Bagno Andrea, Aguiari Paola, Fiorese Michele, Iop Laura, Spina Michele, Gerosa Gino
Department of Industrial Engineering, University of Padova, Padova, Italy.
Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Padova, Italy.
Artif Organs. 2018 May;42(5):540-548. doi: 10.1111/aor.13065. Epub 2017 Dec 27.
Bovine and porcine pericardia are currently used for manufacturing prosthetic heart valves: their design has become an increasingly important area of investigation in parallel with progressively expanding indications for the transcutaneous approach to heart valves replacement. Before being cut and shaped, pericardial tissues are expected to be properly characterized. Actually, the mechanical assessment of these biomaterials lacks standardized protocols. In particular, the role of preconditioning for achieving a constant mechanical response of tissue samples is still controversial. In the present work, the mechanical response to uniaxial load of native bovine and porcine pericardia, with and without preconditioning was assessed; moreover, the mechanical behavior of pericardia was investigated and explained. It was demonstrated that: (i) pericardial tissue samples hold memory of the loading history but just within the extent of the deformation applied; (ii) the behavior of native bovine and porcine pericardia in response to load is explained by a mechanism based on the additive recruitment of collagen fibers; (iii) the current concept that plasticity is absent in pericardium has to be at least in part reconsidered.
目前，牛心包和猪心包被用于制造人工心脏瓣膜：随着经皮心脏瓣膜置换术适应症的逐渐扩大，其设计已成为一个越来越重要的研究领域。在切割和塑形之前，心包组织需要得到恰当的表征。实际上，对这些生物材料的力学评估缺乏标准化方案。特别是，预处理对实现组织样本恒定力学响应的作用仍存在争议。在本研究中，评估了天然牛心包和猪心包在有或无预处理情况下对单轴载荷的力学响应；此外，还对心包的力学行为进行了研究和解释。结果表明：（i）心包组织样本保留了加载历史的记忆，但仅在施加变形的范围内；（ii）天然牛心包和猪心包对载荷的响应行为可通过基于胶原纤维累加募集的机制来解释；（iii）目前认为心包不存在可塑性的概念至少部分需要重新考虑。
