Case Report
Transcather Mitral Valve-in-Valve Replacement: The New Frontier in Heart Valve Therapy
Schilling J and Islam AM*
Department of Medicine, Baystate Medical Center, USA
*Corresponding author: Ashequl M. Islam, Department of Medicine, Tufts University School of Medicine, Program Director, Interventional Cardiology Fellowship Baystate Medical Center, USA
Published: 11 Jul, 2016
Cite this article as: Schilling J, Islam AM. Transcather Mitral Valve-in-Valve Replacement: The New Frontier in Heart Valve Therapy. Clin Surg. 2016; 1: 1051.
Abstract
Introduction: Surgical valve replacement is not always feasible in patients with severe mitral regurgitation from a failing bioprosthetic valve or severe mitral annular calcification. Off-label
use of transcatheter aortic valves has been described in the literature as a possible method of valve
replacement for this patient population. We review the literature on this practice as well as present
two cases of successful implantation of the Sapien XT valve in the mitral position.
Case Series: Two patients were selected for implantation of a transcatheter valve in the mitral
position due to their prohibitively high surgical risk. A transapical approach was used. One of
the patients utilized venous-arterio extracorporeal mechanical oxygenation. The procedure was
performed in a hybrid OR under general anesthesia. Successful implantation of both valves was
achieved with survival beyond 30 days in each patient.
Discussion: There have been 113 cases of valve-in-valve and valve-in-ring procedures described in
the literature. There have also been 11 cases of implantation into a native valve with severe mitral
annular calcification. Both of these methods are feasible, however the architecture of the native
mitral valve annulus is best suited for a dedicated mitral prosthesis. These dedicated transcatheter
mitral valves are undergoing early safety and feasibility trials.
Conclusion: There has been early success with utilizing transcatheter aortic valves in the mitral
position; however this practice will likely be temporary as dedicated transcatheter mitral valves
progress through their development.
Introduction
Mitral valve regurgitation affects four million people and is the second most common valvular heart disease in the US [1]. In the last decade or so, Transcatheter Aortic Valve Replacement (TAVR) has become an alternative approach to surgical aortic valve replacement in high risk and inoperable patients. In the near future, this therapy will possibly be approved for intermediate risk patients. Mitral valve replacement for native or failing bioprosthetic valves has been a challenge in frail, high-risk populations. This is due to prohibitively elevated surgical risk associated with traditional valve replacement or repair. There are numerous reports of off-label transcatheter mitral valve replacement of dysfunctional bioprosthetic mitral valve prosthesis using balloon expandable transcatheter aortic valve bioprosthesis [2]. At this time there are no dedicated transcatheter mitral valves approved for use in the United States; however there are devices are currently in early feasibility and safety trials [3]. We describe two cases of successful transcatheter mitral valve-in-valve replacement with a balloon expandable Sapien XT valve (Edwards Lifesciences) using a transapical approach and review the future of transcatheter mitral valve replacement for primary mitral valve disorders.
Case Presentation
Patient selection
These procedures occurred between March and May 2015 at our single hospital center (Baystate
Medical Center, Springfield, Massachusetts USA). Both valves were replaced due to bioprosthetic
valve degeneration and severe mitral regurgitation resulting in NYHA Heart Failure Class II-III
symptoms and severe pulmonary hypertension despite optimal medical management. These patients
met criteria by the current ACC/AHA guidelines for mitral valve replacement surgery [4]. Both
patients were evaluated by the multidisciplinary heart valve team and, due to prohibitively high STS
risk scores, each was offered transcatheter mitral valve replacement via a trans-apical technique due
to the extremely high risk associated with a traditional replacement procedure. The off-label use of
the device was described to both of the patients and their families and they were in agreement to
proceed despite the risks.
The first patient was an 88 year-old male with chronic atrial
fibrillation with pacemaker insertion for tachy-brady syndrome,
preserved left ventricular ejection fraction, and severe mitral
regurgitation due to a degenerated (#33 porcine valve) mitral valve
bioprosthesis placed 11 years ago. Now he presents with Class IIIIV
NYHA heart failure symptoms. Coronary arteries were normal.
