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92 2—AORTIC VALVE INTERVENTIONS
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valvuloplasty in case of development of severe acute aortic insufficiency with consequent hemodynamic instability.
Valve Insertion, Positioning, and Deployment
The newly prepared valve is then inserted via the Edwards sheath over the LV stiff wire. Initially
there is a fair amount of resistance within the Edwards sheath as the valve system goes through
the nonexpandable portion of the sheath. Passage of the valve system becomes easier as the valve
encounters the expandable portion of the sheath (Fig. 8.3). Occasionally in patients with small/
borderline iliac arteries, it may be necessary to withdraw the sheath slowly as the valve is being
advanced in cases of significant resistance of the valve within the sheath. The advancement of the
valve should be observed on fluoroscopy.
The current S3 system requires valve alignment and positioning on the balloon. This is ac-
complished in the descending aorta, following the manufacturer’s instructions. Once this is
completed, the valve system is advanced across the aortic arch using the retroflex system with
care to avoid scraping debris along the arch. The valve is then advanced into the aortic valve and
positioned with the middle marker on the valve at the annulus (Fig. 8.4A). Once positioning is
Unexpanded 6 mm
Expanded 8 mm
Fig. 8.3 The principle of an expandable sheath. The expandable sheath temporarily enlarges by unfolding
to allow entry of the device (expanded outer diameter 8 mm for the Sapien 3 26-mm valve) and subsequently
recoils to its reduced profile as the transcatheter heart valve passes. This expansion minimizes the force required to insert and pass the delivery system and transcatheter heart valve through the sheath, while maintaining a reduced profile in comparison with standard, nonexpendable introducer sheaths. (From Binder RK,
Rodés-Cabau J, Wood DA, et al. Transcatheter aortic valve replacement with the SAPIEN 3: A new balloonexpandable transcatheter heart valve. JACC Cardiovasc Int. 2013;6(3):293-300.)
AB
Fig. 8.4 The valve is aligned with the middle marker at the level of the aortic annulus (A), identified by the
calcification and the position of the pigtail in the aortic root. The valve is then deployed under rapid ventricular pacing (B). (C) Post–valve-deployment image. (From Munir A, Wahab A, Khan M, Khan H, Htun WW,
Schreiber TL. Transcatheter bicuspid aortic valve replacement in Turner syndrome: A unique experience of
interventional cardiologist. J Cardiol Cases. 2018;17(1):29-32.)
C
8—BALLOON EXPANDABLE TRANSCATHETER AORTIC VALVE REPLACEMENT 93
valvuloplasty
valve still in sheath
Self-expanding prosthesis
stented valve
Edwards sapien valve
CD
CD
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AB
Initial aortic balloon
valvuloplasty
Positioning of
stented valve
CoreValve
Inflation of balloon
with stented valve
Final position of
stented valve
AB
Initial aortic balloon
Positioning of stented
Withdrawal of sheath.
Final position of
Fig. 8.5 Percutaneous aortic valve (Edwards Sapien and CoreValve) replacement. Balloon valvuloplasty
is performed if indicated and the Edwards S3 is placed using fluoroscopic guidance. (From Arora S, Vavalle
JP. Transcatheter aortic valve replacement. In G Stouffer, MS Runge, C Patterson, JS Rossi, eds. Netter’s
Cardiology. 3rd ed. Philadelphia, PA: Elsevier; 2019:377-382.)
confirmed on angiography, the valve is deployed under rapid ventricular pacing at approximately
180 bpm (see Fig. 8.4B). The valve delivery system is inflated once there is confirmation that
the system blood pressure has dropped to its lowest (usually aiming for 20 to 40 mmHg) and
there is minimal pulsatility across the aortic valve. If the initial pacing run does not lead to a
decrease in blood pressure, pacing is stopped and restarted at a higher rate (e.g., 180 to 200 bpm).
The entire volume of the atrion is emptied and balloon inflation held for 3 to 5 seconds
(Fig. 8.5). The balloon is deflated, rapid pacing stopped, and the balloon catheter withdrawn
into the ascending aorta with the wire left in the LV.
