Fatigue Strength of a Novel Heart Valve Bioprosthesis

Abstract

The aim of the study was to evaluate fatigue strength of the supporting frame of the developed heart valve prosthesis designed for "valve-in-valve" reoperation of the incompetent prosthetic valve using finite element method.Materials and Methods. We evaluated fatigue strength of the supporting frames of experimental heart valve prosthesis, developed in the Research Institute for Complex Issues of Cardiovascular Diseases (Kemerovo), intended for redo-implantation. The study was carried out in two successive stages: modeling of supporting frame implantation for each valve dimension and assessment of fatigue strength. The pressure applied to the inner frame side in the region of commissural posts was used as a load.Results. During the implantation phase, a significant increase of mechanical stresses in the corners of the cells with the formation of elastic-plastic hinges was identified. Analysis of fatigue strength of the frame showed a minor level of alternating stress in a loadingunloading cycle: maximal values of 17.2 MPa were observed during hypertensive pressure for 19 mm size. Goodman factor and its distribution on the diagram allowed us to characterize the presence and location of the most critical points of the supporting frames. Maximal values of this parameter ranged from 0.46 to 0.72. Conclusion.The results demonstrated that the tested design of the supporting frame of the experimental heart valve prosthesis provides fatigue life not less than 10 9 cycles.

Computational Blood Flow Simulations in Cardiology and Cardiac Surgery

“…На сегодняшний день разработка искусственных клапанов сердца неразрывно связана с использованием компьютерного моделирования, в том числе и моделирования гидродинамики [1,2]. Основными критериями эффективности и качества данных устройств с точки зрения клинической кардиологии являются их гемодинамика, циклостойкость и реакция организма на имплантацию [3,4]. Стоит отметить, что такие изделия устанавливают на длительный срок: 5 -10 лет, а иногда и на всю жизнь пациента, поэтому сохранение вышеописанных характеристик должно быть заложено в дизайн уже на этапе проектирования, а оценка их изменения должна проводиться не только в краткосрочный, но и в отдаленный периоды.…”