Fenestrated and Branched Aortic Grafts.

The anatomy of the aorta changes in the course of life. Up to the age of 15, its diameter and length increase relatively swiftly. It continues to grow in adulthood: the diameter of the ascending aorta is 20 to 30% greater in 70-year-olds than in 20-year-olds (1). Rapid growth of the aorta—usually segmental—causes an aneurysm. Three quarters of all aneurysms occur in the abdominal aorta. The annual incidence of abdominal aortic aneurysm (diameter >3.0 cm) is 40 in every 100 000 population. Six times more men than women are affected (2– 4). Intervention is required (aneurysmal diameter >5.0 cm) in 10% of patients with a diagnosed abdominal aortic aneurysm (3). In up to 55% of these persons the aneurysm is not amenable to insertion of a conventional tube graft or Y-graft (5). The annual incidence of thoracic aneurysm is 10–15 per 100 000 (6, 7). Men are 1.8 times more frequently affected than women. No population studies of the incidence of thoracic abdominal aneurysm have been published. The pathological aorta can be treated surgically or via the endovascular route. One crucial advantage of the endovascular approach is the minimally invasive access with relatively low strain on the cardiovascular system and thus lower perioperative mortality. In a total of 22 830 patients, mortality was 1.2% for endovascular treatment and 4.8% for open surgery (8, 9). Not every affected aorta is amenable to insertion of a thoracic tube stent graft or infrarenal Y-stent graft. In patients with a juxtarenal or thoracoabdominal aneurysm there is no proximal or distal zone for anchorage (landing zone) and therefore conventional tube and Y-grafts cannot be safely attached. These patients therefore often undergo open surgery. Relatively young and otherwise healthy patients recover comparatively quickly from an open thoracic, thoracoabdominal, or abdominal intervention. However, patients with vascular disease are usually of advanced age and not uncommonly have numerous comorbidities. One of the endovascular treatment options in such cases is the chimney technique. Chimney grafts are placed in the visceral vessels so that their aortic segments lie parallel to the aortic stent graft. However, use of this technique is limited by the elevated risk of leakage between the chimney graft, the aortic stent graft, and the aorta (10, 11). The very first implantation of a stent graft into the thoracic aorta was performed by Volodos in 1987 (12). The first such interventions in Germany—in centers including Freiburg (13)—were carried out in 1995. There have been rapid developments in stent grafts, pre- and intraoperative diagnostic procedures, endovascular instrumentation, catheter techniques, and many other relevant areas. Preoperative diagnostic, high-resolution computed tomography, three-dimensional (3-D) reconstruction of the aorta, preoperative simulation of the intraoperative angiographic visualization, the possibility of treatment in hybrid operating suites, and printing of 3-D models all help in planning the intervention and now form part of standard management. Hydrophilic coating and reduced diameter of the insertion port permit access via distinctly sclerosed vessels. The first fenestrated endovascular aneurysm repair (fEVAR) was carried out by Park in 1996 (14). Fenestrated (Figures 1a ​,, ​,2)2) and branched stent grafts (bEVAR) (Figure 1b) were developed for treatment of patients with juxtarenal, perirenal, or thoracoabdominal aneurysms. Now, with the sole exceptions of the aortic root and the proximal ascending aorta, all segments of the aorta are amenable to endovascular treatment with standard stent grafts. Figure 1 Stent grafts Figure 2 Treatment of a juxtarenal abdominal aortic aneurysm with a fenestrated stent graft