Cochrane Review Summary A summary of findings from the Cochrane Library with implications for critical care nursing
Endovascular Repair of Abdominal Aortic Aneurysm Adam Cooper, RN, MSN
Review Question What 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?
Relevance to Critical Care Nursing 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 first is the traditional open surgical repair (OSR) technique, in which the abdomen is surgically opened and the dilated aorta is repaired by using fabric graft material. • The second approach uses a catheter inserted into the blood vessels in the groin to access the site of the AAA. Once the catheter is in place, a sheath is inserted and creates a tightly sealed tunnel in the artery above and below the aneurysm. This allows blood to pass through it, bypassing the aneurysm, and decreases the risk of any further enlargement or rupture. This technique is referred to as endovascular aneurysm repair (EVAR). 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. Author Adam Cooper is a clinical nurse educator at the Institute for Nursing Excellence and deputy director of the UCSF JBI Centre for Evidence-Based Patient and Family Care, UCSF Medical Center, San Francisco, California. He is also a member of the Cochrane Nursing Care Field. For questions related to this article, contact Adam Cooper at [email protected]. ©2014 American Association of Critical-Care Nurses doi: http://dx.doi.org/10.4037/ccn2014184
www.ccnonline.org
Study Description and Results 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: • Mortality and aneurysm-related mortality rates ◦ Short term (30-day or in-hospital mortality) ◦ Intermediate (up to 4 years from randomization) ◦ Long term (beyond 4 years) • Graft-related complications (eg, endoleak or reintervention required) • Major complications (eg, myocardial infarction, stroke, renal failure, bowel ischemia, or pulmonary complications)
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Secondary outcomes included the following: • Minor complications • Health-related quality of life as measured with standardized questionnaires • Economic analysis: based on an analysis of costs, not charges 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 randomeffects 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.
Summary of Main Results • The pooled analysis of the patients considered fit for
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surgery, 1362 patients randomized to EVAR and 1361 randomized to OSR, showed short-term mortality with EVAR to be significantly lower than with OSR (1.4% vs 4.2%, OR, 0.33, 95% CI, 0.20-0.55; P
Endovascular Repair of Abdominal Aortic Aneurysm Adam Cooper, RN, MSN
Review Question What 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?
Relevance to Critical Care Nursing 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 first is the traditional open surgical repair (OSR) technique, in which the abdomen is surgically opened and the dilated aorta is repaired by using fabric graft material. • The second approach uses a catheter inserted into the blood vessels in the groin to access the site of the AAA. Once the catheter is in place, a sheath is inserted and creates a tightly sealed tunnel in the artery above and below the aneurysm. This allows blood to pass through it, bypassing the aneurysm, and decreases the risk of any further enlargement or rupture. This technique is referred to as endovascular aneurysm repair (EVAR). 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. Author Adam Cooper is a clinical nurse educator at the Institute for Nursing Excellence and deputy director of the UCSF JBI Centre for Evidence-Based Patient and Family Care, UCSF Medical Center, San Francisco, California. He is also a member of the Cochrane Nursing Care Field. For questions related to this article, contact Adam Cooper at [email protected]. ©2014 American Association of Critical-Care Nurses doi: http://dx.doi.org/10.4037/ccn2014184
www.ccnonline.org
Study Description and Results 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: • Mortality and aneurysm-related mortality rates ◦ Short term (30-day or in-hospital mortality) ◦ Intermediate (up to 4 years from randomization) ◦ Long term (beyond 4 years) • Graft-related complications (eg, endoleak or reintervention required) • Major complications (eg, myocardial infarction, stroke, renal failure, bowel ischemia, or pulmonary complications)
CriticalCareNurse
Vol 34, No. 4, AUGUST 2014
Downloaded from http://ccn.aacnjournals.org/ at SERIALS UNIT on December 11, 2014
87
Secondary outcomes included the following: • Minor complications • Health-related quality of life as measured with standardized questionnaires • Economic analysis: based on an analysis of costs, not charges 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 randomeffects 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.
Summary of Main Results • The pooled analysis of the patients considered fit for
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CriticalCareNurse
surgery, 1362 patients randomized to EVAR and 1361 randomized to OSR, showed short-term mortality with EVAR to be significantly lower than with OSR (1.4% vs 4.2%, OR, 0.33, 95% CI, 0.20-0.55; P
