Edwards' ECHO Data: The Latest in the TAVR Durability Debate

Durability has long been a concern for transcatheter aortic valves (TAVR) since long-term experience with the technology is still limited, at least compared to the decades of data from surgical heart valves. New data on the first-generation Sapien TAVR from Edwards Lifesciences is another valuable piece of information in the durability debate, but is it enough to put concerns to rest?

The ECHO data, presented at the Transcatheter Cardiovascular Therapeutics (TCT) conference in Washington, DC on November 1, showed five-year hemodynamic data from patients who were implanted with Sapien in the PARTNER trial. Echocardiograms were conducted on more than 2400 patients at several timepoints: seven days, 30 days, and six months, as well as every year out to five years after the TAVR procedure.

The echo results showed a decrease in patient mean aortic valve (AV) gradient after TAVR implant, then a non-significamt increase starting a few months after the procedure (12.1 mmHg at baseline, 9.2 mmHg at three months, and 10.3 mmHg at 5 years; p=0.63), according to a press release from the Cardiovascular Research Foundation. Major interval changes in AV gradients of 20 mmHg were seen in just 10 patients (0.45%).

Pamela Douglas, MD, director of the Imaging Program at Duke Clinical Research Institute and Ursula Geller professor of research in cardiovascular disease at Duke University, presented the data at TCT. "In the largest, most robust study of its kind, population hemodynamic trends show excellent durabiity of the SAPIEN transcatheter heart valve over five years, with virtually no structural valve determioration," Douglas said in an Edwards Lifesciences press release. "Similarly, large adverse hemodynamic echo findings in individual patients are rare in this protocol-driven database," she added. "Together, these data demonstrate excellent mid-term durability of THV, suggesting that the low 5-year survival observed in this cohort is not due to adverse hemodynamics."

Earlier this year, new worries about TAVR durability were raised by data from a two-center study that showed a significant rate of TAVR degeneration between five and seven years after implantation. Those valves were also older-generation valves from Edwards Lifesciences, including the Cribier-Edwards valve, Sapien, and Sapien XT. The findings drew attention, though research analysts pointed out limitations of the study.

A. Pieter Kappetein, MD, PhD, professor of cardiothoracic surgery at Erasmus University Medical Center in Rotterdam, Netherlands, moderated a TCT session on the valve durability controversy. He noted that valve dysfunction can occur in any of several non-structural and structural ways, including wear and tear, thrombosis, calcification, pannus, endocarditis, delayed embolization, and mechanical trauma, which can include valve crimping.

Surgical valves follow a normal distribution for durability. "There will be valves that fail early and valves that fail late," Kappetein said. While reviewing the literature, he pointed out that TAVR valves differ from surgical valves because they are not always circular. This lack of symmetry may influence the durability of valve tissue. 

Kappetein added that the younger a patient is when receiving a surgical heart valve, the earlier that valve will fail--a point worth remembering when considering TAVR durability. "Patients with aortic stenosis at a young age are just not normal," he said.

Kappetein added, "I think [surgical heart valves] will always last . . . a little bit longer than transcatheter heart valves because [they] don't need to be crimped. They always have more circular, symmetric openings for valve leaflets."

"We are very pleased with the scientifically rigorous 5-year outcomes data presented at TCT," Larry Wood, Edwards' corporate vice president, transcatheter heart valves, said in the company release. "While this research is meaningful and important information for both clinicians and patients, we see this as the starting point for further evaluations, and our intention is to use the PARTNER and PARTNER II Trial data to generate additional longer-term evidence on durability for the Sapien family of heart valves."

That means we haven't heard the last of the durability debate.

[Image courtesy of JSCREATIONZS/FREEDIGITALPHOTOS.NET]