Update on repairs of the thoracoabdominal aorta.

The gold standard of thoracoabdominal aortic aneurysm (TAAA) and chronic dissection repair has long been open surgical repair. Despite recent technological advances in endovascular aortic repair, open operation remains the preferred technique for these highly complex repairs. At experienced surgical centers,1–6 morbidity and mortality rates have greatly improved during the past 40 years, even in patients with extensive repairs (for example, Crawford extent II), chronic aortic dissection, or Marfan syndrome. In our experience with 823 open TAAA repairs from January 2005 through May 2012, the 30-day mortality rate was 4.7% (39 patients), and the rate of permanent paraplegia was 3.8% (31 patients).5 The mean age of the 823 patients was 63.4 ± 13.1 years. The series included 75 emergent repairs (9.1%), 37 ruptured aneurysms (4.5%), 322 chronic dissections (39.1%), and 264 Crawford extent II repairs (32.1%), which are traditionally associated with the greatest risk of early death, spinal cord deficit, and renal failure. Within this series, 96 patients (11.7%) had connective-tissue disorders. Results were better in this subset of younger patients (mean age, 44.6 ± 13.5 yr), 91.6% of whom had aortic dissection—83 with chronic aortic dissection (86.4%) and 5 with acute or subacute dissection (5.2%). The early mortality rate was 3.1% (3 patients), and the rate of permanent paraplegia was 1% (1 patient). The rates of renal failure were similar in patients with connective-tissue disorders (5.2%; 5 patients) and for patients without those disorders (5.5%; 45 patients). These generally favorable results are being achieved despite the increasing complexity of TAAA surgery. Such operations are increasingly being performed in elderly patients who have multiple comorbid conditions. Furthermore, the growing popularity of endovascular thoracic aortic aneurysm repair has produced a group of patients who experience stent-graft failure and require late conversion to open TAAA repair. There is a more frequent use of off-label endovascular approaches in patients with chronic aortic dissection. In 2013, Nozdrzykowski and colleagues7 reported their experience in treating chronic aortic dissection: nearly a quarter of patients who initially underwent endovascular repair experienced a severe complication (such as infection, rupture, new-onset paraplegia, or a fistula) that ultimately required conversion to open surgery. Many of these were emergency conversions, which inherently increase operative risk. Several reports of late conversion to open repair after primary endovascular repair have been published since 20088–11; in 2012, we reported our experience in such repairs.12 Our results are similar to those of standard TAAA repair, except in patients with infection, which severely limits survival prospects. Our current approach includes the selective use of several adjunctive techniques for organ protection, such as left-sided heart bypass, cerebral spinal fluid drainage, selective visceral perfusion, and cold renal perfusion. Prefabricated multibranched grafts (Fig. 1) can be used to separately reattach the visceral arterial branches, thereby minimizing residual native aortic tissue. This is particularly important in patients with connective-tissue disorders, because it prevents the late formation of visceral patch aneurysms.13 In addition, these multibranched grafts shorten ischemic times and facilitate tension-free anastomoses, which might improve hemostasis and prevent late pseudoaneurysm formation. Fig. 1 Illustration shows a completed Crawford extent II thoracoabdominal aortic aneurysm repair with a branched graft. This approach is particularly useful in patients with connective-tissue disorders, because it reduces the amount of native aortic tissue. ... However, the overall philosophical approaches to TAAA differ among surgical centers experienced in TAAA repair, so the choice and selective use of surgical adjunctive techniques vary among centers.14 These differences include whether hypothermic circulatory arrest is used routinely or selectively15; whether intercostal arteries are routinely excluded (as pertains to the Collateral Network Concept)16; the choice of experimental models for staging thoracoabdominal repairs17,18; and the choice of adjunctive procedures for protecting the spinal cord,19 such as epidural cooling20 and using catheters to monitor spinal cord perfusion.21 Although standard graft replacement remains the best approach in most TAAA patients, hybrid repairs that combine open rerouting of the visceral circulation (visceral debranching) and endovascular exclusion of the aneurysm might be useful in selected high-risk TAAA patients. In addition, at our center22 and others,23 stent-grafts have been used successfully to exclude late complications of open TAAA, such as patch aneurysms or pseudoaneurysms. These endograft-within-a-graft approaches might be used more frequently in the future. Finally, a greater overall awareness of thoracic aortic disease is needed so that elective repair can be performed whenever appropriate. Outcomes in survivors of emergent TAAA repair tend to be much worse than those in patients who undergo elective repair, and survivors of acute dissection face a substantial risk of reoperation (as in survivors of DeBakey type I dissection) or of eventual operative repair (as in medically treated survivors of DeBakey type III dissection).