Radial force of thoracic stent graft: an experimental study of mechanical properties and potential clinical implications

Relevance. Thoracic endovascular aortic repair (TEVAR) is rapidly evolving, with expanding clinical indications. These include Stanford type B aortic dissection, aortic arch pathology (non-A, non-B type) managed with endovascular and hybrid techniques (including debranching), as well as aneurysms, penetrating atherosclerotic ulcers, and thoracic aortic ruptures.
Objective. To investigate the mechanical properties of different types of stent grafts and to assess their potential clinical implications.
Materials and Methods. The study included two types of thoracic endografts available on the available commercially medical device market, differing by graft material: polytetrafluoroethylene (PTFE) and polyester. Considering that oversizing (i.e., selecting an endograft diameter exceeding that of the native vessel) is used during procedural planning to ensure sealing, an experimental assessment of the degree of radial compression of stent grafts was performed using a mechanical press. The force required to deform the devices was evaluated as an indirect indicator of radial force on the aortic wall.
Results. Minimal radial force values were observed in the proximal uncovered segments of the endografts, followed by an increase toward the distal direction within the covered portion. The radial force values were recorded in the distal segments of the stent graft with monofilament polyester covering, whereas the lowest values were observed in the proximal region of the PTFE-covered device.
Conclusion. Radial load in the covered segments of the stent graft exceeds that in the uncovered proximal portion. This finding supports the need to position the proximal part of the endograft within the least diseased segment of the aorta to reduce the risk of complications.

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