A comparison of cryopreserved vein allografts and prosthetic grafts for hemodialysis access.

In hemodialysis patients with insufficient vasculature for creation of a native arteriovenous fistula (AVF), a polytetrafluoroethylene (PTFE) graft is commonly utilized. Because of PTFE complications, our group and others have used cryopreserved cadaver femoral vein allografts (Synergraft [SYN], CryoLife, Marietta, GA) in selected patients. Based on our experience with these allografts, we hypothesized that they were more resistant to thrombosis than PTFE grafts. The purpose of this study was to compare the thrombosis rates of SYN and PTFE grafts in a prospective, randomized fashion. Our study was interrupted when the FDA ordered CryoLife, Inc. to retain certain vascular tissue products, and patient accrual stopped in 2003. Most patients referred for hemodialysis access are evaluated with bilateral, upper extremity Doppler ultrasound. Starting in 2001, those with insufficient vasculature for native AVF were offered randomization into the PTFE or SYN groups. All accesses were placed in the upper extremity, above the elbow. Access patency and complications were recorded, and failure was defined as access removal, abandonment, or replacement of > 50% with a new conduit. Prior to FDA interruption of the study, 27 patients were randomized into each group. Patient characteristics were similar, but there were significantly more males and African-Americans in the SYN group. No significant differences were seen in primary or secondary patency, number of thrombectomies, revisions, or total interventions. Significantly more fistulagrams were performed in the SYN group (p < 0.05). No infections were seen in either group, but 2 aneurysms occurred in the SYN group. Nine (33%) patients in each group died with functioning access. Access failures: In the SYN group, 8 of 27 (30%) failed, with 5 failing from multiple access stenoses unresponsive to balloon angioplasty; in the PTFE group 4 of 27 (18%) failed, with 2 failing from multiple stenoses. In conclusion, for initial hemodialysis access in patients without sufficient vasculature for native AVF, our results do not support the routine use of SYN allografts in the general dialysis population.

Experience with cryopreserved cadaveric femoral vein allografts used for hemodialysis access.

The purpose of this study was to review the patency and complications of cryopreserved vein allografts used for hemodialysis access, and to compare them to a group with polytetrafluoroethylene (PTFE) grafts. Patients without adequate vasculature for native fistula were implanted with vein allografts or PTFE grafts at the surgeon's discretion. Only cryopreserved (CRY) veins were used until January 2001, when decellularized, cryopreserved Synergraft (SYN) veins became available. The CRY group had 48 patients; the SYN group, 42 patients; the PTFE group, 100 patients, who were selected from billing records listing PTFE graft insertion. Patient demographics were similar. Primary and secondary patencies were not significantly different at 1 or 2 years between groups. Complications in PTFE versus CRY and SYN groups were as follows: infection, 10 % vs. 0% (p < 0.01); aneurysm, 2% vs. 18% (p < 0.001); and steal syndrome, 12% vs. 12% (p = NS). Significantly more vein allograft patients lost their accesses to aneurysm (p < 0.01) and multiple stenoses (p < 0.05), whereas PTFE patients lost significantly more accesses to infection (p < 0.01) and recurrent thrombosis (p < 0.05). We conclude that cadaver vein allografts have similar patency to PTFE grafts. These allografts are more resistant to infection but significantly more susceptible to aneurysms. When used, vein allografts should be monitored aggressively for the development of aneurysms.

A novel technique designed to minimize the morbidity of failure of arteriovenous access in hemodialysis patients.

The failure of dialysis access grafts leads to significant morbidity rates in patients with end-stage renal disease. We describe a novel technique for the insertion of new polytetrafluoroethylene graft segments designed to reduce this morbidity rate. Patients found to have significant intragraft deterioration at thrombectomy undergo insertion of a new nonanastamosed graft parallel to the existing graft. At the next failure of the existing graft, the nonanastamosed segment is anastamosed and used immediately for dialysis, obviating the need for a temporary catheter. Thirty patients have undergone this technique, and 89% of those who returned to surgery have had successful anastamosis of their new segments. Two patients were found to have inadequate incorporation of their new segments into the subcutaneous tissue, and one became frankly infected.

Safety and efficacy of femoral-based hemodialysis access grafts.

OBJECTIVE: Arteriovenous fistulae traditionally have been placed in the upper extremity. Experience with groin hemodialysis access has been discouraging because of high infection rates and associated limb amputation. We reviewed our experience with angioaccess grafts in the groin to assess safety and viability in our hemodialysis patient population. METHODS: A retrospective review was performed of all groin hemodialysis access grafts placed at a single tertiary care center between June 1990 and February 1998. Demographics, complications, and subsequent treatment were recorded. Graft patency and infection rates were analyzed with life-table analysis. RESULTS: Data were collected on 73 graft insertions. A total of 52 episodes of thrombosis occurred in 26 grafts. Primary patency rate was 71% at 1 year. Secondary patency rate was 83% at 1 year. There was a 22% incidence rate of infection. CONCLUSION: We conclude that the incidence rate of infection and thrombosis in our series of femoral-based hemodialysis grafts is comparable with rates reported in the literature for upper extremity polytetrafluoroethylene angioaccess grafts. Although not considered a first choice, femoral artery-based hemodialysis access is a viable option when arteriovenous fistulae in the upper extremity cannot be constructed.