Open treatment of extent IV thoracoabdominal aortic aneurysms

Aim: Extent IV thoracoabdominal aortic aneurysm (TAAA) open repair is considered relatively safer to repair than other extents of TAAA in terms of both perioperative mortality and spinal cord ischemia. Our purpose is to report our experience and to perform a literature review regarding extent IV TAAA open repair in order to provide an updated benchmark for comparison with any other alternative strategy in this aortic segment. Methods: From 1993 to 2015 we performed 736 open repairs for TAAA (177 extent I, 196 extent II, 141 extent III, 222 extent IV). In extent IV group there were 164 men (73-9%) and the mean age was 67.4±9∗3 years (range 32-84). The aneurysm etiology was degenerative in 198 patients (95.6%). Twelve patients (5.4%) underwent emergent operation. Totally abdominal approach was used in 22.0% of the cases. Until 2006 left heart bypass (LHBP) and cerebrospinal fluid drainage (CSFD) were almost never performed during extent IV repair. Since 2006 we changed our approach with a more aggressive use of LHBP (22.9%) and CSFD (43.4%) in 83 consecutive extent IV. Renal arteries perfusion was performed with 4 °C Ringer's solution until 2009 and with 4 °C Custodiol solution since September 2009 to date. Literature search was performed on several databases (PubMed, BioMed-Central, Embase, and the Cochrane Central Register of clinical trials). Research was updated on March 1th 2015. Results: Perioperative mortality in our overall group of TAAA and in the extents IV was 10.7% and 4.9%, respectively (P=0.01); spinal cord ischemia rate 11.4% and 2.7%, respectively (P=0.0001). In the extents IV treated between 2006 and 2015 we observed a further trend of outcomes improvement with a rate of perioperative mortality and spinal cord ischemia of 1.2%, and 2.4%, respectively. Database searches yielded a total of 767 articles. Excluding non-pertinent titles or abstracts, we retrieved in complete form and assessed 27 studies according to the selection criteria. Nine studies were further excluded because of our prespecified exclusion criteria. The final 18 manuscripts included a total of 2098 patients. In this group median mortality rate was 4.8% (interquartile range 3-6) and the mean incidence of spinal cord ischemia was 1.56±1.54%. Conclusion: Perioperative outcomes after extent IV TAAA open repair were significantly better compared to our overall TAAA series. A more aggressive use of CSFD, LHBP and renal perfusion with Custodiol solution allowed a further trend of outcomes improvement in our series of extent IV TAAA open repair. Literature analysis confirmed during extent IV open repair very satisfactory perioperative outcomes with rates of mortality and spinal cord ischemia dropped to under 5% and 2%, respectively.