atrium, 3D TEE showing an en face view of the mitral valve is used
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