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JACC: CARDIOVASCULAR IMAGING
VOL. 6, NO. 2, 2013
© 2013 BY THE AMERICAN COLLEGE OF CARDIOLOGY FOUNDATION
PUBLISHED BY ELSEVIER INC.
ISSN 1936-878X/$36.00
http://dx.doi.org/10.1016/j.jcmg.2012.12.005
STATE-OF-THE-ART PAPER
Standardized Imaging for Aortic Annular Sizing
Implications for Transcatheter Valve Selection
Albert M. Kasel, MD,* Salvatore Cassese, MD,* Sabine Bleiziffer, MD,†
Makoto Amaki, MD, PHD,‡ Rebecca T. Hahn, MD,§ Adnan Kastrati, MD,*
Partho P. Sengupta, MD‡
Munich, Germany; and New York, New York
The safety and efficacy of transcatheter aortic valve replacement procedures are directly related to
proper imaging. This report revisits the existing noninvasive and invasive approaches that have
concurrently evolved to meet the demands for optimal selection and guidance of patients undergoing transcatheter aortic valve replacement. The authors summarize the published evidence and
discuss the strengths and pitfalls of echocardiographic, computed tomographic, and calibrated aortic
balloon valvuloplasty techniques in sizing the aortic valve annulus. Specific proposals for
3-dimensional tomographic reconstructions of complex 3-dimensional aortic root anatomy are provided for reducing intermodality variability in annular sizing. Finally, on the basis of the sizing
approaches discussed in this review, the authors provide practical recommendations for balloonexpandable and self-expandable prostheses selection. Strategic use of echocardiographic, multislice
computed tomographic, and angiographic data may provide complementary information for determining the anatomical suitability, efficacy, and safety of the procedure. (J Am Coll Cardiol Img 2013;
6:249 – 62) © 2013 by the American College of Cardiology Foundation
T
ranscatheter aortic valve replacement
(TAVR) provides an alternative treatment option for inoperable and high–
surgical risk patients with symptomatic
severe aortic stenosis (1– 4). On the basis of
evidence from a recent randomized trial (5,6),
balloon-expandable prostheses (Edwards
SAPIEN; Edwards Lifesciences, Irvine, California) received U.S. Food and Drug Administration approval for the U.S. market (7).
Similarly, there is extensive evidence for self-
expandable prostheses (CoreValve ReValving
System; Medtronic, Inc., Minneapolis Minnesota), and randomized trials are expected to be
completed in the next few years (3,4,8,9).
The safety and efficacy of the TAVR procedure are directly related to proper imaging,
which is based on patient selection and procedural guidance. However, as opposed to surgical aortic valve replacement, in which surgeons
can directly observe the adaptation of the
prosthesis to the aortic root while suturing,
From the *Clinic for Cardiology and Cardiovascular Diseases, Deutsches Herzzentrum, Technische Universität, Munich,
Germany; †Clinic for Cardiovascular Surgery, Deutsches Herzzentrum, Technische Universität, Munich, Germany; ‡The
Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai School of Medicine, New York, New York; and
§Columbia University Medical Center/New York Presbyterian Hospital, New York, New York. Dr. Kasel is a proctor for
Edwards Lifesciences and Medtronic, Inc. Dr. Bleiziffer is a proctor for Medtronic and JenaValve, and is a steering
committee member of the Engager Pivotal Study. All other authors have reported that they have no relationships relevant
to the contents of this paper to disclose.
Manuscript received November 26, 2012; revised manuscript received December 20, 2012, accepted December 21, 2012.
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TAVR does not permit the prediction of interaction between the sutureless transcatheter prostheses
and surrounding structures before implantation.
Therefore, an in-depth understanding of aortic
root anatomy has become pivotal over the past
few years (10). Thus, imaging techniques have
garnered growing attention because they allow
more precise measurements of the annulus and
aortic root for proper definition of the spatial
orientation of the aortic valve complex. This is
important because these features guide the eligibility of patients for TAVR and allow adequate
device sizing (11).
Herein, we propose 3 techniques for sizing an
aortic valve annulus before TAVR and discuss
their implications for the currently available selection of prostheses. Although the exact utility
and success of these approaches await prospective
confirmation, the step-by-step approaches highlighted here should serve primarily as a guide for
the methodological approaches available for sizing the aortic valve annulus for patients undergoing TAVR.
ABBREVIATIONS
AND ACRONYMS
Studying the Aortic Valve Anatomy
to Match it with an Adequately
Sized Prosthesis
MDCT ⴝ multidetector
computed tomography
TAVR ⴝ transcatheter aortic
valve replacement
TEE ⴝ transesophageal
echocardiography
In TAVR, “sizing” can be defined as the
choice of prosthesis within a range of
available sizes to ensure that it is best
accommodated into the native aortic
root. This sizing is dependent on the observation
of anatomy-device interaction and represents one
of the most important predictors of a successful
procedure (3,4,12).