Pulmonary artery systolic pressures were 65-70mmHg. He was
deemed to be inoperable due to severe comorbidities, frailty and
cachexia and a 30-day risk of surgical mortality above 12%.
The second patient was a 77 year-old female with history of
bioprosthetic mitral valve replacement (#29 tissue valve) for rheumatic
mitral regurgitation, tricuspid valve ring annuloplasty, CABG x2,
biatrial cryomaze, and left atrial appendage ligation 18 months prior.
She presented to an outside facility with recurrent NYHA Class III
heart failure symptoms where cardiac catheterization showed patent
grafts and a PA pressure of 70/25mmHg. Subsequently, she was
transferred to our facility and was found to have severe eccentric mitral
valvular regurgitation through the bioprosthetic valve with severe
biventricular dysfunction. Her left ventricular ejection fraction was
30% without regional wall motion abnormalities. A malfunctioning
and restricted leaflet resulting in severe eccentric mitral regurgitation
was noted on the transesophageal echocardiogram. She was also
felt to be inoperable. It was decided that she should be placed on
transfemoral veno-arterial cardiopulmonary bypass for a short
period intraoperatively as she would not likely tolerate rapid
ventricular pacing required for valve placement and closure of the left
ventriculotomy due to severe left and right ventricular dysfunction.
Figure 1
Figure 2
Figure 3
Procedure
Both procedures were performed in a hybrid operating room
under general anesthesia with endotracheal intubation. Transfemoral
veno-arterial cardiopulmonary bypass support was established in
the second patient. Radial and pulmonary arterial pressures were
measured throughout both procedures. A temporary pacing wire
was advanced from the femoral vein to the right ventricular apex in
both cases. During the procedure, a transesophageal echocardiogram
in addition to fluoroscopy was performed for visualization of valve
placement. In each case a mini thoracotomy was performed at the
left fifth intercostal space in order to obtain access to the LV apex.
Once the LV apex was exposed, plegets and purse-string sutures were
applied prior to obtaining access. Next a left ventricular puncture was
obtained using an 18G needle and a 0.035 inch J-tipped guidewire was
advanced to the left atrium. In one case the wire was advanced into
the right upper pulmonary vein and into the right lower pulmonary
vein in the other for optimal coaxial support. Then a 5F angled glide
catheter was advanced into the pulmonary vein and the guidewire
was exchanged for an extra stiff 0.035 inch Amplatz guidewire. The
catheter was removed with the guidewire in place across the mitral
bioprosthesis and a 26F Edwards delivery sheath was advanced
into the left ventricular cavity (Figure 1). In each case, a 29mm
Edwards XT Sapien valve was loaded onto the delivery system. In the
second case, once the valve delivery system was ready to be inserted
into the left ventricle, the cardiopulmonary bypass system was
started. A predetermined coplanar view as well as transesophageal
echocardiography was used to confirm valve placement just 1-2 mm
above the bioprosthetic ring on the left atrial side. Once advanced
and in position, rapid ventricular pacing at 140 to 180 BPM was
utilized to drop systolic blood pressure less than 40 mmHg during
valve deployment. A trivial paravalvular leak was detected in one case
and post-dilation was performed using an extra 2cc of volume in the
delivery balloon. Final transesophageal echocardiographic imaging
(Figure 2) was performed in both cases and the guidewire was
removed. The venoarterial bypass was discontinued and the femoral
artery was repaired surgically. The apical sheath was then removed
from the left ventricle using rapid ventricular pacing and the pursestring
sutures were drawn for complete hemostasis. A chest tube
was inserted in the left pleural cavity and the femoral catheters and
sheaths were removed. One patient was extubated in the operating
room and the other was extubated later that day. There was survival
at 30 days for both patients and echocardiographic evaluation showed
no evidence of mitral regurgitation.
