Which TAVR Device Is Best? Review Tackles Optimal Selection

Although the majority of patients with symptomatic, severe aortic stenosis can be suitably treated with any of the commercially available transcatheter heart valves, a new review highlights several variables that might lead clinicians to choose one device over another.

Experts stressed there is no evidence one valve is “better” than any other, but said patient characteristics and various anatomic factors, such as the presence of annular and subannular calcification or the need for future coronary access, can influence decision-making.

“There have been a few comparative studies, but they really don’t tell you which valve to use when you’re faced with a given situation,” said Samin Sharma, MD (Icahn School of Medicine at Mount Sinai, New York, NY), senior author of the new review, which was published online September 9, 2020, ahead of print in JAMA Cardiology. The goal of their paper, he said, was to create an unbiased framework, one based on the data and their practical experience, to help doctors choose the best device in certain clinical scenarios.

“However, we want to be clear that in the majority of time you can use any valve,” Sharma told TCTMD.

Five-year results from the CHOICE trial, which were published earlier this year, showed no difference in clinical outcomes among 241 high-risk patients treated with the self-expanding CoreValve (Medtronic) or the balloon-expandable Sapien XT (Edwards Lifesciences). Hemodynamics favored CoreValve, and while structural valve deterioration was uncommon, it did occur more frequently with Sapien XT. In two observational studies published last year, researchers reported that use of the balloon-expandable devices was associated with a low risk of paravalvular regurgitation and mortality when compared with self-expanding valves. Those studies, one an analysis from the FRANCE-TAVI registry and the other using administrative hospital data, were largely considered “thought-provoking” but hardly definitive given the limitations of observational research.

Although head-to-head randomized trials might provide comparative data on clinical endpoints, Sharma said, such trials are designed with ideal TAVR patients in mind as opposed to trickier real-world cases.

Howard Herrmann, MD (University of Pennsylvania Perelman School of Medicine, Philadelphia), who was not involved in the review, agreed that any of three commercially available valves “will do the job” for most TAVR cases. Yet there are nuances to every case that may lead to one valve being more suitable than another, he commented.

“There are a lot of factors I look at, as many as 10 or more, not all of which are decisively in favor of one or another valve but which may influence the decision in one direction or another,” Herrmann told TCTMD. “What is the size of the annulus? Is it in the sweet spot for one valve, but at a fringe point between two sizes for another? I look at the coronary locations, the risk of obstruction, and whether reaccess is going to be important. We look at calcification of the outflow tract, and if it’s severe it’ll push me toward a self-expanding or mechanically expandable valve rather than a balloon-expandable one.”

Other factors that influence the choice of valve include angulation of the aortic root, sinus size, procedural risks, deliverability, the incidence of paravalvular leak (PVL), and the need for a permanent pacemaker.

Ideal Properties for TAVR

In their review, the authors evaluated current TAVR prostheses in commercial use or under clinical investigation, including different iterations of CoreValve, Sapien, and Lotus (Boston Scientific) valves. Some of the devices are no longer commercially available, such as first-generation CoreValve and Sapien prostheses—the most current devices are the CoreValve Evolut Pro+ and Sapien 3 Ultra, respectively—while others are still undergoing clinical testing. The JenaValve (JenaValve Technologies) and J-Valve (JC Medical), both of which are designed to treat native aortic regurgitation as well as aortic stenosis, are still in early feasibility testing, but other valves, such as the self-expanding Acurate neo (Boston Scientific) and Portico (Abbott) devices are being tested in clinical trials.

To TCTMD, Sharma said one of the biggest considerations is the presence/absence of dense annular or subannular calcium. “If you go with a balloon-expandable valve, you’ll have more annular rupture or perforation and so you want to go with a self-expanding valve, or with a third valve type, which is the mechanically expandable valve,” he explained. Lotus Edge, which is approved by the US Food and Drug Administration, is a mechanically expandable valve, as is the Lotus Mantra, which is still being tested in clinical trials.

