AUSTRALIAN MULTICENTRE EVALUATION OF A NEW POLYURETHANE VASCULAR ACCESS GRAFT

Background: A new three-layered cast polyurethane vascular access graft (Thoratec® VAG) is the most recent addition to the list of materials used in the search for the perfect prosthetic graft material for haemodialysis vascular access. Despite its use in 23 countries, a clinical assessment has not been published. Methods: An independent retrospective evaluation by questionnaire was obtained for 145 implantation procedures performed by 30 surgeons. Results: Ninety-two per cent of procedures were performed for an acute need for vascular access and 73% had prior failed vascular access surgery. Patients were hospitalized for a median of 4 days and the graft was initially used at a median of 3 days. Median follow-up was 306 days. Thoratec® VAG had a problem-free (primary) patency of 44.9% and a functional (secondary) patency 64.5% at 1 year. Major causes of graft loss were thrombosis (17%) and infection (11%). Intra-operative thrombosis was the only significant risk factor for subsequent thrombosis (P = 0.013). Infection was less in patients with antibiotic prophylaxis that included vancomycin (P = 0.02). Conclusion: The ability to use the graft soon after surgery is a major advance for patients who urgently need reliable medium to long-term haemodialysis access.     

COMPARATIVE EXPERIENCE OF A SIMPLE TECHNIQUE FOR LAPAROSCOPIC CHRONIC AMBULATORY PERITONEAL DIALYSIS CATHETER PLACEMENT

Background : Chronic ambulatory peritoneal dialysis (CAPD) is now an established technique for renal dialysis. Patients with renal failure cope poorly with major surgery and it is vital that the dialysis catheter tip is sited accurately in the pelvis if long-term catheter function is to be achieved. Laparoscopic placement of CAPD catheters may have potential advantages for renal patients by avoiding the morbidity of a laparotomy. Methods : A retrospective audit was performed of all CAPD catheters inserted at the John Hunter Hospital over a 2-year period. Results of laparoscopically inserted catheters and those placed at laparotomy were compared. Results : Sixty catheters were inserted, 30 laparoscopically and 30 at laparotomy. The mean operative time was 41 min in the laparoscopic patients and 57 min in the laparotomy patients (P= 0.0001). The mean total dose of narcotic administered postoperatively was significantly less in the laparoscopic group (5 mg vs 65 mg, P= 0.00002). There were three minor peri-operative complications in the laparoscopic group and seven peri-operative complications in the laparotomy group, three required reoperation and one resulted in the patient'death. There were no significant differences in the incidence of exit-site infection, catheter blockage, peritonitis, and overall catheter survival, although the laparoscopically placed catheters had been followed up for a shorter period (10 vs 16 months). Conclusions : This laparoscopic technique is safe and effective. Postoperative pain was less than for open placement. Laparoscopically placed catheters had a low incidence of peri-operative complications. Medium-term patency is similar to conventionally placed catheters. This procedure requires no additional equipment to that available for laparoscopic cholecystectomy and takes less time than the open operation.     

Adiponectin, leptin and thyroid hormones in patients with chronic renal failure and on renal replacement therapy: are they related?

BACKGROUND: Renal function affects thyroid function and adipocytokines in many ways. We aimed to assess the adipocytokines adiponectin and leptin in relation to thyroid function in patients with chronic renal failure treated conservatively, in haemodialysed patients and in kidney allograft recipients. METHODS: The study was performed on 33 patients with chronic renal failure, 64 haemodialysed patients, 54 kidney allograft recipients and 38 healthy volunteers. Thyroid volume was estimated sonographically, thyroid hormones were determined by Micropartide Enzyme Immunoassay (MEIA), and serum adiponectin and leptin were assessed by radioimmunoassay. RESULTS: Serum thyroid-stimulating hormone (TSH), free T4 and free T3 were within the normal range. Adiponectin correlated significantly with free T3, haematocrit, haemoglobin, platelet count, body mass index (BMI) and urea in kidney allograft recipients. In haemodialysed patients, adiponectin correlated with free T4 and TSH, whereas leptin correlated with free T3. Multiple regression analysis showed that adiponectin was independently related only to the serum concentration of free T3 and urea in kidney transplant recipients and to free T4 and adequacy of dialysis in haemodialysed patients. In univariate analysis in patients with chronic renal failure, adiponectin correlated with free T3 and platelet count, and in healthy volunteers adiponectin correlated only with free T3 and triglycerides, and leptin correlated with BMI. CONCLUSIONS: We described novel relationships between adiponectin and thyroid hormones in patients with kidney diseases. However, possible pre-existing thyroid dysfunction prior to transplantation (during dialysis therapy) and immunosuppression after transplantation make all these findings relatively complex. Therefore, the relationships between adiponectin and the thyroid axis in patients with chronic renal failure, in haemodialysed subjects or in kidney transplant recipients merit additional studies.