Salzmann D L, Yee D C, Roach D J, Berman S S, Williams S K
Department of Surgery, University of Arizona, Tucson 85724, USA.
J Biomed Mater Res. 1997 Sep 15;36(4):498-507. doi: 10.1002/(sici)1097-4636(19970915)36:4<498::aid-jbm7>3.0.co;2-9.
The search for less invasive treatments for cardiovascular disease has lead to the development of endovascular stent grafts, metallic and alloy stents surrounded by prosthetic vascular graft material. Introduced intravascularly, the deployment of stent grafts requires balloon dilatation of the device which results in expansion of the stent along with the vascular graft material. We hypothesized that balloon dilatation of stent grafts would alter the physical structure of the prosthetic graft material. In this study, noncompliant angioplasty balloons were used to dilate expanded polytetrafluoroethylene (ePTFE), a material commonly used for endovascular stent-graft technology. The maximal outer diameter (inflated balloon within the lumen) and the recoiled outer diameter (balloon removed) of two types of ePTFE, 3-mm inside diameter (i.d.) thin wall (30-micron internodal distance) and 4-mm i.d. standard wall (30-micron internodal distance), were measured to compare material recoil. Following balloon dilatation, ePTFE samples were prepared for scanning electron microscopic examination and the following parameters were measured: wall thickness, internodal distance, nodal width, interfiber distance, and fiber width. Following primary dilatation, both types of ePTFE recoiled approximately 20% regardless of inflated balloon diameter. However, following eight repetitive balloon dilatations, recoil decreased to approximately 10%. Scanning electron microscopic analysis revealed variations in internodal distance and significant decreases in wall thickness, nodal thickness, and interfiber distance. Fiber width was significantly decreased following dilatation of 3 mm, but not 4 mm ePTFE. Our data support our initial hypothesis that balloon dilatation alters the structure of ePTFE.
对心血管疾病采用侵入性较小治疗方法的探索促使了血管内支架移植物的发展，这种移植物是由假体血管移植材料包裹的金属和合金支架。通过血管内引入，支架移植物的展开需要对该装置进行球囊扩张，这会导致支架与血管移植材料一起扩张。我们推测球囊扩张支架移植物会改变假体移植材料的物理结构。在本研究中，使用非顺应性血管成形术球囊来扩张膨体聚四氟乙烯（ePTFE），这是一种常用于血管内支架移植技术的材料。测量了两种类型ePTFE的最大外径（管腔内充气的球囊）和回缩外径（球囊移除后），内径分别为3毫米薄壁（节点间距30微米）和4毫米标准壁（节点间距30微米），以比较材料的回缩情况。球囊扩张后，制备ePTFE样本用于扫描电子显微镜检查，并测量以下参数：壁厚、节点间距、节点宽度、纤维间距和纤维宽度。初次扩张后，无论充气球囊直径如何，两种类型的ePTFE均回缩约20%。然而，在进行八次重复球囊扩张后，回缩率降至约10%。扫描电子显微镜分析显示节点间距存在变化，并且壁厚、节点厚度和纤维间距显著减小。3毫米ePTFE扩张后纤维宽度显著减小，但4毫米ePTFE则不然。我们的数据支持了我们最初的假设，即球囊扩张会改变ePTFE的结构。