During TAVR, the size of the aortic valve
annulus is used as a standard measurement for
quantitative assessment of the site of implantation. By definition, an annulus should be in the
form of a ring. However, previous reports have
questioned the concept of a distinct anatomic
aortic annulus given the structure of the aortic
root and semilunar-shaped cusps (10). Second,
the close anatomical continuity of the left ventricular outflow tract into the ascending aorta
precludes clear identification of the individual
anatomic components (13).
Arguably, the diameter of the aortic root varies
considerably, and it depends primarily on the direction in which the diameter is measured. Piazza et al.
(10) reported that the aortic root has a 3dimensional structure in which 3 main circular
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rings, planes, and a crownlike ring can be recognized, and all of these originate from the aortic
valve leaflets, which are attached throughout the
length of the aortic root. The aortic valve annulus
typically represents the tightest part of the aortic
root and is defined as a virtual ring with 3
anatomical anchor points at the base of each of
the attachments of the aortic leaflets (Fig. 1). The
size of a transcatheter valve prosthesis traditionally relied on the dimensions of the aortic annulus
during systole, with the native leaflets and their
hinge points providing the first resistance and
anchoring force to the prosthesis.
The ability to provide the correct measurement
of the aortic valve annulus is essential to avoid
undersizing and oversizing of transcatheter heart
valves. Undersizing of the aortic valve annulus could
lead to the selection and deployment of a smaller
prosthesis, which could result in paravalvular regurgitation (14) and valve embolization (15). In contrast, oversizing can lead to underexpansion of
the prosthesis, with possible reduced valve durability, conduction disturbances leading to permanent pacemaker insertion, or annular rupture
(16). In general, transcatheter prostheses are
designed to be deployed in annuli that are slightly
smaller than the prostheses. This “controlled”
oversizing is essential for anchoring a sutureless
prosthesis (11).
Because of the particular characteristics of
transcatheter prostheses, a complete assessment
of the anatomy of the aortic valve complex is
required during pre-procedural decision making.
To date, 3 imaging techniques have been predominantly used to perform sizing before TAVR:
echocardiography, multidetector computed tomography (MDCT) imaging, and intraoperative
balloon sizing.
Imaging Tools for Aortic Annular Sizing
Transesophageal echocardiography (TEE). In clinical
practice, patient eligibility and the determination
of prosthesis size are currently based largely on
echocardiography, which is an essential imaging
tool for all patients undergoing TAVR (17,18).
Given the increased understanding of the anatomy of the aortic valve, a single-dimensional
measurement is no longer accepted as the sole
determinant of transcatheter valve sizing. However, 2-dimensional transthoracic echocardiography is the first step to assess aortic valve stenosis
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Figure 1. Normal Anatomy of the Aortic Annulus
The aortic annulus accounts for the tightest part of the aortic root (A) and is defined as a virtual ring (green line) with 3 anatomical
anchor points at the nadir (green points) of each of the attachments of the 3 aortic leaflets (B). LCC ⫽ left coronary cusp; NCC ⫽ noncoronary cusp; RCC ⫽ right coronary cusp.
severity and initial sizing of the aortic valve
annulus. Three reference planes intersecting at
90° to one another are used for quantitative
analysis. The plane of the valve is referred to as
the transverse plane, and the planes orthogonal to
the transverse plane define the sagittal (anteriorto-posterior) and coronal (left-to-right) reference
planes. Although direct comparison of transthoracic echocardiography and TEE has suggested
that systolic sagittal plane measurements on TEE
are approximately 1 mm larger than on transthoracic echocardiography, this may result from
image quality rather than from inherent differences in techniques (19,20). With either modality, in the long-axis view, the annular dimension
measured on the sagittal plane is the shorter one,
while that measured on the coronal plane is the
longer one. Thus, it is of a paramount importance
to ascertain the cross-sectional anatomy of the
annulus, which can be performed in the shortaxis view or more accurately using 3-dimensional
imaging.
The guidelines of the American Society of
Echocardiography (21) and the consensus document on TAVR (11) recommend TEE before
TAVR if there are issues regarding aortic root
anatomy, aortic valve annular diameter, or the
number of cusps. With TEE, the size of the
aortic valve annulus at the level of basal attach-
ment or hinge points of the aortic valve cusps
dictates the size of the prosthesis. Annular size
measurement should be performed using the
enlarged view of the midesophageal long axis
(approximately 110° to 140°, referred to as the
“3-chamber view”) during the early systolic phase
of the cardiac cycle. In this projection, the left
ventricular chamber, outflow tract, and ascending
aorta should be aligned along their long axes to
ensure that the sagittal plane bisects the maximal
diameter of the annulus. Oblique measurements
may lead to overestimation of the annular dimensions (Fig. 2A). Once the aforementioned anatomic structures are aligned, the aortic valve
annulus can be measured following the trailing
edge–to–leading edge convention. The measurement should be performed from the edge of sinus
to the hinge point of the right coronary cusp
perpendicular to the long axis of the aorta (Fig. 2B).
