endoleak

Endoleak is a complication that can arise after endovascular aneurysm repair (EVAR), in which blood continues to flow into the aneurysm sac despite placement of a stent graft. The persistent flow can cause the aneurysm to expand and potentially rupture if not addressed. The term “endoleak” refers to any leakage that follows the introduction of the endovascular device and is not a result of late graft failure or completion of the repair.

There are several classic classifications of endoleak that reflect the source of the blood flow. Type I endoleaks occur when the graft does not seal adequately at the proximal or distal attachment sites, allowing blood to enter from the aortic or iliac arteries. Type II endoleaks arise from back‑flow through collateral branches such as lumbar or mesenteric vessels and are the most frequent. Type III endoleaks result from fabric tears or disconnections between modular graft components. Type IV leaks involve porous graft material that allows blood to seep through the graft itself. A newer subtype, Type V, describes continued sac expansion without an identifiable leak on imaging, often termed endotension.

Diagnosis relies on imaging modalities that can detect low‑velocity flow within the aneurysm sac. Contrast‑enhanced computed tomography provides detailed anatomic information and is the standard, while duplex ultrasonography and magnetic resonance angiography are useful alternatives, especially in patients with renal impairment. In unclear cases, digital subtraction angiography can confirm the presence and source of an endoleak.

Treatment is tailored to the leak type and clinical context. Small, asymptomatic Type II leaks may be monitored with serial imaging, whereas persistent or enlarging leaks generally warrant intervention. Endovascular techniques such as embolization of feeding vessels are common for Type II leaks, while Type I and III leaks usually require graft extension, new cuff placement, or conversion to open surgery. Managing Type IV and V leaks is more challenging and often involves repeated imaging and, if necessary, additional endovascular repair.

The long‑term outlook for patients with endoleak depends on timely identification and appropriate management. Untreated endoleaks can lead to aneurysm sac expansion and increased rupture risk. Therefore, routine post‑EVAR surveillance imaging remains essential for early detection and prompt treatment of endoleaks.