Loss of Stability in a Small-Caliber Vascular Graft

Abstract

The aim of the study is to develop and test a numerical method for assessing a loss of stability in a polymer vascular graft in response to a longitudinal dynamic high-speed load. Materials and Methods. A small-caliber vascular graft made by electrospinning from the composite mixture of polyhydroxybutyrate/ valerate and polycaprolactone polymers was studied. Numerical methods (finite element method) and prototype test (uniaxial tension) were used to assess the loading speeds and the resulting loss of stability, which are critical for small-caliber vascular grafts. Results. The mechanical testing of a vascular graft prototype allowed us to determine its response to quasi-static load. We also showed that the high-speed longitudinal dynamic loads significantly reduced the load-carrying capacity of the structure. This and related effects are suggested to be potential causes of the vessel lumen collapse resulted from irreversible loss of stability. Conclusion. The impact of a dynamic load significantly weakens the vascular graft and affects its elastic and deformation characteristics, leading to the premature critical deformation and eventual occlusion. Therefore, the quality of such products can be improved by a preliminary prognostic work and reinforcement of their construction.