TTK Chitra tilting disc heart valve model TC2: An assessment of fatigue life and durability

Abstract

Average age group of heart valve replacement in India and most of the Third World countries is below 30 years. Hence, the valve for such patients need to be designed to have a service life of 50 years or more which corresponds to 2000 million cycles of operation. The purpose of this study was to assess the structural performance of the TTK Chitra tilting disc heart valve model TC2 and thereby address its durability. The TC2 model tilting disc heart valves were assessed to evaluate the risks connected with potential structural failure modes. To be more specific, the studies covered the finite element analysis-based fatigue life prediction and accelerated durability testing of the tilting disc heart valves for nine different valve sizes. First, finite element analysis-based fatigue life prediction showed that all nine valve sizes were in the infinite life region. Second, accelerated durability test showed that all nine valve sizes remained functional for 400 million cycles under experimental conditions. The study ensures the continued function of TC2 model tilting disc heart valves over duration in excess of 50 years. The results imply that the TC2 model valve designs are structurally safe, reliable and durable.

The effect of decellularisation on the real time mechanical fatigue of porcine aortic heart valve roots

“…A critical step in translation of decellularised heart valve roots for use as replacement heart valves, is to have better understanding of in vitro durability and failure mechanisms due to the impact of cyclic physiological loading. Many studies [24,26,27,[43][44][45][46][47][48] have reported the fatigue and durability of replacement heart valves under accelerated cyclic loading conditions. The fatigue of conventional mechanical and bioprosthetic (glutaraldehyde fixed) replacement heart valves have been evaluated using the accelerated fatigue assessment method and showed similar fatigue in comparison to the fatigue of retrieved in vivo heart valves [47,48].…”

“…Many studies [24,26,27,[43][44][45][46][47][48] have reported the fatigue and durability of replacement heart valves under accelerated cyclic loading conditions. The fatigue of conventional mechanical and bioprosthetic (glutaraldehyde fixed) replacement heart valves have been evaluated using the accelerated fatigue assessment method and showed similar fatigue in comparison to the fatigue of retrieved in vivo heart valves [47,48]. However, for heart valves comprising of leaflets with a greater visco-elastic response, such as polymer materials and (non-glutaraldehyde fixed) biological tissue the fatigue mechanism was not predictive of in vivo wear mechanisms [24][25][26].…”