Frank A. Lederle, MD; Robert L. Kane, MD; Roderick MacDonald, MS; Timothy J. Wilt, MD, MPH
Recent recommendations to screen for abdominal aortic aneurysm (AAA) in high-risk populations and the rapidly increasing use of endovascular repair have led to increased interest in evaluating the effectiveness of treatment options for patients with AAA.
To compare the effectiveness of treatment options, including active surveillance, open repair, and endovascular repair, for unruptured AAAs.
The authors searched MEDLINE, the Cochrane Library, and www.ClinicalTrials.gov through December 2006 with no language restrictions, searched reference lists, and queried experts and study authors.
Randomized trials that compared open or endovascular AAA repair with another treatment strategy and published clinical outcomes.
Data were extracted onto standardized, piloted forms and were confirmed.
Two trials compared open repair with surveillance for small AAAs (nÂ = 2226). Repair did not improve all-cause mortality (relative risk, 1.01 [95% CI, 0.77 to 1.32]) or AAA-related mortality (relative risk, 0.78 [CI, 0.56 to 1.10]). Four trials compared open repair with endovascular repair (nÂ = 1532). Endovascular repair reduced 30-day mortality (relative risk, 0.33 [CI, 0.17 to 0.64]) but not mid-term (up to 4 years) mortality (relative risk, 0.95 [CI, 0.76 to 1.19]). One trial compared endovascular repair with observation in 338 patients who were unfit for open repair. Endovascular repair did not reduce all-cause mortality or AAA-related mortality, but high crossover and procedural mortality rates complicate interpretation of results.
Few trials have been published. Those published were of small to moderate size and were not U.S. trials of endovascular repair.
Repairing AAAs smaller than 5.5 cm has not been shown to improve survival. Endovascular repair is associated with lower operative mortality than open repair, similar mid-term mortality, and unknown long-term mortality and has not been shown to improve survival in patients unfit for open repair. Long-term trial data comparing endovascular repair with open repair are needed, as is another trial comparing endovascular repair with observation in high-risk patients.
AAA = abdominal aortic aneurysm.
ADAM = Aneurysm Detection and Management Veterans Affairs Cooperative Study; RR (random) = relative risk by random-effects model; UKSAT = United Kingdom Small Aneurysm Trial.
DREAM = Dutch Randomized Endovascular Aneurysm Management Trial; ESPAS = Eindhoven Stent Prothesis for Aneurysm Study; EVAR = Endovascular Aneurysm Repair trial 1; EVR = endovascular repair; RR (random) = relative risk by random-effects model.
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Jikei University School of Medicine
May 24, 2007
Endovascular Abdominal Aortic Repair
TO THE EDITOR: According to the critical review by Dr. Lederle and colleagues, endovascular abdominal aortic repair (EVAR) reduced 30-day mortality by 3 times compared with open repair (1.6% vs. 4.8%) but not mid -term all-cause mortality (1). Furthermore, EVAR has not been shown to improve survival in patients unfit for open repair. These results are probably disappointing for patients awaiting EVAR.
Truly, EVAR is frequently associated with complications and reintervention, which are likely to worsen the long-term outcomes. Early and late complication rates are undoubtedly reduced by selecting a high- volume center or experienced endovascular surgeon. In 20-50 per cent of patients, endoleak and endotension are complicated in the early and late course of EVAR (2). These EVAR-specific complications often lead to reintervention with a high mortality rate, although the protocol for management of endoleak and endotension is controversial.
The development of endoleak and endotension is closely related to graft material. Recently, a new Excluder low-permeability device (ELPD), which is expected to protect fluid leak via membrane by adding a new membrane with low permeability to the original Excluder (OGE), became available. In a study comparing ELPD with OGE, the average size decrease in aneurysm size after 1-year follow-up in the ELPD group was 63.9 per cent, significantly better than 25 per cent in the OGE group (3).