The valve is then assessed by echocardiography (transthoracic echocardiography [TTE] or
TEE) for positioning, stability, placement, perivalvular leaks, and gradients. Echocardiography
also looks at LV function to rule out development of new wall motion abnormalities, pericardial
effusion, or new valvular abnormalities such as worsening mitral regurgitation or new right
ventricular (RV) dysfunction.
Access Site Closure
The large sheath is withdrawn with the stiff wire still in place and the Perclose sutures deployed
to seal the arteriotomy; the wire is subsequently removed if there is good hemostasis. Close
monitoring of blood pressure (BP) and heart rate is important at this stage, as a precipitous drop
in BP may be an indication of acute vascular injury, iliac dissection, perforation, or rupture.
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Completion iliac angiography may or not be performed according to operator preference. We
recommend completion iliac angiography if there was resistance advancing the sheath, borderline
iliac anatomy, or in cases of a drop in BP after sheath withdrawal. If there is normal renal function, we typically perform completion iliac angiography in all cases. The pigtail catheter is withdrawn to the level of the iliofemoral bifurcation and 30 to 40 mL of contrast injected. This will
demonstrate any stenosis or extravasation at the site of the Perclose sutures.
If completion angiography is satisfactory, the contralateral access sites are closed either with
manual pressure or vascular closure devices.
Summary and Take-Home Points
n
TAVR with a balloon-expandable prosthesis has been shown to be safe and effective.
n
Adequate knowledge of the device and procedural planning, along with appropriate patient
selection, is important to achieve optimal outcomes.
n
Balloon-expandable devices are inserted during rapid ventricular pacing.
CHAPTER 9
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Transcatheter Aortic Valve
Replacement Using
Self-Expanding Valve
Abdallah El Sabbagh Gurpreet Sandhu
Self-Expanding Transcatheter Aortic Valve
Replacement: The Medtronic CoreValve System
Currently in the United States, the most widely used self-expanding transcatheter aortic valve is
the Medtronic CoreValve system. This transcatheter valve is made of a self-expanding nitinol
frame with leaflets composed of porcine pericardium. The Medtronic CoreValve system has
undergone two design iterations to improve the outcomes after implantation based on trial and
registry data. The first-generation Medtronic CoreValve was evaluated in the CoreValve US
Pivotal Trial, which had two main studies: the extreme-risk and the high-risk study. The CoreValve US Pivotal Trial Extreme Risk Study looked at the outcomes of transcatheter aortic valve
replacement (TAVR) in patients with severe aortic stenosis who have a prohibitive risk for sur-
1
gery.
The endpoint of all-cause mortality and major stroke in the TAVR arm was noninferior to
that in the medical therapy arm. The second CoreValve US Pivotal Trial High Risk Study was a
prospective randomized study comparing outcomes of patients with severe aortic stenosis and
high surgical risk undergoing surgical aortic valve replacement (SAVR) to TAVR.
follow-up, TAVR was shown to be noninferior to SAVR with respect to mortality and stroke
endpoints. There was less major bleeding and atrial fibrillation with TAVR compared with
SAVR; however, there were more vascular complications and greater need for a pacemaker and
larger paravalvular leak in the TAVR arm. These trials led to Food and Drug Administration
(FDA) approval of the Medtronic CoreValve system in patients with high or prohibitive surgical
risk. To improve the outcomes pertaining to bleeding, paravalvular leak, and pacemaker need,
several changes were made to the device design itself (Fig. 9.1). The second-generation
Medtronic CoreValve Evolut R had a lower height to improve the hemodynamics and an extension distally to the skirt for a better seal to improve the paravalvular leak rate. The delivery system
also improved with an in-line sheath that brought the diameter of the delivery system from 24F
to 14F to lessen the vascular complications (Fig. 9.2). It also provided a recapture feature, which
allowed better positioning to prevent deep implantation, which can cause a heart block needing
pacemaker implantation.
The next clinical trial looked at outcomes of TAVR versus SAVR in intermediate-risk patients
with severe aortic stenosis.
second-generation Evolut system. The trial showed that TAVR was noninferior to SAVR with
respect to the combined endpoint of mortality and stroke, with higher rates of paravalvular leak
and pacemaker insertion in the TAVR arm. These results led to the approval of the use of a selfexpanding valve in patients with severe aortic stenosis and intermediate surgical risk. In a subgroup
3
Sixteen percent of the CoreValve devices used in this trial were the
2
At 1-year
95
96 2—AORTIC VALVE INTERVENTIONS
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CoreValveEvolut REvolut PRO
Fig. 9.1 The Medtronic CoreValve system has undergone two design iterations to improve outcomes
after implantation based on trial and registry data. The current valve is the Evolut Pro.
