Choice of AAA Repair Method Still Divides Surgeons

BY JEFF EVANS

LONDON -- The identical results of the two major trials that have been completed comparing endovascular and open repair of abdominal aortic aneurysms leaves interpretation of the data largely up to the preferences of individual surgeons and their patients, according to speakers who debated the issue at the Charing Cross 28th International Symposium.

Much of the controversy that surrounds the interpretation of the Endovascular Aneurysm Repair 1 (EVAR 1) trial and the Dutch Randomized Endovascular Aneurysm Management (DREAM) trial is centered on the value that should be placed on the reduction of aneurysm-related mortality and the faster postoperative recovery that is seen with endovascular repair in the face of its higher incidence of complications and reinterventions.

The EVAR 1 trial randomized 1,082 patients with AAAs at least 5.5 cm in diameter who were fit enough to receive either procedure. DREAM randomized 351 similar patients with an AAA diameter of at least 5 cm.

The equivocation on the interpretation of these two adequately powered trials suggests that at least part of this indecisiveness may "be due to the difficulty that we have as clinicians to view the data objectively. The fact of the matter is that most of us are going to have a preference one way or the other," said Dr. Richard Gibbs of the regional vascular unit at St. Mary's Hospital, London.

In the EVAR 1 trial, endovascular repair had a 3% lower absolute operative mortality than did open repair (1.7% vs. 4.7%). This translated into a threefold higher relative risk of death from open repair, compared with endovascular repair--about 1 in 60 for the endovascular procedure and about 1 in 20 for open surgery. "Don't tell me that that is not clinically important," said Dr. Peter L. Harris of the Royal Liverpool (England) University Hospital. After 4 years of follow-up, aneurysm-related mortality remained 3% lower for endovascular repair than surgical repair (4% vs. 7%), a risk of death of about 1 in 25 for endovascular repair and 1 in 14 for open surgery.

EVAR Not a DREAM?

"A disease-specific treatment can have only a disease-specific effect," Dr. Harris commented, "and ruptured aneurysm is a relatively low-risk cause of death."

All-cause mortality was the same for open surgery and endovascular repair in each trial: 28% after 4 years in EVAR 1 and 10% after 2 years in DREAM. But this does not mean that the benefit of lower aneurysm-related mortality is not relevant, Dr. Harris argued.

If you tell a 70-year-old man with a 6.5-cm AAA that you are going to treat him with one of two available options and that the modality that you are choosing has a threefold higher risk of death, you don't tell the man that the difference between the two "doesn't matter because you're going to die anyway," he pointed out.

But Dr. Gibbs called the reduction in aneurysm-related mortality in EVAR 1's endovascular repair group a "large red herring" and questioned its real-world relevance. "Do you think your patient who had an EVAR and fortunately has not perished will say later when he is dying that 'I'm pretty pleased I'm not dying of an aneurysm-related cause'?" he asked.

In both arms of the EVAR 1 trial, 32% of all deaths had cardiovascular causes, which indicates that cardiovascular disease is "waiting to get the patients" who survive repair. It is especially "depressing" to note that statins were used by 38% of patients in the EVAR 1 trial, fewer than half of patients in the DREAM trial, and only 18% of patients in the European Collaborators on Stent/Graft Techniques for Aortic Aneurysm Repair (EUROSTAR) registry, Dr. Gibbs said. "I think it's perfectly reasonable to say that 100% of them should have been [at least] on aspirin," he added.

Dr. Harris called the additional expense of endovascular repair in the EVAR 1 trial over open surgery-- œ3,311, or about $6,000--a "marginal cost"; this additional expense was related to the expense of conducting the trial, which included more CT scans, greater numbers of reinterventions, and longer lengths of stay in the hospital than is common in current practice. "So the costs that we have available are not relevant to today's practice," he added.

'THE [RESULTS OF THE DREAM AND EVAR 1] TRIALS HAVE SWUNG THE CHOICE OF VASCULAR SURGEONS AWAY FROM EVAR.'

During the 4 years of the EVAR 1 trial, each participating hospital performed endovascular repairs in an average of only 4 patients per year. Even with so few endovascular repairs performed at each center each year, this procedure had lower aneurysm-related mortality and better initial health-related quality of life after the operation than did the "established treatment of open surgery," said Dr. Krassi Ivancev of the department of radiology at Malm” (Sweden) University Hospital.

The estimate of overall survival at 4 years in the EVAR 1 trial represented only 17% of the entire cohort. Although EVAR 1 was more than three times the size of the DREAM trial, both reported on nearly 60% of their cohorts at 2 years, said Dr. Jan D. Blankensteijn of the department of vascular surgery at Radboud University Nijmegen (the Netherlands) Medical Center.

He and his associates surveyed 192 surgeons who perform AAA repairs in the Netherlands. When presented the scenario of a 65-year-old man with a 6.5-cm AAA without comorbidities who was suitable for both open or endovascular repair, more surgeons indicated that they would have preferred open, rather than endovascular, repair prior to knowing the results of the EVAR 1 and DREAM trials (72% vs. 28%).

About the same ratio of surgeons favored endovascular repair over open surgery for a man aged 77 years with a 6.5-cm AAA and mild comorbidities but suitable vascular anatomy. The results of the two trials did not substantially change their decision on either of these patients. Of the 129 vascular surgeons in the survey, 29 switched their opinion on the two examples from endovascular to open repair, only 15 changed their opinion from open to endovascular repair, Dr. Blankensteijn said.

"The DREAM and EVAR 1 trials have not swung the choice toward EVAR. If anything, the trials have swung the choice of vascular surgeons away from EVAR," he concluded.