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

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.

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.

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.

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.