She said this year's TVT was exciting because it was the first in-person meeting since 2019, and there was a lot of new technology discussed in sessions. This included first reports on clinical use of new technologies for the mitral valve and tricuspid valve.

"The question is which ones will come out in the wash and which of these technologies will become the most successful," Asgar said. "We also need to find the pace for these technologies. When are we going to use transcatheter edge-to-edge repair (TEER) versus who is going to need replacement."

There were high hopes that other transcatheter valve technologies would see a similar path taken by transcatheter aortic valve replacement (TAVR), moving from workbench to clinical practice in a relatively short time with excellent outcomes. However, several experts at TVT described the aortic valve as the low-hanging fruit, and there are problems that need to be solved for other valve positions. 

The mitral valve is more of a "D" shape, has a very small landing area to place a valve, has tethering cords attached to the leaflets and any device placed there needs to have a small profile to prevent over hang into the left ventricular outflow tract (LVOT) to prevent blood flow obstruction. Anchoring a valve in this high pressure, dynamic environment may require different strategies beyond just outward expansion of the valve body. This has led to developing ways to clip the edges of the valve to the annulus or sandwich the native valve between two sections of a transcatheter valve. 

"One of the things we have learned is that mitral anatomy is much more complex than aortic, so there have been many different strategies and technology developed to implant a mitral valve," Asgar explained. 

These include anchor the device to the native leaflets or radial force on the valve annulus. The latest approach was shown by the startup vendor Innovalve at TVT 2022. Asgar said it uses a star-shaped set of arms to twirl and wrap up the chordae tendineae and valve leaflets and the valve is deployed over the wrapped components of the valve to better anchor it and possibly remove LVOT issues from the native leaflets. 

This complexity also varies from. Patient to patient, requiring intense pre-procedural screening to plan implants and decide if a patient's anatomy is suitable for a transcatheter valve implant. 

"Depending on the device, you can have screening failure rates of between 20% to 65%, based on the size of the valve, the way it anchors and what the impact is on the LVOT," Asgar explained. "Some of these devices are better suited for calcium, although the majority of the devices are being targeted for mitral regurgitation." 

Computed tomography (CT) is used to prescreen patients and images are used to model the valve in a simulated environment to check sizing and LVOT obstruction.

"Sometimes modeling with CT does not reflect what happens in real life," she said. "So the big challenge really is LVOT obstruction, anterior leaflet movement into the LVOT, which can make things worse, and how we can mitigate that."

She said there are techniques to overcome LVOT obstruction such as LAMPOON and SESAME to use a transcatheter cutting wire to cut the native valve leaflets or perform a myectomy to ensure an unobstructed LVOT. However, Asgar said it is better to just avoid LVOT issues that require a separate procedure. 

The first transcatheter mitral valves have moved into clinical trials. Asgar said there is a lot of interest in the ongoing SUMMIT clinical trial of the Tendyne device vs. TEER. She said another big trial is APOLLO, the clinical trial for Medtronic's Intrepid valve. 

Tricuspid transcatheter devices will likely gain FDA before new mitral valve technology

Despite the wide interest in mitral devices, Asgar and other experts at TVT said devices for the tricuspid valve will likely jump ahead. Of mitral technologies and gain FDA clearance more quickly. 

"In the tricuspid, we don't have this LVOT obstruction issue," Asgar explained. "We may have sizing issues and AV block issues that require pacemakers, but we realized there are a lot of these patients out there. The surgical outcomes are less optimal that mitral valve surgery outcomes, so this is really a population that has an unmet need. The surgical data on valve replacement is not great, but what we are seeing with transcatheter valve placement is very encouraging." 

Because of surgical outcomes, the tricuspid valve has been ignored until recently, because transcatheter valves offer a new approach that is much less invasive. 

She said there is great data from the Edwards Lifesciences Evoque tricuspid valve and with tricuspid TEER. She said the TRILUMINATE trial will soon end its enrollment and will provide the first data on TEER vs. medical therapy. 

There have been concerns about treating patients with pacemaker or ICD leads that cross the tricuspid valve into the heart, but Asgar said there is early data showing TEER can still be performed and a reasonable result can be obtained. 

Related TMVR, TTMV and TAVR Content:

VIDEO: Transcatheter tricuspid devices likely to gain FDA clearance before new mitral advances —  Azeem Latib, MD

VIDEO: The state of TAVR in 2022 — Interview with Michael Mack, MD

VIDEO: MitraClip vs. surgical mitral valve replacement — Interview with Joanna Chikwe, MD

VIDEO: Transcatheter myectomy to prevent LVOT obstruction in mitral valve replacement — Interview with Adam Greenbaum, MD

Links to all the late-breaking structural heart studies at TVT 2022

VIDEO: How to build a structural heart program — Interview with Charles Davidson, MD

TAVR's success has changed how cardiologists and surgeons view aortic valve replacement

Find more structural heart content and video