Because in this long-axis view, the plane passes
posteriorly between the commissure situated within
left and noncoronary cusps, a distinct anatomic
landmark (such as the hinge point of a cusp) cannot
be clearly delineated. Proper attention is required to
avoid measurement of bulky commissural calcium
that is often present within the sinus of Valsalva,
leading to overestimation of the actual annular size.
The measurement must exclude ectopic calcifications, with the points measured outside the calcifi-
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Figure 2. Aortic Annular View With Transesophageal
Echocardiography
Midesophageal long-axis zoomed-up view (“3-chamber view”)
during the early systolic phase of the cardiac cycle (A). The left
ventricular chamber (LV), the outflow tract (OT), the aortic valve
(AV), and the ascending aorta (AA) are aligned. An orthogonal
plane is considered as a reference (B, dotted yellow line). The 4
edges of the aortic sinus (yellow points) are the landmarks: the
sinotubular junction defines the upper reference plane, and the
insertion point of the aortic valve leaflets on the outflow tract
defines the lower reference plane. The aortic valve annulus is
measured as the distance between the hinge point of the right
cusp and the edge of the sinus at the side of the commissures
between the left and noncoronary cusps, including calcifications
(red line with arrowheads). It is useful to select the landmarks by
moving frames in cine loop back and forth to rule out artifacts (C).
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cations. In some cases, real-time imaging may help
distinguish side-lobe and reverberation artifacts
from real structures (Fig. 2C). Although measurements from 2 to 5 beats can be averaged, it is
important to remember that cyclic variation in
the location of the sagittal plane occurs with
respirations or within the RR cycle. An enlarged
short-axis view on TEE illustrates the aortic valve
opening and location and extent of calcifications.
The new generation of ultrasound scanners offers
multiplanar imaging with simultaneous acquisition of short-axis and long-axis planes, a feature
that could be helpful for finding a plane that
bisects the annulus, especially when patients are
examined with limited echocardiographic windows.
Two-dimensional TEE possesses the inaccuracy observed in monoplanar displays. Furthermore,
2-dimensional TEE has some specific drawbacks due
to the unique measurements required for TAVR.
Although the operator can obtain a symmetric visualization of the cusps, their measurement could prove
challenging (20,22,23). Although 3-dimensional
TEE lacks adequate standardization and is not yet
routinely available, there is some evidence suggesting
that this method is a valid alternative for more precise
pre-procedural measurements in the setting of
TAVR, potentially reducing the possibility of sizing
errors (24 –27).
We propose a 3-step approach, referred to as the
“turnaround rule,” to easily define aortic valve annular size (Fig. 3). Two-dimensional TEE is performed to obtain a short-axis view of the aortic
valve. Three-dimensional TEE is then performed
over zoom mode to acquire loops with the narrowest possible depth, with adjustment of lateral width
and elevation width for obtaining a volume containing the whole aortic root, the left ventricular outflow tract, and part of the ascending aorta; volume
rates of at least 10/s will allow an accurate assessment of early systole. The loop is then assessed with
a 3-dimensional commercially available software
package with standard short-axis views of the aortic
valve (Fig. 4) in mid systole used as a reference
frame. First, the transverse and sagittal and coronal orthogonal planes are oriented along the
aortic root such that all planes intersect at the
center of the opened valve, with the sagittal and
coronal planes aligned parallel to the long axis of
the ascending aorta. Second, the orthogonal
planes are rotated to identify the most caudal
attachments of the aortic valve leaflets (hinge
points). It is important to remember that the
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Figure 3. Alignment of Aortic Root Planes With 3-Dimensional Transesophageal Echocardiography
The colors used through selected images (lines and planes) reflect the 3-dimensional schematic reconstructions. The center axis of the
left ventricular outflow tract (LVOT) is chosen as a reference with the transverse plane (1) placed parallel to the sinotubular junction (red
dots). The planes orthogonal to the transverse plane are rotated (2) for delineating the hinge point of the left and right coronary
sinuses. The transverse plane is moved toward the left ventricular outflow (3) to arrive at the level of the hinge points of the aortic leaflet insertion. The orthogonal plane is further rotated (4) to ensure that the transverse plane also crosses through the hinge point of the
noncoronary cusp (NCC). The longest (D1) and the shortest (D2) diameters, the circumference, and the area of the annulus are measured.
Abbreviations as in Figure 1.
hinge-point plane refers to the virtual annular
plane. The transverse plane is repositioned from
the aorta toward the ventricle until it reaches the
level of the hinge points. In the setting of severely
calcified and immobile cusps, bulky calcifications
of the cusps may extend into the plane of the
annulus in systole, making an accurate measurement more difficult. In addition, acoustic artifacts
Figure 4. Artifacts With Computed Tomographic Angiographic Scans
Image distortion caused by motion artifacts is depicted (A, B, red arrows).
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such as side lobes or acoustic shadowing may
reduce accuracy. Finally, the orthogonal planes
are repeatedly rotated (the turnaround rule) to
ensure that the hinge points of the aortic valve
leaflets are transected by the transverse plane.