The reviewers highlight numerous “ideal” properties of a transcatheter aortic valve prosthesis: minimal vascular access size, optimal effective orifice area (EOA), minimal PVL, suitability for a wide range of annulus sizes, ability to be repositioned or retrieved, and long-term durability, among others. The valve should also be associated with a low risk of permanent pacemaker implantation and/or new conduction abnormalities and allow for easy coronary reaccess.

With respect to the incidence of new conduction abnormalities after TAVR, the published rates range broadly depending on the prosthesis. Higher radial force exerted on the aortic annulus, left ventricular outflow tract, and membranous septum (where the conduction system lies) may reduce the risk of PVL but increase the risk of conduction abnormalities. Self-expanding and mechanically expandable valves—where force is applied after implantation—may contribute to the need for a new permanent pacemaker. For that reason, patients with a preexisting right bundle branch block or short membranous septum might be better suited for a balloon-expandable device, according to the authors.

“The need for a pacemaker becomes more important in younger patients, the middle-aged patients 55 or 65 years old,” said Sharma. In the most recent low-risk trials—PARTNER 3 and the Evolut TAVR in Low-Risk Patients trial—the rate of new permanent pacemaker was 6.5% at 30 days with Sapien XT and 17.4% with Evolut. “Many times, patients will come to us and they know the self-expanding valve has higher rates of [need for permanent] pacemaker and say, ‘I want the Edwards valve.’ Nowadays, patients are knowledgeable and the need for a pacemaker comes into the equation, certainly more so in the younger patients. Sometimes it does help us decide which valve to use.”

Getting Back Into the Coronaries

As for the coronary arteries, TAVR devices with a taller frame typically complicate reaccess more than those with a lower frame, they note. For that reason, the Sapien balloon-expandable valve might be a better option in patients with a high likelihood of future PCI. At Mount Sinai Hospital, Sharma said, they use self-expanding valves in roughly 60% of their cases, but coronary reengagement over the long term remains an issue with these valves.

“Self-expanding valves are good acutely and rarely cause coronary obstruction, but reengagement will always be challenging with the self-expanding valve,” said Sharma. “I can tell you we face this problem nearly every day. We have more patients coming back with coronary artery disease. In our earliest cases, in 2010, 2011, and 2012, those extreme- or high-risk patients died within a few years even if they had no CAD. There was little chance of them coming back. Now, as we move into intermediate- and low-risk [patients] and they’re surviving 3 years, 5 years, or 7 years, they’re coming back, even if they didn’t have significant coronary disease at the time of deployment.”

For Herrmann, however, the issue of coronary reaccess after TAVR might not be as problematic as it’s currently made out to be.

“I think the number of patients who require coronary reaccess—either emergently or for an acute coronary syndrome—is actually surprisingly small,” he said. “Secondly, most of the time you can access the coronaries with either valve. It might be more difficult with the self-expanding valve, and there are some tricks we’ve all had to learn, but in daily practice it hasn’t been a very common event. I don’t think it’s a major decision point for me, but it can be one of the minor ones.”

Long-term Durability

The jury is still out on the long-term durability of TAVR devices given the limited data, especially in younger patients at low risk. Hemodynamic parameters, such as lower mean aortic valve gradient and larger EOA, have been documented in supra-annular, self-expandable valves compared with balloon-expandable valves, but whether this affects durability over the long term is unknown.

“My gut feeling is that as far as durability is concerned, once you get out to 10 years, there may be a slight difference in favor of the self-expandable valve compared with the balloon-expandable,” said Sharma. “That’s just my personal opinion based on the higher effective orifice size with the self-expanding valve.”

To TCTMD, Herrmann said valve hemodynamics influence his choice of valve and, like Sharma, he believes better hemodynamic results likely will have a long-term impact.

“Hemodynamics are important, particularly in patients who are younger, more active, or who have small annuluses,” he said. “Many women have a small annulus and they may be more at risk for patient-prosthesis mismatch. Hemodynamics affect the durability of the valve, I believe, although that hasn’t been proven yet.”