Anatomical Considerations and Open Surgery to Treat Juxtarenal Abdominal Aortic Aneurysms.

INTRODUCTION: Historically, the open approach to the abdominal aorta has been transperitoneal (TP). In comparison, a retroperitoneal (RP) incision exposes the lateral wall of the suprarenal aorta for clamp application and midline structures such as the duodenum and pancreas are not encountered. Proximal clamp position for open repair of juxtarenal abdominal aortic aneurysm (JR-AAA) is suprarenal, supra-superior mesenteric, or supraceliac. While RP and TP approaches have previously been compared for physiological reasons, there are currently no randomized controlled trials comparing these methods from an anatomical perspective. AIMS: The primary aim is to examine the evidence for adopting an RP approach for JR-AAA and compare it with TP approach from an anatomical perspective. The secondary aim is to assess optimum proximal clamp position and its effect on renal function and mortality for the 2 approaches. METHODS/DESIGN: Literature was reviewed searching databases Medline and Embase for studies on clamp positioning in JR-AAA repair using a TP or RP approach, up to December 2017. CONCLUSIONS: There is no clear evidence for the optimum cross-clamp position for open repair of JR-AAAs. More proximal clamps provide adequate operative space with the possible downside of increased afterload leading to visceral and renal ischemia. Clamps placed inferior to the superior mesenteric artery allow continued bowel and hepatic perfusion with the potential to cause trauma to the adjacent aortic branches during application. As far as the optimum approach is concerned, many series show a strong trend for RP as a more proximal clamp is required. Significant numbers develop renal failure after JR-AAA repair, with most recovering fully irrespective of the clamp position.

The Significance of Hypothermia in Abdominal Aortic Aneurysm Repair.

BACKGROUND: The aim of this study was to review the literature on the association between hypothermia and outcomes in open and endovascular abdominal aortic aneurysm (AAA) repair. The secondary aim was to determine whether there is a difference in body temperature in patients undergoing either transperitoneal (TP), retroperitoneal (RP), or endovascular surgical repair of the abdominal aorta (EVAR). METHODS: MEDLINE, Web of Science, and Trip searched for all studies on temperature in the context of aortic surgery or endovascular aortic interventions. To be included in the review, the papers had to be related to intraoperative or postoperative hypothermia and/or normothermia, with regards to either open or endovascular repair of the abdominal aorta. Thoracic or thoracoabdominal aortic repairs were not included for review. RESULTS: Eight studies involving 765 patients were eligible. Of these, 6 studies looked at open elective AAA repair involving 605 patients. Only 2 studies investigated emergency AAA repair and consisted of 160 patients where only 35 of those patients underwent emergency EVAR. Normothermic patients had a shorter length of stay in the intensive care unit (P = 0.0008), while hypothermia was independently associated with higher rates of organ dysfunction, in-hospital mortality, and prolonged hospital length of stay. In ruptured AAAs, the lowest average intraoperative temperature was recorded in open repair compared with EVAR (P = 0.02). There was no statistically significant difference in postoperative temperature between patients undergoing elective RP repair and those having TP surgery. CONCLUSIONS: The studies identified in this review have shown that hypothermia has numerous deleterious effects on outcomes in AAA repair - whether or not these adverse outcomes are those such as higher rates of organ dysfunction, mortality or prolonged hospital length of stay, can only be done at the single paper level and not at a literature review level, due to multiple confounding variables. Despite these limitations, the benefits of this review are numerous. This article highlights the importance of core body temperature and outcomes of AAA repair. Furthermore, it brings forth the need to standardize the method of core body temperature measurement and method of rewarming. Given the body of evidence so far, these standardized data collection points will be important for national vascular quality improvement initiatives. Only through rigorous analysis of standardized dataset can firm recommendation regarding peri- and postoperative temperature management be made.