The annulus is typically oval in its appearance,
with the minimal dimension in the sagittal plane
and the maximal dimension in the coronal plane.
These measurements, as well as the perimeter and
annular area, can then be measured on the transverse plane. A mean annular diameter (the mean
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of the minimal and maximal diameters) or a mean
annular diameter (from the perimeter or area) can
be calculated.
MDCT imaging. Over the past few years, MDCT
imaging has become an essential tool for providing detailed and reliable description of the complex 3-dimensional aortic root anatomy in patients undergoing TAVR. Indeed, tomographic
images of the aortic annulus, commissures, and
sinuses of Valsalva, where the coronary arteries
originate, provide an in-depth understanding of
Figure 5. Alignment of Aortic Root Planes With Multislice Computed Tomography
The colors used through selected computed tomography images (lines and contours) reflect the 3-dimensional schematic reconstructions (top). The center axis of the left ventricular outflow tract and ascending aorta is chosen as a reference with the 3 planes locked in
a 90° angle. The crosshair are moved in the middle of the aortic root to align the longitudinal axis in coronal and sagittal planes
(A, B, bottom, orange/blue lines). The transverse plane is aligned at the level of the valve (C, valve plane), dragging this plane down
from the aorta towards the ventricle (A, B, bottom, white arrows) until the most caudal attachment of the aortic valve leaflets (hinge
points) come into view (D, transverse plane). The transverse plane is the basis for the alignment of the hinge point plane which refers
to the virtual annulus plane in which no valve structure is visible. A ⫽ anterior; L ⫽ left; P ⫽ posterior; R ⫽ right.
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the framework within which the aortic valve
leaflets are suspended (20,28 –31). These preoperative assessments are required because of the
lack of direct valve visualization when the procedure is performed. Consensus regarding TAVR
recommends the use of MDCT systems with at
least 64 detectors and spatial resolution of 0.5 to
0.6 mm (11).
Suggested scanning protocols for annular sizing during TAVR include electrocardiographically synchronized (gated) imaging of the aortic
root, which is important to avoid motion-induced
artifacts (Figs. 4A and 4B). Image reconstruction
can be performed in the desired phase of the
cardiac cycle, and in contrast to transesophageal
echocardiographic measurements, MDCT imaging does not report any significant differences
with respect to diameters, which are acquired
during the systolic or diastolic phase (28). We
recommend using the phase of the cardiac cycle
with the best image quality. Reconstruction of
the annulus should be performed orthogonally in
relation to the central axis of the left ventricular
outflow tract; this permits correct understanding
of minimal and maximal diameter, circumfer-
ence, and area, while emphasizing the presence of
a noncircular aortic valve annulus (reported in up
to 40% of patients who may need TAVR)
(20,24,30,32,33).
The turnaround rule is useful to define the
aortic valve annular size with the help of simple
multiplanar rendering software (with the 3 planes
locked at a 90° angle), and it is integrated in
almost all of the workstations used for cardiac
imaging. First, the crosshairs should be moved to
the middle of the aortic root, and the longitudinal
axis in the coronal and sagittal plane should be
aligned (double oblique planes) (Figs. 5A and
5B). Second, the transverse plane should be
aligned at the level of the valve (valve plane) by
dragging this plane down from the aorta toward
the ventricle until the most caudal attachments of
the aortic valve leaflets (hinge points) come into
view (Figs. 5C and 5D). Finally, the transverse
plane should be rotated around its own axis to
align the longitudinal planes (coronal oblique and
sagittal oblique planes) to ensure that the hinge
points of the aortic valve leaflets individually
touch the transverse plane (Figs. 6A to 6D).
Ideally, when the orientation of the transverse
Figure 6. Spatial Reconstruction of the Aortic Annulus With the “Turnaround Rule”
Scheme (A) and computed tomographic images (B to D): the transverse plane is turned clockwise around its own axis to align one at a
time the nadirs of the aortic valve leaflets with the transverse plane in 3 steps (1–3). The distances to the coronary ostia can be measured in the longitudinal axis at a right angle to the hinge point plane (B, C, red arrows). Abbreviations as in Figure 1.
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plane is correct, all 3 aortic valve leaflets appear or
disappear simultaneously by moving this plane in
a caudal or cranial fashion. If the planes need to
be realigned to minutely adjust the transversal
plane, it should be ensured that all 3 cusps touch
the plane again while the transverse plane is
turned around 1 more time. Once the hinge point
plane is aligned, the measurement can be performed in this plane or 1 section below (in the
upper outflow tract) because of the excellent
spatial resolution associated with previous generation of MDCT systems. However, it must be
remembered that in the current setting of clinical
practice, although imaging refinements are available, the proper identification and alignment of
the plane on which the virtual ring is situated
might be difficult because of heavy calcifications
or extremely oval annuli. Both of these issues
could lead to distortion of the aortic root. In
these cases, patients would benefit most from
multimodality imaging (20,22,34,35).
