No Long-term Mortality Difference Between Endovascular vs. Open AAA Repair

 

 

Endovascular repair of abdominal aortic aneurysm (AAA) holds an edge over surgery for the first 3 years after treatment in terms of all-cause mortality, but the 2 treatments result in similar long-term survival. Surprisingly, however, younger patients stand to benefit most from the less invasive treatment, according to a paper published in the November 22, 2012, issue of the New England Journal of Medicine.


The findings represent full follow-up from the OVER (Open Versus Endovascular Repair) trial, which previously showed an advantage for endovascular repair in an interim analysis published in the Journal of the American Medical Association in October 2009. Perioperative mortality within 30 days was lower with endovascular than with open repair at 0.5% vs. 3.0% (P = 0.004), though the difference was no longer significant at 2 years when analyzing 80% of the patient population.

For the OVER trial, Frank A. Lederle, MD, of the Veterans Affairs Medical Center (Minneapolis, MN), and colleagues randomized 881 patients with asymptomatic AAA to either endovascular (n = 444) or open (n = 437) repair at 42 Veterans Affairs hospitals in the United States. The study period ranged from 2002 to 2005, and follow-up lasted up to 9 years (mean, 5.2 years). In all, 96% of the cohort underwent the assigned treatment.

Curves Converge After 3 Years

The current analysis, in a departure from the interim results, demonstrated lower mortality with endovascular repair both at 2 years and 3 years. But the benefit was not sustained thereafter, and Kaplan-Meier curves showed similar cumulative risk of death at 8 years (table 1).

Table 1. All-Cause Mortality: Endovascular vs. Open Repair

 

 

HR

95% CI

P Value

At 2 Years

0.63

0.40-0.98

0.04

At 3 Years

0.72

0.51-1.00

0.05

At 8 Yearsa

0.97

0.77-1.22

0.81

a Kaplan-Meier estimate.

Endovascular repair was associated with lower mortality among patients aged younger than 70 years (HR 0.65; 95% CI 0.43-0.98; P = 0.04) but with higher mortality among older patients (HR 1.31; 95% CI 0.99-1.73; P = 0.06). The interaction between treatment group and age was highly significant (P = 0.006). Further analyses suggested that the difference observed in younger patients may arise from cancer-related death.

Compared with surgery, mortality after endovascular repair tended to be higher when AneuRx (Medtronic, Minneapolis, MN) was the intended graft (HR 1.49; 95% CI 0.93-2.40; P = 0.06 for interaction between treatment group and device type). The AneuRx graft was used in 6 of the 10 patients with aneurysm-related deaths after endovascular repair and in 2 of 3 patients with nonfatal ruptures.

There were 10 aneurysm-related deaths in the endovascular group (2.3%) and 16 in the open repair group (3.7%; P = 0.22). Six aneurysm ruptures occurred in the endovascular group (1.4%); four took place more than 5 years after treatment, and half were fatal. There were no ruptures in the surgical group (P = 0.03).

Though the number of patients requiring secondary therapeutic procedures was higher with endovascular compared with open repair at 22.1% vs. 17.8%, the difference did not reach significance (P = 0.12). The number of hospitalizations also was similar between the 2 groups.

Over 8 years, there were no differences between endovascular and open repair with regards to health-related quality of life and erectile function.

Frailty May Play a Role

Though a “procedure associated with late failures would seem to be less desirable for use in younger patients,” the rupture rate was low and tended to occur in older patients and those who did not complete recommended follow-up or secondary treatments, the investigators note. “Pending longer-term data, we therefore consider endovascular repair to be a reasonable option in patients younger than 70 years of age who are likely to adhere to medical advice.”

In a telephone interview with TCTMD, Dr. Lederle said it was somewhat surprising that “mortality in the endovascular group caught up with the open group. That doesn’t always happen in studies. A lot of times, there will be an intervention and the 2 curves will be parallel.

“We’re not really sure what that [means],” he continued. “What we speculate in the paper is that perhaps the more invasive procedure, open repair, [initially] caused some deaths in the most frail patients, and an equivalent number of the most frail patients in the endovascular group then died of other causes in the next few years until finally we were back to where we started. It’s not terribly clear.”

No Clear Winner

Based on the current findings, Joshua A. Beckman, MD, of Brigham and Women’s Hospital (Boston, MA), asks in an editorial accompanying the paper, “Is the dream of endovascular repair over?”

Admittedly, “it has substantially reduced the pain and suffering associated with AAA repair and rightly has overtaken open repair as the primary form of treatment,” he writes. The less invasive treatment, on the other hand, “has neither expanded AAA repair to new populations nor reduced long-term mortality when compared with open repair.” The dream may be over, Dr. Beckman notes, “but the reality of better procedural recovery for patients today is certainly a step forward.”

Dr. Lederle agreed that, although endovascular technology is progressing and outcomes are improving, “the original hope that this would be a panacea for older and sicker patients does not seem to be the case.”

In short, “it’s a mixed message,” he said. Endovascular repair “is less debilitating, but you have more follow-up and more aortic-related problems later on, and in the end survival is similar. The good news is that patients and physicians can talk about these choices and they don’t have to feel compelled to go one way or the other.”

Standing by ‘Endovascular First’

Barry T. Katzen, MD, of Baptist Cardiac and Vascular Institute (Miami, FL), described OVER as “a phenomenal study . . . in terms of the work that was done.”

In a telephone interview, he expressed surprise that the early edge for endovascular repair disappeared over time. “I’m not sure that there’s a clear explanation,” Dr. Katzen agreed. The positive news, he added, is that rates of secondary procedures were equivalent, though the finding speaks to the need for surveillance after both treatments.

Another factor affecting mortality may be the devices that were used, Dr. Katzen noted. “You have to wonder if a single device were removed from the analysis whether results would be different.”

As for the clinical implications, “[y]ou need a good physician to try to find the best solution for a specific patient in the end. It’s not always black and white,” Dr. Katzen advised. “This [study] confirms that there are a lot of factors that have to be taken into account. . . . In the right patients, I think an ‘endovascular first’ strategy is still warranted.”

 


Sources:

1. Lederle FA, Freischlag JA, Kyriakides TC, et al. Long-term comparison of endovascular and open repair of abdominal aortic aneurysm. N Engl J Med. 2012;367:1988-1997.

2. Beckman JA. Is the dream of EVAR over? N Engl J Med. 2012;367:2041-2043.

 

 

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Disclosures
  • The study was supported by the Cooperative Studies Program of the Department of Veterans Affairs Office of Research and Development.
  • Disclosure statements provided by Drs. Lederle and Beckman are available with the full article at NEJM.org.
  • Dr. Katzen reports consulting for Medtronic Vascular and WL Gore and receiving research funding from Cook Medical.

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