Long-term results show endovascular repair comparable to open for AAA patients

Last Updated: 2019-05-29

By Gene Emery

NEW YORK (Reuters Health) - Whether an abdominal aortic aneurysm (AAA) is repaired through an endovascular procedure or through open surgery makes little difference in long-term survival, according to results of a new clinical trial.

The findings, reported in the May 30 New England Journal of Medicine, conflict with two European studies which found that endovascular repair produced poorer long-term outcomes.

"We're showing that the patients receiving endovascular (repair) live a long time without incident. It's a less painful and less invasive procedure that is durable over time," coauthor Dr. Julie Freischlag, dean of the Wake Forest School of Medicine in Winston-Salem, North Carolina, told Reuters Health by phone.

She and her colleagues randomly assigned 881 Veterans Affairs patients to one of the two procedures and followed them for up to 14 years afterward. All of the surgeries were elective and all patients were asymptomatic.

From the perspective of all-cause mortality, endovascular repair scored better during the first four years, open was better during the subsequent four years and endovascular, once again, had the lower rate after the eight-year mark.

However, "none of these trends were significant," the researchers report.

The all-cause death rate was 68.0% in the 444 who received endovascular repair versus 70.0% in the 437 who received open surgery (P=0.61).

Rates were 2.9 and 3.2 percentage points higher with open surgery from six months to four years and after eight years or more, respectively. The rate was 3.4 percentage points higher for endovascular repair during years 4 to 8.

In the United States, the endovascular procedure has become increasingly popular to the point where 80% of patients with an AAA receive it. The rest usually aren't eligible because their anatomy is not suitable, such as when their arteries are too small, said Dr. Freischlag, who is also CEO of Wake Forest Baptist Health.

She said the results may have their biggest impact in Europe, where endovascular repair has been less popular.

"It will change policy because some institutions in Europe and other countries have thought this wasn't a suitable operation," she said. "We know now that patients will live for a decade, which is different from years ago when aneurysm patients, even after repair, had only a 5-year survival rate of 75%."

And in some countries where patients are underinsured, they've been forced to undergo open surgery and remain at the hospital for up to two weeks - instead of one day for endovascular repair - because, in order to get the endovascular repair, they have to spend $10,000 or so out of their own pocket for the endovascular graft.

By showing that the graft has long-term viability, insurance there may begin to cover it "and hopefully that will allow that kind of repair to be affordable for everyone," Dr. Freischlag said.

The rates of aneurysm-related death were 2.7% with endovascular repair and 3.7% with open repair, a non-significant difference. Most fatalities were perioperative.

Endovascular repair seemed to produce fewer deaths than open repair in patients under 70. The opposite was true among older patients, but the researchers said that finding should be interpreted with caution because no correction was made for multiple comparisons.

Historically, endovascular repair was initially promoted as a better option for old and frail patients.

Although aneurysm rupture occurred in only eight patients, the rate was significantly higher with endovascular repair - 1.6% versus 0.2% with open surgery.

The rate of secondary procedures was also significantly higher with endovascular repair - 26.7% of patients had at least one, compared with 19.8% who had open surgery.

The study, known as OVER, also produced a puzzling finding seen in other comparisons of the two techniques - open repair seemed to increase the risk of death from chronic obstructive lung disease (COPD).

In this test, the risk was 52% higher, or 8.2% with open repair versus 5.4% with endovascular repair, though the difference fell short of significance (between-group difference, -2.8 percentage points; 95% confidence interval, -6.2 to 0.5).

The reason, said Dr. Freischlag, remains a mystery and may not be explained by the extra four or five hours required for open repair.

"We've looked at cancer because of the increased X-rays and no one has found an increase in that. We're at a bit of a loss to explain" the lung-disease deaths, she said. "It isn't intuitive."

The higher rates of death of COPD seen in the European trials were also not significant, she said.

The researchers said changes in devices and techniques over time may explain why the two European trials suggested a higher death rate from endovascular repair. Those trials also had higher 30-day death rates.

The study was funded by the Department of Veteran Affairs Office of Research and Development.

SOURCE: https://bit.ly/2ExvpoG

N Engl J Med 2019.