For patients who undergo elective repair of abdominal aortic aneurysm, long-term mortality is not significantly different between those who have endovascular surgery and those who have open surgery, according to a report published online Nov. 22 in the New England Journal of Medicine.
Perioperative survival was superior with the endovascular approach, and that advantage lasted for up to 3 years. But from that point on, survival was similar between patients who had undergone endovascular repair and those who had undergone open repair, said Dr. Frank A. Lederle of the Veterans Affairs Medical Center, Minneapolis, Minn., and his associates.
Dr. Frank A. Lederle
Three large, randomized clinical trials compared the two surgical approaches: the United Kingdom Endovascular Repair 1 (EVAR 1) trial, the Dutch Randomized Endovascular Aneurysm Management (DREAM) trial, and the Open versus Endovascular Repair (OVER) Veterans Affairs Cooperative Study in the United States. All three studies initially showed a survival advantage with the endovascular procedure in the perioperative period. But longer follow-up in the EVAR 1 and DREAM studies suggested that this advantage was lost at approximately 2 years, due to an excess in late deaths among patients who had undergone endovascular repair.
Dr. Lederle and his colleagues now report the long-term findings of the OVER trial, and they also found that at approximately 3 years, the survival curves between the two study groups converged.
The OVER trial was conducted at 42 VA medical centers across the country and involved 881 patients. The mean patient age was 70 years, and, as is typical in VA cohorts, 99% of the subjects were male.
All patients had abdominal aortic aneurysms with a maximal external diameter of at least 5 cm, an associated iliac-artery aneurysm with a maximum diameter of at least 3 cm, or a maximal diameter of at least 4.5 cm plus either rapid enlargement or a saccular appearance on radiography and CT examination.
A total of 444 study subjects were randomly assigned to endovascular repair and 437 to open repair. They were followed for up to 9 years (mean follow-up, 5.2 years). During that time, there were 146 deaths in each group.
All-cause mortality was significantly lower in the endovascular group at 2 years, but that difference was only of borderline significance at 3 years and disappeared completely thereafter. Similarly, the restricted mean survival was no different between the two groups at 5 years and at 9 years (N. Engl. J. Med. 2012;367:1988-97 [doi:10.1056/NEJMoa1207481]).
The time to a second therapeutic procedure or death was similar between the two groups, as were the number of hospitalizations after the initial repair, the number of secondary therapeutic procedures needed, and postoperative quality of life.
The most likely explanation for the convergence of the survival curves over time is that the frailest patients in the open-repair group died soon after that rigorous procedure, while the frailest patients in the endovascular-repair group survived that less invasive surgery but succumbed within a year or two, Dr. Lederle and his associates said.
When the data were analyzed according to patient age, an interesting result emerged: Patients younger than age 70 had better survival with endovascular than with open repair, while patients older than age 70 had better survival with open than with endovascular repair. This was surprising, given that "much of the early enthusiasm for endovascular repair focused on the expected advantage among old or infirm patients who were not good candidates for open repair," they noted.
Even though the rate of late ruptures was higher for the endovascular approach, it was still a very low rate, "with only six ruptures during 4,576 patient-years of follow-up." Moreover, four of these six late ruptures occurred in elderly patients, three of whom didn’t adhere to the recommended follow-up.
"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," Dr. Lederle and his colleagues said.
Nevertheless, endovascular repair "does not yet offer a long-term advantage over open repair, particularly among older patients, for whom such an advantage was originally expected," they noted.
This study was supported by the Department of Veterans Affairs Office of Research and Development. Dr. Lederle reported no financial conflicts of interest; one of his associates reported ties to Abbott, Cook, Covidien, Gore, and Endologix.