Abstract No. 2 ■ ABSTRACT OF THE YEAR Interim results from the prospective, randomized AVeNEW study

Abstract

To assess the results using the ePTFE-covered, self-expanding COVERA Vascular Covered Stent for the treatment of stenotic lesions in the venous outflow of upper extremity hemodialysis arteriovenous (AV) fistulae. Thirty-five centers in the United States, Europe, Australia, and New Zealand randomized 280 patients with stenotic lesions (≥ 50%) and clinical or hemodynamic evidence of AV fistula dysfunction to either PTA alone (n = 138) or PTA followed by covered stent placement (n = 142). Primary endpoints were 6-month target lesion primary patency (TLPP) and 30-day safety. Secondary measures included TLPP, access circuit primary patency (ACPP), index of patency function (IPF), and the number of reinterventions needed to maintain patency at 12 months, with ongoing data collection to 3 years. Safety at 30 days was non-inferior between groups (P = 0.002) while TLPP at 180 days (Kaplan-Meier analysis) was superior for the covered-stent group (78.7%) compared with the PTA group (47.9%; one-sided P < 0.001). 83.9% of patients were followed to 12 months; 34 patients died (10.6% covered-stent group; 14.5% PTA group) while 10 patients withdrew or were lost to follow-up (4.2% covered-stent group; 2.9% PTA group) prior to 12-month evaluation. TLPP (K-M analysis) was superior for the covered stent group (57.5%) compared to the PTA (21.2%; P < 0.001) at 365 days. ACPP was also significantly better for the covered-stent group at 12 months, 28.9% versus 17.7% respectively (P = 0.02). The mean number of reinterventions in the access circuit to maintain patency was 0.8 + 1.0 for the covered-stent group compared to 1.7 + 1.3 for the PTA group. AVeNEW is the first level-one clinical trial dedicated to the use of a covered stent designed to treat stenoses in AV fistulae. The covered stent provided significantly better TLPP and non-inferior safety compared to the randomized PTA group at 6 months. At 12 months, TLPP was statistically better for the covered-stent group (P < 0.001) as was ACPP (P = 0.02) while about half as many reinterventions were required to maintain secondary circuit patency.