Fundamental study on small-diameter vascular graft incorporated with new design concepts of mechanical compatibility and tissue morphogenesis.

为了减少自体动脉与人工动脉在整个压力区的顺应性不匹配，我们提出了一种同轴双管人工动脉，它由一个增强顺应性的内管和一个较低顺应性的外管组成，这两个管都是使用控制良好的多微孔分段聚氨酯（SPU）膜制造的。将内管与外管同轴组装成双管移植物。首先，以犬颈总动脉为靶动脉，测量其压力-直径（P-D）关系，并将其作为靶动脉。两个决定性变量，压力引起的扩张性的每一个管和管间的空间距离，定义和制定在几个模型的同轴双管SPU移植物，其中有不同的管间的空间距离，血管密度和壁厚。内胎的膨胀性决定了低压区的膨胀性 ...更多信息 ns，这是调整使用壁厚和微孔。较薄的膜具有较高的孔隙率导致高的压力诱导的膨胀性。另一方面，在高压区域中的低压诱导的可膨胀性使用具有较厚壁和较低微孔性的外管来实现。利用理论值，通过管间距确定了低压区到高压区的转变点。在此基础上，我们提出了一种与犬颈动脉具有良好顺应性的同轴双管移植物的原型模型，该移植物通过将高顺应性的内管（涂有与肝素混合的光反应明胶）插入到低顺应性的外管（涂有光反应亲水聚合物）中来同轴组装。将28个同轴双管顺应性移植物以端对端方式植入犬颈总动脉长达12个月。总通畅率为85.7%（24 / 27）。并且没有观察到破裂或囊状形成。新生动脉壁由血管瘤向管腔表面和内管腔内重建，早期以肌成纤维细胞和炎性细胞为主，晚期以富含胶原的细胞外基质为主。用亲水性聚合物涂层防止外管表面上的粘附。植入1个月后，模型的“J”型曲线基本保持不变，但后期SPU膜的组织长入、组织粘附和生物降解等因素对植入的同轴双管型人工血管的力学性能产生影响。少

In order to minimize compliance mismatch between native artery and arterial graft prosthesis over the entire pressure regions, we proposed a coaxial double tubular artificial graft, which consists of an enhanced compliant inner tube and a less compliant outer tube, both of wihch were fabricated using well-controlled multiply micropored segmented polyurethane (SPU) films. Double tubular grafts were coaxially assembled by inserting the inner tube into the outer tube.Firstly, the pressure-diameter (P-D) relationship of canine common carotid arteries, which exhibited a "J" curve, was determined as a targeted artery. Two determinant variables, the pressure-induced distensibility of each tube and the intertubular space distance, were defined and formulated in several models of coaxial double tubular SPU grafts, which had various intertubular space distances, micropore densities and wall thicknesses. Tire distensibility of the inner tube determined the distensibility in the low-pressure regio … More ns, which was adjusted using wall thickness and microporosity. Thinner films with higher porosities resulted in a high pressure-induced distensibility. On the other hand, a low pressure-induced distensibility in the high-pressure regions was realized using an outer tube with a thicker wall and lower microporosity. The transition point from low- to high-pressure regions was determined by the intertubuiar distance using the theoretical values. On the basis of these results, we presented a prototype model of a coaxial double tubular graft that exhibited well-matched compliance with canine carotid artery.The graft was coaxially assembled by inserting the high-compliant inner tube (coated with photoreactive gelatin mixed with heparin) into the less-compliant outer tube (coated with photoreactive hydrophilic polymer). Twenty-eight coaxial double-tubular compliant grafts were implanted into the canine common carotid arteries up to 12 months in end-to end fashion. The overall patency rate was 85.7% (24 / 27). and neither rupture nor aneurysmal formation was observed. The neoarterial wall was reconslructed form the anastomoses into the luminal surface and into the imer-tubular space of the double-tubular graft, mainly with the myofibroblasts and inflammatory cells in the early stage and collagen-rich extracellular matrices in the late stage of implantation. Adhesion was prevented on the surface of the outer tube with the hydrophilic polymer coating. Although the "J" curve of the implanted prototype model was preserved at 1 month-implantation, the tissue ingrowth, the tissue-adhesion and the biodegradation of the SPU films were clarified to affect the mechanical property of the implanted coaxial double-tubular graft in the late stage. Less