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Once alignment has been performed, it is possible to trace a polygonal line that circumscribes the
aortic valve annulus (visible at the transverse plane
level) to determine its area and perimeter. Minimal
and maximal dimensions can be manually determined through the center point of this annulus,
with the mean diameter being the mean of these 2
measures or calculated using the area or circumference (Fig. 7). Bioprostheses are supposed to have
a circular cross-section. In this respect, the diameter derived from this ideal circumference is
calculated as: (perimeter of the traced polygon)/␲, while the area is calculated as: [2 ⫻
✓(area of traced polygon in mm2/␲)] (36,37).
The distance of the valve plane from the coronary
ostia should be measured in the longitudinal axis
at right angle to the hinge point plane (Figs. 6B
and 6C). The importance of MDCT measurements performed at the transverse plane level and
the potential drawbacks associated with erroneous measures are described in Figure 8.
Figure 7. Aortic Annular Measurements at Hinge-Point Plane
(A) Minimal and (B) maximal dimensions are drawn manually through the center point of the aortic valve annulus.
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Figure 8. Errors During Measurements at the Level of the Aortic Root
False measurements, as well as correct aortic annular definition at the hinge-point plane, are illustrated.
Several lines of evidence have demonstrated
that MDCT measurements of the virtual basal
ring (mean diameter, circumference, and area) are
more reproducible than echocardiography
(20,29,33). The use of MDCT measurements
could result in changes in strategy in a greater
number of patients compared with TEE (20)
because of its close correlation with direct surgical measures (38,39) and a high degree of reproducibility (37).
Annular sizing and the assessment of aortic root
orientation would allow the prediction of the aortic
root angle before the procedure (40,41). This might
potentially decrease the number of aortograms required during the procedure and therefore reduce
the procedure time and need for contrast, thereby
improving the precision of bioprostheses deployment (40).
Calibrated balloon aortic valvuloplasty. Although
there have been continual advances in imaging
techniques, the characteristics of degenerative
aortic valve stenosis can lead to very challenging
scenarios in the setting of TAVR. Furthermore,
because of conflicting measurements obtained
with multimodal imaging, annular sizing using 2
different prosthesis sizes, asymmetric calcifications, or eccentric leaflets, there can be uncertainties regarding the selection of an optimal prosthesis for TAVR (20,42). In those cases, balloon
aortic valvuloplasty (43) after proper calibration
(44 – 46) could be used as a tool for direct annular
sizing and correct prosthesis selection in the
Figure 9. Aortic Annular Sizing Through Balloon Valvuloplasty
and Simultaneous Aortography
Indirect signs of proper measurements: the lack of movement of
the balloon within the aortic valve (yellow line with arrowhead), the possible waist of the balloon at the level of the
annulus (red arrows), the residual contrast medium regurgitation between the maximally inflated balloon and the hinge
points of the valve (blue arrow), and the calcified leaflets
splayed against coronary ostia (green arrow).
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Figure 10. Recommendations for Balloon-Expandable and Self-Expandable Prosthesis Selection
Commercially available prostheses are presented (Edwards SAPIEN [A] and SAPIEN XT [B].
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Figure 10. Continued
Edwards Lifesciences; CoreValve ReValving System [C], Medtronic, Inc.) with ideal measurements and requested oversizing. For Edwards
SAPIEN and SAPIEN XT prostheses, the 23-mm and 25-mm balloons provided from the manufacturer can be used for sizing. AsAo ⫽
ascending aorta; BAV ⫽ balloon aortic valvuloplasty; CoV ⫽ CoreValve; CT ⫽ computed tomography; MD ⫽ mean diameter; SXT ⫽
Edwards SAPIENT XT; TEE ⫽ transesophageal echocardiography. aRange provided by the manufacturer. bRange suggested according to
the authors’ personal experience. cComputed tomographic confirmation is required.
catheterization laboratory. For instance, previous
reports have suggested that balloon aortic valvuloplasty could directly influence the change in
the size of the prosthesis in up to 25% of
patients (45).
As illustrated in Figure 9, during rapid pacing,
balloon valvuloplasty performed simultaneously
with contrast injection at the level of the ascend-
ing aorta can provide an indirect confirmation of
adequate sizing through several signs: first, the
lack of balloon movement within the aortic valve;
second, the waist of the balloon present at the
level of annulus; and third, the absence of regurgitation of the residual contrast medium between
the maximally inflated balloon and hinge points
of the valve. Moreover, during balloon valvulo-
Figure 11. Annular Calcifications and Bioprosthesis Oversizing
Annulus without calcification (A), annulus with moderate calcifications (B), and annulus with severe or diffuse calcifications (C).
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plasty, operators can reliably predict the final
position of the splayed calcified leaflets to exclude
the potential risk for coronary ostia occlusion
after TAVR.