Tetsuji Fujita, MD and Takao Ohki, MD, Department of Surgery Jikei University School of Medicine Tokyo, Japan 105-8461
1. Lederle FA, Kane RL, MacDonald R, Wilt TJ. Systemic review: Repair of unruptured abdominal aortic aneurysm. Ann Intern Med. 2007; 146: 735-41
2. Gorham TJ, Taylor J, Raptis S. Endovascular treatment of abdominal aortic aneurysm. Br J Surg 2004; 91: 815-27.
3. Haider S, Najjar SF, Cho JS, Rhee RY, Eskandari MK, Matsumura JS, Makatoun MS, Morasch MD. Sac behavior after aneurysm treatment with the Gore Excluder low-permeability aortic endoprosthesis: 12-month comparison to the Excluder device. J Vasc Surg 2006; 44: 694-700.
Shizuoka Medical Center
June 1, 2007
Open Repair versus Endovascular Repair of Abdominal Aortic Aneurysm
In a systematic review for repair of unruptured abdominal aortic aneurysm (AAA) by Lederle and colleagues (1), endovascular repair reduced not all- cause (relative risk, 0.95 [CI, 0.76 to 1.19]) but AAA-related mid-term mortality (relative risk, 0.53 [CI, 0.31 to 0.92]) compared with open repair. The most recently, however, the results of the Endovascular Aneurysm Repair (EVAR) I trial, one of the 3 trials included in the systematic review, was updated: the number of patients enrolled increased (from 1082 to 1252) and the follow-up was extended (from median 2.9 years to mean 3.8 years) (2). Therefore, we performed a meta-analysis of currently available results of randomized, controlled trials of endovascular versus open repair of AAA including updated results of EVAR I trial (2).
Our comprehensive search identified 3 randomized trials that have published mi-term follow-up results: the Dutch Randomized Endovascular Aneurysm Management (DREAM) trial (3), the EVAR I trial (2), and a trial from Montreal, Canada (4). Two of the 3 individual trials demonstrated a statistically nonsignificant benefit of endovascular over open repair for mid-term AAA- related mortality (relative risk, 0.27 [CI, 0.06 to 1.19] in the DREAM trial; relative risk, 0.61 [CI, 0.36 to 1.03] in the EVAR I trial), but only the Montreal trial demonstrated a statistically nonsignificant benefit of open over endovascular repair (relative risk, 3.00 [CI, 0.13 to 69.52]). Pooled analysis of the 3 trails demonstrated a statistically nonsignificant reduction in mid- term AAA-related mortality with endovascular relative to open repair in a random- effects model (relative risk, 0.57 [CI, 0.32 to 1.02]). There was neither between-study heterogeneity of results analyzed by means of standard chi- square tests (P = 0.35) nor evidence of significant publication bias assessed using an adjusted rank-correlation test (P = 0.60). Pooled analysis also demonstrated a statistically nonsignificant reduction in mid-term all- cause mortality with endovascular relative to open repair (relative risk, 0.98 [CI, 0.81 to 1.18]).
Despite the results of the systematic review by Lederle and colleagues (1), the present meta-analysis of all the currently available results of randomized, controlled trials failed to demonstrate significant benefit of endovascular over open repair for not only all-cause but also AAA-related mid-term mortality.
1. Lederle FA, Kane RL, MacDonald R, Wilt TJ. Systematic review: repair of unruptured abdominal aortic aneurysm. Ann Intern Med. 2007;146:735-41. [PMID: 17502634]
2. EVAR trial participants. Patient fitness and survival after abdominal aortic aneurysm repair in patients from the UK EVAR trials. Br J Surg. 2007;94:709-16. [PMID: 17514695]
3. Blankensteijn JD, de Jong SE, Prinssen M, van der Ham AC, Buth J, van Sterkenburg SM, et al. Two-year outcomes after conventional or endovascular repair of abdominal aortic aneurysms. N Engl J Med. 2005;352:2398-405. [PMID: 15944424]
4. Soulez G, Therasse E, Monfared AA, Blair JF, Choiniere M, Elkouri S, et al. Pain and quality of life assessment after endovascular versus open repair of abdominal aortic aneurysms in patients at low risk. Vasc Interv Radiol. 2005;16:1093-100. [PMID: 16105921]
Lederle FA, Kane RL, MacDonald R, Wilt TJ. Systematic Review: Repair of Unruptured Abdominal Aortic Aneurysm. Ann Intern Med. 2007;146:735-741. doi: 10.7326/0003-4819-146-10-200705150-00007
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Published: Ann Intern Med. 2007;146(10):735-741.
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