Aortic Bifurcation Morphology Alone is Not Able to Predict Outcome in Patients Submitted to Elective Endovascular Abdominal Aortic Aneurysm Repair

Abstract

Purpose: The aim of the present study was to evaluate the impact of the aortic bifurcation (AB) morphological characteristics, analyzed on computed tomography angiography (CTA), on outcomes of patients with abdominal aortic aneurysms (AAAs), treated by endovascular aneurysm repair (EVAR) in a single-center experience.

Materials and methods: A retrospective analysis was conducted using a prospectively collected database. Morphological features considered as potentially impacting outcomes were maximum AB diameter (AB_max), minimum diameter (AB_min), mean diameter (AB_average), AB area (AB_area), and AB calcification (AB_{calcification}) and thrombosis (AB_thrombosis). Outcome measures were perioperative, 30-day, and midterm AAA-related reinterventions and all-cause mortalities.

Results: Investigators reviewed 306 preoperative CTA scans. Maximum aortic diameter was 51.4 ± 12.4 mm (range 40-110), and mean AB_max was 24.2 ± 8.8 mm (range 10-60), AB_min 17.0 ± 5.4 mm (range 4-40), AB_average 20.6 ± 6.5 mm (range 9-47.5), and AB_area 35.2 ± 24.2 mm² (range 6-176). AB_{calcification} ≥ 50% was present in 63 patients (20.6%), and AB_thrombosis ≥ 50% in 102 patients (33.3%). Technical success was obtained in all cases, without perioperative reintervention or death. At 30-day follow-up, the reintervention rate was 3.3%, and mortality rate was 1.3%. At a mean follow-up period of 35 ± 28.6 (range, 1-72) months, reintervention and mortality rates were 6.5 and 4.9%, respectively. None of the analyzed thresholds were predictive of adverse outcomes. At multivariate analysis, association of a narrowed AB with severe calcification of the distal aorta showed a significant differences in terms of reinterventions (p = 0.009).

Conclusions: Our limited experience seems to reveal that a cutoff of ≤ 20 mm for AB diameter, as in current guidelines, is ineffective in predicting outcomes after EVAR.

Keywords: AAA preoperative characteristics; Abdominal aortic aneurysms; Aortic area; Aortic bifurcation diameter; Circumferential calcification; EVAR; EVAR outcomes; Thrombus load.