US Patent 7914568 Biliary stent-graft

A stent-graft which is particularly useful for applications in biliary ducts. An expandable stent is provided with a covering of a material which is substantially impervious to body fluids and tissue ingrowth and has an increased resistance to bacterial attachment due to its lack of porosity and reduced surface texture. A preferred covering is porous PTFE film rendered substantially non-porous by a coating of a polymeric material such as FEP. The resulting stent has a thin wall for minimum pre-deployment diameter and for minimum interference with fluid flow through the device after implantation. It has good flexibility, allowing its use in curved ducts.