A three-dimensional mechanical analysis of a stentless fibre-reinforced aortic valve prosthesis

Failure of bioprosthetic and synthetic three-leaflet valves has been shown to occur as a consequence of high tensile and bonding stresses, acting on t he leaflets during opening and closing. Moreover: in the stented prostheses , whether synthetic or biological, the absence of contraction of the aortic base, due to the rigid stent, causes the leaflets to be subjected to an un physiological degree of flexure, which is related to calcification. It is s hown that the absence of the stent, which gives a flexible aortic base and leaflet attachment, and leaflet fibre-reinforcement result in reduced stres ses in the weaker parts of the leaflets in their closed configuration. It i s postulated that this leads to a decrease of tears and perforations, which may result in a improved long-term behaviour. The effect of a flexible lea flet attachment and aortic base of a synthetic valve is investigated with a finite element model. Different fibre-reinforced structures are analysed w ith respect to the stresses that are likely to contribute to the failure of fibre-reinforced prostheses and compared with the results obtained for a s tented prosthesis. Results show that for the stentless models a reduction o f stresses up to 75% is obtained with respect to stented models with the sa me type of reinforcement. (C) 2000 Elsevier Science Ltd. All rights reserve d.