Comparison of endovascular and open surgical repairs for abdominal aortic aneurysm

Abstract

Objectives: Evaluate treatment options for nonruptured abdominal aortic aneurysms (AAA); the relationship of hospital and physician volume to outcomes for endovascular repair (EVAR); affect of patient and AAA factors on outcomes; cost-benefits of treatments.

Data sources: PubMed, Cochrane Library, FDA, and other electronic websites until May 2006. Reference lists and content experts were used to identify additional reports.

Review methods: Randomized controlled trials (RCT) of open surgical repair (OSR), EVAR, or active surveillance, systematic reviews, nonrandomized U.S. trials, and national registries were used to assess clinical outcomes. Volume-outcome articles published after 2000 were reviewed if they reported the relationship between U.S. hospital or physician volume and outcomes, were population-based, and the analysis was adjusted for risk factors. Cost studies included at least 50 EVAR and provided data on costs or charges, and cost-effectiveness analyses.

Results: Initial or attained diameter is the strongest known predictor of rupture. The annual risk of rupture is below 1 percent for AAA <5.5 cm in diameter. Among medically ill patients unfit for OSR with AAA >/=5.5 cm, the risk of rupture may be as high as 10 percent per year. Early/immediate OSR of AAA <5.5 cm (two trials n=2,226) did not reduce all-cause mortality compared with surveillance and delayed OSR. Results did not differ according to age, gender, baseline AAA diameter or creatinine concentration. Two RCT with followup of at least 2 years compared EVAR to OSR for AAA >/=5.5 cm. EVAR reduced postoperative 30-day mortality compared to OSR (1.6 percent EVAR vs. 4.7 percent OSR, RR = 0.34 [0.17 to 0.65]). Early reduction in all-cause mortality with EVAR disappeared before 2 years. Post-operative complications and reinterventions were higher with EVAR. Quality of life differences were small and disappeared after 3-6 months. One RCT of patients with AAA >/=5.5 cm judged medically unfit for OSR (n=338), reported no difference in all-cause mortality or AAA mortality between EVAR and no intervention (HR = 1.21; 95 percent CI 0.87 to 1.69). Forty-eight nonrandomized reports evaluated EVAR. Patient, AAA characteristics, and outcomes were similar to RCT comparing EVAR to OSR. A volume outcome relationship has been shown for OSR, but there are no data adequate to estimate the effect of hospital or physician volume on EVAR outcomes or to identify a volume threshold for policymakers. Immediate OSR for AAA <5.5 cm costs more and does not improve long-term survival compared to active surveillance and delayed OSR. The cost effectiveness of EVAR relative to OSR is difficult to determine. However, compared to OSR for AAA >/=5.5 cm, EVAR has greater in-hospital costs primarily due to the cost of the prosthesis. EVAR has shorter length of stay, lower 30-day morbidity and mortality but does not improve quality of life beyond 3 months or survival beyond 2 years, and is associated with complications, need for reintervention, long-term monitoring, and higher long-term costs. Compared to no intervention in patients medically unfit for OSR, EVAR costs more and does not improve survival or quality of life.

Conclusions: For AAA <5.5 cm in diameter, active surveillance with delayed OSR results in equivalent mortality but lesser morbidity and operative costs due to fewer interventions compared to immediate OSR. For AAA >/=5.5 cm, EVAR has not been shown to improve long-term survival or health status over OSR though peri-operative outcomes are improved. EVAR does not improve survival in patients who are medically unfit for OSR. EVAR is associated with more complications, need for reintervention, monitoring, and costs compared to OSR or no intervention. U.S. RCT are needed using approved EVAR devices to evaluate patient outcomes.