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Original article

Blankensteijn JD et al. (2005) Two-year outcomes after conventional or endovascular repair of abdominal aortic aneurysms. N Engl J Med 352: 2398–2405   PubMed

Synopsis

Background

The findings of two studies have shown that patients receiving elective endovascular repair of abdominal aortic aneurysm have a better short-term prognosis than patients receiving more-invasive conventional open repair. Uncontrolled trials, however, have suggested that the long-term prognosis of endovascular repair is less promising, with higher rates of complications and reintervention.

Objective

To compare the long-term outcomes of elective endovascular abdominal aortic aneurysm repair with those of elective open abdominal aortic aneurysm repair.

Design and intervention

The Dutch Randomized Endovascular Aneurysm Management (DREAM) trial was a randomized, multicenter study that enrolled patients who had an abdominal aortic aneurysm with a diameter of 5 cm or more. Patients who were deemed suitable for both surgical strategies were then randomly assigned either endovascular or open aneurysm repair. Eligible patients underwent physical assessments, including abdominal helical CT angiography, abdominal color duplex ultrasonography and ankle–brachial blood-pressure index calculation before discharge from hospital, at day 30 and at months 6, 12, 18 and 24. If patients had undergone endovascular repair, abdominal radiography was included in the follow-up assessments before discharge and at months 12 and 24. Analyses were done by intention to treat.

Outcome measures

The main outcomes were all-cause death, aneurysm-related death, reintervention and complications. The composite primary endpoint comprised moderate and severe complications, and death during surgery. The secondary endpoints were complications and number of deaths at 2 years after intervention.

Results

Of the 351 patients who were included in the trial, 173 were assigned endovascular repair and 178 were assigned open repair. As a result of patient withdrawal and death, 171 and 174 patients underwent endovascular and open repair, respectively. After 2 years there was no difference in survival between the two surgery groups; 89.7% of the endovascular surgery patients survived compared with 89.6% of the open repair patients (95% CI –6.8 to 6.7, P = 0.86). Although not significant, there were more aneurysm-related deaths in the open repair group than in the endovascular repair group (5.7% versus 2.1%); however, this difference was due to the difference in the number of aneurysm-related deaths in the short-term perioperative period. There was no difference in the long-term frequency of aneurysm-related death between the groups. Furthermore, both groups had similar numbers of patients who survived without moderate or severe complications; 65.6% of endovascular repair patients compared with 65.9% of open repair patients (95% CI –10.0 to 10.6, P = 0.88). The long-term reintervention rates were similar for both groups.

Conclusion

Blankensteijn et al. found that there was no long-term survival advantage with endovascular repair when compared with open repair. The better outcomes of endovascular repair are limited to 1 year after surgery, possibly because of its less-invasive nature.

Commentary

The DREAM trial was one of two prospective, randomized European trials designed to compare mortality and complications in patients undergoing elective open abdominal aortic aneurysm repair with long-term outcomes in patients undergoing endovascular abdominal aortic aneurysm repair.^{1, 2} This article by Blankensteijn and colleagues follows the first DREAM report published in 2004,¹ which documented a decrease in 30-day operative mortality (4.6% with open repair versus 1.2% with endovascular repair, risk ratio 3.9, P = 0.1) and a decrease in the composite endpoint of operative mortality and severe complications (risk ratio 2.1, P = 0.1) with endovascular repair. Despite not attaining what is considered statistical significance, the authors concluded that "endovascular repair is preferable to open repair". Importantly, they also added that "long-term follow-up is needed to determine whether this advantage is sustained".¹

The present article by Blankensteijn et al. sought to determine whether the mortality and complication rate advantage that endovascular abdominal aortic aneurysm repair seemed to have over conventional repair, was sustained in the long term. It appears that with only mid-term follow-up, however, this advantage is not sustained. After only 2 years following randomization, the cumulative survival rates in patients who underwent endovascular abdominal aortic aneurysm repair and open repair were nearly identical at 90%. When mortality was examined with longer follow-up in the present study, the authors acknowledged that the small but apparent survival advantage with endovascular repair in the short term did not reach statistical significance. Moreover, the small advantage in survival was based entirely on the initial difference in 30-day mortality between the treatment groups. The survival curves for the two groups converge at 9 months when there was an unexplained cluster of deaths in the endovascular group that were, importantly, not believed to be aneurysm-related deaths. Similar trends in aneurysm-related mortality, and survival without moderate or severe complications, were also found when treatments were compared.

Almost concurrently, the results of the Endovascular Aneurysm Repair 1 (EVAR-1) trial³ were published, confirming the DREAM trial results and suggesting that 4 years after randomization there is no difference in all-cause mortality for patients undergoing endovascular abdominal aortic aneurysm repair compared with open repair. The EVAR-1 trial, which was a much larger trial than DREAM and randomized over 1,000 patients in the UK, also examined the difference in costs between the two treatment groups and reported significantly increased costs with endovascular repair.

So the practical question is: how does this data affect the treatment of patients who have a greater than 5 cm abdominal aortic aneurysm and are good candidates for either open or endovascular repair? In an extensive editorial accompanying the EVAR-1 trial paper, Cronenwett suggests that younger patients with longer life expectancy are best treated by open repair.⁴ By contrast, elderly patients with more comorbidities and suitable aortic anatomy should be offered endovascular repair. Clearly, a patient's preference should be part of the decision-making process. Until level 1 or 2 data with longer term follow-up are available, this moderate approach seems justified in patients with a greater than 5 cm abdominal aortic aneurysm.

Acknowledgments

The synopsis was written by Hannah Camm, Associate Editor, Nature Clinical Practice.

References

1. Prinssen M et al. (2004) A randomized trial comparing conventional and endovascular repair of abdominal aortic aneurysms. N Engl J Med 351: 1607–1618 | Article | PubMed | ISI | ChemPort |
2. Greenhalgh RM et al. (2004) Comparison of endovascular aneurysm repair with open repair in patients with abdominal aortic aneurysm (EVAR trial 1), 30-day operative mortality results: randomised controlled trial. Lancet 364: 843–848 | Article | PubMed | ISI | ChemPort |
3. EVAR trial participants (2005) Endovascular aneurysm repair versus open repair in patients with abdominal aortic aneurysm (EVAR trial 1): randomised controlled trial. Lancet 365: 2179–2186 | Article |
4. Cronenwett JL (2005) Endovascular aneurysm repair: important mid-term results. Lancet 365: 2156–2158 | Article | PubMed | ISI |

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Subject areas under which this article appears: Intervention