Fenestrated and branched stent-grafts for thoracoabdominal, pararenal and juxtarenal aortic aneurysm repair

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.