New randomized controlled trials for abdominal aortic aneurysm treatment should focus on younger, good-risk patients

In their editorial, Spanos et al¹ concluded that new randomized controlled trials (RCTs) are needed to compare endovascular aneurysm repair (EVAR) with open surgical repair (OSR). They observed that current surgical society guidelines depend on outdated RCTs showing perioperative superiority for EVAR that is lost during the long-term follow-up period. The shortcomings of those trials included the learning curve in the early days of EVAR, evolving approaches to reintervention, and advances in technology leading to improvements in EVAR durability.

Modern observational studies have confirmed that the perioperative morbidity and mortality of EVAR are unquestionably better than those of OSR for all patients²; however, the long-term outcomes remain unclear. The rates of secondary interventions after EVAR have improved over time but have remained greater than those after OSR, although most are for minor endovascular procedures.^2,3

We believe that clinical equipoise for a new trial does not exist. Ethically, the long-term benefits for OSR must be potentially clinically significant enough to offset the known perioperative morbidity and mortality benefits of EVAR. Furthermore, the willingness of physicians and patients in the general population to randomize (or adhere to randomization) is likely to be low given the current status of EVAR as the de facto standard for anatomically appropriate patients.

However, certain populations exist in which equipoise between OSR and EVAR might be found. We have shown that for patients aged <70 years, the perioperative mortality is clinically insignificant for both surgical methods, with mortality rates <1%.^3,4 This population is also likely to have a longer life expectancy, making long-term, patient-centered outcomes important. Using age and other risk measures to identify a population for whom the perioperative outcomes will be similar and, hence, the differences in long-term outcomes more important, can address these ethical questions.

A new RCT is needed; however, the time for repeating such a study that includes all patients has passed. The solution is to focus our efforts on populations for whom equipoise, ethics, and adherence to randomization can be achieved to maximize the feasibility and clinical effects. Studying the long-term outcomes of younger, good-risk patients will help define the role of EVAR and OSR in the care of patients with aneurysms for years to come.