Ultrathin-wall vascular grafts for endovascular surgery

Abstract

 The purposes of this study were to develop ultrathin-wall grafts suitable for stent-graft procedures and to examine the feasibility of the grafts from the physical point of view. We fabricated ultrathin-wall grafts with a wall thickness of 42 to 137 μm, using 50 denier polyester threads consisting of 72 polyester monofilaments. We studied the following physical properties of the ultrathin wall: the surface structure of the grafts, the longitudinal tensile strength of the grafts, the water permeability of the grafts, and the size of introducers through which the stent grafts can pass. In ultrathin-wall grafts with a wall thickness of 75 μm or more, a regular surface structure with zero planimetric porosity was recognized. In those with a thickness less than 64 μm, the porosity increased as the wall thickness decreased. The longitudinal tensile strengths of the 75 μm and 64 μm grafts were 13.1 ± 0.9 and 9.5 ± 0.9 kg, respectively. The water permeability of the 75-μm grafts was 380 ml/min, and that of the thinner grafts increased as the wall thickness decreased. Stents with a diameter of 40 mm covered with the ultrathin-wall grafts could pass through introducers with an inner diameter of 18 French. We conclude that the newly developed ultrathin-wall grafts are physiologically suitable for endovascular surgery.