Treatment of thrombosed dialysis ateriovenous (AV) grafts in the radiology interventional suite requires percutaneous mechanical thrombectomy, along with angioplasty of the underlying stenotic lesion. We analyzed the anatomic reasons for unsuccessful percutaneous thrombectomy of AV grafts, and assessed the feasibility of surgical salvage. The radiologic reports of all thrombosed AV grafts undergoing unsuccessful percutaneous mechanical thrombectomy during a 5-year period were analyzed for the specific problem precluding restoration of graft patency. We also compared the features of patients with unsuccessful graft thrombectomy to those with successful thrombectomy. Of 77 AV grafts undergoing unsuccessful percutaneous thrombectomy, only six (or 8%) could be revised surgically. Inability to salvage the graft surgically was because of: severe draining vein occlusion or stenosis (30 patients); severe central vein lesion (12); multiple intragraft stenoses (11); large pseudo-aneurysms (six); venous anastomotic occlusion (six); and arterial anastomotic occlusion (four). When compared with 211 patients with successful graft thrombectomy, those with unsuccessful thrombectomy were more likely to have a forearm graft (53% vs. 27%, p < 0.001), and more likely to have a lesion in the draining vein (42% vs. 10%, p < 0.001), the central vein (17% vs. 3%, p < 0.001), or within the graft itself (23% vs. 1%, p < 0.001). An unsuccessful percutaneous graft thrombectomy is more likely in forearm than in upper arm grafts, and more likely if there is a lesion in the draining vein, central vein, or within the graft itself. Surgical salvage of a thrombosed AV graft after an unsuccessful percutaneous intervention is rarely feasible. Most patients have a severe anatomic lesion that cannot be repaired, and require creation of a new vascular access. © Journal compilation © 2008 Blackwell Publishing.