At a recent dialysis access conference we discussed the role of PTA and alternatives for the treatment of venous stenosis. Historically, the treatment has ranged from atherectomy, to cutting balloon angioplasty, to covered stent graft placement. The results of percutaneous angioplasty of dialysis access venous outflow associated lesions has been marginal.
Our recent discussion centered on the FlAIR covered stent graft device from BARD Peripheral. This device which is similar to the Fluency device, has some very impressive results from a well controlled study. The Fluency device is a carbon coated, e PTFE encapsulated nitinol stent with an off label use in dialysis access. The Flair differs by its complete coverage with PTFE as compared to the Fluency which has 2 mm of bare metal exposed at each end of the graft
The theoretic benefit is that this configuration of entirely covered stent may decrease the risk of intimal hyperplasia.
The Flair Endograft is the first endovascular technology that has shown results superior to angioplasty in the treatment of dialysis access related stenosis. In the results from the randomized study, lead by principal investigator Dr Ziv Haskal of New York Presbyterian/ Columbia University Medical Center, 190 patients with hemodynamically significant stenosis of > 50% at the graft to vein anastomosis were randomized to PTA alone group vs PTA followed by FlAIR endograft placement.
The 6 mo treatment area primary patency was 51% for the FLAIR vs 23% for PTA alone. Access circuit primary patency (ACCP), which is an indicator of restenosis, was 38% in the FLAIR group and 20% in the control group. The Binary restenosis rate at 6 months, determined by an independent core lab assessment, was lower in the FLAIR group (28 %) compared to the PTA alone group (78%)
In graft to vein lesions, the most common type of lesion responsible for access occlusion in bridge grafts, this device appears to have superior patency and comparable safety.
Some questions exist. Can these results be extrapolated to stenosis that occur within autogenous fistulas and at various locations such as mid body fistula, swing point and central alike.
The theoretical benefit of the design over the previous iteration, The Fluency, is that the stent is entirely covered with ePTFE. It will be interesting to see what the price differential is between the two devices. Importantly, the FLAIR, if approved will be indicated for dialysis access as opposed to off label use pattern of The Fluency.
