Fig. 4

Drawing illustrating the physiopathology of type II endoleak. a Schematic representation of an abdominal aortic aneurysm (AAA) with a normal bowel circulation, supplied by superior mesenteric artery (SMA) and inferior mesenteric artery (IMA); b blood circulation after a typical EVAR: normal flow in the SMA, that provides blood to the major part of the bowel through collateral circles shared with the territories irrigated by the IMA; no flow in the IMA, that originates from the excluded aneurysm sac; c type II endoleak: collateral vessels provide retrograde blood flow to the IMA, bringing blood inside the aneurysm sac