García Páez J M, Carrera A, Herrero E J, Millán I, Rocha A, Cordón A, Sainz N, Mendez J, Castillo-Olivares J L
Clínica Puerta de Hierro de Madrid, Servicio de Cirugía Experimental and Medicina Preventiva, Spain.
J Biomater Appl. 2001 Jul;16(1):68-90. doi: 10.1106/3JXM-UTPN-PXTG-72DT.
Using a hydraulic stress simulator, the mechanical behavior of the porcine pericardium used in the construction of cardiac valve leaflets was characterized following the same procedure employed with calf pericardium in Part 1 of this study. One hundred fifty pairs of tissue samples were subjected to tensile testing to rupture. One of the two samples from each of 120 pairs (four series of 30 pairs each) was saturated with commercially available threads made of nylon, silk, Prolene or Gore-Tex, while the other sample in each of these pairs was left unsewn. The remaining 30 pairs were employed as controls in which neither of the two samples was subjected to suturing. The sutured tissue samples showed a significant decrease in tensile strength at rupture (range: 11.61 to 21.22 MPa) when compared with unsutured samples (range: 50.80 to 89.45 MPa; p < 0.01). When these results were compared with their equivalent in calf pericardium, no significant differences were observed (the mean values at rupture in calf pericardium ranged between 211.61 MPa and 26.04 MPa). Again, the application of morphological and mechanical selection criteria to ensure the homogeneity of the samples provided excellent fit with respect to the stress/strain curves. The interaction of the different suture materials with the pericardial tissue was also assessed by comparing the mechanical behavior of the sutured samples with that of the control samples. At the working stress of a cardiac valve leaflet, 0.250 MPa, samples sewn with Gore-Tex were found to show the least difference in behavior with respect to the controls, indicating that this material presented the lowest degree of interaction with the pericardium. In conclusion, the suture clearly has deleterious effects on the resistance of both calf and porcine pericardium, which showed no statistically significant differences in terms of resistance to rupture when their respective sutured or unsutured samples were compared, except in the case of porcine pericardium sewn with silk, which presented lower resistance to rupture in all the zones studied. These findings suggest that the hypothesis that porcine pericardium is less resistant is erroneous. The Gore-Tex suture also presented a lower degree of interaction with the porcine pericardium, with values similar to the working stress of a cardiac valve leaflet. This methodology and the results should be evaluated in dynamic studies, such as fatigue testing, that not only confirm the resistance of the material but establish the durability of the samples being assayed.
使用液压应力模拟器，按照本研究第1部分中对小牛心包所采用的相同程序，对用于构建心脏瓣膜小叶的猪心包的力学行为进行了表征。150对组织样本进行拉伸测试直至破裂。来自120对样本（共四个系列，每个系列30对）中的每一对的两个样本中的一个，用尼龙、丝线、普理灵或戈尔特斯制成的市售缝线进行缝合，而这些对中的另一对样本中的另一个则不进行缝合。其余30对样本用作对照，其中两个样本均不进行缝合。与未缝合的样本（范围为50.80至89.45MPa；p<0.01）相比，缝合后的组织样本在破裂时的拉伸强度显著降低（范围为11.61至21.22MPa）。当将这些结果与其在小牛心包中的等效结果进行比较时，未观察到显著差异（小牛心包破裂时的平均值在211.61MPa和26.04MPa之间）。同样，应用形态学和力学选择标准以确保样本的同质性，使得应力/应变曲线具有良好的拟合度。还通过比较缝合样本与对照样本的力学行为，评估了不同缝合材料与心包组织的相互作用。在心脏瓣膜小叶的工作应力0.250MPa下，发现用戈尔特斯缝合的样本与对照样本相比，行为差异最小，这表明该材料与心包的相互作用程度最低。总之，缝合显然对小牛和猪心包的抗性均有有害影响，当比较它们各自缝合或未缝合的样本时，在破裂抗性方面未显示出统计学上的显著差异，但用丝线缝合的猪心包除外，在所有研究区域中其破裂抗性均较低。这些发现表明，认为猪心包抗性较低的假设是错误的。戈尔特斯缝线与猪心包的相互作用程度也较低，其值与心脏瓣膜小叶的工作应力相似。这种方法和结果应在动态研究中进行评估，如疲劳测试，这不仅能确认材料的抗性，还能确定所检测样本的耐久性。
