Invited commentary

This study demonstrates important differences in outcomes after endovascular aneurysm repair (EVAR) that are associated with aneurysm size. When reading this article, it is important to keep in mind a critical fact: these patients were selected for repair at a given aneurysm size. Decisions about aneurysm repair must be made within the context of the natural history of the abdominal aortic aneurysm (AAA), the risk of repair, and the patient’s life expectancy. The results indicate that the surgeons in this clinical trial took these factors into account when they selected patients for repair.

Patients with smaller aneurysms in this study were significantly younger, had better operative risk, and had more favorable anatomy for EVAR. Their AAAs were likely repaired at a smaller size because their life expectancy suggested potential benefit from “early” repair1 or they had a higher than typical risk of rupture (eg, female or family history of aneurysm)2 or both. It is logical to assume that they had EVAR rather than open repair owing to favorable anatomy for EVAR.

Older patients with more comorbidities might not have been considered candidates for repair at a smaller aneurysm size because they were not ideal candidates for either open repair or EVAR. They underwent repair when the natural history of rupture became worse than the expected results from repair. Less ideal anatomy for EVAR may have been accepted in these higher-risk patients because the alternative of open repair was worse.

The data suggest that the surgeons in this study achieved their goal in most patients. Small AAAs selected for repair had a very low rate of aneurysm-related death over 5 years—lower than one would expect relative to the natural history of small aneurysms. Patients with larger aneurysms selected for repair had worse outcomes than patients with smaller aneurysms selected for repair, but still appeared to receive benefit from repair. For patients with an AAA of >6 cm, the 92% freedom from aneurysm-related death over 5 years in this study is not ideal, but still well below the expected natural history of rupture.2 These data amplify the EUROSTAR data indicating similar trends and suggesting a similar rationale for patient selection.3

Thus, one should not infer from this study that all small aneurysms should have EVAR, or that EVAR should be avoided in large aneurysms. Yes, smaller aneurysms with good anatomy have better outcomes than larger aneurysms, but these aneurysms should have better outcomes to justify repair, because they also have a lower risk of rupture during observation.

EVAR also remains appropriate in properly selected patients with large aneurysms. The higher rates of rupture for large aneurysms under observation and the greater incidence in large-aneurysm patients in this study of such comorbidities as congestive heart failure and chronic obstructive pulmonary disease, among others, may still make EVAR the best option relative to open repair or observation. Of course, not all patients with large aneurysms and severe comorbidities should undergo EVAR, but this study indicates that EVAR remains a reasonable option in properly selected patients. Whether in clinical trials or in clinical practice, aneurysm size should be taken into account, retaining the context of the risk of rupture, the short-term and long-term risk of repair, and the patient’s overall life expectancy.