Dilatation of stent-grafts by luminal pressures: experimental evaluation of polytetrafluoroethylene (PTFE) and woven polyester grafts

Purpose: To evaluate the effect on dilatation of three types of covering ma terials used for endovascular stent-grafts. Methods: Stent-grafts with three types of covering material [0.1-mm polytet rafluoroethylene (PTFE), 0.2-mm PTFE, and 0.15-mm woven polyester] were pla ced in a fluid circuit. For the pulsatile pressure test, the luminal pressu re of 190/ 130 mmHg was loaded up to 300,000 pulses. For the static pressur e test, the luminal pressure was increased from 50 to 300 mmHg at 50-mmHg i ncrements. The percent of dilation of each stent-graft was compared. Results: The 0.1-mm PTFE stent-graft was significantly more dilated than th e 0.2-mm PTFE and the 0.15-mm woven polyester stent-graft (p < 0.005) in bo th examinations. There was no significant difference between the 0.2-mm PTF E and the 0.15-mm woven polyester stent-grafts. The dilatation of the 0.1-m m PTFE stent-graft was irreversible. Conclusion: The 0.15-mm woven polyester and the 0.2-mm PTFE stent-grafts ma y be preferable to the 0.1-mm PTFE stent-graft with regard to dilatation an d deformity.