Navitor Shuts Out Leaky TAVR, but Pacemaker Rates a Concern?

Paravalvular leak (PVL) was largely eliminated with the Navitor, a new iteration of the Portico transcatheter aortic valve replacement (TAVR) device boasting a new sealing cuff.

In the Portico NG study, the valve was associated with no moderate or severe PVL at 30 days; four in five patients left TAVR with none or trace PVL, the rest having mild PVL.

TAVR with the Navitor also resulted in zero deaths at 30 days among 120 patients with symptomatic severe aortic stenosis and high surgical risk, reported Lars Søndergaard, MD, DMSc, of Rigshospitalet in Copenhagen, during the virtual European Association of Percutaneous Cardiovascular Interventions (EuroPCR) meeting.

Navitor was given CE Mark last week by European regulators. It remains an investigational device not commercially available in the U.S.

The device is the next-generation version of Abbott's Portico valve, featuring an active outer fabric cuff to reduce PVL, plus a new fabric material for better sealing with the inner cuff. The self-expanding valve also has intra-annular leaflets and large frame cells.

"Absence of any moderate or greater PVL and low rate of mild PVL suggests an active sealing cuff is an effective design to mitigate PVL," Søndergaard said.

Navitor is "definitely an improvement over the previous generation," commented Gilbert Tang, MD, of Mount Sinai Health System in New York City, who cited the "excellent" and clinically significant PVL data.

The first-generation Portico valve had failed to improve outcomes over other commercially available valves in the PORTICO IDE trial.

Notably, that trial had been paused for 11 months in 2014-2015 due to concerns that Portico had a problem with valve-related thrombosis. Investigational use resumed after independent review found reduced leaflet mobility to be a class effect across TAVR valves.

Now, the sticking point with the Navitor appears to be permanent pacemakers: in the present study, new pacemaker implantation was required for 15% of study participants, though these patients largely had pre-existing conduction abnormalities, according to Søndergaard.

What exactly those conduction abnormalities were is an important question, as is whether there was a relationship between implant depth and outcomes, Tang noted in an interview.

"With other existing commercially available platforms in the U.S., if you implant in the optimal manner, the permanent pacemaker rate will be well less than 10%," he said. "Modifying implant technique may further reduce the pacemaker rate," he suggested.

Josep Rodés-Cabau, MD, of Quebec Heart and Lung Institute at Laval University, agreed that the 15% pacemaker rate is the only potential point of concern -- but not necessarily surprising, given the higher-risk cohort in the study.

"There's some debate about this outer cuff in the valves, whether or not these can increase the pacemaker rate, but I'm not sure about that. I think it's more about implanting the valve as high as possible. And this is something that can be improved with more experience," Rodés-Cabau commented in an interview with MedPage Today.

Søndergaard reported low rates of other safety outcomes, such as disabling stroke (0.8%) and life-threatening bleeding (2.5%). There were zero deaths at 30 days.

Portico NG was a single-arm study conducted in Europe, Australia, and the U.S.

The 120 participants were an average age of 83.5 years, and 58.3% were women. Patients comprised a high-risk cohort, with many deemed frail despite a mean Society of Thoracic Surgeons score of 4.0%.

TAVR with the Navitor resulted in a 97.5% procedural success rate. Three people needed an additional Navitor valve due to malposition of the first device or movement upon post-dilatation, Søndergaard said.

Valve hemodynamics were favorable 30 days after Navitor TAVR: the mean gradient was 7.4 mm Hg and the effective orifice area was 2.0 cm².

As for functional status, 97% of patients were in New York Heart Association (NYHA) class I or II at 30 days, with 85% having had an improvement by at least one NYHA class from baseline. Six-minute walk test results improved by 21 meters over baseline.

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