Fig. 9.2 The delivery system for the Evolut valve uses an in-line sheath with an external diameter of
14F and allows valve recapture.
analysis of this trial, the second-generation device design did not seem to have affected the outcomes related to pacemaker and paravalvular leak, although it only was used in a small number of
patients. Registry data studies, however, showed that the use of the CoreValve Evolut R was associated with lower rates of moderate to severe paravalvular leak, vascular complications, and
pacemaker implantation.
4–6
The device underwent further design changes, which led to the most
recent iteration called the Medtronic CoreValve Evolut Pro, which had an additional external
pericardial layer around the skirt to provide a better seal and lower the risk of paravalvular leak.
Outcomes of CoreValve Evolut Pro are still being studied. One important caveat is that the newer
Evolut Pro does not come in a 34-mm size and requires the use of a 16F in-line sheath as opposed
to the 14F in-line sheath in most of the models of the second-generation CoreValve Evolut.
Therefore the CoreValve Evolut Pro device requires a cutoff of a 5.5-cm vessel diameter to allow
passage of the delivery system.
Patient Selection
Candidates for TAVR include patients with severe aortic stenosis at an intermediate, high, or
prohibitive risk for SAVR, as well as for a failed surgical aortic bioprosthesis who have a high risk
9—TRANSCATHETER AORTIC VALVE REPLACEMENT USING SELF-EXPANDING VALVE 97
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for open surgery. Optimal candidates should have an acceptable 1-year survival to be considered
for TAVR.
Patients with known hypersensitivity to any medication or component used during the procedure, active sepsis or endocarditis, and mechanical valves have a contraindication for this procedure.
Anticoagulation should be held for this procedure, with low-molecular-weight heparin bridging
used for those at risk for thromboembolic events.
The following are patient anatomic factors that are important when considering the use of the
self-expanding CoreValve system:
n
Severe annular calcification: use of a self-expanding system rather than a balloon-expandable
system is preferable in these patients to help prevent annular rupture
n
Failed surgical bioprosthetic valves with a small diameter: given the CoreValve’s supraannular
position, the effective orifice area (EOA) is larger with the CoreValve compared with the
equivalent balloon-expandable annular TAVR prosthesis.
n
Patients at high risk of coronary obstruction: due to the advantage of a recapturable system,
although if coronary obstruction occurs after deployment of the valve, cannulation of the
coronary ostium can be more challenging with the CoreValve system compared with the
balloon-expandable valve.
n
Patients with poor cardiac reserve who cannot tolerate rapid pacing because the CoreValve
can be deployed without requiring rapid pacing, especially when the cardiac function is
diminished.
n
Horizontal aortas do not favor the use of a self-expanding valve, and the flexible delivery
system with the balloon-expandable device offers better alignment with the valve orientation.
Procedural Planning
Every patient who is being evaluated for this procedure has to be seen by a noninterventional
valve specialist, cardiovascular surgeon, and interventional cardiologist, and a decision has to be
made by the entire heart team. For procedural planning, patients would typically need the following
testing:
1. Transthoracic echocardiography
2. Cardiac computed tomography angiogram (CTA) and CTA of the chest, abdomen, and pelvis
3. Coronary angiogram
4. Labs
5. Electrocardiogram (ECG)
6. Chest x-ray
7. Pulmonary function testing
8. Frailty evaluation
The following steps in planning are for native aortic valve stenosis. The next section will
discuss specific considerations in planning valve-in-valve procedures.
1. Access planning: Transfemoral access is used for 90% of procedures and is the main focus
of this chapter (Fig. 9.3). Alternative access can be used when femoral access is not
available; this is described in Chapter 11.
CTA of the abdomen and pelvis is used to evaluate candidacy for transfemoral access.
