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178 3—MITRAL VALVE INTERVENTIONS
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Fig. 16.4 Procedural fluoroscopy of mitral valve-in-valve. (A) Septal balloon dilation and flossing. (B) Transcatheter valve deployment over ventricular rail.
screening for left ventricular outflow tract (LVOT) gradients, which could compromise the
LVOT after valve replacement. However, due to shadowing from the valve prosthesis or surgical sewing ring, TTE has decreased sensitivity and is often inadequate to fully evaluate
the failing metallic mitral prosthesis. Therefore TEE (Fig. 16.4) should be performed in
preparation for the procedure and is superior for the evaluation of mitral regurgitation, the
mechanism of prosthesis failure, and the presence of PVL.
the presence of left atrial appendage thrombus and can be used in evaluation of prosthesis/
annular dimensions.
2
TEE is also useful to rule out
Computed Tomography Angiography
Although not necessary for the majority of valve-in-valve procedures, gated CTA provides
superior anatomic definition for procedural planning (Fig. 16.5) and is critical for planning of
mitral valve-in-ring and for valve-in-valve procedures where a high risk of LVOT obstruction
has been identified, typically due to a highly angulated mitral prosthesis position. CTA provides precise fluoroscopic angles and high special resolution measurements to guide the intervention. For patients with mitral rings, CTA provides an accurate annular area measured in
diastole to determine optimal prosthesis size, and also delineates the circumferential extent of
the annular ring. In general, patients with incomplete rings are not considered candidates for
valve-in-ring due to inadequate anchoring and risk of prosthesis embolism. CTA provides
precise fluoroscopic angles with high spatial resolution to guide the intervention. For patients
with mitral rings, CTA provides an accurate annular area measured in diastole to determine
optimal prosthesis size and also delineates the circumferential extent of the annular ring. In
general, patients with incomplete rings are not considered candidates for valve-in-ring due to
inadequate anchoring and risk of prosthesis embolism. Based on the angles of the mitral
annulus or existing valve, the ideal fluoroscopy angles for valve deployment can be estimated.
Another benefit is identifying the optimal location of atrial septal puncture as well as significant septal thickening or scarring that poses a challenge. The septal puncture should be
16—PERCUTANEOUS MITRAL VALVE-IN-VALVE AND VALVE-IN-RING 179
Pre Post
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150 150
100
Art
50
LA
0
45 mmHg
Fig. 16.5 Intraprocedural hemodynamics of mitral valve-in-valve for severe regurgitation. Simultaneous arterial and left atrial pressure tracings with large v-wave in the left atrium from mitral regurgitation and systemic
hypotension before valve deployment. Post–valve deployment shows significant improvement in systemic
blood pressure with decrease in v-wave pressure correlating with reduction in regurgitation.
Art
LA
100
50
0
positioned so that there is adequate room in the left atria and to ensure appropriate angles for
valve positioning and stability during deployment. A critical consideration for procedural planning is assessment of LVOT obstruction risk. Because of the intimate relationship of the mitral
annulus with the aortic valve annulus and LVOT, any valve that protrudes past the annulus and
into the LVOT can potentially create a clinically significant systolic gradient. Therefore it is
important to consider the aortomitral angle and the LVOT size during systole. In patients
undergoing valve-in-valve, the prior prosthetic valve can provide landmarks for deployment,
with the goal of the ventricular strut edges being at the level of the prior valve struts or even
to cover just the prosthesis leaflets. In these patients the anterior leaflet has usually been removed or is already immobilized and therefore unlikely to cause obstruction. In the case of
valve-in-ring, the presence of the native anterior leaflet poses a potential risk, as it will be
displaced anteriorly toward the LVOT, potentially obstructing blood flow. Therefore the length
of the anterior leaflet in conjunction with aortomitral angle and LVOT size in systole should
be evaluated to ensure adequate area once the anterior leaflet is permanently displaced. CTA
computer-assisted detection software is available, which can help in planning by placing various-sized virtual valves based on the patient anatomy to evaluate the “neo-LVOT” after valve
deployment. Ideally the anticipated neo-LVOT should be larger than 250 mm
deployment, though current limited data suggest an area as low as 190 mm
2
2
after valve
may be sufficient.12
In patients in whom the LVOT area will be prohibitive to replacement, two options can be
considered. First, alcohol septal ablation 4 to 6 weeks before the procedure can be attempted
to maximize LVOT diameter. Second, a novel percutaneous laceration of the anterior mitral
leaflet, or “Lampoon” procedure, can be performed at the time of the procedure to minimize
the risk of the anterior leaflet causing obstruction.
