Moczar M, Houël R, Ginat M, Clérin V, Wheeldon D, Loisance D
Service de Chirurgie Thoracique et Cardiovasculaire, CNRS UPRES A 7054 - Association Claude Bernard, Hôpital Henri Mondor, Créteil, France.
J Heart Valve Dis. 2000 Jan;9(1):88-95; discussion 95-6.
Porcine, specially manufactured bioprosthetic valves regulate blood flow from the left ventricle to pump sac (inflow valve) and from the pump to the aorta (outflow valve) in a wearable, electrically powered left ventricular support system (LVAS, Novacor). The increased need for long-term circulatory assistance requires information on the evolution of these valves when exposed to specific hemodynamic conditions and inflammatory reactions in the device. The study aim was to examine structural changes in valves from explanted LVASs.
Thirteen patients (11 males, two females; mean age 42 years (range: 17-64 years) were supported for a mean of 285 days (range: 37-1,293 days) with LVAS. Histologic sections from explanted inflow and outflow valves were studied immunohistochemically using peroxidase-labeled antibodies and avidin-biotinylated peroxidase complex for detection.
In the macroscopically normal inflow valves (11/13), the outflow surface (facing the pump) was covered with a discontinuous deposit of fibrin, macrophages and granulocyte elastase. Fibrinogen, IgG, complement proteins C1q and C3 had infiltrated the extracellular matrix (ECM) between 37 and 1,293 days. The crevices were enlarged during circulatory support, and fibrinogen/fibrin insudations were detected in the spongiosa. The collagen layers in the fibrosa were disrupted after 293 days, and eroded on the inflow surface in the ventricularis after 1,293 days. In a deteriorated valve from a patient with endocarditis, Gram-positive bacteria and metalloproteinases were concentrated in the ECM. In the macroscopically normal (11/13) outflow valves, fibrin and complement proteins had penetrated the ECM from the inflow side (facing the pump), while macrophages and granulocytes were localized mainly on the outflow surface. IgG and complement proteins were detected on and beneath the cusp surface up to 200 days and covered the disrupted ECM as implant time progressed.
Structural changes appear to progress more rapidly in the inflow than in the outflow of bioprosthetic valves. This difference indicates that the effects of biological factors are modulated by mechanical stress.
在一种可穿戴的电动左心室辅助系统（LVAS，诺瓦科尔）中，特制的猪生物瓣膜调节着从左心室到泵囊（流入瓣膜）以及从泵到主动脉（流出瓣膜）的血流。长期循环辅助需求的增加，需要了解这些瓣膜在特定血流动力学条件和装置中的炎症反应下的演变情况。本研究的目的是检查取出的LVAS瓣膜的结构变化。
13例患者（11例男性，2例女性；平均年龄42岁（范围：17 - 64岁））接受LVAS辅助治疗，平均时间为285天（范围：37 - 1293天）。对取出的流入和流出瓣膜的组织切片进行免疫组织化学研究，使用过氧化物酶标记抗体和抗生物素蛋白 - 生物素化过氧化物酶复合物进行检测。
在宏观正常的流入瓣膜（11/13）中，流出表面（面向泵）覆盖有不连续的纤维蛋白、巨噬细胞和粒细胞弹性蛋白酶沉积物。在37至1293天期间，纤维蛋白原、IgG、补体蛋白C1q和C3渗入细胞外基质（ECM）。在循环支持期间，缝隙扩大，在海绵层中检测到纤维蛋白原/纤维蛋白渗出。293天后，纤维层中的胶原层被破坏，1293天后，心室层的流入表面被侵蚀。在一名患有心内膜炎患者的 deteriorated瓣膜中，革兰氏阳性菌和金属蛋白酶集中在ECM中。在宏观正常的（11/13）流出瓣膜中，纤维蛋白和补体蛋白从流入侧（面向泵）渗入ECM，而巨噬细胞和粒细胞主要位于流出表面。在瓣叶表面及其下方直至200天均检测到IgG和补体蛋白，随着植入时间的延长，它们覆盖了受损的ECM。
生物瓣膜流入侧的结构变化似乎比流出侧进展更快。这种差异表明生物因素的作用受到机械应力的调节。
