EVAR with Flared Iliac Limbs has a High Risk of Late Type 1b Endoleak

Abstract

Introduction: Re-interventions are still the Achilles' heel of endovascular aneurysm repair (EVAR). Ectatic common iliac arteries (CIA) can be treated with flared iliac limbs but a dilated artery used as sealing zone could increase the risk of a late type 1b endoleak. The aim of the present analysis was to evaluate the risk of late type 1b endoleak after EVAR in patients with CIA limbs ≥20 mm compared with those <20 mm.

Methods: A retrospective analysis was performed of patients treated by EVAR at the study institution between 2006 and 2012, including patients with available information about the type of iliac stent grafts and a minimum follow-up (FU) of 3 years with contrast enhanced CT, or those that had developed a type 1b endoleak earlier. The cohort was divided into two groups: Group I included iliac limbs with a distal diameter <20 mm, and Group II included all iliac limbs with a distal diameter ≥20 mm.

Results: Of 692 limbs (346 patients), 239 limbs (34.5%) from 129 patients were included in the analysis. Mean CT FU was 53 months, 178 had an iliac stent graft diameter <20 mm (Group I), and 61 a diameter of ≥20 mm (Group II). Mean oversizing for iliac limbs was 17.2% (IQR 14) and there was no case of immediate type 1b endoleak. For the whole group, 18 type 1b endoleaks occurred during FU (7.5%) after a mean of 37.7 months (range 4-96). Eleven of 61 (18%) iliac limbs in Group II developed a type 1b endoleak during FU in contrast to 7/178 (3.9%) in Group I (OR 5.3, 95% CI 1.98-14.59, p = 0,001). The ROC curve analysis indicated a limb diameter of 19 mm as a cutoff value for a higher probability of developing a type 1b endoleak.

Conclusion: Patients treated with iliac limbs ≥20 mm had a fivefold higher risk of late (mean 37 months) type 1b endoleak compared with patients treated with a distal iliac limb diameter <20 mm.

Keywords: Bell bottom technique; EVAR; Flared limbs; Type 1b endoleak.