Single limb patency of polytetrafluoroethylene dialysis loop grafts maintained by traumatic fistulization.

The purpose of this report is to describe an unusual presentation of obstructive neointimal hyperplastic lesions in loop prosthetic dialysis grafts. The case histories and imaging studies of two patients with partial graft thrombosis are presented. The literature of unexpected fistulae from prosthetic dialysis grafts to adjacent veins is reviewed. Signs and symptoms that would lead a clinician to suspect the diagnosis are emphasized. There were two dialysis grafts with partial thrombosis and arterial limb patency maintained by iatrogenic fistula. These fistulae occurred from the erosion of pseudoaneurysms in one case and an apparent needle stick without pseudoaneurysm in the other. Both grafts had high-grade stenotic lesions affecting the venous outflow. In the first case this was not recognized until the graft reclotted 2 days after thrombectomy. In the most extreme cases of graft/vein fistulae, i.e., partial graft thrombosis with arterial limb patency maintained by the fistula there is always associated venous anastomotic or outflow stenoses which must be addressed.

Reinforced versus nonreinforced polytetrafluoroethylene grafts for hemodialysis access.

BACKGROUND: Two major types of polytetrafluoroethylene (PTFE) graft material have been available for the past 20 years. Previous studies have suggested that nonreinforced PTFE performs better as a hemodialysis conduit than reinforced PTFE. We have had experience with both materials for the past 20 years. METHODS: This is an outcome study that is based on concurrent and retrospective data. Patients were accrued into the study from 1987 to 1995. There were 632 grafts that were entered onto a data base and analyzed by a biostatistician. RESULTS: Nonreinforced PTFE performed better than reinforced PTFE in every category and subgroup. Both mean duration and life-table analysis of the primary patency were statistically significant (P < 0.05). The secondary patencies were similar, with 80% of the nonreinforced and 77% of the reinforced functioning at 1 year. The median duration for secondary patency of all grafts was 1,554 days. Diabetic patients comprised 50% of the patient population. CONCLUSION: Nonreinforced PTFE performs better than reinforced PTFE as a hemodialysis conduit. Until a multicentered prospective randomized study can be achieved, a preponderance of data suggests that nonreinforced PTFE should be the material of choice for hemodialysis access.

Local delivery of heparin with balloon angioplasty: results of a prospective randomized trial.

PURPOSE: To evaluate the effectiveness of local delivery of heparin via hydrogel-coated balloons in the treatment of vascular stenoses associated with hemodialysis access. MATERIALS AND METHODS: This was a randomized, prospective trial comparing treatment with hydrogel-coated balloon catheters delivered with heparin coating (n = 33) and without (n = 26). All patients were undergoing hemodialysis, and all stenoses involved the venous anastomosis of a dialysis graft or a native vein. The heparin-treated balloons were soaked in concentrated heparin and delivered in a protected manner to help prevent washout of heparin. RESULTS: The mean primary patencies were 143 days with heparin treatment and 214 days without heparin (P = .174). The mean assisted primary patencies were 165 days with heparin and 194 days without (P = .315). The mean secondary patencies were 351 days with heparin and 384 without (P = .81). CONCLUSION: In this population with this technique, the treatment outcome of venous outflow stenosis in patients with dialysis grafts is not improved with local delivery of heparin.

Percutaneous transluminal angioplasty versus endovascular stent placement in the treatment of venous stenoses in patients undergoing hemodialysis: intermediate results.

PURPOSE: This report describes intermediate findings from an ongoing prospective randomized trial comparing the results of percutaneous transluminal angioplasty (PTA) with results of endovascular stent placement in patients undergoing hemodialysis. PATIENTS AND METHODS: Among 87 consecutive patients with venous stenoses or occlusions, 47 (54%) were treated with PTA alone and 40 (46%) were treated with PTA and stent placement. RESULTS: For peripheral sites, the primary patency rates for PTA at 60, 180, and 360 days were 55%, 31%, and 10%, respectively, and for stents were 36%, 27%, and 11%, respectively (P = .6528). The secondary patency rates for PTA at 60, 180, and 360 days were 94%, 80%, and 71%, respectively, and for stents were 73%, 64%, and 64%, respectively (P = .1677). For central sites, the primary patency rates for PTA at 60, 180, and 360 days were 81%, 23%, and 12%, respectively, and for stents were 67%, 11%, and 11%, respectively (P = .4595). The secondary patency rates for PTA were 100% at each interval, and for stents were 100%, 89%, and 78%, respectively (P = .5408). CONCLUSION: Intermediate results suggest that, overall, there is no difference in the patency rates for peripheral venous stenoses in dialysis patients treated with PTA or PTA and endovascular stent placement. At this time, the numbers of patients are too small to conclude if certain sites such as larger central veins will respond better to one treatment or the other.

Does the use of erythropoietin in hemodialysis patients increase dialysis graft thrombosis rates?

Erythropoietin (EPO) is highly efficacious in the treatment of the anemia of chronic renal failure. Evidence for a reported serious side effect, increased dialysis graft thrombosis, is equivocal. Sixty-four hemodialysis patients utilizing polytetrafluoroethylene (PTFE) grafts were treated with EPO. The patients served as their own historical controls. There were 1.188 thrombectomies and 0.222 mechanical problems per 1,000 patient-days prior to the initiation of EPO treatment. With EPO, the values were 0.656 and 0.222, respectively. Patients were separated into low-, medium-, and high-dose EPO groups and analyzed within groups for the effect of EPO and between groups for a dose-dependent response. According to an analysis of variance procedure, there was no statistically significant differences between the groups, which suggests that EPO is not thrombogenic to dialysis grafts.

Liver transplantation for severe Amanita phalloides mushroom poisoning.

Amanita phalloides mushroom poisoning is an increasingly common and potentially lethal problem for which liver transplantation offers definitive therapy in selected patients. When significant liver dysfunction appears, early transfer to a liver transplant center is important to identify appropriate candidates and to begin the search for a donor organ. The clinical course of five severely poisoned patients, four of whom underwent liver transplantation, is reviewed. Indications for transplantation included primarily a markedly prolonged prothrombin time that was only partially correctable and a constellation of findings including metabolic acidosis, hypoglycemia, hypofibrinogenemia, and increased serum ammonia, following a marked elevation in serum aminotransferase levels. Unlike viral fulminant hepatic failure, grade III or IV hepatic encephalopathy, marked elevation of the serum bilirubin level, and azotemia were not indications for transplantation. Resected livers demonstrated hepatocyte viability of 0% to 30%. Manifestations of Amanita poisoning complicating preoperative and/or postoperative care included severe diarrhea, gastrointestinal hemorrhage, hypophosphatemia, bowel edema, and marrow suppression with lymphopenia, thrombocytopenia, and neutropenia. All five patients are well 1 year later. This largest experience with liver transplantation for Amanita poisoning further defines the early clinical and laboratory indications for, and the unique complicating features of, transplantation in this setting.