As a cardiothoracic surgeon, can you talk about your history with transcatheter aortic valve replacement (TAVR) and how it has informed your work as a program director for TVT?

While my background is as a cardiac surgeon, I have been involved in TAVR since 2007, so from the early conception of TAVR to the present day. I have seen TAVR grow, and become a more predictable and reliable alternative to treat aortic stenosis. In the aortic stenosis field, being a surgeon pre 2007 or pre TAVR approval, surgery used to be the only option. Over time, TAVR has changed from being an option for high-risk patients to intermediate-risk patients to low-risk patients. TAVR has become a first-choice option because it is less invasive and the results are robust. From my perspective, the bigger challenge now is expanding indications. TAVR indications have expanded to a point for native aortic stenosis. Aortic valves are tri-leaflet valves, but the indication expansion over the last 4 years means we are seeing whether it can be applied to bicuspid valves as well, and also be considered for the treatment of aortic regurgitation. These are some unanswered questions at present. For a bicuspid valve, the anatomy can be very different in every patient. For example, it could be a true bicuspid, which is type 0, or could be type 1, which is the most common. The amount of calcification in bicuspid valve patients can be quite varied and these patients also tend to be on the younger side. We need to understand if we are giving patients the best result at a younger age or are we actually setting them up for a more difficult re-operation when they get slightly older? These are important questions the TVT meeting is going to address as well. We are also looking ahead to emerging technologies to treat aortic regurgitation and have now seen two dedicated devices. One is the JenaValve, and another is the J-Valve (JC Medical). There are some early results in terms of safety and effectiveness in the J-Valve from compassionate use in the Western world, and we will hear about that as well in the meeting.

Can you share more about aortic regurgitation?

Aortic regurgitation results from a thinning of the aortic valve leaflets. There is no calcium present (unlike with aortic stenosis). Its treatment requires a specific device. At present, aortic regurgitation is seen in slightly younger patients, but we feel that similar to aortic stenosis in its early days, lot of aortic regurgitation is not diagnosed correctly and not intervened upon at the same (or right) time. As a result, many high- or intermediate-risk patients with aortic regurgitation could probably benefit from a less invasive technology. We are seeing momentum towards the availability of this technology.

What else is important for TAVR that will be under discussion at TVT?

We are going to hear a great deal about optimization of results and lifetime management. The goal is greater durability, meaning we want TAVRs to last longer. Similarly, we are going to hear a lot about what the options are going forward when TAVR fails. Discussions right now center on two options, essentially. One is whether you should re-implant another TAVR valve, which is a complex subject at present. The second option is whether surgeons like me should take out the TAVR device. What are the implications of each option and what are the challenges? Is the mortality higher in either of these patient groups?

It is interesting that surgeons may have to go in and remove the valve.

We have already been doing this for the last several years, so there is a good amount of expertise now among some cardiothoracic surgeons. Two years ago, I did a live case to demonstrate the techniques, so the emphasis now is on education. There will be a lot of conversation at the TVT meeting around this topic. So, is the first procedure low risk? Yes, we can treat patients with low risk, whether with surgery or TAVR. Now we want patients to have a second procedure that is also reliable, low risk, and with low complications, so the focus is shifting towards the second intervention rather than the first intervention.

What do we know about the durability of the currently available valves?

We have 5-year data now on the PARTNER trial, so we are going to have that conversation at TVT. When we are discussing durability for high-risk patients, 5 to 7 years is maybe enough for both surgical procedures as well as TAVR. When we are discussing durability for low-risk patients, the majority are going to degenerate before the end of their lifetime.

Durability may be device-specific. One of the challenges we have around evaluation in the TAVR market is that designs are changing frequently. However, for good reasons, the Evolut R (Medtronic) and Sapien 3 (Edwards Lifesciences) valves have remained constant for the last several years, so we will probably have a better understanding of those data when they are discussed in terms of different registries in Europe, the 5-year outcomes of the PARTNER trial, and the Evolut R low risk trial. These data presented at TVT will be very relevant to future conversations.

Does the TAVR valve itself affect durability? In the United States now, 4 designs are approved or are nearing approval: Sapien 3, Evolut R, Portico (Abbott Vascular), and Acurate (Boston Scientific). Whether the valve design confers any advantage is still being learned. We also have to consider how best to optimize valve implantation. As a surgeon, when I implant a surgical valve, it is always circular, and there is no change to the aortic valve as a result. We now know that TAVR device implantation differs from surgery in terms of its potential impact on the valve leaflets. One of our fellows, Dr. Miho Fukui, has published on the deformation of TAVR prostheses. What we do know may be just the tip of the iceberg. We still don't understand the implications in terms of durability and attendees will learn a lot at TVT about these topics.

Any final thoughts?

Although the TVT meeting is based in the United States, there will also be experience shared from outside the U.S. We will hear about more devices and, importantly, about other procedures that complement TAVR, such as cerebral protection. We will be hearing about leaflet modification for second TAVR procedures. There will be important sessions regarding complications. Although TAVR complications are very low, across the 900-plus centers doing TAVR in the U.S., can the complication rate be lowered even further? TVT will offer robust discussion on these topics so that our patients get the best out of these procedures with the lowest complications.

Finally, a major part of TVT is focused on structural imaging, including echo and computed tomography (CT), with its own designated track at the meeting. Imaging is the backbone of what we do. There is a lot of attention on imaging not only from TVT, but from all the imaging societies, where a structural specialization is evolving within echo and CT.

As you know, TVT is not solely focused on TAVR, but is organized into 6 tracks: the imaging and TAVR tracks, and there are also left atrial appendage/patent foramen ovale, heart failure, mitral, and tricuspid tracks. In mitral, we have the FDA-approved therapies MitraClip (Abbott Vascular) and Pascal (Edwards Lifesciences), and there are many emerging therapies undergoing pivotal trials as well as efficacy and safety trials. These rapidly growing areas are more complex than TAVR, and are also important topics planned for discussion at TVT.

Find more: 
TVT Newsroom (With a Special Focus on TAVR)