Prosthesis Selection after Aortic Annular Sizing
Once definitive measurements have been made,
the prosthesis with the correct size that adequately fits the annular diameter should be selected on the basis of charts provided by manufacturers and one’s own experience (Figs. 10A to
10C). Because balloon-expandable valves are designed to reach a definite diameter and form after
deployment, they can change the shape of the
annulus remarkably. In contrast, self-expandable
prostheses are more prone to accommodate native
anatomies. Thus, for TAVR, especially with
balloon-expandable prostheses, procedural success and inherent risks are highly dependent on
proper annular sizing. In this regard, it must be
acknowledged that balloon-expandable transcatheter prostheses (Edwards SAPIEN, available
only in the United States, and SAPIEN XT,
available only in Europe) are available in 3-mm
step sizes (namely, 23 and 26 mm for the Edwards SAPIEN valve and 23, 26, and 29 mm for
the SAPIEN XT valve), while self-expandable
transcatheter prostheses are available in 3-mm
step sizes up to 29 mm, with a newly available
2-mm step size of 31 mm. This aspect could
represent a problem when measurements of the
aortic annulus are in the overlapping area between 2 different prosthesis sizes. In such cases,
attention must be paid to the extent of calcification of the leaflets to avoid the risk for aortic root
rupture. In cases of annuli without calcification
(Fig. 11A), the valve size should be at least ⱖ1
REFERENCES
1. Webb JG, Wood DA. Current status
of transcatheter aortic valve replacement. J Am Coll Cardiol 2012;60:
483–92.
2. Genereux P, Head SJ, Van Mieghem
NM, et al. Clinical outcomes after
transcatheter aortic valve replacement using valve academic research
consortium definitions: a weighted
meta-analysis of 3,519 patients from
16 studies. J Am Coll Cardiol 2012;
59:2317–26.
3. Genereux P, Head SJ, Wood DA, et
al. Transcatheter aortic valve implantation 10-year anniversary: re-
mm bigger than the annular size. However, in
cases of moderate calcification (Fig. 11B), the
valve size should be ⱖ0.5 mm bigger than annular size, and for severe or diffuse calcification
(Fig. 11C), the chosen valve size could be nearly
equal to the annular size. With the currently
available bioprostheses, up to 97% of patients are
anatomically suitable for TAVR, suggesting that
a wide array of bioprostheses will permit the
management of patients with severe aortic stenosis who are at high or prohibitive risk for surgery
(47– 49).
Conclusions
As technology and imaging rapidly evolve, refinements to TAVR procedures are expected to
diminish the uncertainty that still surrounds their
widespread application, potentially leading to an
increase in frequency resembling that seen with
percutaneous coronary intervention over the past
2 decades. As the procedures become simpler and
safer, it is more likely that they will be performed
more often. Therefore, clear and easily available
3-dimensional imaging and device ameliorations,
in addition to increasing the experience of operators, will play a pivotal role for TAVR, especially
in the setting of patient eligibility and prosthesis
selection. The overall aim is to avoid the serious
consequences due to undersizing or oversizing in
this clinical scenario.
Reprint requests and correspondence: Dr. Albert M. Kasel,
Deutsches Herzzentrum, Technische Universität, Lazarettstrasse 36, Munich, Germany. E-mail: markus.kasel@
googlemail.com. OR Dr. Partho P. Sengupta, Mount Sinai
School of Medicine, One Gustave L. Levy Place, Box
1030, New York, New York 10029. E-mail: partho.
[email protected].
view of current evidence and clinical
implications. Eur Heart J 2012;33:
2388 –98.
4. Genereux P, Head SJ, Wood DA, et
al. Transcatheter aortic valve implantation: 10-year anniversary. Part II:
clinical implications. Eur Heart J
2012;33:2399 – 402.
5. Leon MB, Smith CR, Mack M, et
al. Transcatheter aortic-valve implantation for aortic stenosis in patients who cannot undergo surgery.
N Engl J Med 2010;363:1597– 607.
6. Smith CR, Leon MB, Mack MJ, et
al. Transcatheter versus surgical
aortic-valve replacement in high-
risk patients. N Engl J Med 2011;
364:2187–98.
7. U.S. Food and Drug Administration.
Edwards SAPIEN Transcatheter
Heart Valve (THV)-P100041.
Available at: http://www.fda.gov/
MedicalDevices/ProductsandMedical
Procedures/DeviceApprovalsand
Clearances/Recently-Approved
Devices/ucm280840.htm. Accessed
January 4, 2013.
8. Buellesfeld L, Gerckens U, Schuler
G, et al. 2-year follow-up of patients
undergoing transcatheter aortic valve
implantation using a self-expanding
valve prosthesis. J Am Coll Cardiol
2011;57:1650 –7.
JACC: CARDIOVASCULAR IMAGING, VOL. 6, NO. 2, 2013
FEBRUARY 2013:249 – 62
9. Ussia GP, Barbanti M, Petronio AS,
et al. Transcatheter aortic valve implantation: 3-year outcomes of selfexpanding CoreValve prosthesis. Eur
Heart J 2012;33:969 –76.
10. Piazza N, de Jaegere P, Schultz C,
Becker AE, Serruys PW, Anderson
RH. Anatomy of the aortic valvar complex and its implications for transcatheter implantation of the aortic valve. Circ
Cardiovasc Interv 2008;1:74 – 81.
