Graft design and selection of fenestrations vs. branches for renal and mesenteric incorporation in endovascular treatment of pararenal and thoracoabdominal aortic aneurysms

To address target vessels in pararenal and thoracoabdominal aortic aneurysms with fenestrated and branched grafts, two solutions are available: fenestrations (holes in the graft) and directional side-branches. Fenestrations work well for target vessels that have a close to 90-degree take-off from the aorta, and when the main graft at the level of the target vessel is adjacent or close to the aortic wall. Directional side-branches work well when target vessels have a steeper take-off angle and when there is a larger gap to be bridged. A third option of "inner branches" has been evaluated by our group to address target vessels that are not very suitable for either a fenestration or a directional side-branch. Most pararenal aneurysms are treated with fenestrated grafts, whereas thoraco-abdominal aneurysms are treated mostly by grafts incorporating both fenestrations and branches. In Nuremberg, 347 patients were treated with fenestrated/branched grafts for thoraco-abdominal aneurysms. A stent-graft with fenestrations only was used in 108 (31.1%) patients, a stent-graft with branches only in 104 (30.0%) patients, and a stent-graft with a combination of fenestrations and branches in 135 (38.9%) patients. For the RA s (N.= 625) fenestrations were used in 408 (65.3%) and branches in 217 (34.7%). For the SMA (N.= 341) fenestrations were used in 169 (49.6%) and branches in 172 (50.4%). For the CA (N.= 297), fenestrations were used in 84 (28.3%), and branches in 213 (71.7%). Target vessel patency at 3 years was 98.2 +/- 0.9% for vessels targeted with fenestrations and 92.2 +/- 1.9% for vessels targeted with branches (P= 0.009).