Debate Over Low-Risk TAVR Hinges on Definition of Patient Population and Shared Decision-Making

WASHINGTON, DC—No surprise: discussion over whether patients with severe aortic stenosis at low-risk for surgery should be offered TAVR peppered the agenda at TCT 2016.

In August, the US Food and Drug Administration (FDA) expanded the indication of two balloon-expandable devices (Edwards Lifesciences) and CE Mark status was awarded to a self-expanding device (Medtronic) for use in patients at intermediate risk. In addition, two pivotal trials of selected low-risk patients treated with either TAVR or surgery are ongoing.

Yet many are still unsure as to how far this procedure should advance into lower and lower risk groups. In a debate session Tuesday, an informal poll of the audience revealed about an 80/20 split in favor of keeping TAVR away from this population, at least for now.

Taking Sides

In a presentation in favor of offering the procedure to all patients, Michael Mullen, MD (Barts Heart Center, London, England), argued that the disagreement is more “subtle” than being for or against low-risk TAVR. Rather the emphasis should be on offering TAVR to everyone, he explained.

“I don’t think this debate is about the data,” Mullen said after outlining the results from several well-known recent TAVR trials. “This debate is much more about patient choice. It's about consent and the rights of the patient to decide what treatments and risks they want to accept. It's also about our role as doctors, whether it is to have a paternalistic role and tell patients what we think they should have or a more modern kind of diagnosis, explanation, and counseling.”

As such, every patient should have “a right to at least consider” TAVR, he concluded. “It doesn’t mean they all have to have it.”

However, cardiac surgeon Wilson Szeto, MD (University of Pennsylvania Medical Center, Philadelphia)—taking the contrary stance in the debate—reminded the audience about the holes in most people’s understanding of low-risk. “This is a very heterogeneous group of patients, and they very have different clinical implications with TAVR,” he said. “The limitations of TAVR are amplified in younger, lower risk patients, and we do need to pause and really think about what we are doing with our patients.”

With regard to paravalvular leak, Szeto said he is still awaiting confirmation from the data that rates of this complication are acceptable, particularly in younger patients. And as for questions of valve durability, which was another hot topic at TCT 2016, he said he would not consider the current available evidence “long-term” and that patients should be followed through at least 10 years.

For lower-risk patients, while “there is clinical equipoise in selected patients,” Szeto concluded, the discussion “really isn’t about TAVR versus surgery. It is about management of valve-related disease. “As you get younger, I think the discussion should be more about mechanical versus bioprosthetic. For a 50-year-old gentleman, that's the first conversation you should have. And then you can dive into the nuances of TAVR versus surgery.”

Shared Decision-Making Is a ‘False Truth’

Discussing the presentations, session co-moderator Andreas Baumbach, MD (Bristol Heart Institute, England), noted that an issue, particularly in the TAVR space, is that often “the discussions and guidelines and evidence comes way behind the clinical practice. We’ve been doing lower-risk patients for so long, and in everyday practice it's become the norm. Here we are still discussing it.”

He agreed that operators are not in agreement over the exact definition of “low risk” and encouraged further refinement in practice.

But there are other procedural and anatomical issues beyond surgical risk that complicate this decision, said panelist Stephen Brecker, MD (St. George’s Hospital, London, England). If a 68-year-old patient came into his clinic, one of the first things he would think of is if the patient has a bicuspid valve, he said. “And we know that bicuspid valves are not just a yes or no answer. There is bicuspid anatomy that is very suitable for TAVR, and there is bicuspid anatomy that is wholly unsuitable for TAVR.”

In this case, the patient “more or less has a different disease,” Baumbach noted.

On the topic of shared decision-making, Brecker said, “we’ve been there before with angioplasty and CABG.” While he agrees with the idea of including patients in discussions of their care, “asking the patient is a false truth because we can all direct a patient to what they are going to choose,” he said.

Panelist David Holmes Jr, MD (Mayo Clinic, Rochester, MN), called the concept of shared decision-making as “ugly” and a “terrible term.” Specifically, the objective tools developed to aid patients in their decisions are “awkward,” he explained.

Nevertheless, “with increasing guidelines and increasing new devices, it's going to be mandated part of care [in the United States],” Holmes said. “That will put the patient at the center of these things.”