11. Holmes DR Jr, Mack MJ, Kaul S, et
al. 2012 ACCF/AATS/SCAI/STS
expert consensus document on transcatheter aortic valve replacement.
J Am Coll Cardiol 2012;59:1200 –54.
12. Jilaihawi H, Chin D, Spyt T, et al.
Prosthesis-patient mismatch after
transcatheter aortic valve implantation with the Medtronic-CoreValve
bioprosthesis. Eur Heart J 2010;31:
857– 64.
13. Anderson RH. Clinical anatomy of
the aortic root. Heart 2000;84:670 –3.
14. Detaint D, Lepage L, Himbert D, et
al. Determinants of significant paravalvular regurgitation after transcatheter aortic valve: implantation impact
of device and annulus discongruence.
J Am Coll Cardiol Intv 2009;2:821–7.
15. Tay EL, Gurvitch R, Wijeysinghe N, et
al. Outcome of patients after transcatheter aortic valve embolization. J Am
Coll Cardiol Intv 2011;4:228 –34.
16. Blanke P, Reinohl J, Schlensak C, et
al. Prosthesis oversizing in balloonexpandable transcatheter aortic valve
implantation is associated with contained rupture of the aortic root. Circ
Cardiovasc Interv 2012;5:540 – 8.
17. Vahanian A, Alfieri O, Al-Attar N, et
al. Transcatheter valve implantation
for patients with aortic stenosis: a
position statement from the European
Association of Cardio-Thoracic Surgery (EACTS) and the European
Society of Cardiology (ESC), in collaboration with the European Association of Percutaneous Cardiovascular
Interventions (EAPCI). Eur Heart J
2008;29:1463–70.
18. Jayasuriya C, Moss RR, Munt B.
Transcatheter aortic valve implantation in aortic stenosis: the role of
echocardiography. J Am Soc Echocardiogr 2011;24:15–27.
19. Moss RR, Ivens E, Pasupati S, et al.
Role of echocardiography in percutaneous aortic valve implantation. J Am
Coll Cardiol Img 2008;1:15–24.
20. Messika-Zeitoun D, Serfaty JM, Brochet E, et al. Multimodal assessment
of the aortic annulus diameter: implications for transcatheter aortic valve
implantation. J Am Coll Cardiol
2010;55:186 –94.
21. Zamorano JL, Badano LP, Bruce C,
et al. EAE/ASE recommendations for
the use of echocardiography in new
transcatheter interventions for valvular
heart disease. J Am Soc Echocardiogr
2011;24:937– 65.
22. Tuzcu EM, Kapadia SR, Schoenhagen P. Multimodality quantitative imaging of aortic root for transcatheter
aortic valve implantation: more complex than it appears. J Am Coll Cardiol 2010;55:195–7.
23. Blanke P, Siepe M, Reinohl J, et al.
Assessment of aortic annulus dimensions for Edwards SAPIEN Transapical Heart Valve implantation by computed tomography: calculating average
diameter using a virtual ring method.
Eur J Cardiothorac Surg 2010;38:
750 – 8.
24. Ng AC, Delgado V, van der Kley F, et
al. Comparison of aortic root dimensions and geometries before and after
transcatheter aortic valve implantation
by 2- and 3-dimensional transesophageal echocardiography and multislice
computed tomography. Circ Cardiovasc Imaging 2010;3:94 –102.
25. Altiok E, Koos R, Schroder J, et al.
Comparison of two-dimensional and
three-dimensional imaging techniques
for measurement of aortic annulus diameters before transcatheter aortic
valve implantation. Heart 2011;97:
1578 – 84.
26. Santos N, de Agustin JA, Almeria C,
et al. Prosthesis/annulus discongruence assessed by three-dimensional
transoesophageal echocardiography: a
predictor of significant paravalvular
aortic regurgitation after transcatheter
aortic valve implantation. Eur Heart J
Cardiovasc Imaging 2012;13:931–7.
27. Janosi RA, Kahlert P, Plicht B, et al.
Measurement of the aortic annulus
size by real-time three-dimensional
transesophageal echocardiography.
Minim Invasive Ther Allied Technol
2011;20:85–94.
28. Tops LF, Wood DA, Delgado V, et
al. Noninvasive evaluation of the aortic root with multislice computed tomography implications for transcatheter aortic valve replacement. J Am
Coll Cardiol Img 2008;1:321–30.
29. Schoenhagen P, Tuzcu EM, Kapadia
SR, Desai MY, Svensson LG. Threedimensional imaging of the aortic valve
and aortic root with computed tomography: new standards in an era of transcatheter valve repair/implantation. Eur
Heart J 2009;30:2079 – 86.
30. Akhtar M, Tuzcu EM, Kapadia SR,
et al. Aortic root morphology in patients undergoing percutaneous aortic
valve replacement: evidence of aortic
root remodeling. The Journal of thoracic and cardiovascular surgery 2009;
137:950 – 6.
31. Schoenhagen P, Numburi U, Halliburton SS, et al. Three-dimensional
Kasel et al.
