EVAR Equals Open Repair for AAA? Look Closer

Frank J. Veith, MD


February 27, 2013

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Hi. I am Frank Veith, Professor of Vascular Surgery at New York University and the Cleveland Clinic. Today I am going to talk about the OVER trial, which is a trial comparing open aneurysm repair with endovascular aneurysm repair (EVAR) in patients who could undergo either form of treatment. The long-term results of the OVER trial were just published in the New England Journal of Medicine[1] and were very interesting.

The conclusion of the OVER trial was that the 2 treatments, open repair and EVAR, for abdominal aortic aneurysm have essentially equivalent results. EVAR is not better and it's not worse. If you look at the long-term survival curves of the 2 groups of patients, at the end they are equivalent. However, randomized trials can be misleading. They are thought to be the Holy Grail of evidence-based medicine, and all practice should be based on randomized trials, but it's not quite that simple. Randomized trials can have flaws and they can be misinterpreted. The OVER trial, in my opinion, is subject to some misinterpretation. Two previous, older trials comparing the same 2 treatments, the DREAM trial[2] and the EVAR1 trial,[3] arrived at essentially similar conclusions -- that long-term survival after the 2 therapies is about the same. All of these 3 trials, but particularly the OVER trial, have some considerations that are worth mentioning.

In all 3 trials, and particularly the OVER trial, the 30-day mortality for EVAR was much lower than it was for open repair, and the survival curves remained disparate for 3 years in the OVER trial. So, it took 3 years for the so-called "catch-up" in mortality to occur, and after 3 years the results were equal. But there is a problem with this: For an aneurysm patient, what could be more important than increased lifespan? If you look at the OVER trial results, the space between the survival curves for the 2 forms of treatment represents increased survival for patients.

On that basis, I don't believe that the 2 treatments are equivalent, because what could be more important to a patient with an aneurysm, most of them elderly, than living longer? In addition, the OVER trial, like the other 2 trials, is not reflective of the current state-of-the-art of EVAR. We now have better grafts, more skilled operators, more experience, and we know how to handle problems better, so the equivalence in long-term survival and the catch-up phenomenon in the OVER trial and the other 2 trials proves that EVAR is the better form of treatment for a patient who could have either.

Randomized trials are great; these were all good, well-conducted, and flawless trials in many respects, but they have to be considered in the light of possible missed interpretations and other factors, such as those that I have mentioned.

In conclusion, just because it is a randomized controlled trial, and published in a leading journal like the New England Journal of Medicine or Lancet, doesn't mean that it's absolute or necessarily completely correct. I am Dr. Frank Veith.