[en] To improve TIPS patency by inserting polytetrafluoroethylene(PTFE)-covered spiral Z-stents in swine. Using PTFE covered spiral Z-stents lined with TIPS tract from the portal vein wall to the inferior vena caval orifice of the right hepatic vein,TIPS were created in seven young swine. The animals were followed up by portal venography and venous pressure was measured at two-week intervals for 12 weeks or until shunt occlusion. After sacrifice, resected liver was examined grossly and prepared for histology. The fifty percent patency rate using lifetime analysis was 83% at 4 weeks, 33% at 6 weeks, 17% at 8 weeks and 0% at 10 weeks. Venography demonstrated that the predominant sites of stenosis were the portal vein wall(2/6), the TIPS tract(2/6) and the IVC orifice of the right hepatic vein(2/6). One swine died 11 days after TIPS due to illness, and bile leaks were discovered in two of the seven animals. Histologic study demonstrated intimal hyperplasia in either the portal vein wall or the end of the stent at which the IVC orifice was located as well as thrombus and pseudointimal hyperplasia in the TIPS tract. PTFE-covered spiral Z-stents were easily placed and significantly improved TIPS patency