Initial Report of Use of COVERA STENT in Dialysis Access
Interventional Radiology, Shaare Zedek Medical Center, Israel
BACKGROUND: Recurrent stenosis after balloon angioplasty is a leading cause of arteriovenous hemodialysis access failure. Balloon angioplasty is often complicated by immediate recoil and restenosis, due to intimal hyperplasia. Salvage stenting of the stenotic segment may be necessary to prevent access thrombosis. Covered stents ("stent-graft") have demonstrated superior patency of hemodialysis access circuits when compared with bare metal stents. We present our initial, and previously unreported, experience with the COVERA (Bard Peripheral Vascular Inc. Tempe, Az, USA) stent graft.
PURPOSE: to assess the safety and efficacy of the COVERA stent graft for the treatment of restenosis in the venous outflow of hemodialysis access grafts and fistula.
METHODS: The trial retrospectively reviewed 38 patients from a high-volume vascular access unit, who underwent placement of the COVERA stent graft for recoil, rupture or rapid stenosis recurrence. The number of previous angioplasty procedures, indication for stent graft and size of stent graft as well as major and minor adverse events were recorded . study end points included safety and accuracy of Covera deployment and 6 month primary patency rates of the target lesion and of the entire vascular access circuit. Follow up was assessed by angiography at 3-6 months post deploymentr or, Duplex ultrasound or by contacting the patients dialysis center. Images from follow up studies were reviewed. With restenosis was defined as> 50% narrowing of the stent graft lumen.
RESULTS: Deployment was successful in 100% with no cases of significant malpositioning. At 6 months the restenosis rates were 0.5 under the treatment with COVERA stent graft. the primary average patency was 3 months and the access average patency was 2.8 months. 50% of study population showed improvement in the luminal diameter as was assessed by Duplex ultrasound. The incidences of major and minor adverse events at 6 months were 2 and 1 respectively.
CONCLUSIONS: In this study, the use of the COVERA stent demonstrated safe and accurate deployment with acceptable primary target lesion and access circuit short-term restenosis rates. Major and minor adverse events were minimal. The COVERA stent graft appears to be a safe and effective option use in arteriovenous fistulae and grafts.