Endovascular Repair of Abdominal Aortic Aneurysm

A summary of findings from the Cochrane Library with implications for critical care nursingWhat is the effectiveness of endovascular aneurysm repair versus conventional open surgical repair in patients with abdominal aortic aneurysm considered fit for surgery, and endovascular aneurysm repair versus best medical care in those considered unfit for surgery?The abdominal aorta is one of the body’s large blood vessels that supplies blood to the major organs in the chest and abdomen. When this vessel abnormally enlarges (dilates) or balloons outward, it is referred to as an abdominal aortic aneurysm (AAA). Because of the large amount of blood supplied by the abdominal aorta, if an AAA ruptures, it is often fatal. Therefore, repairing a AAA before any kind of rupture is critical. The current standard is that AAAs that are larger than 5.5 cm are usually surgically treated and repaired.There are 2 main procedural approaches to repair an AAA:The EVAR approach does not require surgery, so it is less invasive than OSR and provides a less dangerous option for patients who are deemed unfit for surgery.This summary is based on a Cochrane systematic review that included data from 5 randomized controlled trials (RCTs). All patients with an AAA diagnosed by ultrasound or computed tomography in whom treatment was thought to be indicated (not defined) were included. Studies were excluded wherein the size of the aneurysm was not clear. Only patients with an asymptomatic AAA undergoing elective aneurysm treatment were considered; patients undergoing emergency repair of an aneurysm were excluded. Of the 5 RCTs included, 4 compared EVAR with OSR (n=2790) and 1 compared EVAR with no intervention (n=404).Primary outcomes included the following:Secondary outcomes included the following:The 3 reviewers independently evaluated the studies, considered them for inclusion, and assessed their quality. Any disagreements were resolved by discussion. The reviewers independently extracted data by using pro forma designed by the Cochrane Peripheral Vascular Disease (PVD) Group. Risk of bias was assessed using the RevMan “Risk of bias” assessment tool. All studies were of high quality with good randomization and allocation concealment, reported all predefined outcomes, and used intention to treat (ITT) analysis. Studies were excluded if data were inadequate or if they used an inadequate randomization technique. No exclusion was made on the basis of language or publication status.Odds ratios (ORs) with a 95% confidence interval (CI) were used as the measure of effect for each dichotomous outcome, and a calculation for a summary statistic for each outcome using either a fixed-effect or random-effects model was conducted. I2 statistic was used to assess heterogeneity. Statistical analyses were performed according to the guidelines for reviews outlined in the Cochrane PVD Group’s module by using RevMan software (version 5.2.3). In addition, ITT analysis for the intermediate and long-term outcomes was used.This systematic review and meta-analysis of data from 5 RCTs showed that in patients considered fit for surgical repair of an AAA, EVAR was associated with lower short-term mortality than OSR. However, this benefit faded at the intermediate and long-term followups. Operative complications, health-related quality of life, and sexual dysfunction were generally comparable between EVAR and OSR, though the incidence of pulmonary complications was slightly higher in the OSR group than in the EVAR group. For patients considered unfit for surgery, the results of a single study indicated no short- or long-term benefits of EVAR over no intervention with regard to all-cause mortality. These results can aid clinicians and patients in their clinical decision making for treatment of an AAA.1