Stent Grafts Better for Failed Dialysis Access Sites

NEW ORLEANS—Stent grafts are more effective than balloon angioplasty in establishing and maintaining patency of collapsed dialysis access grafts, according to researchers.

Data presented at the Society of Interventional Radiology's 38th Annual Scientific Meeting showed that use of a stent graft was associated with fewer follow-up interventions per unit time per patient compared with percutaneous transluminal balloon angioplasty alone.

“Results of the study exceeded our expectations, and that is a boon for dialysis patients,” said lead study author Ziv Haskal, MD, Professor of Vascular and Interventional Radiology at the University of Maryland School of Medicine in Baltimore. “Dialysis is very demanding and anything that prevents access sites from failing and reduces the need for invasive treatments of surgery will dramatically improve patients' quality of life.”

The data are the prospective, randomized 12-month results from the two-year RENOVA trial, which enrolled 270 dialysis patients with collapsed vascular access sites. Of these patients, 138 underwent stent graft placement and 132 underwent balloon angioplasty.

After a 12-month follow-up, researchers found that 2.5 times more patients in the stent graft group than the PTA group were able to continue to use their dialysis access grafts. The treatment area patency rate 47.8% for stent grafts compared with 24.8% for angioplasty. The Index of Patency Function was 5.3 for the stent graft group compared with 4.4 for the angioplasty group. In addition, access circuit patency was 2.3 times better at 12 months with the stent graft compared with the angioplasty group. These findings are especially relevant because until now grafts had been considered short-term solutions, with 75% requiring invasive interventions in under a year, Dr. Haskal said. 

“This study lays further foundation for considering grafts as longer term tools,” Dr. Haskal told Renal & Urology News. “We simply had never considered grafts as longer term tools for dialysis when fistulae could not be created. This could increase confidence in the use of AV access grafts in patients who cannot receive native AV [arteriovenous] fistulae for hemodialysis. The number of Americans requiring hemodialysis continues to markedly grow and thus notable numbers of patients will require grafts.  This will really help them.”

At baseline, the two treatment arms had similar demographics and clinical criteria. At 12 months, the two groups had similar rates of adverse events (96.2% of the angioplasty group and 92.8% of the stent graft group experienced at least one adverse event). Thrombosis and infection rates were not different in two groups. Stenosis requiring intervention, however, occurred significantly more frequently in the angioplasty than the stent graft group (82.6% vs. 60.1%).

The new data are the first to show long-term improvements in AV graft function by anything other than balloon angioplasty, which he noted is a costly, invasive, painful procedure. Stent grafts have the potential to improve patient quality of life and also reduce overall healthcare costs.

“It was a wholly foreign concept when we started,” Dr. Haskal said. “People told me it was crazy. Anecdotally, we now have patients who have these stent grafts that are still open after three years. That is practically unheard of. This controlled study proves that we can achieve durable long-term solutions for these patients, reducing their invasive procedures and thus improving their quality of life.”

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