Debra S. Chong, Ramesh Batra, Ben Lindsey, Alex M. Seifalian, George Hamilton
Department of Surgery and Interventional Science, Royal Free Hospital, London, UK, London, United Kingdom.
OBJECTIVES: The compliance, non-thrombogenicity and biodurability of POSS-PCU graft has been reported in in vitro studies. In vivo studies reveal high patency rate at 9 months (to be published data). A further application of this graft could be in vascular access, where currently PTFE (polytetrafluoroethylene) is the prosthetic conduit of choice. Resilience to puncture with large gauge (15-17 Ch) dialysis needles is vital for a graft being used as vascular access conduit. We performed ex-vivo tests to compare this specific property between POSS-PCU and PTFE grafts.
METHODS: A flow circuit containing human blood was used to mimic the arterial system using a phantom pulse generator. Lengths of test graft (8-10cm) were connected to the circuit and submerged in a 2-litre isotonic (0.9%) saline bath. The pulse generator was set at 80 beats/ minute. A single 15 Ch dialysis needle was used to puncture the full wall thickness of the graft. Samples of saline bath were taken at distances of 2.5 cm and 5 cm from the puncture site at 5-minute intervals, for a period of 30 minutes. The concentration of red blood cells (cells/ litre) were calculated at each time and location point for each graft being compared.
RESULTS: Macroscopically, the POSS-PCU graft “self-sealed” within seconds after the initial puncture whereas the PTFE puncture site had not sealed by 30 minutes. There was about 15 times lower concentration of red blood cells seen in the samples with POSS-PCU graft compared with PTFE at both 2.5 and 5 cm. POSS-PCU as compared to PTFE leaked less red blood cells over a total of 30 minutes. The results were statistically significant (p<0.0001) when analyzed with the Friedman test.
CONCLUSIONS: A significantly better resilience to needle puncture of POSS-PCU over PTFE graft suggests an improved alternative for vascular access surgery. This may result in safer, earlier needling and possibly also reflect better long-term durability.
AUTHOR DISCLOSURES: R. Batra, Nothing to disclose; D. S. Chong, Nothing to disclose; G. Hamilton, Nothing to disclose; B. Lindsey, Nothing to disclose; A. M. Seifalian, Nothing to disclose.
Posted April 2012