Pentosanpolysulfate coating of silicone reduces encrustation

Background and Purpose: A significant problem associated with catheterizati on in the urinary tract is the encrustation of the catheter materials. One approach to reducing encrustation is to alter the surface properties of the catheters, We evaluated the effectiveness of coating with pentosanpolysulf ate (PPS), a semisynthetic polysaccharide similar to heparin, in reducing e ncrustation and the foreign-body inflammatory response to silicone stents i n the bladders of male New Zealand White rabbits, Materials and Methods: Sixteen rabbits were divided into three groups to re ceive placement in their bladders of uncoated (N = 7), PPS-coated (N = 7), or sham matrix-processed silicone rings (N = 2) via open cystotomy, After 5 0 days of maintenance on normal food and water, all rabbits were sacrificed , and the air-dried, unfixed silicone ring surfaces were examined by scanni ng electron microscopy, Bladders and remaining silicone rings were removed and preserved separately. Silicone rings, cleaned of all encrustation, were stained with toluidene blue to determine the presence or absence of PPS co ating on the surface. Results: Histologic examination revealed normal tissue in bladder sections exposed to coated silicone rings and an inflammatory response in sections f rom bladders having uncoated silicone rings, Coating with PPS was associate d with an eightfold reduction in the amount of encrustation of silicone and a marked reduction in the inflammatory response of the bladder wall to the foreign body, Conclusions: A PPS coating may be useful in reducing the encrustation of lo ng-term indwelling silicone stents or catheters in the human urinary tract.