Chuter Timothy A M
Division of Vascular Surgery, University of California San Francisco, San Francisco, CA 94143, USA.
Semin Vasc Surg. 2007 Jun;20(2):90-6. doi: 10.1053/j.semvascsurg.2007.04.006.
The neck of a juxtarenal aneurysm is often too short for stable hemostatic stent-graft implantation. Fenestrations (holes) in the stent-graft permit implantation at a more favorable level by providing a route for flow to the renal arteries. In cases of pararenal and thoracoabdominal aortic aneurysm, the aorta around the renal and visceral arteries is too dilated for hemostatic contact with the wall of the stent-graft. There is a gap, which must be bridged by a branch of the stent-graft. In a fenestrated branched stent-graft, balloon-expanded covered stents run transaxially from fenestrations in the wall of the primary stent-graft to the branch arteries (renal or visceral). In a cuffed branched stent-graft, self-expanding covered stents curve outward from axially oriented cuffs on the primary stent-graft to the branch arteries. The two approaches share the same basic modular pattern of in situ construction, but differences between them have important consequences for the long-term efficacy and stability of the resulting branched stent-graft. Unibody branched stent-grafts suffer from an irreducible complexity of stent-graft manufacture and insertion technique, which has limited their application to a small number of cases. Most published reports contain a mixture of fenestrated and branched techniques, focus on short-term results, and provide little information on the relative merits of each approach. However, the enormous potential advantages of endovascular repair of visceral segment aneurysms and promising short-term results continue to drive the dissemination of branched stent-graft technology.
肾旁动脉瘤的颈部通常过短，难以稳定植入止血性支架移植物。支架移植物上的开窗（孔）通过为血流流向肾动脉提供路径，使得能够在更有利的位置进行植入。对于肾旁和胸腹主动脉瘤病例，肾动脉和内脏动脉周围的主动脉扩张过度，无法与支架移植物壁实现止血接触。存在一个间隙，必须由支架移植物的分支来桥接。在开窗分支型支架移植物中，球囊扩张式覆膜支架从主支架移植物壁上的开窗沿轴向延伸至分支动脉（肾动脉或内脏动脉）。在带袖口分支型支架移植物中，自膨式覆膜支架从主支架移植物上轴向定位的袖口向外弯曲至分支动脉。这两种方法具有相同的原位构建基本模块化模式，但它们之间的差异对最终分支型支架移植物的长期疗效和稳定性具有重要影响。一体式分支型支架移植物在支架移植物制造和插入技术方面存在不可简化的复杂性，这限制了它们仅应用于少数病例。大多数已发表的报告包含开窗和分支技术的混合内容，侧重于短期结果，并且几乎没有提供关于每种方法相对优点的信息。然而，内脏段动脉瘤血管内修复的巨大潜在优势和有前景的短期结果继续推动着分支型支架移植物技术的传播。
