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 Following placement of the valve, the catheter is withdrawn, and the placement and function of the valve confirmed with transthoracic echocardiography.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.