Late type III endoleaks are common in early generation Endologix AFX stent grafts

Objective: Early generation Endologix AFX endovascular abdominal aortic aneurysm (AAA) stent graft devices are at risk of developing type IIIa (intercomponent/overlap-related) as well as type IIIb (fabric tear) endoleaks over time. Current follow-up studies are limited to short (<24 months) and midterm (24-48 months) reports. The purpose of this study was to identify the incidence of type III endoleaks associated with these endografts over a long-term follow-up (>4 years) period and discuss current management strategies.

Methods: A retrospective, single-institution cohort analysis of all Endologix AFX endografts implanted from October 2011 to October 2016 was performed. Patient characteristics, imaging, and follow-up were obtained via chart review. Type III endoleaks were characterized based on computed tomography angiogram/operative findings and confirmed by two surgeons. Statistical analysis was performed with SAS v9.4.

Results: Sixty-three patients underwent AFX stent graft implantation for aneurysmal disease. Forty-seven patients comprised the final cohort for analysis after exclusions were made for primary iliac aneurysms as well as off-label use of the device (eg, hypogastric snorkel) or primary occlusive indications. The average age was 73.3 years, with the longest follow-up being 8.7 years (median, 5.2 years). Most AAAs (89.2%) were fusiform, with initial median diameter 5.5 cm. Initial 30-day mortality was 0%. Of the initial cohort, 10 (21.3%) type III endoleaks were treated, of which six (60%) were type IIIa and four (40%) were type IIIb. By time-to-event analysis at latest follow-up, freedom from type III intervention was 48% at 8 years. The median time to type III endoleak discovery was 4.7 years (range, 1.1-7.2 years), an interval that was similar for type IIIa and type IIIb leak types (P = .73). Patients with type III endoleaks had average sac growth of 1.3 cm over the follow-up interval compared with a net decrease for patients without type III endoleaks (P < .0001). Of the 10 patients treated for type III leaks, seven (70%) underwent complete endovascular re-lining, one (10%) had partial re-lining, and two (20.0%) underwent open endograft explant with aortic graft reconstruction. Reintervention 30-day mortality was 0% for all approaches.

Conclusions: Early generation Endologix AFX stent grafts have a high rate of type III endoleaks, with freedom from type III leak <50% at 8-year follow-up. Most of these are not detected until several years (>4.5 years) after initial implantation, beyond the range of the follow-up interval of most published reports. Long-term imaging surveillance is critical, and a low threshold for complete relining should be considered with any sign of sac enlargement, even if endoleak is not clearly demonstrated in patients with early generation Endologix AFX grafts.