Vascular access: Covera stent superior to plain balloon angioplasty in stenotic lesions

Bart Dolmatch

A covered stent provides significantly better target lesion primary patency than percutaneous transluminal angioplasty (PTA) of stenotic lesions in the venous outflow of upper extremity haemodialysis arteriovenous (AV) fistulae, according to interim results from the AVeNEW study announced at the Society of Interventional Radiology (SIR) 2020 Virtual Sessions (13–14 June).

Other findings presented by lead author Bart Dolmatch (Mountain View, USA) in the Abstract of the Year session were that safety was non-inferior with the expanded polytetrafluoroethylene (ePTFE)-covered, self-expanding Covera vascular covered stent (BD) at six months and, at 12 months, target lesion primary patency was statistically better for the covered-stent group, as was access circuit primary patency. In addition, about half as many reinterventions were required to maintain secondary circuit patency in the Covera stent group.

AVeNEW is a prospective, randomised study in 35 centres in the USA, Europe, Australia, and New Zealand, and is the first level-one clinical trial dedicated to the use of a covered stent designed to treat stenoses in AV fistulae.

Researchers randomised 280 patients with stenotic lesions (≥50%) and clinical or haemodynamic evidence of AV fistula dysfunction to either PTA alone (n=138) or PTA followed by covered stent placement (n=142). Primary endpoints were six-month target lesion primary patency and 30-day safety. Secondary measures included target lesion primary patency, access circuit primary patency, index of patency function, and the number of reinterventions needed to maintain patency at 12 months, with ongoing data collection to three years.

It found that safety at 30 days was non-inferior between groups (p=0.002). Target lesion primary patency at 180 days (Kaplan-Meier analysis) was superior for the covered-stent group compared to the PTA group (78.7% vs. 47.9%, respectively, one-sided p<0.001).

Among the 280 participants, 34 died (10.6% covered-stent group, 14.5% PTA group), and 10 patients withdrew or were lost to follow up (4.2% covered-stent group, 2.9% PTA group) prior to 12-month evaluation, leaving 83.9% of patients for follow up. Target lesion primary patency (Kaplan-Meier analysis) was superior for the covered stent group compared to the PTA (57.5% vs. 21.2%, respectively, p<0.001) at one year. Access circuit primary patency 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 for the covered-stent group compared to 1.7+1.3 for the PTA group.

The research was originally scheduled to be presented in person at SIR’s Annual Scientific Meeting, 28 March–2 April, in Seattle, USA, before the meeting was cancelled due to COVID-19 concerns. See all our coverage of the virtual event here.


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