Discussion
Use of a transcatheter aortic valve in the mitral position has
been described in Europe since 2009 [5]. However, as more centers
have adopted TAVR worldwide, off-label mitral valve replacement
procedures are becoming more common. Use of the Sapien and
Melody valves has been described in cases of primary degeneration
of bioprosthetic valves and native mitral valves in the setting of severe
Mitral Annular Calcification (MAC). Both degenerative bioprosthetic
valves (or mitral rings) and severe MAC offer a reliable and durable
surface to anchor external stent of the transcatheter valve, although
occasional paravalvular leaks and rare and delayed atrial migration
of the transcatheter prosthesis has been described. Delivery of a
transcatheter valve into a native mitral valve without MAC or a prior
bioprosthesis has not been attempted due to lack of an anchoring
substrate.
Two approaches are possible for placement of the valve. The
first is a transapical approach, similar to that used in TAVR and as
described in our patients. The second is a trans-septal approach via
femoral venous access and antegrade delivery of the valve delivery
system through a puncture of the interatrial septum from the left
atrium into the mitral annulus. Although, the second approach is
technically more demanding, it is possibly less invasive and risky in
often very sick and frail patients.
Recently, a case series of these transcatheter mitral valve
procedures was published as part of a larger review of both aortic and
mitral valve-in-valve (or valve-in-ring) replacements. They found that
a total of 113 mitral valve-in-valve and valve-in-ring replacements
have been reported. Of these cases, 36% were performed transseptally,
and 64% were performed trans-apically. As in our cases, these
were offered to older individuals where the re-operative risks were
prohibitively high. They found an all-cause 30-day mortality rate of
8.5% and 14-month rate of 20.5%. The major non-fatal complications
associated with this off-label procedure are left ventricular outflow
tract (LVOT) obstruction and moderate residual paravalvular leaks.
Four of the cases showed late development of valve thrombosis which
may be an early signal that prolonged anticoagulation could be the
preferred strategy for these patients [2].
A second procedure being performed is transcatheter valve
implantation in the setting of severe Mitral Annular Calcification
(MAC). The proposed theory is that a large amount of calcification
of the mitral annulus provides a ring-like scaffolding to support the
valve. This procedure was first described in 2013 where a Sapien valve
was implanted transapically onto a native valve. Since then, ten other
cases have been reported [6]. Long-term data is unknown; however
short-term feasibility and survivability have been established.
Thus far, all cases have been in the setting of primary valvular
dysfunction. Though functional mitral regurgitation may benefit
from this procedure, the lack of an anchoring substrate in these native
valves is currently the prohibitive factor.
At this time, dedicated mitral valve prostheses are being
developed by multiple companies and are in preclinical and early
clinical or feasibility trials. Early results have been mixed and
continued development is needed before large-scale clinical trials
can be initiated. One such valve is the Tendyne valve (Abbot). It is a
trileaflet porcine pericardial valve attached to a D-shaped nitinol selfexpanding
frame. The valve is tethered apically to help with stability
and seating. The implantation data in the first 12 patients was recently
presented showing survival to discharge in all patients. Another valve
is the CardiaAQ (Edwards Lifesciences) which is a bovine pericardial
trileaflet valve anchoring to both the atrial and ventricular sides of
the mitral annulus without exerting radial pressure. It has shown
early feasibility and is enrolling subjects in an international multicenter
study beginning in June 2016. A third valve is the Tiara valve
(Neovasc Inc.) which uses bovine pericardial leaflets and is anchored
to the atrium as well as natural valve leaflet apparatus [7]. Another
valve is the Twelve valve (Medtronic) first implanted in 2015 and is
undergoing a pilot study in Poland [8] (Figure 3).
Conclusion
Presently, the only widely available option for trans-catheter mitral valve replacement is the off-label use of trans-catheter aortic valve prostheses. As seen in ours and other case series, the safety, feasibility, short and intermediate-term success are quite acceptable in patients who are otherwise not surgical candidates. Valve-in-valve and valve-in-ring implantation are the most common, however traditional trans-catheter valve implantation in a native valve with severe MAC is also possible. Several trans-catheter mitral valve replacement concepts are in early clinical or feasibility trials. At the same time, several advancements have occurred in minimally invasive or less invasive mitral valve repair surgeries in the last two decades.
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