Physical properties of polytetrafluoroethylene bypass material after balloon dilation.
OBJECTIVE
To evaluate the performance characteristics of 3-mm and 6-mm polytetrafluoroethylene (PTFE) grafts after radial dilation comparable to their use in endovascular applications.


METHODS
PTFE conduits with 3- and 6-mm internal diameters were radially expanded three, four, and five times the original diameter with angioplasty balloons. Internal diameter, outer diameter, wall thickness, radial and longitudinal shortening, internodal distance, radial and longitudinal tensile strength, water entry pressure, and suture retention strength were measured and compared with nondilated samples.


RESULTS
After dilation, the diameter of the 3- and 6-mm PTFE conduits recoiled approximately 23%, and the length shortened insignificantly. The wall thickness decreased to approximately half, and the internodal distance did not change. Porosity decreased as evidenced by a slight increase in the water entry pressure. Longitudinal and radial tensile strength, as well as suture retention strength, were decreased.


CONCLUSIONS
Dilation of PTFE graft, as used in endovascular applications, by three to five times results in moderate elastic recoil. This needs to be taken into consideration if the material is used without a supporting inner stent. Because of the absence of significant change in porosity, perigraft fluid collections are not likely to occur. Significant decrease in suture retention strength after dilation poses a risk of localized tear and potential procedure failure.
Cardiovascular and Interventional Radiology Section, University of Texas Health Science Center at San Antonio 78284-7800, USA.
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Palmaz
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Sprague
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Palmaz
D000800:Angioplasty, Balloon / Q000295:instrumentation; D001807:Blood Vessel Prosthesis; D002404:Catheterization / Q000295:instrumentation; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004548:Elasticity; D004867:Equipment Design; D004868:Equipment Failure; D008422:Materials Testing; D011138:Polytetrafluoroethylene / Q000737:chemistry*; D016062:Porosity; D011312:Pressure; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012307:Risk Factors; D015607:Stents; D013314:Stress, Mechanical; D013499:Surface Properties; D013537:Sutures; D013718:Tensile Strength; D014867:Water
D014867:Water; D011138:Polytetrafluoroethylene