13
180 3—MITRAL VALVE INTERVENTIONS
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Transseptal Balloon-Expandable Mitral Valve
Implantation Technique
Our preferred route for delivery is the transseptal approach, which is technically feasible in almost
all patients and provides rapid recovery and low procedural morbidity. In the early development
of the transseptal technique, a transapical rail was utilized for additional support; however, with
the improvement in support and maneuverability of the most recent SAPIEN delivery systems,
this is no longer necessary.
Patients are placed under general anesthesia, and intraprocedural TEE imaging is used in ad-
dition to fluoroscopic guidance. Vascular access is obtained via the common femoral vein, and one
Perclose ProGlide device (Abbott Vascular, Santa Clara, CA) is deployed in a preclosure fashion.
The Edwards eSheath is then introduced. Next a 5F pacing catheter is advanced into the right
ventricle for rapid pacing during valve deployment. Transseptal puncture is then performed under
TEE guidance. Once crossed, an Inoue wire (Toray Industries, Tokyo, Japan) is advanced and the
septum is dilated with an Inoue dilator. Unfractionated heparin is administered, aiming for an
activated clotting time goal greater than 300 sec. The left atrial pressure is measured and recorded.
A 9F Dexterity steerable introducer (Spirus Medical, West Bridgewater, WA) is then inserted into
the left atrium and used to advance a pigtail catheter across the mitral valve and into the left ventricular apex. A small or extra-small curve Safari wire (Boston Scientific, Marlborough, MA) is
then positioned in the left ventricular apex. After removal of the pigtail and Dexterity guide, the
atrial septum is dilated with a 12-mm Mustang (Boston Scientific, Marlborough, MA). After
inflation for 30 seconds, the balloon can be “flossed” by advancing and inflating it in the atrium
and pulled back through the atrial ostomy, then advanced across the septum to the mitral valve to
ensure a smooth path for the transcatheter valve and delivery system (Fig. 16.6A).
The valve is then mounted into the delivery catheter with skirt orientation toward the atrial
side (toward the delivery system handle) and advanced into the vena cava. The balloon is pulled
back to align it within the crimped valve, and this should be performed in a straight section of the
inferior vena cava. The delivery catheter is then advanced over the Safari wire. In order for the
delivery catheter and valve to cross the atrial septostomy, counterclockwise rotation with no or
minimal catheter flexion is typically required. Once across, the valve is positioned using a right
anterior oblique orthogonal fluoroscopic view as well as TEE guidance. The SAPIEN central
marker is typically aligned with the sewing ring or annuloplasty ring, and ideally 10% to 20% of the
valve prosthesis should be on the atrial side of the sewing ring after deployment (see Fig. 16.6B).
The ventricular edge of the new prosthesis should ideally be at the level or just inside of the previous
prosthesis ventricular edge (Fig. 16.7).
Valve expansion should be completed steadily over a 5- to 8-second period under direct fluo-
roscopy until minor valve stent flaring is achieved on the ventricular side; this may require up to
2 mL of additional volume beyond full deployment depending on the prosthesis size. Rapid ventricular pacing at 160 to 180 beats per minute (bpm) during valve deployment can be performed
to ensure stability, but is not essential. Ventilation can also be held at the time of deployment for
further stabilization. Fine movements of the Safari wire and delivery system can be made during
deployment to assist in positioning.
If there is concern for LVOT obstruction (e.g. for valve-in-ring), a pigtail catheter can be
inserted into the left ventricle for simultaneous monitoring of left ventricular and aortic pressures. The left atrial pressure should be measured postdeployment to assess the procedural result
(Fig. 16.8).
