Bard's Flair Stent Graft Bests Balloon Angioplasty in Study

February 10, 2010—Bard Peripheral Vascular, Inc. (Tempe, AZ) announced that Ziv J. Haskal, MD, et al published trial results in the New England Journal of Medicine (NEJM) showing that the Bard Flair endovascular stent graft maintains the patency of dialysis access grafts more effectively than balloon angioplasty alone (2010;362:494–503). The Flair device has been approved by the US Food and Drug Administration for use in treating stenoses at the venous anastomosis of expanded polytetrafluoroethylene or other synthetic arteriovenous access grafts. In an accompanying editorial in NEJM, “Fistula First, Stent Graft Second,” Robert K. Kerlan, Jr, MD, and Jeanne M. LaBerge, MD, further discuss the Flair investigators' findings and their implications (2010;362:550–552).

According to the company, the randomized Flair trial demonstrated the superiority of this new therapy over balloon angioplasty. At 6 months, the treatment area in patients who received a Flair stent graft was more than twice as likely to be functioning when compared to patients who received balloon angioplasty alone. Adverse events, patient demographics, and clinical variables were statistically equivalent between both groups during the trial.

“For the first time, clinicians have compelling evidence that we can significantly improve outcomes over balloon angioplasty in this underserved and difficult-to-treat patient population,” commented Dr. Haskal, who is principal investigator for the trial. “The durable benefit we observed in the trial, as demonstrated by superior patency and freedom from repeat interventions, strongly supports a fundamental change in how we care for hemodialysis patients.”

Dr. Haskal remarked to Endovascular Today that an additional benefit of the Flair device was demonstrated in the study. “The endovascular stent graft does much more than simply provide a barrier to recoil of surrounding scar tissue,” he observed. “It actually converts the turbulent flow of the original surgical anastomosis to one with laminar flow, and this appears to prevent later complications— the low shear stress reduces the stimulus that develops the adjacent next-generation stenosis.”

An in-depth interview with Dr. Haskal on the Flair trial, along with an analysis of advances in salvaging hemodialysis access beyond angioplasty by Bart Dolmatch, MD (“Maintenance of Hemodialysis Access With Covered Stents”), was featured in the February 2009 issue of Endovascular Today (2009;8:65–69).

As detailed in NEJM, the background of the study is the knowledge that the leading cause of failure of a prosthetic arteriovenous hemodialysis access graft is venous anastomotic stenosis. Balloon angioplasty, the first-line therapy, has a tendency to lead to subsequent recoil and restenosis; however, no other therapies had been proven to be more effective. This study was designed to compare conventional balloon angioplasty with an expanded polytetrafluoroethylene endovascular stent graft for revision of venous anastomotic stenosis in failing hemodialysis grafts.

The investigators conducted a prospective, multicenter trial that randomly assigned 190 patients who were undergoing hemodialysis and had a venous anastomotic stenosis to undergo either balloon angioplasty alone or balloon angioplasty plus placement of the stent graft. Primary endpoints included patency of the treatment area and patency of the entire vascular access circuit.

At 6 months, the investigators found that the incidence of patency in the treatment area was significantly greater in the stent graft group than in the balloon angioplasty group (51% vs 23%; P < .001), as was the incidence incidence of patency of the access circuit (38% vs 20%; P = .008). In addition, the incidence of freedom from subsequent interventions at 6 months was significantly greater in the stent graft group than in the balloon angioplasty group (32% vs 16%; P = .03, by the log-rank test; P = .04, by the Wilcoxon rank sum test). The incidence of binary restenosis at 6 months was greater in the balloon angioplasty group than in the stent graft group (78% vs 28%; P < .001). The incidences of adverse events at 6 months were equivalent in the two treatment groups, with the exception of restenosis, which occurred more frequently in the balloon angioplasty group (P < .001).

From these results, the investigators concluded that percutaneous revision of venous anastomotic stenosis in patients with a prosthetic hemodialysis graft was improved with the use of a stent graft, which appears to provide longer-term and superior patency and freedom from repeat interventions than standard balloon angioplasty.