Teenage TAVR: Should Practice Forge on While Guidelines Grow Up?

CHICAGO, IL—Taking the long view, one of the leaders in the field of transcatheter aortic valve replacement says he expects usage to more than quadruple in the next 10 years, up from approximately 70,000 TAVR cases performed in 2015 to nearly 300,000 in 2025. Right now, he said, the procedure remains underutilized, mainly because of policy and reimbursement issues, as well as outdated clinical guidelines.

Speaking at TVT 2016, Martin Leon, MD (Columbia University Medical Center, New York, NY), said the clinical guidelines for the management of patients with valvular heart disease, such as those from the American Heart Association/American College of Cardiology and European Society of Cardiology, are “anachronistic and don’t reflect clinical practice.”

In the United States and Europe, TAVR is a class I recommendation (level of evidence B) for patients at prohibitive surgical risk. It is considered a reasonable alternative to surgery in patients with severe aortic stenosis who are at high risk for surgery (class IIa, level of evidence B).

For Leon, though, the guidelines should be updated to reflect the evidence, including secondary endpoints that capture the benefit and value of TAVR, as well as “common sense.” He argued that for those ineligible for surgery, TAVR should be a class I indication (level of evidence A), as it should be for patients at extremely high risk for surgery. For the high-risk patient, including nonagenarians, TAVR should also be performed over surgery (class I, level of evidence B).

Moreover, acknowledging the provocative nature of his presentation, Leon said he would also like to see TAVR extended to two groups currently not eligible for it. In his opinion, TAVR should be strongly preferred in intermediate-risk patients, while it “may be considered” in low-risk patients, with physicians proceeding “cautiously” in this low-risk patient group, at least until the randomized controlled trials have been completed.

As reported by TCTMD, those trials are currently underway. PARTNER 3, using the Sapien 3 valve (Edwards Lifesciences), will enroll approximately 1,300 patients identified by a heart team as being at low risk for mortality if they were to undergo surgical valve replacement (STS score < 4). Similarly, Medtronic is enrolling 1,200 patients with severe aortic stenosis who have a less than 3 percent risk of mortality, as determined by a heart team, and randomizing them to treatment with the CoreValve Evolut R device or surgical aortic valve replacement.

Moving Into Low-Risk Patients

Neil Moat, MD (Royal Brompton Hospital, London, England), provided a surgeon’s perspective, commenting on the appropriate use of TAVR today, as well as speculating on its future. In the high-risk patient, he said TAVR is superior to surgery in terms of early mortality, with the difference sustained out to 2 or 3 years. The procedure is also associated with a lower incidence of early morbidity, including bleeding events, acute kidney injury, and new-onset atrial fibrillation.

However, Moat stressed that additional studies are still needed to validate the outcomes over longer follow-up and to evaluate the safety and benefit of TAVR in low-risk patients with severe aortic stenosis. The biggest question mark in moving TAVR into low-risk populations is device durability, he said.

“I really believe this will be the key determinant of the eventual growth and application of TAVR in the younger and lower-risk patient population,” he said. The surgical literature is littered with studies showing a “honeymoon period” for aortic bioprostheses, with the valves showing excellent durability until 7 years, when “they suddenly fall off the cliff.” 

The issue of durability is particularly newsworthy given emerging data suggesting valve deterioration among patients who received the earliest devices. In May, Danny Dvir, MD (St. Paul's Hospital, Vancouver, Canada), presented data at EuroPCR 2016 showing that among elderly patients who survive at least 5 years after TAVR with an early-generation balloon-expandable device (Edwards Lifesciences), approximately half would see their valves degenerate by 8 years.

In his presentation Leon, as well as others, challenged the definition of “degeneration” used in the analysis, noting that the clinical definition of structural valve deterioration—freedom from reintervention—was never discussed. Still, given the sensitivity of durability, Leon said TAVR investigators have a responsibility to track patients long-term for any potential issues. He said the PARTNER studies have now extended clinical and echocardiographic follow-up to 10 years.    

For Moat, the answer to the durability question is not likely going to emerge from long-term follow-up of the high-risk studies, mainly because very few patients survive long enough to be evaluated. “Let us not forget the lessons learned by the cardiac surgical community,” said Moat. “Like all of us, we’re keen to implant new devices and technologies, but if we do that without following patients carefully, we potentially put patients at risk. This certainly happened in the surgical world, implanting devices that led to suboptimal midterm outcomes.”

In addition to durability, Moat noted several reports have raised the issue of restricted leaflet mobility with the transcatheter heart valves, of which the clinical significance still needs to be determined. 

Growth of TAVR to 2025

Today, TAVR accounts for 32% of all aortic-valve replacements, but in the next decade the field is expected to explode, increasing from $1.5 billion to a $7 billion dollar global industry, Leon said.

“The economic concerns due to high procedure costs have influenced TAVR growth, certainly as compared with surgery,” he continued. “I think there are now improved efficiencies of clinical care pathways, which have reduced the differences and narrowed the gap…. In most centers, it is certainly a profitable procedure.”

Leon pointed to Medicare Provider Analysis and Review (MEDPAR) data showing that the total index hospitalization costs—which have been adjusted to reflect the commercial price of the device—was $59,893 for transfemoral TAVR. In contrast, the total hospitalization cost in the PARTNER cohort B study, published in 2010, was $76,063. Since that time, costs have been steadily declining.

Leon also cited the cost-savings associated with the simplified, “minimalist” transcatheter aortic valve replacement procedure, which is performed without general anesthesia and developed to get patients mobile early and discharged quickly. Using this approach, the total index hospitalization costs are $45,485 and the length of stay is 3 days (versus 6.4 days, on average, according to 2015 MEDPAR data).

As for Moat, he said different healthcare systems may struggle to adopt TAVR in a significantly wider swath of low-risk patients. For example, in the United Kingdom, the cost of the entire surgery is still cheaper than that of a single TAVR device.

Related Stories:

• Valve Degeneration Data Dearth Spurs Calls for Universal Definitions and Clinical Guidance
• Digesting the Valve Degeneration Data: One Month Later, Reactions from TAVR Experts Range from ‘Disturbed’ to Indifferent
• Signal of Poor Durability Seen with First-Generation TAVR Devices