Aortic Annular Sizing for TAVR
imaging in the context of minimally
invasive and transcatheter cardiovascular
interventions using multi-detector computed tomography: from pre-operative
planning to intra-operative guidance.
Eur Heart J 2010;31:2727– 40.
32. Leipsic J, Gurvitch R, Labounty TM,
et al. Multidetector computed tomography in transcatheter aortic valve implantation. J Am Coll Cardiol Img
2011;4:416 –29.
33. O’Brien B, Schoenhagen P, Kapadia
SR, et al. Integration of 3D imaging
data in the assessment of aortic stenosis: impact on classification of disease
severity. Circ Cardiovasc Imaging
2011;4:566 –73.
34. Delgado V, Kapadia S, Schalij MJ,
Schuijf JD, Tuzcu EM, Bax JJ. Transcatheter aortic valve implantation: implications of multimodality imaging in
patient selection, procedural guidance,
and outcomes. Heart 2012;98:743–54.
35. Bloomfield GS, Gillam LD, Hahn
RT, et al. A practical guide to multimodality imaging of transcatheter aortic valve replacement. J Am Coll Cardiol Img 2012;5:441–55.
36. Schultz CJ, Moelker A, Piazza N, et
al. Three dimensional evaluation of
the aortic annulus using multislice
computer tomography: are manufacturer’s guidelines for sizing for percutaneous aortic valve replacement helpful? Eur Heart J 2010;31:849 –56.
37. Jilaihawi H, Kashif M, Fontana G, et
al. Cross-sectional computed tomographic assessment improves accuracy
of aortic annular sizing for transcatheter aortic valve replacement and reduces the incidence of paravalvular
aortic regurgitation. J Am Coll Cardiol 2012;59:1275– 86.
38. Dashkevich A, Blanke P, Siepe M, et
al. Preoperative assessment of aortic
annulus dimensions: comparison of
noninvasive and intraoperative measurement. Ann Thorac Surg 2011;91:
709 –14.
39. Kempfert J, Van Linden A, Lehmkuhl
L, et al. Aortic annulus sizing: echocardiographic vs. computed tomography derived measurements in comparison with direct surgical sizing. Eur
J Cardiothorac Surg 2012;42:627–33.
40. Gurvitch R, Wood DA, Leipsic J, et al.
Multislice computed tomography for
prediction of optimal angiographic deployment projections during transcatheter aortic valve implantation. J Am
Coll Cardiol Intv 2010;3:1157– 65.
41. Kurra V, Kapadia SR, Tuzcu EM, et al.
Pre-procedural imaging of aortic root
orientation and dimensions: comparison
between x-ray angiographic planar imaging and 3-dimensional multidetector
row computed tomography. J Am Coll
Cardiol Intv 2010;3:105–13.
261
262
Kasel et al.
Aortic Annular Sizing for TAVR
42. Cerillo AG, Mariani M, Glauber M,
Berti S. Sizing the annulus for transcatheter aortic valve implantation:
more than a simple measure? Eur
J Cardiothorac Surg 2012;41:717– 8.
43. Cribier A, Savin T, Berland J, et al.
Percutaneous transluminal balloon
valvuloplasty of adult aortic stenosis:
report of 92 cases. J Am Coll Cardiol
1987;9:381– 6.
44. Babaliaros VC, Liff D, Chen EP, et
al. Can balloon aortic valvuloplasty
help determine appropriate transcatheter aortic valve size? J Am Coll Cardiol Intv 2008;1:580 – 6.
45. Babaliaros VC, Junagadhwalla Z, Lerakis S, et al. Use of balloon aortic
valvuloplasty to size the aortic annulus
JACC: CARDIOVASCULAR IMAGING, VOL. 6, NO. 2, 2013
FEBRUARY 2013:249 – 62
before implantation of a balloonexpandable transcatheter heart valve.
J Am Coll Cardiol Intv 2010;3:114 – 8.
46. Cerillo AG, Mariani M, Berti S,
Glauber M. Sizing the aortic annulus.
Ann Cardiothorac Surg 2012;1:245–56.
47. Jilaihawi H, Bonan R, Asgar A, et al.
Anatomic suitability for present and
next generation transcatheter aortic
valve prostheses: evidence for a complementary multidevice approach to
treatment. J Am Coll Cardiol Intv
2010;3:859 – 66.
48. Jilaihawi H, Chakravarty T, Weiss
RE, Fontana GP, Forrester J, Makkar RR. Meta-analysis of complications in aortic valve replacement:
comparison of Medtronic-CoreValve,
Edwards-SAPIEN and surgical aortic
valve replacement in 8,536 patients.
Catheter Cardiovasc Interv 2012;80:
128 –38.
49. MacDonald I, Pasupati S. Transcatheter aortic valve implantation: know
the differences between the currently
available technologies. Eur Heart J
2010;31:1663–5.
Key Words: aortic stenosis y
computed tomography y
echocardiography y patient
selection y transcatheter aortic
valve implantation.