EVAR Takes the Lead in Continuing Debate Over Best Therapy for Ruptured AAAs

New York, NY—During a session at last week’s 2015 VEITH Symposium devoted to analyzing the IMPROVE trial and understanding its importance, participants took part in an admittedly unscientific poll.

Asked to choose the preferred intervention for ruptured abdominal aortic aneurysms (rAAAs)—endovascular or open surgical repair—only a few hands out of several hundred tentatively rose in support of surgery.

With adequate experience, endovascular aneurysm repair (EVAR) can be performed in nearly all rAAA cases, symposium chair Frank J. Veith, MD, of the Cleveland Clinic (Cleveland, OH) and New York University (New York, NY), told TCTMD. Veith dedicated his presentation on November 19, 2015, to debunking IMPROVE’s main comparison of 30-day mortality between EVAR and surgery.

“So many people in medicine think that a randomized trial is right up there with God, but that’s baloney,” Veith said in the interview. The main problem with IMPROVE, he explained, is that while “well designed and conducted,” many patients crossed over from their initial treatment strategy—more than half of those assigned to EVAR, for example, had surgery. Moreover, 44% of patients assigned to the surgical arm did not get any intervention at all.

“If you exclude half the patients from the intention to treat, you’ve got to look at per protocol. [The IMPROVE investigators] looked at it but didn’t pay any attention to it,” Veith said. Analyzing the findings by the therapy that patients actually received results in 30-day mortality rates of 25% for EVAR and 38% for open repair.

“To me it seems that the IMPROVE trial clearly shows that EVAR is the better treatment for rAAA patients—if it can be done,” Veith concluded in his presentation.

Three factors can help increase survival in EVAR patients, he noted: hypotensive hemostasis, proper use of aortic balloon control, and proper treatment of abdominal compartment syndrome.

IMPROVE Researchers Speak

Bookending the session were 2 presentations by IMPROVE investigators.

In the first, Janet T. Powell, MD, PhD, stood by the study’s main conclusion that EVAR and surgery result in similar survival, saying that neck length may be more influential that treatment type. She cited an analysis, published earlier this year in the European Heart Journal, that shows a link between neck length and 30-day mortality (adjusted OR 0.72 for each 15-mm increase in length; 95% CI 0.59-0.92; P = .007).

The relationship, also seen in the AJAX and ECAR trials, “is independent of all known confounders and explains why observational studies show a benefit for EVAR but randomized trials do not,” Powell commented. As the EHJ paper explains, “the long aneurysm neck patients get EVAR and the short aneurysm neck patients get open repair.”

Robert J. Hinchliffe, MD, St. Georges Vascular Institute (London, England), then concluded the session by outlining 1-year data from IMPROVE. Although there was no survival benefit with EVAR, he conceded, the less invasive approach led to improvements in patient-centered outcomes including earlier discharge home and better quality of life. Moreover, the endovascular strategy is cost effective, suggesting “that emergency [EVAR] should become more widely available,” Hinchcliffe said.

Strategies Differ Among Centers

Thomas Larzon, MD, PhD, of Örebro University (Örebro Sweden), agreed with Veith that “RCT data can not be generalized.”

Sharing his experience with an EVAR-only approach to rAAA, Larzon said, “The overall strategy at my center is that we use the same technique [with rAAA] as with elective cases.” Specifically, this means use of a percutaneous technique with local anesthesia if possible and the fascia suture technique for closure, with no need for presuturing, he explained. One or two balloons are used, when appropriate to control blood pressure, and other techniques include chimney graft and Onyx (ev3) embolization.

With this approach, he reported, only 9% of patients were unsuitable for intervention between 2009 and 2013. Nearly two-thirds of those who had EVAR did so with local anesthesia, 27% had aortic balloon occlusion, and half had at least 1 adjunctive technique, with the latter having no influence on mortality risk.

Thus, surgery “can be replaced by EVAR with appropriate management of existing adjunct techniques,” Larzon commented. “Team training is crucial.”

Also in support of EVAR, Marc R.H.M. van Sambeek, MD, PhD, of Catharina Hospital (Eindhoven, the Netherlands), said that his center’s experience differs from the IMPROVE evidence. “EVAR in rAAAs with hostile infrarenal aortic necks appears technically feasible and safe in experienced hands,” he noted, reporting similar 1-year rates of endograft-related complication and secondary intervention despite more challenging anatomy.

Other presentations came down in favor of surgery, although the audience remained unconvinced. In particular, Willem Wisselink, MD, of VU University Medical Center (Amsterdam, the Netherlands), argued that midterm results for reinterventions and mortality are “no better after EVAR for rAAA than after open repair,” he said, citing a paper published earlier this year in the European Journal of Vascular and Endovascular Surgery.

However, Matthew M. Thompson, MD, of St Georges Vascular Institute (London, England), pointed out that much of the difference between EVAR and surgery comes down to system-level factors. Data published in the Lancet show that patients in the United States are more likely than those in the United Kingdom to be treated at teaching hospitals and to undergo intervention, with a greater proportion of treated patients receiving EVAR vs surgery. These factors, he suggested, may explain why in-hospital mortality is higher for rAAA patients in the United Kingdom.