Improved Endovascular Aortic Repair Durability in Patients Achieving Increased Shortest Apposition Length: A Multi-Centre Analysis

Objective: Endovascular aortic repair (EVAR) for an aneurysm of the abdominal aorta (AAA) is associated with long-term complications, such as endoleaks, resulting in a significant re-intervention rate. This study investigates the prognostic value of (change of) proximal seal length on post-EVAR computed tomography angiography (CTA) for predicting type 1a endoleak. It further proposes a risk-stratified imaging follow-up algorithm. 

Design: Multicentre, retrospective, observational study of consecutive patients who underwent elective EVAR for infrarenal AAA between 2015 and 2018 at 3 high-volume hospitals in the Netherlands. 

Materials and Methods: Aorta morphology and endograft position analysis was performed. Shortest apposition length (SAL) was measured on the first post-EVAR CTA and, if available, on the last CTA. Change of SAL through time was categorized as increasing, stable, or decreasing and correlated with type 1a endoleak and secondary interventions for endoleak. Kaplan–Meier analysis was used to calculate type 1a endoleak free and re-intervention-free survival. 

Results: Three hundred ten AAA patients with a median follow-up of 51 (Q1, 17; Q3, 71) months were included. A median SAL of 22.8 mm (Q1, 15.9; Q1, 30.4) was measured on the first post-EVAR CTA. In 168 of 310 patients (54%), a second post-EVAR CTA was available, in which 71 (42%) showed increasing SAL over time. No type 1a endoleak developed in the increasing SAL group, whereas 1 of 43 (2%) in the stable group and 10 of 54 (19%) in the decreasing group developed type 1a endoleak. Five years post-EVAR, type 1a endoleak-free survival was 100% in the increasing SAL group versus 97.1% in the stable SAL group (p=0.195), and 81.6% in the decreasing SAL group (p<0.001). The re-intervention for all types of endoleak-free survival was 100% in the increasing SAL group versus 84.6% in the stable SAL group (p<0.001), and 60.7% (p<0.001) in the decreasing SAL group. 

Conclusion: Increasing SAL after EVAR for infrarenal degenerative AAA is an indicator of durable success without type 1a endoleak and endoleak-associated secondary intervention within 5 years. Decreasing SAL is associated with development of type 1a endoleak after EVAR. Evaluation of (change of) the proximal seal could be a valuable part of follow-up after EVAR. 

Clinical Impact: Evaluation of proximal seal length after endovascular aortic repair offers valuable prognostic information regarding the risk of type 1a endoleak. Implementation could refine current follow-up algorithms to better stratify patients who have a substantial risk of type Ia endoleak from patients who may benefit from limited image surveillance.