Mao J, Wang Y, Philippe E, Cianciulli T, Vesely I, How D, Bourget J-M, Germain L, Zhang Z, Guidoin R
Department of Surgery, Faculty of Medicine, Laval University and Axe médecine régénérative, centre de recherches du CHU, Ferdinand-Vandry Building, Room 4873, 2325, rue de l'Université, Québec G1V 0A6, QC, Canada.
Department of Cardiology, Hospital of the Government of the City of Buenos Aires "Prof. Cosme Argerich", Pi y Margall 780, C1155AHB Ciudad Autónoma de Buenos Aires, Argentina.
Morphologie. 2017 Jun;101(333):77-87. doi: 10.1016/j.morpho.2017.03.003. Epub 2017 Apr 22.
Cross-linking and anti-calcification of prosthetic heart valves have been continuously improved to prevent degeneration and calcification. However, non-calcific structural deteriorations such as cuspal dehiscences along the stent still require further analysis.
Based upon the previous analysis of an explanted valve after 7 years, a fresh commercial aortic valve was embedded in poly(methyl methacrylate) (PMMA) and cut into slices to ensure the detailed observation of the assembly and material structures. A pericardial patch embossed to provide the adequate shape of the cusps was investigated after paraffin embedding and appropriate staining. The microstructural damages that occurred during manufacturing process were identified and evaluated by light microscopy, polarized microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
The wavy collagen bundles, the key structure of the pericardium patch, were damaged to a great extent at suture sites along the stent and in the compressed areas around the stent post. The fixation of the embossed pericardium patch along the plots of the stent aggravated the microstructural modifications. The damages mainly appeared as the elimination of collagen bundle waviness and delamination between the bundles.
Considering the modes of failure of the explant, the damages to the collagen bundles may identify the vulnerable sites that play an important role in the cusp dehiscence of heart valve implants. Such information is important to the manufacturers. Recommendations to prevent in vivo cusp dehiscence can therefore be formulated.
人工心脏瓣膜的交联和抗钙化技术一直在不断改进，以防止其退化和钙化。然而，诸如沿支架的瓣叶裂开等非钙化结构退化仍需进一步分析。
基于对一个植入7年后取出的瓣膜的先前分析，将一个新的商用主动脉瓣嵌入聚甲基丙烯酸甲酯（PMMA）中并切成薄片，以确保对组件和材料结构进行详细观察。对一个经压花以提供合适瓣叶形状的心包补片进行石蜡包埋和适当染色后进行研究。通过光学显微镜、偏光显微镜、扫描电子显微镜（SEM）和透射电子显微镜（TEM）识别并评估制造过程中发生的微观结构损伤。
心包补片的关键结构——波浪状胶原束，在沿支架的缝合部位以及支架柱周围的压缩区域受到了很大程度的损伤。压花心包补片沿支架区域的固定加剧了微观结构的改变。损伤主要表现为胶原束波浪状的消失以及束间分层。
考虑到取出瓣膜的失效模式，胶原束的损伤可能确定了在心脏瓣膜植入物瓣叶裂开中起重要作用的易损部位。此类信息对制造商很重要。因此可以制定预防体内瓣叶裂开的建议。