Once valve evaluation is complete, wires and delivery catheter can be withdrawn. TEE evalu-
ation of the iatrogenic atrial septal defect usually demonstrates a small defect with left-to-right or
mild bidirectional shunting and does not require closure. However, if there is a large amount of
shunting, significant right-to-left shunting due to underlying pulmonary hypertension, or presence
16—PERCUTANEOUS MITRAL VALVE-IN-VALVE AND VALVE-IN-RING 181
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C
Fig. 16.6 Computed tomography analysis for procedural planning of mitral valve-in-ring. (A) Native left ventricular outflow tract (LVOT) measurement and (B) neo-LVOT area measurement based on expected valve size
and anterior leaflet protrusion. (C) 3D remodeling to determine appropriate fit of valve within annulus and
(D) visualization of anchor points and relative atrial and ventricular involvement with appreciation of the
importance of the aortomitral angle.
of right-sided thrombus with right-to-left shunt, closure of the septostomy is recommended. Once
all sheaths are removed, hemostasis can be achieved with the previously placed closure device,
followed by gentle manual pressure for 5 minutes. Protamine can be administered and anticoagulation restarted in 6 hours.
D
Step by Step: Mitral Valve-in-Valve/Valve-in-Ring
See Figs. 16.9 through 16.15.
Transapical Technique
As discussed previously, the transseptal approach has advantages over the transapical technique
but requires transseptal skills and has a learning curve. Many operators may still feel more comfortable with the transapical technique, and therefore it is briefly included here. Beyond this,
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Fig. 16.7 Intraprocedural fluoroscopy of mitral valve-in-ring. (A) Right anterior oblique (RAO) projection of valve
deployment within annuloplasty ring over ventricular rail with approximately 20% of valve on the atrial side and
80% on the ventricular side. (B) Left anterior oblique (LAO) caudal projection during valve deployment ensuring
positioning and adequate deployment within annuloplasty ring. (C) Initial D shape of annuloplasty ring (D) with
circularization of the ring after valve deployment.
D
some patients may have prohibitive factors such as difficult atrial septal anatomy or vascular
access issues, which preclude a transseptal approach.
The transapical technique is best suited for a hybrid operating room setting with general
anesthesia and fluoroscopy guidance. A right ventricular pacing wire should be placed, as described previously. Transapical access is obtained via a small anterior thoracotomy at the fifth or
sixth intercostal space based on CT guidance. Coronary angiogram may be helpful to document
coronary location and avoid coronary artery injury. Once the left ventricular apex is identified, it
is secured via pledgeted sutures. The left ventricle is then accessed, and a soft J guidewire can be
used to cross the mitral valve. After this, a 6F catheter can be introduced across the valve. The
guidewire is then exchanged for a 0.035-mm Amplatz Extra Stiff wire (Cook Medical, Bloomington, IN) to provided added support for the upsizing to a 26F Ascendra I delivery system
(Edwards Lifesciences, Irvine, CA). The appropriate-sized valve is selected and confirmed based
on TEE imaging. Note that the Edwards SAPIEN valve will be crimped onto the delivery catheter in the opposite direction for transapical compared with transseptal access. The valve is then
16—PERCUTANEOUS MITRAL VALVE-IN-VALVE AND VALVE-IN-RING 183
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A
C
Fig. 16.8 Transesophageal echocardiography (TEE) pre- and postprocedure with evidence of mild left ventricular outflow tract (LVOT) obstruction. (A) Preprocedural eccentric mitral regurgitation in the setting of prior
mitral valve annuloplasty and repair. (B) 3D showing D-shaped annuloplasty ring. (C) Fixed native anterior
leaflet (yellow arrow) in diastole and (D) systole causing mild LVOT obstruction. Peak-to-peak gradient was
measured to be 13 mmHg and there was no evidence of hemodynamic compromise.
B
D
Fig. 16.9 Transseptal puncture is performed under transesophageal echocardiography (TEE) guidance.
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Fig. 16.10 An Inoue wire is placed in the left
atrium and used to advance an Innoe dilator
across the intraatrial septum
advanced and positioned under both fluoroscopic and echocardiographic guidance with similar
positioning and deployment to the transseptal approach.
Procedural Complications
With appropriate preprocedural planning, LVOT obstruction risk can be minimized (Fig. 16.16).
However, if there is evidence of LVOT obstruction after valve deployment, traditional treatments
of LVOT obstruction can be attempted, including fluids, beta-blockers, and vasoconstriction
medications, which can result in improved gradients and negate the need for further intervention.
Alcohol septal ablation has been accomplished as a bailout strategy to relieve LVOT obstruction
Fig. 16.11 A 9F Dexterity steerable introducer is
then inserted into the left atrium and used to advance a pigtail catheter across the mitral valve and
into the left ventricular apex.
