Next-Generation Navitor Valve Shows Promise in High-risk TAVI Patients

PARIS, France—A next-generation self-expanding transcatheter aortic heart valve has demonstrated low adverse event rates and good hemodynamics at 1 year in patients with high-to-extreme surgical risk.

The Navitor transcatheter aortic valve builds on its precursor, the Portico valve (both Abbott), with a novel active outer fabric sealing cuff, called the Naviseal, designed to prevent paravalvular leak (PVL). It also features a stent design for optimized radial force across a range of sizes, according to researcher Dave Smith, MD (Morriston Hospital, Swansea, Wales).

Navitor “offers both a safe and effective treatment option for patients with severe symptomatic aortic stenosis who are either high or extreme surgical risk,” said Smith, who presented the 1-year findings last week at EuroPCR 2022.

Navitor received CE Mark approval in May 2021 for patients with aortic stenosis at high or intermediate surgical risk, but it is not yet commercially available in the United States.

The study’s 120 patients (mean age 83.5 years; 58.3% female) with symptomatic severe aortic stenosis, who were enrolled at 19 sites in Europe, Australia, and the United States, had a high comorbidity burden, Smith reported. More than half (56.7%) had NYHA class III or IV symptoms at baseline, and the mean STS score was 4%. Additionally, 83.3% had at least one frailty factor.

Procedures were most often performed via transfemoral access (99.2%), with a mean total procedure time of 72.8 minutes. Balloon aortic valvuloplasty was performed preprocedurally in most patients (92.5%), and 32.5% received it after TAVI. About one-third of patients each received the 25-, 27-, and 29-mm valves. Just 3.3% were treated using a 23-mm device.

Procedural success was high at 97.5%, with no deaths or surgical conversions during TAVI. Three patients required an additional Navitor valve due to either malposition of the first device or movement of the first device on postdilatation, Smith reported.

All-cause mortality at 1 year was 4.2%. Beyond 30 days, there were no additional strokes (one occurred at day 4 post-TAVI), acute kidney injury, or major vascular complications. Life-threatening bleeding was reported in 5.0%, and 16.8% of the population underwent pacemaker implantation by 1 year (of these 18 patients, 13 already had preexisting conduction abnormalities).

By 1 year, mean gradient had declined to 7.5 mm Hg and effective orifice area had increased to 1.9 cm². Paravalvular leak was zero or trace in 70.2% of patients, mild in 28.8%, and moderate in a single patient (1.0%); no severe PVL was reported. Almost all patients (97.2%) had NYHA class I or II symptoms at 1 year.

What Navitor Adds

As to whether the Navitor valve needs to be implanted differently than prior-generation devices, “we are all learning to standardize and optimize our valve implants with self-expanding valves. This valve is no different,” Smith said. “[It] can be commissurally aligned, and I think it should be implanted with a cusp-overlap technique.”

But every valve can be optimally implanted with a slightly different technique, he continued. Compared with the first-generation Portico valve, for example, Navitor’s deployment “is much more stable in terms of positioning,” Smith said. “Secondly, it does not require a lot of wire manipulation either. So unlike different types of self-expanding valves, I think wire manipulation with Navitor is at a minimum compared to other valve types, which may again lend itself to benefit with pacemaker rates.”

Following Smith’s presentation, session co-moderator Juan Granada, MD (Cardiovascular Research Foundation, New York, NY), asked for some clarification about the nearly 30% rate of mild PVL that was observed at 1 year: “The question is when you actually go into intermediate-risk patients, is that [going to be the same]?”

Without a solid answer at this point, Smith said the ongoing VANTAGE of the Navitor valve in intermediate- and low-risk patients should shed some light. “This is a high-to-extreme-risk population, [and] some of the annuli into which these valves were implanted were not the most pleasant and heavily calcified,” he said. “So, to get a 20% mild PVL rate in this population actually was not bad, to be honest. In fact, I think it's testament to the sealing attributes of the Naviseal design that it's achieved that.”

Granada also pointed to what he called the “high” percentage of valve predilatation. “I'm not going to criticize. Actually, I think it's smart,” he said.

This behavior might “be a bit of a throwback” to what operators did with the first-generation Portico device, Smith said. “This would probably be based on caution, . . . and I think if you look at most experienced operators with Navitor, you would not see that rate of predilatation.”

Panelist Jonathan Schwartz, MD (Sanger Heart & Vascular Institute, Charlotte, NC), commented that the Portico device has only been available in the United States since September 2021. “Presumably this will be coming out soon,” he said. “How do you sell this to the American population? Where does it fit in our choice of implantable valves?”

Smith highlighted that Navitor is “an intra-annular leaflet location valve, and when we talk about the future of patient management, that's clearly a huge focus now. It may be the case that having an intra-annular leaflet location will aid future coronary access.” Additionally, data from the Portico IDE study has not shown any red flags regarding hemodynamic function of the valve, he added.