Abdominal aortic aneurysm surgery

Associate Editor-In-Chief:

Indications for Surgery
The treatment options for asymptomatic AAA are immediate repair, surveillance with a view to eventual repair, and conservative. There are currently two modes of repair available for an AAA: open aneurysm repair (OR), and endovascular aneurysm repair (EVAR).


 * Conservative treatment is indicated in patients where repair carries a high risk of mortality and also in patients where repair is unlikely to improve life expectancy. The two mainstays of the conservative treatment are smoking cessation and blood pressure control.
 * Surveillance is indicated in small aneurysms, where the risk of repair exceeds the risk of rupture. As an AAA grows in diameter the risk of rupture increases. Although some controversy exists around the world, most vascular surgeons would not consider repair until the aneurysm reached a diameter of 5cm. The threshold for repair varies slightly from individual to individual, depending on the balance of risks and benefits when considering repair versus ongoing surveillance. The size of an individual's native aorta may influence this, along with the presence of comorbitities that increase operative risk or decrease life expectancy.
 * Open repair (operation) is indicated in young patients as an elective procedure, or in growing or large, symptomatic or ruptured aneurysms. Open repair has been the mainstay of intervention from the 1950's until recently.
 * Endovascular repair first became practical in the 1990's and although it is now an established alternative to open repair, its role is yet to be clearly defined. It is generally indicated in older, high-risk patients or patients unfit for open repair. However, endovascular repair is feasible for only a proportion of AAA's, depending on the morphology of the aneurysm. The main advantage over open repair is that the peri-operative period has less impact on the patient (less time in intensive care, less time in hospital overall, earlier return to normal activity). Disadvantages of endovascular repair include a requirement for more frequent ongoing hospital reviews, and a higher chance of further procedures being required. According to the latest studies, the EVAR procedure doesn't offer any overall survival benefit. Regarding unruptured aneurysms, EVAR is associated with lower operative mortality than open repair but unknown long-term mortality

Pre-Operative Assessment

 * The ADAM trial suggested that the "biological age," as reflected by the condition of the vital organs such as the lungs, kidneys, heart was more important than the chronological age as a determinant of operative outcome. ADAMref4
 * Patients with poor renal and pulmonary function have worse operative outcomes
 * Chronic obstructive pulmonary disease
 * Elevated creatinine concentrations
 * Electrocardiographic evidence of ischemia
 * Aortic factors implicated in postoperative morbidity and mortality include:
 * Extensive atheromatous disease
 * Mural calcification
 * Thrombosis
 * Juxtarenal extension of aneurysm
 * Inflammatory aortic aneurysms
 * The increased risk resulted from:
 * Longer suprapenal clamping time
 * Need for complex dissection
 * Increased hemodynamic stresses

Acknowledgements
The content on this page was first contributed by: C. Michael Gibson M.S., M.D.