The significance and management of the leaking endograft.

Endoleak is the persistence of blood flow outside the lumen of an endograft, but within an aneurysm sac or adjacent vessel being treated by the graft. Diagnosis may be difficult, and treatment remains somewhat controversial. The purpose of this article is to discuss the clinical significance and appropriate management of endoleaks within the context of our current understanding of this phenomenon. The diagnosis of an endoleak can be made by conventional angiography, duplex ultrasound, intravascular ultrasound (IVUS), and computed tomography (CT) angiography. All of these modalities are effective, although CT angiography may be the most sensitive. Endoleaks can be categorized into 5 classes: (1) perigraft flow around the proximal end of the endograft; (2) perigraft flow around the distal end of the endograft; (3) flow through a defect in the body of the endograft; (4) flow between segments of a multicomponent endovascular graft; and (5) flow between arterial branches within an aneurysm sac. The first 4 classes have been shown to represent a clinical situation in which systemic arterial pressure is transmitted to an inadequately excluded aneurysm sac, placing the sac at risk of rupture. In contrast, branch-flow leaks do not appear to carry an increased risk of rupture, provided there is no increase in aneurysm sac diameter. However, an increase in the diameter of an aneurysm sac after endograft implantation may be a sign of occult endoleak, even if not visualized by current imaging techniques. Thus, we believe that collateral branch leaks with no associated aneurysm sac expansion may be observed with regular follow-up by CT angiography. All other endoleaks should be treated with adjunctive endovascular maneuvers or explanation of the endograft with standard open repair-in short, routine follow-up imaging on endografts to detect the presence of late endoleaks or aneurysm sac expansion.