Prospective, randomized, multicenter clinical study comparing a self-expanding covered stent to percutaneous transluminal angioplasty for treatment of upper extremity hemodialysis arteriovenous fistula stenosis.

Use of a covered stent after percutaneous transluminal angioplasty (PTA) was compared to PTA alone for treatment of upper extremity hemodialysis patients with arteriovenous fistula (AVF) stenoses. Patients with AVF stenosis of 50% or more and evidence of AVF dysfunction underwent treatment with PTA followed by randomization of 142 patients to include a covered stent or 138 patients with PTA alone. Primary outcomes were 30-day safety, powered for noninferiority, and six-month target lesion primary patency (TLPP), powered to test whether TLPP after covered-stent placement was superior to PTA alone. Twelve-month TLPP and six-month access circuit primary patency (ACPP) were also hypothesis tested while additional clinical outcomes were observed through two years. Safety was significantly non-inferior while six- and 12-month TLPP were each superior for the covered stent group compared to PTA alone (six months: 78.7% versus 55.8%; 12 months: 47.9% versus 21.2%, respectively). ACPP was not statistically different between groups at six-months. Observed differences at 24 months favored the covered-stent group: 28.4% better TLPP, fewer target-lesion reinterventions (1.6 ± 1.6 versus 2.8 ± 2.0), and a longer mean time between target-lesion reinterventions (380.4 ± 249.5 versus 217.6 ± 158.4 days). Thus, our multicenter, prospective, randomized study of a covered stent used to treat AVF stenosis demonstrated noninferior safety with better TLPP and fewer target-lesion reinterventions than PTA alone through 24 months.

Long-Term Results from the Pivotal Multicenter Trial of Ultrasound-Guided Percutaneous Arteriovenous Fistula Creation for Hemodialysis Access.

PURPOSE: To report the 5-year results from the Pivotal Multicenter Trial of Ultrasound-Guided Percutaneous Arteriovenous Fistula (pAVF) Creation for Hemodialysis Access. MATERIALS AND METHODS: The retrospective review of 107 intent-to-treat (ITT) patients from the pivotal trial provided a long-term follow-up population (LTP) of 85 patients with a median follow-up duration of 50 months (range, 12-60 months). Data evaluated in the LTP group were fistula maturation and usage, secondary procedures, and complications. The Kaplan-Meier analysis of primary patency, assisted primary patency, cumulative patency, and functional patency (time from 2-needle cannulation to abandonment) were performed for the ITT population. RESULTS: In the LTP, 99% (84 of 85) of fistulae were mature, with 99% (78 of 79) of patients requiring hemodialysis using their pAVF. Sustained fistula use (2-needle cannulation at the prescribed rate, 2 of 3 sessions) was achieved in 92% (78 of 85) of patients, with 7 patients not using their pAVF because they were not on dialysis (n = 4), were on peritoneal dialysis (n = 2), and refused to use fistula (n = 1). Fistula maintenance was required in 31.8% (27 of 85) of patients and included fistula dysfunction (21.2%), thrombosis (5.9%), cannulation injury (12.9%), and arm swelling (4.7%). The number of procedures performed per patient per year to maintain function and patency was 0.32 (91 of 288) for years 2-5. The cumulative patency rates were 89.5%, 88.4%, 88.4%, 85.6%, and 82.0% for years 1, 2, 3, 4, and 5, respectively. The functional patency was 91.8% at the end of the study. There were no major complications related to pAVF during the long-term follow-up. CONCLUSIONS: Percutaneous fistulae have provided clinically effective and durable access for hemodialysis with low complications. The continued use and evaluation of pAVF are warranted.

The Pivotal Multicenter Trial of Ultrasound-Guided Percutaneous Arteriovenous Fistula Creation for Hemodialysis Access.

