Venous Stents: How to Choose Among the Wealth of Options

MIAMI BEACH, FL—Venous stenting, an arena in which physicians once had to make do with just a handful of options, is now so crowded with approved, dedicated devices that clinicians may be hard-pressed to choose among the new tools.

At this week’s ISET 2024, Erin H. Murphy, MD (Atrium Health, Charlotte, NC), helped out by giving attendees a rundown on what the various venous stents offer, but said it’s a “little tough” to provide blanket advice on which one is best. “What I can do is tell you the differences and the similarities, and you can pick what’s best for your patient,” she said in her presentation.

Venous stents must meet certain demands that arterial stents do not. Venous disease requires larger and longer stents compared with peripheral artery disease. Flexibility is important, too, because the iliofemoral vein is very tortuous, but strength is required to withstand the forces posed by crossing the inguinal ligament.

Just 5 years ago, the only possible stents for venous interventions were Palmaz (previously made by Cordis) and Wallstent (Boston Scientific), both used off-label. “It’s only been since 2019 that we’ve had this explosion of new technology,” Murphy noted.

The Venovo (Bard) and Vici (Boston Scientific) stents got the US Food and Drug Administration’s approval in 2019, followed by the Zilver Vena (Cook) and Abre (Medtronic ) stents in 2020. The Duo device (Philips), said Murphy, is expected to make its US debut within the next few months. All have CE Mark approval in Europe.

Earning FDA approval “has been really impactful, to be honest. It’s allowed for expansion and increased access across the board,” as well as collaborative efforts in research and training, Murphy said. “It certainly drives competition between the companies. . . . Now everybody wants the newer and the better: that’s good for physicians, that’s good for patients, that’s good for the whole space.”

Kush R. Desai, MD (Northwestern University, Chicago, IL), who told TCTMD he uses a variety of venous-stent types, said, “I don’t think off-label stents are being used very much anymore.”

Following the FDA’s sign-off, the transition to the “purpose-built” devices in the field was rapid, he added.

One advantage, beyond being designed for a specific indication, is that these newer stents have undergone more rigorous study than their predecessors. The investigational device exemption (IDE) studies, with oversight and adjudication, add a “measure of veracity to outcomes, which I think is important for a disease space,” said Desai. “So while the trials were specifically designed for device approval, a secondary benefit is they provided independent examination of what’s actually happening to these patients.”

Now everybody wants the newer and the better: that’s good for physicians, that’s good for patients, that’s good for the whole space. Erin H. Murphy

There have not yet been any head-to-head trials between venous stents, and the differences across IDE studies make them hard to compare. As a start, though, Murphy explored the variations in material, design, delivery, portfolio, and attributes.

One similarity: all of the venous-specific stents are made of nitinol, Murphy pointed out. “This is not an accident. Nitinol has properties that contribute specifically to addressing the needs of a venous stent. [The main attribute is] superelasticity, where the metal can fully recover following these large deformations and movements and different loads that they experience in the venous system. It’s one of the few metals that have this property at room temperature.”

Wallstent, the off-label predecessor, features a braided design meant to decrease the odds of fracture, but with the newer devices, the metal itself does that job.

For interventionalists, the venous stents come in a variety of lengths and sizes. Abre and Venovo have the largest diameters available: up to 20 mm, which Murphy noted isn’t big enough for caval stenting (Wallstent comes in 22 and 24 mm).

The Abre, Venovo, and Duo use triaxial delivery systems that provide stable, predictable deployment, said Murphy. “The tactile feedback on these is all pretty good.” Sheath sizes for these three range from 8 to 10 Fr. Zilver Vena is smaller, at 7 Fr. “None of them are recapturable,” she observed.

With venous stents, radial resistive strength and compression resistance are key. Murphy reported that Abre, Venovo, and Duo are “all a bit stronger” than the Zilver Vena, though the latter is “considerably more flexible.”

Moving forward, she said, endurance is a crucial feature in venous stenting. The current standard for testing is to evaluate durability at 10 years, based on the older age of most patients who receive arterial stents. However, “from a venous standpoint, we’re putting these in very young people. There’s DVTs in 16-year-old girls on oral contraceptives, so those stents have to last them a lifetime,” Murphy pointed out, adding that Medtronic has raised the bar by bench testing Abre out to 50 years of use.

As to “what we’re seeing from a clinical perspective: all I can say [is] Abre, Zilver Vena seem to fracture a little less than Venovo, but all of them have been really low fracture rates,” she said.

Importantly, each of the approved venous stents has been shown to improve quality of life and functioning. Murphy suggested this “could translate to significant gains for both the individual patient as well as society, with reduced economic burden and medical costs associated with venous disease.”

Knowing how to choose among the devices is hard for now, she said, but will become easier with experience.

For now, said Desai, physicians tend to make their decision based on the usual list of factors: what type their hospital stocks, what they’ve trained in, and operator preference. A lot of the latter is “driven by anecdote. . . . Even though you can’t compare the IDE trials, they all do kind of have similar results, particularly in the very challenging and the much less challenging populations,” he observed.