TAVR's success has changed how cardiologists and surgeons view aortic valve replacement
One of the key trends in transcatheter aortic valve replacement (TAVR) therapy in 2022 has been the need to establish a protocol for lifetime patient management of heart valve patients. This was a key trend echoed by several key opinion leaders at the 2022 Transcatheter Valve Therapeutics (TVT) Structural Heart Summit in June. It was clear at the meeting that the standard-of-care thinking on TAVR replacements has shifted from just getting a valve implanted and managing immediate complications to looking decades down the road and considering the patient's long-term health.
The patients eligible for TAVR as opposed to open heart surgery are getting less sick and younger. This has caused the numbers of patients seeking aortic valve replacements to rapidly rise in recent years, far exceeding what was previously thought to be population of treatable patients in need of new aortic valves. However, surgeons said they now realize many patients were screened out, referring physicians decided their patients would not fair well with such an invasive surgery, or patients would not even consider undergoing open heart surgery. For these reasons, many patients never made it before surgeons.
When TAVR was created, it was aimed at a niche market of patients who were very old and too sick to undergo surgical aortic valve replacement (SAVR). But as trials over the past decade have gone on, the indication for TAVR has been opened to nearly all patients. Patients, and referring physicians, who may have previously rejected surgery started to change their minds when TAVR came along.
In just a decade, TAVR has gone from a brand new treatment option to the choice for 84% of U.S. aortic valve replacement procedures. While the percentage of surgical aortic replacement is now just 16%, the number of surgeries has gone up as more patients are now seeking treatment advice from cardiologists because of the appeal of TAVR.
However, most structural heart experts say a majority of these patients would be better off with SAVR first, because any valve implanted will wear out after about a decade or so and need to be replaced. They say it is much easier to do surgery when patients are young, rather than when they are older and need one or two TAVR valves explanted.
"We have gone so far since the old days when it was just about getting the valve in the patient, getting the patient off the table and getting a good result," Azeem Latib, MD, section head and director of interventional cardiology and director of structural heart interventions for Montefiore Health System and a program director for the 2022 TVT meeting, explained. "Now the focus has really changed. The words I have heard in every TAVR session this year has been 'lifetime management.' That's really what everyone is talking about. And it has really happened because in the low-risk patient indication TAVR now has. We are treating younger and younger patients, so we want better outcomes. And it is not just about outcomes immediately after the procedure, but what happens to that patient 10, 15 or 20 years from now."
How to best manage aortic valve replacement patients — TAVR or SAVR first?
The big question is how to best manage aortic valve patients over the long term, and the consensus at TVT appeared to be to go with SAVR first when the patient is younger and can tolerate surgery better. Then, if needed, TAVR can be used a decade or more later for a valve-in-valve (VIV) procedure. This may even need to be followed by another TAVR VIV years after the second procedure.
"If you are 80 years old, you are really only going to need one procedure, just because of your life expectancy," explained TAVR pioneer Michael Mack, MD, chairman of the cardiovascular service line at Baylor, Scott, White Health. "But when you get down into your early 60s, you are going to need two or three valve replacement procedures. By the time you get to three procedures, one of those is going to be surgery. You cannot get the Russian doll effect of TAVR in TAVR in TAVR, so one of them is going to have to be be surgery, and the decision is going to be which order surgery comes. Is it going to be first or second? You don't want it to be third. You don't want to do a complex explant procedure on someone in their 80s, but I am afraid that might be where we are going."
He said patients and referring physicians need to understand that synthetic valve prosthesis do not last forever and they will wear out. And, there just is not enough room in the valve annulus to accommodate several layers of hardware, because each new valve overlaid onto of one below it shrinks the side of the annulus. Mack said you reach a point where there is not enough room for the valve leaflets to function, or the blood flow becomes insufficient.
Mack said longer-term management of valve patients and the complementary roles of TAVR and SAVR was the focus of many sessions at TVT this year. He said many experts favor surgical valve replacement first and two TAVR procedures later in life to eliminate the need for open heart surgery when the patient is much older and more frail. However,
Latib said their is no clear consensus yet on whether surgery or TAVR should come first as a practical standard-of-care. But he said most patients clearly want the less invasive option versus open heart surgery.
More and more younger patients in their 60s are being referred to heart teams because of the appeal of TAVR, explained Brijeshwar Maini, MD, FACC, a structural heart cardiologist and the national and Florida medical director of cardiology at Tenant Health.
"We say to them, 'could we do a TAVR on you? Of course we could, but you are 65 years old, so we think you should get the good old surgical valve put in. And at some point down the road when this valve goes bad, we will do a TAVR on you,'" he said. "I think its education of the referring cardiologist, the primary care physicians and the patients. As a cardiologist, I always tell my patients we need to do what is best for you, so don't worry about the size of the incision or puncture you are going to have in your groin, they need to say 'I got fixed and I am going to have a good life,' ands that is what is important."
Vendors working to address longer-term care of TAVR patients
Latib said vendors have been iterating their devices to improve their durability and performance, and their expert physicians on their advisory panels are now calling for more iterations to help extend the life of TAVR valves as a big need. He said cardiologists have asked for TAVR devices that enable coronary artery access, have good outcomes without issues with paravalvular leak (PVL), good hemodynamics, low complication rates and pacemaker rates in the single digits. And now, the vendors are being asked to set the patient up for another procedure 10-15 year down the road.
