Stent Grafts Better Than Angioplasty for Failing Dialysis-Access Grafts

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Using a stent graft to keep open failing arteriovenous dialysis grafts results in better patency and fewer reinterventions than angioplasty alone. Twelve-month results of the RENOVA trial were presented Monday, April 15, 2013, at the Society of Interventional Radiology Scientific Meeting in New Orleans, LA.

Researchers led by Ziv J. Haskal, MD, of the University of Maryland School of Medicine in Baltimore (Baltimore, MD), randomized 270 patients at 28 US sites who had patent but failing arteriovenous dialysis access grafts to angioplasty with (n = 138) or without (n = 132) stent graft implantation. The device used was a self-expanding nitinol stent covered in carbon-impregnated ePTFE (Flair Endovascular Stent Graft, Bard Peripheral Vascular, Tempe, AZ).

At 12 months, primary patency of the access circuit and treatment area, average number of months between interventions (index of patency function), and stenosis requiring intervention were all improved in the stent graft group (table 1).

Table 1. Twelve Month Outcomes

Overall adverse events were similar between the stent graft and angioplasty groups (92.8% vs. 96.2%; P = NS).

“Results of the study exceeded our expectations, and that is a boon for dialysis patients,” Dr. Haskal said in a press release. In an e-mail communication with TCTMD, he added, “This is the first study to show long term improvements in [arteriovenous] graft function by anything over balloon angioplasty—a costly invasive painful procedure performed upwards of 100,000 times per year for US patients. This treatment has the potential to improve patient quality of life by reducing these, prolonging graft function, and reducing health-care costs.”

Patients undergoing hemodialysis for treatment of end-stage renal disease numbered more than 341,000 in the United States in 2008. Guidelines recommend that such patients receive hemodialysis through autogenous fistulas, but those lacking suitable veins typically require placement of prosthetic grafts, which experience high failure rates. The most common cause of failure is stenosis at the venous anastomosis of the graft.

‘Necessary Evils’ No Longer?

“Dialysis grafts have been viewed as necessary evils—a hemodialysis access with repeated failure requiring costly painful interventions,” Dr. Haskal said. “This could increase confidence in the use of arteriovenous access grafts in patients who cannot receive native arteriovenous fistulae for hemodialysis.”

Dr. Haskal and colleagues also compared the Flair stent graft with angioplasty in a separate randomized trial in a similar population, with 6-month results appearing in the New England Journal of Medicine (Haskal ZJ, et al. NEJM. 2010;362:494-503).

In the earlier study, “we proved this approach was markedly superior to the existing practice of balloon angioplasty, potentially changing the impact for hundreds of thousands of patients,” Dr. Haskal said. “[The new] study lays the foundation for considering grafts as longer-term tools. We simply had never considered grafts as longer-term tools for dialysis when fistulae could not be created.”

Study Details

The mean deployed stent graft length was 45 mm (SD 4.9 mm). Inclusion criteria required a patent but failing upper extremity arteriovenous graft with ≥ 50% venous anastomotic stenosis associated with hemodynamic, functional, or clinical abnormalities. The RENOVA trial is scheduled to last 2 years.

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