Measurements are performed along the diameter of the common femoral, external iliac,
common iliac, and abdominal aorta on a double-oblique axis using reformatted images and
by measuring the minimal luminal diameters, excluding the calcified portions. Adequate
vessel diameter should be more than or equal to 5.5 mm for the Evolut Pro and the 34-mm
Evolut R, whereas it should be more than or equal to 5 mm for the 23-, 26-, and 29-mm
Evolut R CoreValve. Next, evaluation of anterior calcification is performed by looking at
the axial cross-sectional images at the level of the femoral head, paying particular attention
98 2—AORTIC VALVE INTERVENTIONS
23/24/29 mm Evolut pro and 34 mm Evolut R ≥ 5 mm
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CTA Abdomen/pelvis
Vessel diameter
23/24/29 mm Evolut R ≥ 5 mm
Fig. 9.3 Access planning for transfemoral transcatheter aortic valve replacement (TAVR).
Assessment of anterior calcium To rtuosity
to the presence of anterior calcification. The presence of anterior calcium in the common
femoral artery at the level of the femoral head precludes use of a Perclose device and
increases the risk of vascular complications and would be an indication to proceed with
alternative access. Following that, attention is paid to the tortuosity across the path of the
valve from the common femoral artery all the way to the aortic root. Many times, the
tortuosity straightens when a stiff wire is used during the procedure, and this can be
evaluated during the preprocedural coronary angiogram by placing a stiff wire and seeing
if that straightens the tortuosity. Also, the presence of any plaque, calcification, dissection,
or aneurysm along the pathway of the delivery system or catheters should be noted and
factored in the decision-making. Finally, in cases where an embolic protection device is
anticipated, the origin of the right brachiocephalic artery and the left common carotid
artery should be assessed to make sure no significant plaque is present.
2. Aortic root: The next step in planning is to focus on the aortic root (Fig. 9.4).
A. Sizing: Sizing of the self-expanding valve is made by measuring the annular perimeter
(not area). After a size is chosen, the next step is to ensure that the other measurements,
including the sinus of Valsalva diameter and height, are adequate to accommodate the
shape of the valve chosen.
B. Orientation of the root: The CTA provides the coplanar angle, which is the fluoro-
scopic angle at which the noncoronary right and left cusp are aligned and is important
for valve positioning and deployment. As mentioned, horizontal aortic roots are less
favorable for self-expanding valves because the delivery sheath can bias one side of the
aortic wall, which would make it difficult to position and deploy the valve coaxially.
C. Calcification: The presence of heavy calcification in the leaflets and/or left ventricular
outflow tract is a risk factor for paravalvular leak, annular rupture, and heart block. This
favors self-expanding valves over balloon-expanding valves, given the risk of annular
rupture, although care should be taken if predilation or postdilation of the valve is
required when using a self-expanding valve.
D. Coronary arteries: A coronary angiogram is performed to assess for the presence of an
obstruction or atherosclerosis. Percutaneous coronary intervention is performed if there
is a large ischemic territory, such as the proximal left anterior descending artery or left
main coronary artery.
9—TRANSCATHETER AORTIC VALVE REPLACEMENT USING SELF-EXPANDING VALVE 99
valsalva height
Tr
using the ViV app
cardiac CTA
ostium distance
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Cardiac CTA
Coplanar angle Coronary artery
and sinus of
Fig. 9.4 Preprocedural assessment of the aortic root by computed tomography (CT).
Aortic annular
perimeter
Sinus of valsalva
diameter
LVOT size
The risk of coronary artery obstruction, by displacing a calcified leaflet or by prosthetic leaflet eclipse, is increased when the coronary height, measured from the annulus
to the origin of the left or right coronary artery on the cardiac CTA, is less than 10 cm
and/or the sinus of Valsalva diameter is less than 28 cm on average.
E. Rhythm-related considerations: A baseline ECG is important to assess the risk of need-
ing a pacemaker. A baseline right bundle branch block increases that risk. If the patient
has a device with a defibrillator function, the latter should be temporarily deactivated
during the TAVR procedure. One of the advantages of self-expanding valves is that it is
possible to deploy these valves without needing rapid pacing, which is important in
patients who have poor cardiac function and depressed ejection fraction.
Planning Valve-in-Valve Therapy
Using the Self-Expanding Valve
Access planning is similar to the native TAVR. The main difference is the sizing and assessment
of the risk of coronary obstruction (Fig. 9.5).
