ABSTRACT
An abdominal aortic aneurysm (AAA) may continue to expand following apparently successful repair by endoluminal graft technique, even in the absence of endoleak. This phenomenon is most likely due to maintenance of high pressure within the aneurysm sac, presumably by pressure transmission from the adjacent aortic lumen (1). We have postulated that, in most cases, this pressure may be transmitted through thrombus, which is acting to seal the endograft from flowing blood, but which is not an adequate barrier to totally exclude the aneurysm sac from pressure effects. However, it is likely that there are other causes of endotension, including transmission of pressure across the wall of an endograft itself, perhaps associated with high porosity or other factors.
