Design and mechanical behaviors of sutureless prototype composite nitinol stent-grafts

Abstract

The stent-graft has always been a key device in endovascular treatments. However, most stents are integrated with graft by sutures, which may fracture or untie, leading to implant failure. This study reports a new sutureless composite stent-graft fabricated by braiding technology, which can combine various materials. The proposed sutureless braided stent-graft was constructed by incorporating bare/covered nitinol (NiTi) yarns into a polyethylene terephthalate multifilament at specific distributions. This technique generates a structure with alternately arranged metal and polymeric sections that equip the stent-graft with structural support and flexibility, respectively. The results showed significantly improved biomechanical performance (radial compression, bending and torsion resistance) of the stent-graft with covered NiTi yarns compared to bare NiTi yarns. This research presents important clinical implications in stent-graft manufacture and provides further study with an innovative stent-graft design.

The Technological Advancement to Engineer Next‐Generation Stent‐Grafts: Design, Material, and Fabrication Techniques

“…(iii) SEM image of ePTFE for node-fibril microstructure representation (scale bar: 10 μm); [41] b) Schematic of the braiding process (blue line denotes PET fibers and red line denotes covered NiTi yarns), [82] and fabricated SGs with different parameters. [81] Left: Reproduced with permission. [82] Copyright 2018, Elsevier Ltd., Right: Reproduced with permission.…”

“…[82] Copyright 2018, Elsevier Ltd., Right: Reproduced with permission. [81] Copyright 2017, SAGE Publications. c) Production of the small caliber electrospun SG and SEM image of the graft (scale bar:10 μm).…”

“…The low porosity in the braided structure can play the shielding role of the SG without the need for a graft cover. [81,82] Due to the increased stent stiffness (radial and longitudinal), host artery hemodynamics can be negatively influenced by the noncompliant behavior of the implanted region, resulting in an overall pressure drop and an increase in pulse-wave velocity. [50] The concept of a braided stent entered a new era with the commercialization of the multilayer flow modulator (MFM; Cardiatis, Isnes, Belgium), bringing a new paradigm and shifting the focus of treatment from traditional aneurysm exclusion (physical barrier) to reconstruction of the parent vessel (functional barrier).…”

“…The low porosity in the braided structure can play the shielding role of the SG without the need for a graft cover. [ 81,82 ] Due to the increased stent stiffness (radial and longitudinal), host artery hemodynamics can be negatively influenced by the non‐compliant behavior of the implanted region, resulting in an overall pressure drop and an increase in pulse‐wave velocity. [ 50 ]…”

“…Left: Reproduced with permission [82]. Copyright 2018, Elsevier Ltd., Right: Reproduced with permission [81]. Copyright 2017, SAGE Publications.…”