The Progression of Billowing of Endologix AFX2® Abdominal Aortic Aneurysm Device as a Precursor for the Rupture of an Abdominal Aortic Aneurysm.

Despite recent publications indicating billowing (aneurysmal degeneration of the outer fabric material manifesting as a bulging sac of contained contrast due to weakening of the fabric material between the metal struts) as a benign finding, we present a unique case of billowing that resulted in aneurysmal rupture with the AFX2® stent graft (Endologix, Inc., Irvine, CA). AFX2® consists of an inner metallic endoskeleton with multiple metallic struts covered by a polytetrafluoroethylene graft fabric. It allows the flow of blood or contrast beyond the border of the metallic endoskeleton without evidence of endoleak or rupture secondary to the outer cover being anchored to the endoskeleton with polypropylene sutures only at the proximal and distal ends. Our report raises the concern that although billowing may be a relatively common manifestation with Endologix stent grafts, clinicians have to be diligent as the phenomenon may progress to abdominal aortic aneurysm rupture.