Transcatheter valvular repair and implantation has become increasingly
common in treating patients diagnosed with valvular heart diseases.
While conditions such as aortic stenosis, mitral regurgitation,
and tricuspid regurgitation have traditionally been treated with
open surgery, transcatheter aortic valve replacement is indicated for
patients with severe aortic stenosis regardless of their surgical risk,
and transcatheter mitral valve repair is indicated for degenerative
mitral regurgitation for patients at high surgical risk and for severe
functional mitral regurgitation regardless of surgical risk.
This video will provide an overview of three transcatheter
valvular therapies currently available in the United States.
Transcatheter valvular repair and implantation was first developed
as a treatment for aortic stenosis.
Transcatheter aortic valve implantation involves placing a catheter from the
femoral artery into the heart and across the diseased valve to place either a
self-expanding valve or, as seen in this video, a balloon-expandable valve.
Calcium in the diseased aortic valve serve as anchors, holding
the artificial valve in place.
A post implant aortogram is performed to assess the aortic regurgitation
and verify position of the valve.
Following placement of the valve, the catheter is withdrawn, and the placement
and function of the valve confirmed with transthoracic echocardiography.
TAVI was first approved by the FDA in 2011, and as of 2019, is
currently approved for patients with severe, symptomatic aortic stenosis
regardless of surgical risk level undergoing open surgery and can be
performed using a balloon-expandable or a self-expanding valve.
The 2020 American College of Cardiology and American Heart Association
guidelines list both TAVI and surgical aortic valve replacement,
or SAVR, as Class I recommendations, meaning a strong recommendation for
use as first-line therapies, for any symptomatic patient with severe
aortic stenosis regardless of surgical risk and for asymptomatic patients
with severe aortic stenosis and an ejection fraction of less than
50%, regardless of surgical risk.
It is important to consider that the ultimate recommendation for TAVI
or SAVR for each patient considers patient characteristics and preferences
since the current guidelines don't distinguish between choice of
therapy based on the traditional low, intermediate, or high-risk designations.
Approval for all surgical risk categories was based on data
from a series of eight randomized clinical trials conducted between
May 2007 and November 2018.
A summary of the primary endpoints for these RCTs can be found in a JAMA
review on transcatheter procedures for valvular disease published in
the June 22nd, 2021 issue of JAMA.
Transcatheter valve-in-valve procedures have evolved as a less
invasive option for patients with bioprosthetic aortic valve failure.
Bioprosthetic valves can fail by stenosis, regurgitation, or both.
In the example here, pressure tracings reveal that the valve
has failed due to stenosis.
The procedure involves implanting a transcatheter aortic valve
inside of the failing bioprosthetic valve, allowing a patient to avoid
a second or third sternotomy.
Similarly, transcatheter mitral valve-in-valve procedures have been
successfully performed as well.
This procedure uses a transseptal puncture to access the mitral valve.
Then, an aortic valve prosthesis is implanted within the failing
bioprosthetic mitral valve, and studies have demonstrated a low complication
rate and low 30-day mortality.
Transcatheter mitral valve edge-to-edge repair is a treatment option for mitral
regurgitation and is performed under general anesthesia with fluoroscopic
and transesophageal echocardiography guidance throughout the procedure.
The device is inserted through the femoral vein and requires a transseptal
puncture to access the left atrium.
The device is advanced across the left atrium and across the mitral valve
into the left ventricle, grasping the anterior and posterior leaflet of the
mitral valve to approximate the leaflets at the location of the regurgitant jet.
Often, more than one clips is deployed during the procedure
to achieve an optimal reduction in mitral regurgitation.
In the current ACC/AHA guidelines, for degenerative, or primary, mitral
regurgitation, mitral valve surgery is a class I indication for patients
with severe, symptomatic mitral regurgitation and for asymptomatic
patients with left ventricular ejection fractions of less than 60%.
Transcatheter edge-to-edge mitral valve repair using the MitraClip
device is a class 2A treatment option, meaning a moderate recommendation,
for high or prohibitive surgical risk patients with degenerative mitral
regurgitation and suitable anatomy.
In patients with severe functional, or secondary, mitral regurgitation,
the guidelines recommend mitral valve surgery as a class 2B recommendation,
meaning weak recommendation, only if guideline directed medical therapy
has failed and patients continue with persistent New York Heart
Assocation class III-IV symptoms.
The guideline recommends transcatheter edge-to-edge mitral valve repair
as a class 2A indication for patients with symptomatic functional
mitral regurgitation with LVEF of 20%-50% after guideline directed
medical therapy that is supervised by a heart failure specialist.
Three randomized clinical trials conducted between September 2005 and
March 2017 investigated the safety and efficacy of transcatheter edge-to-edge
repair in patients with moderately severe or severe mitral regurgitation,
and functional mitral regurgitation.
The Endovascular Valve Edge-to-Edge Repair Study II data led to the initial
FDA approval of the technology for degenerative mitral regurgitation
therapy in high-risk patients.
Currently, commercially available transcatheter tricuspid valve
therapies are approved in the European Union and are being investigated in
several trials in the United States.
Devices used in the Triluminate, Clasp TR, and Cardioband trials are approved
in the EU for use, with the device in Evoque still in investigational trials.
The devices from Clasp TR, Triluminate, and Evoque are in pivotal trials
in the US, with Cardioband in the early feasibility study stage.
For more information on this and other procedures and trials
discussed in this video, read the full clinical review at JAMA.com.