PURPOSE: To evaluate safety and efficacy of arteriovenous fistulas (AVFs) created with a thermal resistance anastomosis device. MATERIALS AND METHODS: A prospective single-arm trial at 5 sites enrolled 107 patients. Patients underwent ultrasound (US)-guided anastomosis creation between the proximal radial artery and perforating vein with the Ellipsys Vascular Access System (Avenu Medical, Inc, San Juan Capistrano, California) followed by separate maturation procedures. Primary endpoints were brachial artery flow volume ≥ 500 mL/min and target vein diameter ≥ 4 mm in > 49% of patients and absence of device-related complications at 90 days. RESULTS: AVFs with fused anastomoses were created in 95% (102/107) of patients. Maturation procedures included anastomotic balloon dilation in 72% (77/107), brachial vein embolization in 32% (34/107), cubital vein ligation in 31% (33/107), and surgical transposition in 26% (28/107) of patients. Primary flow and diameter endpoints were achieved in 86.0% (92/107) of patients, exceeding performance goal of 49% (P < .0001). No major adverse events were attributed to the device. Cumulative patency was 91.6%, 89.3%, and 86.7% at 90 days, 180 days, and 360 days. Target dialysis veins were cephalic, basilic, and brachial veins in 74% (73/99), 24% (24/99), and 2% (2/99) of patients. Two-needle dialysis was achieved in 88% (71/81) of patients on hemodialysis at a mean 114.3 days ± 66.2. Functional patency was 98.4%, 98.4%, and 92.3% at 90 days, 180 days, and 360 days. CONCLUSIONS: The Ellipsys® Vascular Access System met primary safety and efficacy endpoint goals in the US pivotal trial.

Prospective, Randomized, Concurrently-Controlled Study of a Stent Graft versus Balloon Angioplasty for Treatment of Arteriovenous Access Graft Stenosis: 2-Year Results of the RENOVA Study.

PURPOSE: To present final, 2-year data from randomized comparison of an expanded polytetrafluoroethylene stent graft (SG) and percutaneous transluminal angioplasty (PTA) for treatment of arteriovenous graft (AVG) anastomotic stenoses. MATERIALS AND METHODS: A 28-site, prospective, controlled US study enrolled 270 patients with malfunctioning AVG anastomotic stenoses of ≥ 50%; 138 patients underwent SG placement, and 132 underwent PTA alone. Follow-up imaging and intervention were event-driven. RESULTS: The study was completed by 191 patients (97 SG, 94 PTA). Five patients were lost to follow-up or withdrew; 74 patients died during the study (38 SG, 36 PTA). At 12 months, treatment area primary patency (TAPP) was SG 47.6% versus PTA 24.8% (P < .001), access circuit primary patency (ACPP) was SG 24% versus PTA 11% (P = .007), and index of patency function (IPF) was SG 5.2 months/intervention ± 4.1 versus PTA 4.4 months/intervention ± 3.5 (P = .009). At 24 months, TAPP was SG 26.9% versus PTA 13.5% (P < .001), ACPP was SG 9.5% versus PTA 5.5% (P = .01), and IPF was SG 7.1 months/intervention ± 7.0 versus PTA 5.3 months/intervention ± 5.2; estimated number of reinterventions before graft abandonment was 3.4 for SG patients versus 4.3 for PTA patients. There were no significant differences in adverse events (P > .05) except for restenosis requiring reintervention rates of 82.6% in PTA patients versus 63.0% in SG patients (P < .001). CONCLUSIONS: At 2 years, SG use provided a sustained, greater than 2-fold advantage over PTA in treatment area and overall access patency. Time to subsequent intervention was longer in the SG group.

Patient selection, education, and cannulation of percutaneous arteriovenous fistulae: An ASDIN White Paper.

End-stage kidney disease patients who are candidates for surgical arteriovenous fistula creation commonly experience obstacles to a functional surgical arteriovenous fistula, including protracted wait time for creation, poor maturation, and surgical arteriovenous fistula dysfunction that can result in significant patient morbidity. The recent approval of two endovascular devices designed to create a percutaneous arteriovenous fistula enables arteriovenous fistula creation to be placed in the hands of interventionalists, thereby increasing the number of arteriovenous fistula providers, reducing wait times, and allowing the patient to avoid surgery. Moreover, current studies demonstrate that patients with percutaneous arteriovenous fistula experience improved time to arteriovenous fistula maturation. Yet, in order to realize the potential advantages of percutaneous arteriovenous fistula creation within our hemodialysis patient population, it is critical to select appropriate patients, ensure adequate patient and dialysis unit education, and provide sufficient instruction in percutaneous arteriovenous fistula cannulation and monitoring. In this White Paper by the American Society of Diagnostic and Interventional Nephrology, experts in interventional nephrology, surgery, and interventional radiology convened and provide recommendations on the aforementioned elements that are fundamental to a functional percutaneous arteriovenous fistula.