14
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Fig. 16.12 A small preshaped wire (e.g., Safari wire)
is then positioned in the left ventricular apex. This is
used to advance a 12-mm Mustang balloon across
the intraatrial septum. This is inflated for 30 seconds
and then “flossed” across both the atrial septum and
the mitral valve to ensure a smooth path for the
transcatheter valve and delivery system.
Fig. 16.13 The delivery catheter is advanced over
the Safari wire. In order for the delivery catheter
and valve to cross the atrial septostomy, counterclockwise rotation with no or minimal catheter
flexion is typically required. Once across, the valve
is positioned using a right anterior oblique
orthogonal fluoroscopic view, as well as transesophageal echocardiography (TEE) guidance.
The SAPIEN central marker is typically aligned with
the sewing ring or annuloplasty ring.
and can be considered if conservative measures are unsuccessful and surgical correction is not an
option.
PVL can stem from valve undersizing, underdeployment, or irregularities of the mitral annulus due to calcifications or rigid annuloplasty rings that do not conform to the transcatheter
valve shape. Because of the lack of deformation, rigid rings may predispose to PVL more so than
compliant semirigid or flexible rings. If PVL is felt to be due to underdeployment, additional
balloon dilation can be attempted, with additional volume added to the existing delivery balloon.
Care should be taken to avoid any air in the system, as balloon rupture is possible. Additional
dilation with a noncompliant balloon can be considered, but this increases the risk of damage to
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Fig. 16.14 The SAPIEN central marker is aligned with the sewing ring or annuloplasty ring, and ideally 10%
to 20% of the valve prosthesis should be on the atrial side of the sewing ring after deployment. Valve expansion should be completed steadily over a 5- to 8-second period under direct fluoroscopy until minor valve
stent flaring is achieved on the ventricular side; this may require up to 2 mL of additional volume beyond full
deployment, depending on the prosthesis size.
Fig. 16.15 After valve deployment, evaluation with transesophageal echocardiography (TEE) is performed to
assess valve position, ensure prosthesis stability, and assess for prosthetic and paraprosthetic regurgitation.
The left ventricular outflow tract size and gradient can also be measured. TEE also provides an assessment
of overall systolic function and rules out pericardial effusion.
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Paravalvular leak
• Rigid annuloplasty
• Incomplete valve
expansion or under
sizing
• Preexisting defect
external to surgical
sewing/annuloplasty
Valve embolization
• Incomplete
annuloplasty
• Inadequate valve
expansion or under
sizing
• Atrial migration
during deployment
Fig. 16.16 Pitfalls leading to complications in transcatheter mitral valve implantation.
LVOT obstruction
• Long native anterior
mitral leaflet
• Septal hypertrophy
• Low aortomitral angle
• Ventricular migration
during valve
deployment
the prosthetic valve and generally should be avoided. If balloon expansion fails, percutaneous
PVL closure can be attempted.
Device embolization or migration occurs due to inadequate ventricular positioning, undersizing, or insufficient anchoring. In patients with incomplete annuloplasty rings, the risk of poor
anchoring of the Edwards valve is significantly increased, and the procedure may need to be
avoided altogether. Flaring of the valve stent ends minimizes, but does not eliminate, the risk of
valve migration. If migration occurs but has minimal movement, another valve can be deployed
within the migrating valve to anchor both valves and ensure no further embolization. However,
if there is severe malposition or overt embolization, the primary course of action is emergent
cardiac surgery to retrieve the device and replace the valve.
Left ventricular perforation by the anchoring wire has been reported and was a major cause of
early bleeding complications with the transseptal technique; however, this risk has been reduced with
improvements and modifications to the wires used.
15
Intraprocedural TEE can identify pericardial
effusion if this occurs and pericardiocentesis performed if evidence of tamponade. If considerable
hemodynamic compromise remains, emergent surgical repair may be required.
Postprocedural Care
Most patients are extubated immediately postprocedure and monitored on telemetry. On postprocedural day 1, a limited TTE is obtained to evaluate valve function and obtain baseline
hemodynamics, to assess right and left heart function, and to rule out pericardial effusion.
Close monitoring of access sites should be performed to rule out any vascular complications or
bleeding. Unless there is evidence of bleeding complications, patients are bridged with heparin
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