UK EVAR Trials Published and Presented at Charing Cross Symposium

April 11, 2010 — Principal investigator Professor Roger Greenhalgh, MD, and trial manager Louise C. Brown, PhD, presented the 10-year follow-up results from the United Kingdom's EVAR 1 and EVAR 2 trials of endovascular aneurysm repair (EVAR) versus open repair of abdominal aortic aneurysm (AAA) at the Charing Cross International Symposium in London. The findings were also published online ahead of print in the New England Journal of Medicine. EVAR 1 studied patients deemed fit for open surgical repair, and EVAR 2 studied patients deemed unfit for open surgical repair.

In EVAR 1, the investigators concluded that in this large, randomized trial, EVAR was associated with a significantly lower operative mortality than open surgical repair of AAA. However, no differences were seen in total mortality or aneurysm-related mortality in the long-term. EVAR was also associated with increased rates of graft-related complications and reinterventions and was more costly.

The background of the study is that few data are available on the long-term outcomes of EVAR compared with open repair.



The study was composed of 1,252 patients presenting with large AAAs (≥ 5.5 cm in diameter) at 37 hospitals in the United Kingdom from 1999 through 2004. The investigators randomly assigned the patients to undergo either EVAR or open repair; 626 patients were assigned to each group. Patients were followed for rates of death, graft-related complications, reinterventions, and resource use until the end of 2009. Logistic regression and Cox regression were used to compare outcomes in the two groups.



The investigators reported that the 30-day operative mortality was 1.8% in the EVAR group and 4.3% in the open repair group (adjusted odds ratio for EVAR compared with open repair, 0.39; 95% confidence interval [CI], 0.18–0.87; P = .02). The EVAR group had an early benefit with respect to aneurysm-related mortality, but the benefit was lost by the end of the study, at least partially because of fatal endograft ruptures (adjusted hazard ratio, 0.92; 95% CI, 0.57–1.49; P = .73). By the end of follow-up, there was no significant difference between the two groups in the rate of death from any cause (adjusted hazard ratio, 1.03; 95% CI, 0.86–1.23; P = .72). The rates of graft-related complications and reinterventions were higher with EVAR, and new complications occurred up to 8 years after randomization, contributing to higher overall costs.

In the EVAR 2 study of AAA patients who were physically ineligible for open repair, the investigators found that EVAR was associated with a significantly lower rate of aneurysm-related mortality than no repair. However, EVAR was not associated with a reduction in the rate of death from any cause. Also, the rates of graft-related complications and reinterventions were higher with endovascular repair, and it was more costly than not intervening.

According to the investigators, EVAR of AAA was originally developed for patients who were considered to be ineligible for open surgical repair but data are lacking on the question of whether EVAR reduces the rate of death among these patients.

EVAR 2 was composed of 404 patients considered ineligible for surgery presenting with large AAAs (≥ 5.5 cm) at 33 hospitals in the United Kingdom from 1999 through 2004. The EVAR 2 investigators randomly assigned the patients to undergo either endovascular repair (n = 197) or no intervention (n = 207). Patients were followed for rates of death, graft-related complications, reinterventions, and costs until the end of 2009. Cox regression was used to compare outcomes in the two groups.



The EVAR 2 investigators found that the 30-day operative mortality was 7.3% in the EVAR group. The overall rate of aneurysm rupture in the group with no intervention was 12.4 (95% confidence interval [CI], 9.6–6.2) per 100 person-years. Aneurysm-related mortality was lower in the EVAR group (adjusted hazard ratio, 0.53; 95% CI, 0.32–0.89; P = .02). This advantage did not result in any benefit in terms of total mortality (adjusted hazard ratio, 0.99; 95% CI, 0.78–1.27; P = .97). A total of 48% of patients who survived EVAR had graft-related complications, and 27% required reintervention within the first 6 years. During 8 years of follow-up, endovascular repair was considerably more expensive than no repair (cost difference, £9,826 [US $14,867]; 95% CI, £7,638–12,013 [$11,556–18,176]).
 


Perspective on these trials was provided to Endovascular Today by Matt Thompson, MD, FRCS, who is Professor of Vascular Surgery at St. George's Vascular Institute, St. George's Hospital in London.

“The 10-year results for the EVAR 1 and 2 trials provide long-term data concerning the outcomes of endovascular and open repair,” commented Professor Thompson. “The most significant new finding of these trials was the lower rate of aneurysm-related death in the patients considered unfit for open surgical intervention (EVAR 2) and suggests a benefit to endovascular repair in these patients. The interpretation of the trials, and in particular the reintervention rates, must be done with the knowledge that the trials reflect the state of endovascular practice at the time of patient entry into the trials a decade ago.”