Recently, a novel self-expanding endoprosthesis, the Wrapsody Cell-Impermeable Endoprosthesis (CIE; Merit Medical), was developed to improve access to the dialysis outflow circuit. Speaking to Renal Interventions, Robert Jones, an interventional radiologist at Queen Elizabeth Hospital Birmingham (Birmingham, UK), and Richard Bond, a vascular surgeon at Fiona Stanley Hospital (Perth, Australia) detail their experience with the device.
Bond was the first in the world to commercially implant Wrapsody CIE three years ago. “The first patient I remember well,” he says. “She had a left brachiocephalic fistula that had been put in place in 2014, and it had been working in the two years before I saw her in 2019. The main problem was that she was getting a lot of pain when the AVF was used for haemodialysis, and it was taking five to six hours to dialyse.” He adds that she “experienced bleeding from the fistula following dialysis.”
Bond explains that she was diagnosed with a particularly tight cephalic arch stenosis. Despite four previous treatment attempts by the radiology team rapid restenosis of her cephalic arch occurred each time. With her referral to Bond and the renal team, the initial treatment plan was to ligate the fistula. However, Bond opted for the Wrapsody CIE instead.
When asked why he chose Wrapsody CIE, he notes that, due to the anatomical anomaly present in this patient, no other endoprosthesis would have yielded a positive outcome. In addition, he indicates that the device’s design, specifically its tactile feel, made it a good treatment option. For Bond, the whole process was “very, very intuitive” and use of the device was “very straightforward”. As for the patient, he notes that she tolerated the procedure quite well: “The next day, the patient was achieving all of her dialysis goals, and her pain was resolved overnight. She is due for her three-year angiogram this month— she has not had any issues with dialysis.”
Jones echoes Bond’s suggestion that Wrapsody is straightforward to use. “It tracks very well through the vessel, over the wire and through the stenosis. On deployment the device remains stable, and the trigger delivery system is very responsive.”
On the device’s design, Jones highlights its unique tri-layer configuration, with its polytetrafluoroethylene (PTFE) inner layer, its cell-impermeable layer, and expanded PTFE (ePTFE) outer layer that allows it to be embedded into the vessel wall. He also cites its optimised radial strength and relative compression resistance.
“For me,” he says, “one of the most interesting design features is the softened end-rows. These are designed in a scalloped fashion with the aim of reducing stress at the interface between the edge of the stent and the normal adjacent vessel, which will hopefully reduce the incidence of edge stenosis—the Achilles’ heel of stent grafts.”
“It is also fairly unique in that there are larger diameter devices in its portfolio, including 14mm and 16mm devices, something not currently offered by other manufacturers. This will allow us to treat patients with central or thoracic vein stenosis, where larger diameter devices are often required for safe and effective treatment.”
Jones became more aware of the device and its potential after participating in its first-in-man study as part of the data monitoring committee. “My interest in the research related to this device stems from the concept that it has great potential for overcoming many of the shortcomings of stent grafts.” The first-in-man study yielded a target lesion primary patency rate of 84.6% and access circuit primary patency rate of 65.9% for Wrapsody at twelve months’ follow-up. These results, Jones says, told us that Wrapsody is “safe and effective for treating vascular access outflow stenosis”.1
Since his first implantation three years ago, Bond has treated approximately 25 patients with the device. Yet he states that, in the beginning, he was less excited. In particular, Bond believes the device’s clinical benefits will be particularly evident in the cephalic arch and central veins: “These are areas that are lacking in any good, suitable treatment option. There, it is really exciting, with a nice combination of flexibility and strength for the angles involved in those vessels.”