Stent Graft versus Balloon Angioplasty for Failing Dialysis-Access Grafts

Abstract

Conclusion: Revision of a venous anastomotic stenosis of a prosthetic dialysis access graft with a stent graft provides longer-term patency and freedom from repeat intervention than revision with standard balloon angioplasty. Summary: Secondary patency of hemodialysis grafts is at best 50% at 3 years. Many interventions are typically required to maintain dialysis-access graft patency. The authors sought to test the hypothesis that revision of venous anastomotic stenosis with stent grafts constructed with the same material as the dialysis-access graft itself would improve long-term patency compared with that provided by revision with balloon angioplasty alone. Theoretically, stent graft revision would prevent elastic recoil associated with balloon angioplasty alone and prevent intimal hyperplasia in-growth at the venous anastomosis, resulting in improved patency of the revised grafts. This was a prospective multicenter trial. There were 190 patients undergoing hemodialysis with dialysis-access grafts and a venous anastomosis stenosis that were randomly assigned to receive balloon angioplasty alone or balloon angioplasty plus placement of a stent graft at the site of the venous anastomotic lesion. Patency of the treatment area and patency of the entire vascular access graft were the primary end points. At 6 months, patency of the treatment area was greater in the stent graft group than in the balloon angioplasty group (51% vs 23%, P < .001). Six-month patency of the dialysis access circuit was improved in the stent graft group vs the balloon angioplasty group (38% vs. 20%, P = .008). Freedom from subsequent intervention at 6 months was also greater in the stent graft group than in the balloon angioplasty group (32% vs 16%, P = .03). Restenosis was greater in the balloon angioplasty group than in the stent graft group (78% vs 28%, P < .001). Other adverse events at 6 months were equivalent in the two treatment groups. Comment: There is still a need for dialysis-access grafts. Results of this study suggest stent grafts provide better patency in treating venous anastomotic strictures of dialysis-access grafts than that provided by balloon angioplasty alone. Although the results are statistically significant, there are details to be considered before declaring the results clinically significant. Grafts in this study were treated before actual thrombosis. Many access grafts do not come to revision until they have thrombosed, and it is controversial whether surveillance and treatment of patent, but not thrombosed dialysis grafts, actually results in overall prolongation of usable access. In addition, 6 months after revision with a stent graft, there is primary patency in only half the patients. Stent grafts are more expensive than balloon angioplasty alone. It is therefore unclear whether the increased patency at 6 months will translate into longer-term cost-effectiveness and whether an approach of graft surveillance with treatment with this technology of narrowed venous anastomotic areas discovered with surveillance will result in meaningful overall clinical benefit or cost savings.