Planning of the sizing of the valve-in-valve procedure requires a few steps:
1. Review of old surgical reports to see the type and size of surgical valve used.
2. Depending on the type of valve, sizing can be done using the valve-in-valve mobile ap-
plication, which gives the true internal diameter, and based on that gives recommendation
on the size of the valve and the optimal positioning during deployment.
Ht:
19
Stent ID: 25
Tr ue ID
THV
Selector
ue internal diameter
24
Fig. 9.5 Valve planning considerations for valve-in-valve procedures.
Actual internal diameter on
Virtual valve to left main
100 2—AORTIC VALVE INTERVENTIONS
Step 1:
sheath inser
Step 2:
sutures and upsiz
main access site
to 8
f
in the 6
and pacemak
in the 6
Step 4:
angiograph
up accurate
coplanar angle
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3. A CTA is also performed because sometimes the true internal diameter can be larger than
the actual internal diameter, especially if there is granulation tissue on the bioprosthetic
valve. This is why sizing has to be confirmed with a CTA by measuring the actual internal
diameter of the bioprosthetic valve.
The aortic valve-in-valve procedure is associated with up to six times the risk of coronary occlusion compared with native aortic valve replacement. Although low coronary heights can increase the
risk of coronary artery obstruction, the most important measurement that is strongly associated with
a high likelihood of coronary artery obstruction is the virtual transcatheter valve to coronary distance,
which is measured by placing a virtual valve in the bioprosthetic actual internal diameter on the CTA
and measuring the distance from the virtual valve to the coronary ostium. A cutoff of 4 mm or less
subjects the patient to a high risk for coronary obstruction after the valve-in-valve procedure.
Another consideration is the risk of prosthesis–patient mismatch after a valve-in-valve procedure.
This is particularly true if there is a 19-mm surgical bioprosthetic valve.
Procedure Steps
See Fig. 9.6 for illustrations of this procedure.
1. Access is obtained with 6F sheaths in the bilateral common femoral artery and one in the
femoral vein.
2. At the site of the transcatheter valve insertion, the 6F sheath is removed and two Perclose
sutures are deployed using a preclose technique at 10 o’clock and 2 o’clock, and the sheath
is then upsized to 8F.
Access and
tion
Perclose
Fr sheath
ollowed by pigtail
Fr artery
er
Fr vein
Coplanar
y to set
6 Fr
e
8 Fr + 2
Perclose sutures
Fig. 9.6 Procedural steps.
6 Fr 6 Fr
6 Fr +
Pacemaker
6 Fr +
Pigtail
9—TRANSCATHETER AORTIC VALVE REPLACEMENT USING SELF-EXPANDING VALVE 101
VB
20
Step 3:
system inser
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3. A balloon-tipped pacemaker catheter is then placed in the femoral vein and positioned in
the right ventricle. It is tested at 80 beats per minute.
4. A 5F pigtail is then positioned in the noncoronary cusp, and the C-arm is set up at the
coplanar angle determined by the CTA. The pigtail is then connected to a power injector,
and an aortogram is performed to confirm the presence of coplanar alignment of the three
cusps of the aortic valve.
5. The next steps differ depending on whether or not predilation is needed (Fig. 9.7). If it is
determined that predilation of the aortic valve is required, then a large-bore introducer
sheath needs to be positioned first before the aortic valve is crossed, as opposed to using
the in-line sheath of the CoreValve in case predilation is not needed. If predilation is
needed, the following steps are done: A JR4 diagnostic catheter is advanced into the
Delivery
tion
Ye s
Introducer sheath
insertion
18 Fr if using 23/24/29 mm Evolut R
Fr if using 23/24/29 mm Evolut Pro
and 34 mm Evolut R
BAV needed?
No
InLine sheath
insertion
Or
14 Fr if using 23/24/29 mm Evolut R
16 Fr if using 23/24/29 mm Evolut Pro
and 34 mm Evolut R
BA
InLine sheath insertion into
introducer sheath
Fig. 9.7 Delivery system procedural steps will vary, depending on whether balloon aortic valvulo-
plasty is performed.
AV
14 or 16 Fr introducer sheath exchanged
for 14 or 16 Fr InLine sheath
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