The one-year data from the SAVVE trial represent the “most encouraging clinical data that have ever been produced for a bioprosthetic deep vein valve” in more than half a century of attempts at developing such a device, according to one leading venous disease specialist.
Manj Gohel, MD, from Cambridge University Hospitals in Cambridge, England, cautiously welcomed what he described as an outstanding set of one-year results for the VenoValve device (enVVeno Medical) but also reflected on patient selection, durability and health economics challenges to come. “There have been efforts to treat deep venous reflux for at least 50 years,” says the Cambridge University Hospitals consultant. “A native valve—a healthy normal valve—is a thing of beauty: it is incredibly flexible, mobile, is not thrombogenic at all, and is also really strong. So that is a tough ask for anything prosthetic. And, for half a century, people have been trying to do this and have generally failed.”
Case selection will pose the greatest challenge, Gohel explains. “Deep reflux is very common. Of all the patients I see, probably a third, if not a half, of them will have deep venous reflux. The potential population is enormous, but we need to be very selective of the people we put through this procedure because it is still going to be experimental, expensive and invasive.” As such, for Gohel, VenoValve implantation is a third-line treatment option after superficial vein procedures and deep venous stenting “for those people who have still not responded.”
Further, Gohel says he will be closely following the durability of the device as longer-term data emerge. “The one-year data are nice, but one year is nothing in the grand scheme of things when it comes to venous disease. The problem is, if you get device failure, then the risk is you might get thrombosis of this prosthesis, and that is effectively a DVT [deep vein thrombosis].”
Gohel says he will also be following the price at which the VenoValve device enters the market in light of health economics considerations. “Venous ulceration is extremely expensive, but even with the very best treatments, the best they do is improve the ulceration rate and reduce recurrence rates by 50%—you don’t cure the problem,” he points out. “Even then, cost effectiveness is only just demonstrated, because the treatments that you are carrying out—dressing the ulcers—cost money, but they are still relatively cheap next to a very expensive procedure. So, you’ve got to get a lot of ulcer healing benefit in order to demonstrate cost effectiveness.”
Ultimately, says Gohel, reducing the level of invasiveness of the procedure will be key. “At the moment, the procedure is an open surgery and has to be performed by a vascular surgeon,” he adds. “A lot of these patients are quite elderly and frail. You may not want to be putting many of them through relatively major surgery, so the percutaneous valve—which I know [enVVeno Medical] are working on—is going to be a really important next step.”
Recent years have brought other efforts to produce innovative technology that treats deep venous reflux, adding to the 50-year canon of vein valve replacement attempts.
“There was one valve called the Sail [flow regulator] valve, that there was a lot of interest in, and that had some first-in-man data, but that has disappeared,” recalled Gohel. “There was the endovenous, percutaneous valve called Blueleaf, which also disappeared. So we don’t want to get too excited, but [Food and Drug Administration] approval is a big thing.”
