An in Vitro Twist Fatigue Test of Fabric Stent-Grafts Supported by Z-Stents vs. Ringed Stents

Abstract

Whereas buckling can cause type III endoleaks, long-term twisting of a stent-graft was investigated here as a mechanism leading to type V endoleak or endotension. Two experimental device designs supported with Z-stents having strut angles of 35° or 45° were compared to a ringed control under accelerated twisting. Damage to each device was assessed and compared after different durations of twisting, with focus on damage that may allow leakage. Stent-grafts with 35° Z-stents had the most severe distortion and damage to the graft fabric. The 45° Z-stents caused less fabric damage. However, consistent stretching was still seen around the holes for sutures, which attach the stents to the graft fabric. Larger holes may become channels for fluid percolation through the wall. The ringed stent-graft had the least damage observed. Stent apexes with sharp angles appear to be responsible for major damage to the fabrics. Device manufacturers should consider stent apex angle when designing stent-grafts, and ensure their devices are resistant to twisting.

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“…[1][2][3][4][5] However, the optimal ancillary tools and the ideal stentgraft designs have not yet been identified. [6][7][8][9] For emergent traumatic aortic tears or ruptured aneurysms, treatment choices may be limited to what is available off-the-shelf.…”

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“…And subsequent short-and midterm clinical results were promising compared with those of open surgery [2]. However, not all long-term outcomes were fully satisfied [3,4]. us, further research is needed to reduce incidences of long-term complications.…”

Compliance Study of Endovascular Stent Grafts Incorporated with Polyester and Polyurethane Graft Materials in both Stented and Unstented Zones

“…However, stent-graft migration, endoleaks [3,4,5,6,7], and fatigue phenomenon [8,9,10,11,12] such as fraying of the yarns and holes in the fabric tubes may occur after surgery, resulting in a high risk of aneurysm rupture [6,13]; secondary interventions are required in approximately 15% to 20% of patients [14]. …”

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