Patrice Wendling

May 31, 2016

PARIS, FRANCE — Up to half of first-generation transcatheter aortic-valve replacement (TAVR) devices will degenerate within 8 years, according to a long-term report of TAVR durability out to 10 years[1].

Freedom from valve degeneration was quite good at 4 years, at 94%, but dropped off to 82% from 4 to 6 years and fell significantly to about 50% at 6 to 8 years.

Principal investigator Dr Danny Dvir (St Paul's Hospital, Vancouver, BC) stressed to the media that device degeneration is not the same as failure but estimated that about 40% of degenerated devices would eventually fail.

The late-breaking data made a splash when reported at EuroPCR 2016, where the merits of TAVR's seemingly inevitable expansion to lower-surgical-risk patients were debated that very afternoon.

Dvir cautioned that the report is very preliminary but added, "The risk for structural valve degeneration after TAVR should be considered, especially when treating relatively young patients and those at lower surgical risk."

Physicians must also be mindful of the limitations of the bioprostheses they implant and whether these valves can be safely and effectively treated by a valve-in-valve approach, if the valves fail years later.

Invited discussant Dr A Pieter Kappetein (Erasmus Medical Center, Rotterdam, the Netherlands) said the report is not unexpected, although it may give some the chance to say "I told you so."

Valve durability has somewhat disappeared as a discussion point in recent years and did not play a major role in 80- or 85-year-olds but will play a role in younger patients, he said. "Maybe newer-generation valves may show better results. We don't know yet." But this report "points us to the fact that trials in lower-risk patients are justified. We just cannot start implanting those valves in lower-risk patients."

Early Days of TAVR

Dr Danny Dvir

The investigators looked at 704 patients who underwent TAVR between April 2002 and April 2011 in Vancouver, BC and Rouen, France with Edwards Lifesciences balloon-expandable Cribier, Sapien, and Sapien XT devices. Long-term echocardiographic exams were performed during home visits. Device degeneration was defined as at least moderate regurgitation and/or a mean aortic gradient >20 mm Hg not present within 30 days of the procedure and not related to endocarditis.

A total of 378 patients remained after researchers excluded those with more than one transcatheter heart valve implanted, valve-in-valve implantation, device failure or death within 30 days of TAVR, infective endocarditis after TAVR, or <90 days of echocardiographic follow-up. This typical high-risk TAVR population had an average age of 82.6 years, Society of Thoracic Surgeons PROM score of 8.3%, and mean aortic-valve gradient of 42.3 mm Hg, and more than a third had renal failure (46.3%), atrial fibrillation (39.6%), or a prior MI (36.2%). The median survival times was 51 months; two patients survived 10 years.

Device degeneration occurred in 35 patients (regurgitation in 23 and stenosis/mixed in 12) at a median of 61 months (interquartile range 36–79 months).

Three Cribier valves (8.6%) degenerated, as did 19 Sapien valves (54.3%) and 13 Sapien XT valves (37.1%), Dvir said.

Renal failure was the strongest correlate for valve degeneration (P=0.004).

Future studies should explore long-term durability of next-generation and other transcatheter heart valve platforms, he said. "This is a good time to create a solid, large registry of cases to evaluate for [transcatheter heart valve] long-term durability."

Eye-opener

Session cochair and EuroPCR course director Dr William Wijns (Cardiovascular Center Aaslt, Belgium) told heartwire from Medscape the study is "an eye-opener that we have to be very attentive about the issue of durability" but that it remains "hypothesis generating" because it's coming from just two centers and a restricted population in which only two patients were alive at 10 years.

"The real question is, 'Are there differences between surgical valves and TAVI valves?' and I do not think that there are data to support any differences. Out to 5 years we know there is no difference," he said.

What the present study highlights, however, is the need to better understand pathophysiological mechanisms and how to improve medical therapy and devices. "It does not have any impact on the technology the way we use it today, but it's an important aspect as we look forward to younger, low-risk patients. No question about that."

Dvir reports consulting for Edwards Lifesciences, Medtronic, and St Jude Medical. Kappetein reports no relevant financial relationships. Wijns reports honoraria from Biotronik and Medtronic, serving as a board member for Argonauts and genae, and institutional grant/research support from AstraZeneca, Biotronik, Boston Scientific, Medtronic, Micell, Microport China, St Jude , and Terumo.

Follow Patrice Wendling on Twitter: @pwendl. For more from theheart.org, follow us on Twitter and Facebook.

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