Evaluation of Expanded Polytetrafluoroethylene–covered Stents for the Treatment of Venous Outflow Stenosis in Hemodialysis Access Grafts

Abstract

Purpose To investigate the use of an expanded polytetrafluoroethylene–coated nitinol stent-graft in patients with failing hemodialysis access circuits and compare grafts with and without a heparin-coated surface. Materials and Methods A single-institution retrospective review of 16 patients (average age, 55 years; seven men) treated for hemodialysis access circuit stenoses was performed. Patients had a prosthetic arteriovenous (AV) graft ( n = 10) or autogenous AV fistula ( n = 6), all with clinically relevant access stenoses that were refractory to angioplasty alone; 10 patients also had access circuit thrombosis at the time of treatment. Stents were placed in the basilic ( n = 4), brachial ( n = 7), cephalic ( n = 4), and femoral ( n = 1) veins. Study endpoints included primary treatment area patency, primary circuit patency, primary assisted circuit patency, and secondary circuit patency, followed to a maximum of 6 months. Results Primary treatment area patency rates at 30 days and 180 days were 75% and 31%, respectively. Secondary patency rates at the same time points were 88% and 68%, respectively. Mean primary treatment area patency was 93 days. Thrombosis was a major cause of failure, occurring in seven of 11 cases of primary treatment area patency loss. Subgroup analysis demonstrated that the heparin-coated configuration ( n = 7) showed a 6-month primary patency rate of 57%, compared with 11% for the stent-grafts without heparin bonding ( n = 9; P = .06). Conclusions Overall, the majority of deployed stent-grafts lost primary patency within 6 months, with thrombosis a major cause of failure. However, the addition of a heparin-coated surface appeared to improve results in these otherwise treatment-refractory access circuits.