Purinya B, Kasyanov V, Volkolakov J, Latsis R, Tetere G
Laboratory of Biomechanics, Riga Technical University, Latvia.
J Biomech. 1994 Jan;27(1):1-11. doi: 10.1016/0021-9290(94)90027-2.
Porcine bioprosthesis were treated with 0.625% glutaraldehyde and stabilized under changing pressure from 4 to 30 mmHg. Bovine pericardium and 12 biovalves (of age between 14 days and 80 months) after implantation in the human body were investigated (7 porcine PB and 5 pericardial bioprosthesis--PCB). Circumferential and radial strips from porcine aortic valve leaflets, bovine pericardium and bioprosthetic leaflets were studied in light, transmitting and scanning electron microscopy. Uniaxial load tests were carried out to examine the deformability and strength of these tissues. Microscopic examination of the biovalves revealed that the PB and PCB tissue retained its original architecture, but with alterations in detailed structure. The collagen bundles stuck together with vacuolization between them. There were some areas of the collagen structure fragmentation which could lead to complete necrosis. Eighty months after implantation in patients, the PCB became more extensible and its ultimate strain increases 2.5 times. Ultimate stress decreases in the radial direction from 9.43 to 2.88 MPa, and in the circumferential direction from 9.43 to 6.44 MPa. Forty-eight months after implantation, PB tissue's ultimate stress decreases in the circumferential direction from 4.06 to 1.99 MPa. At the same time ultimate strain increases from 13 to 22%. This study is to improve the methods of tissue stabilization in 0.625% glutaraldehyde solution for the first 48 h at cyclic, changing construction of biovalves soft supporting stent after 48 h.
猪生物假体用0.625%的戊二醛处理，并在4至30 mmHg的变化压力下进行稳定处理。对植入人体后的牛心包和12个生物瓣膜（年龄在14天至80个月之间）进行了研究（7个猪生物瓣膜和5个心包生物假体——PCB）。对猪主动脉瓣叶、牛心包和生物假体瓣叶的周向和径向条带进行了光镜、透射电镜和扫描电镜研究。进行单轴载荷试验以检查这些组织的可变形性和强度。对生物瓣膜的显微镜检查显示，猪生物瓣膜和PCB组织保留了其原始结构，但详细结构有所改变。胶原束粘在一起，其间有空泡化。胶原结构存在一些碎片化区域，可能导致完全坏死。在患者体内植入80个月后，PCB变得更具延展性，其极限应变增加了2.5倍。极限应力在径向方向上从9.43 MPa降至2.88 MPa，在周向方向上从9.43 MPa降至6.44 MPa。植入48个月后，猪生物瓣膜组织的极限应力在周向方向上从4.06 MPa降至1.99 MPa。与此同时，极限应变从13%增加到22%。本研究旨在改进在0.625%戊二醛溶液中最初48小时的组织稳定方法，以及在48小时后对生物瓣膜软支撑支架进行循环变化结构处理。
