Comparison of outcomes following endovascular repair of abdominal aortic aneurysms based on size threshold.

INTRODUCTION

Size threshold for operative repair of abdominal aortic aneurysms (AAAs) has been determined based on risks and outcomes of open repair vs surveillance. The influence of endovascular aneurysm repair (EVAR) on this threshold is less established. The purpose of this study is to determine whether long-term outcomes following EVAR are affected by maximum diameter at the time of treatment.

METHODS

Patients undergoing EVAR with modular stent grafts from 2000 to 2011 were identified from a prospectively maintained database and stratified by maximum aortic diameter at the time of repair: small (4.0-4.9 cm), medium (5.0-5.9 cm), and large (≥6.0 cm). Comparisons of demographics, indications for repair, perioperative complications, and long-term outcomes were made using analysis of variance, χ(2), and Kaplan-Meier plots.

RESULTS

Seven hundred forty patients were identified: 157 (21.2%) small, 374 (50.5%) medium, and 209 (28.2%) large. Patients differed by mean age (69.3 ± 8.09, 71.7 ± 8.55, and 73.6 ± 8.77 years for small, medium, and large, respectively; P < .001), coronary artery disease (42% small, 57% medium, 51.2% large; P = .01), prior coronary angioplasty (14.6% small, 18.2% medium, 9.6% large; P = .02), congestive heart failure (5.7% small, 15.2% medium, 19.6% large; P = .01), prior vascular surgery (7% small, 15.8% medium, 10% large; P = .016), and chronic obstructive pulmonary disease (21% small, 27% medium, 33% large; P = .038). Small AAAs were more frequently symptomatic (19.7% small, 7.5% medium, 8.1% large; P < .001). There was no difference in perioperative complication rates (P = .399), expansion ≥5 mm (2.6% small, 5.6% medium, 7.2% large; P = .148), or all-type endoleak (40.8% small, 41.7% medium, 44.5% large; P = .73). Small AAAs developed fewer type I endoleaks (5.1% vs 6.95% medium and 14.8% large; P = .001). Compared with small AAAs, both medium (P = .39) and large (P < .001) required secondary intervention more frequently, with hazard ratios of 2.32 (95% confidence interval, 1.045-5.156) and 4.74 (95% confidence interval, 2.115-10.637), respectively. Ten-year survival was 72%, 63.1%, and 49.8% in the small, medium, and large groups, respectively (P < .001) with one rupture-related death after EVAR in the large group. All-cause mortality differed among the 75- to 84-year-old patients (30.4% small, 51.6% medium, 55.7% large; P = .017).

CONCLUSIONS

EVAR for small AAAs shows improved long-term outcomes than for age-matched patients with larger aneurysms.