AT TCT 2016

WASHINGTON (FRONTLINE MEDICAL NEWS) – First-generation, balloon-expandable transcatheter aortic valves had a less than 1% rate of valve failure in planned echocardiography examinations during follow-up that extended as long as 5 years after valve placement in more than 2,400 patients, a demonstration of durability that experts uniformly called “reassuring.”

This finding from patients who underwent transcatheter aortic valve replacement (TAVR) in the first U.S. pivotal trial for these devices, PARTNER 1 parts A and B , and during the subsequent continued-access program at PARTNER 1 study sites, represents the largest and longest systematic ultrasound follow-up of TAVR patients, Pamela S. Douglas, MD , said at the Transcatheter Cardiovascular Therapeutics annual meeting.

This evaluation of 2,404 TAVR patients in the PARTNER 1 trial examined by echocardiography and encompassing 6,493 patient-years of follow-up is the “largest core-lab based study of transcatheter heart valves to date. These data demonstrate excellent durability of transcatheter heart valves, suggesting that the low 5-year survival observed in this cohort is not related to adverse hemodynamics or transcatheter heart valve deterioration,” said Dr. Douglas, professor of medicine at Duke University, Durham, N.C.

Her findings showed that out of the 2,482 patients treated with TAVR (and including those without echo follow-up) either in the trial or during the continued access program and followed for a median of 2.9 years and an average of 2.6 years, 20 patients (0.8%) required a reintervention. Four of these 20 patients (0.2% of the total cohort) showed a “classic pattern” of aortic valve deterioration marked by an increased valve pressure gradient and a reduced valve area, she reported.

“Reintervention was rare, became less frequent over time, and was usually not due to structural deterioration of the transcatheter heart valve,” she said. But Dr. Douglas also cautioned that among the patients who received the first-generation, balloon expandable Sapien valve in this cohort, just 39% survived to 5 years, and a mere 282 patients (11%) actually underwent echocardiographic examination at 5 years.

“This is one of several steps we need to take to figure out the durability of transcatheter valves,” said Jeffrey J. Popma, MD , professor of medicine and an interventional cardiologist at Beth Israel Deaconess Medical Center, Boston. He noted that data are needed from follow-up periods of 8 or 10 years, but these data will not be available until intermediate- or low-risk patients undergo TAVR in controlled circumstances and have long-term follow-up.

“Ten-year follow-up data will essentially be impossible” for the high-risk or inoperable patients treated with TAVR in the PARTNER 1 trial, which focused on the sickest patients with aortic stenosis, said Dr. Popma, lead investigator for several studies of TAVR using self-expanding aortic valves and marketed as CoreValve devices.

“We obviously need to follow patients longer. The 5-year results look terrific, and so very reassuring, but we need to keep an eye on this as we move TAVR into less sick and younger patients,” said Dr. Robert O. Bonow , professor of cardiology at Northwestern University, Chicago. “Durability is the remaining frontier in terms of moving TAVR into younger patients,” Dr. Bonow said at the meeting, which was sponsored by the Cardiovascular Research Foundation.

These data continue to show that “transcatheter valves have looked hemodynamically superior to surgically-placed valves with respect to the VARC (Valve Academic Research Consortium)–2 criteria” for prosthetic valve function, Dr. Popma noted. “I think the benefits of surgical valves have been overstated and the benefits of transcatheter valves understated,” he said.

“Surgical valves have not been held to the same [very demanding] standard as transcatheter valves,” Dr. Douglas agreed.

The data Dr. Douglas reported contrast with longer-term follow-up reported in May 2016 for 378 patients who underwent TAVR at either of two pioneering centers in a retrospective review. Those data suggested a valve degeneration rate of about 50% after 8 years, Danny Dvir, MD , reported at the annual congress of the European Association of Percutaneous Cardiovascular Interventions. Speaking recently in an interview, Dr. Dvir acknowledged some of the challenges in trying to derive valve durability information from a relatively small number of very-high-risk patients who underwent TAVR very early during development of the procedure.

Some TAVR experts have also questioned the criteria that Dr. Dvir used to identify valve structural valve degeneration for this analysis. “The criteria he used were much more stringent that the criteria we have used to assess surgically-placed valves,” said Michael J. Reardon, MD , professor of cardiovascular surgery at Houston Methodist Hospital. “If surgically-placed aortic valves were subjected to the same criteria Dr. Dvir applied then they would perform even worse,” Dr. Reardon said in an interview.

PARTNER 1 was sponsored by Edwards Lifesciences, the company that had marketed the Sapien first-generation, balloon expandable TAVR system. Dr. Douglas has received research support from Edwards. Dr. Bonow had no disclosures. Dr. Popma has been the lead investigator for several studies of a self-expanding TAVR system sponsored by Medtronic, and he has also received research funding from several other companies, has been a consultant to Boston Scientific and Direct Flow, and owns equity in Direct Flow. Dr. Dvir has been a consultant to and received research support from Edwards, Medtronic, and St. Jude. Dr. Reardon has been a consultant to Medtronic.

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