Biomechanics Section, Mechanical Engineering Department, KU Leuven, Celestijnenlaan 300 box 2419, 3001, Leuven, Belgium.
Cardiac Surgery, Department of Cardiovascular Sciences, KU Leuven, UZ Herestraat 49 box 276, 3000, Leuven, Belgium.
Biomech Model Mechanobiol. 2023 Oct;22(5):1555-1568. doi: 10.1007/s10237-023-01694-6. Epub 2023 Feb 10.
The pulmonary autograft in the Ross procedure, where the aortic valve is replaced by the patient's own pulmonary valve, is prone to failure due to dilatation. This is likely caused by tissue degradation and maladaptation, triggered by the higher experienced mechanical loads in aortic position. In order to further grasp the causes of dilatation, this study presents a model for tissue growth and remodeling of the pulmonary autograft, using the homogenized constrained mixture theory and equations for immuno- and mechano-mediated mass turnover. The model outcomes, compared to experimental data from an animal model of the pulmonary autograft in aortic position, show that inflammation likely plays an important role in the mass turnover of the tissue constituents and therefore in the autograft dilatation over time. We show a better match and prediction of long-term outcomes assuming immuno-mediated mass turnover, and show that there is no linear correlation between the stress-state of the material and mass production. Therefore, not only mechanobiological homeostatic adaption should be taken into account in the development of growth and remodeling models for arterial tissue in similar applications, but also inflammatory processes.
在 Ross 手术中，使用患者自身的肺动脉瓣替换主动脉瓣，其中的肺动脉移植物由于扩张而容易发生故障。这可能是由于组织降解和适应性不良引起的，原因是在主动脉位置经历了更高的机械负荷。为了进一步了解扩张的原因，本研究提出了一种肺动脉移植物组织生长和重塑的模型，使用均匀化约束混合理论和免疫及机械介导的质量转化方程。与主动脉位置肺动脉移植物动物模型的实验数据相比，模型结果表明炎症可能在组织成分的质量转化中起重要作用，因此随着时间的推移，移植物会发生扩张。我们假设免疫介导的质量转化可以更好地匹配和预测长期结果，并且表明材料的应力状态与物质生成之间没有线性相关性。因此，在为类似应用中的动脉组织开发生长和重塑模型时，不仅应考虑机械生物稳态适应，还应考虑炎症过程。