"I think all the companies have realized that they need to move their technologies in that direction," Latib explained. "The bar has been set really high and so we are going to see a lot of new technologies or iterations of devices."
The Edwards Lifesciences Sapien X4, the forth generation of the Sapien valve, is about to start the ALLIANCE pivotal trial. It is designed specifically for lower-risk patients with a lower frame height for better coronary access and it is the first balloon-expandable valve that allows the operator to turn the valve to align the commissures, which also will aid further coronary access. The valve is also designed to reduce the need to use oversized valves to ensure a good fit in the anatomy.
"What this means is, when you do the next valve you are not going to have issues with coronary access and having a more physiologically aligned valve on the commissures made help the valve last longer," Latib said.
Medtronic also working on technology for better commissural alignment, Latib said.
He said the Abbott Portico and Boston Scientific Acurate Neo2 TAVR systems are also undergoing revisions to make them more user friendly and compatible with the shifting needs of TAVR.
Durability of TAVR valves appears to be as good as surgical valves
Surgery is still considered the standard-of-care in younger patients because no synthetic valve can last as long as most younger patients will live. Mack's opinion is that ideally a patient should get a surgical valve, followed by two later TAVR valves. He said patients do much better with surgery the younger they are, while TAVR can be safely used in very sick and elderly patients who have a higher surgical-risk scores.
Surgical valves are considered the most durable, with 10-12 years of durability before they will start to degrade and need to be replaced. It was widely thought that TAVR valves, with thinner leaflets and a frame that needed to be crimped into a catheter, would not have very good durability. However, data continues to show TAVR valves do have good durability.
"I don't think there is any reason for concern that the durability is less than surgical valves," Mack said. "I would find it heard to believe the durability would get better, but there is nothing to do other than wait," Mack explained. "That is why in the ongoing low-risk trials we have 10 year followup planned in all those patients specifically to answer this durability question."
With the need to crimp the valve into a catheter, it was widely expected TAVR valve would have less durability. When these first valves were created, it was designed for very sick older patients, so durability was not the primary concern at the time. But trial data seems to show no early signs of TAVR valves lasting any less that surgical valves.
"I was one of those who felt the durability was going to be less because we crimp it to put it in, the leaflets are thinner than they are with surgical valves. I thought it was going to be less, but so far that is not the case," Mack said.
Mack said the durability of a TAVR vs. SAVR valve really does not matter, because in the end, neither will likely last patients for their entire lifespan. So he reiterated that the order should be surgery first and multiple TAVR procedures later as the patient ages.
The latest data on the Medtronic Core valve presented at the 2022 American College of Cardiology (ACC) meeting showed the durability with TAVR so far is out-performing SAVR valves, which came as a surprise in many. The pooled data from the CoreValve SURTAVI trials found patients who received a transcatheter supra-annular self-expanding heart valve had significantly less structural deterioration in the valve after five years than similar patients who had SAVR. Overall, patients with structural valve deterioration (SVD) in their artificial valve were about twice as likely to die or need to be rehospitalized as those who did not.
The study is the largest to assess SVD in patients who participated in randomized trials comparing TAVR and SAVR and the first to show less structural valve deterioration after five years among patients treated with TAVR compared with SAVR, Reardon said.
Reardon said bioprosthetic surgical valves have an average lifespan of about 15 years. In older patients whose life expectancy may be limited by age and other health problems, valve durability has been less of a concern, Reardon said. Previous studies suggest, however, that younger patients are at higher risk for SVD because their valves fail more quickly and because they have a longer potential life span. Previous studies had not clearly established whether the risk of SVD is higher with TAVR or with SAVR.
The 5-year data from the ACC late-breaking study found SAVR valves had a 4.38% incidence of SVD, while TAVR was significantly lower at 2.57%.
“Durability of the replacement valve becomes increasingly important in younger patients,” said Michael J. Reardon, MD, professor of cardiothoracic surgery and Allison Family Distinguished chair of cardiovascular research at Houston Methodist DeBakey Heart and Vascular Center, who presented the data at ACC. "Now that we have gotten. TAVR approved for all risk levels, younger, healthier patients are being referred to my valve clinic and we are trying to decided whether to use a surgical or TAVR valve. The patients ask us depending on the valve, how long is it going to last. This trial was designed to answer that question. Certainly for this early data, and for moderate or greater aortic stenosis, TAVR did better than surgery."
Reardon added they will also collect 10-year data on the intermediate- and low-risk trials to determine the valve deterioration level in these patients using TAVR and SAVR.
"We will get 10 year data in a lower risk, younger group of patients that are going to live longer and we are going to find out which valves last longer," he said.
Dave Fornell has covered healthcare for more than 17 years, with a focus in cardiology and radiology. Fornell is a 5-time winner of a Jesse H. Neal Award, the most prestigious editorial honors in the field of specialized journalism. The wins included best technical content, best use of social media and best COVID-19 coverage. Fornell was also a three-time Neal finalist for best range of work by a single author. He produces more than 100 editorial videos each year, most of them interviews with key opinion leaders in medicine. He also writes technical articles, covers key trends, conducts video hospital site visits, and is very involved with social media. E-mail: dfornell@innovatehealthcare.com