Translumbar Embolization of Type 2 Endoleaks after Endovascular Repair of Abdominal Aortic Aneurysms

Abstract

ENDOVASCULAR repair of abdominal aortic aneurysms is a rapidly proliferating technique. Unlike conventional “open” aneurysm repairs, patients may develop immediate or delayed “endoleaks” requiring remediation either by catheter-based or surgical intervention. Endoleaks are classified into one of four categories (1,2). A leak at an attachment site (proximal, middle, or distal) is classified as type 1. In collateral endoleaks (type 2), blood travels from a branch vessel in the nonstented portion of the aorta or iliac arteries. Blood flow then takes a circuitous route, emptying into the aneurysm sac via retrograde flow through a lumbar artery, inferior mesenteric artery, or other vessel originating from the aneurysm. This type of leak is the most common and is unrelated to the type or configuration of stent-graft used. Endoleaks that are a result of a defect in, or failure of, the graft material are defined as type 3, whereas those resulting from stent-graft wall porosity are called type 4. Most controversial is the fate of branch vessel (type 2) endoleaks, usually arising from inferior mesenteric artery or lumbar artery retrograde flow into the excluded abdominal aortic aneurysm sac. While some of these leaks have been demonstrated to thrombose with the passage of time, distressing reports of continued abdominal aortic aneurysm enlargement from untreated branch endoleaks are accumulating (3–5). One of the barriers to catheterbased remediation of type 2 endoleaks has been access to the offending vessel supplying the excluded abdominal aortic aneurysm sac. Access to the inferior mesenteric artery can be gained by catheterization of the superior mesenteric artery and selecting the inferior mesenteric artery through collaterals. This approach is tedious, time-consuming, and not always successful, particularly if there is an incomplete arc connecting the SMA-IMA axis (6– 10). Patent lumbar arteries are even less easily accessed. Translumbar access to the abdominal aorta was first introduced more than 70 years ago (11,12). Modifications made this technique of clinical value in the 1960s (13). Even though the long history and safety of this procedure is well documented, at the present time, translumbar angiography is usually reserved for patients with poor peripheral vascular access. The purpose of our investigation was to access the feasibility of direct aneurysm sac puncture and endoleak embolization via a translumbar approach. MATERIALS AND METHODS