Endoleak lumbar arteries

Endoleaks are a major concern for those engaged in EVAR (Table 3, Fig. 4). This phenomenon describes the continuation of blood flow into the extragraft portion of the aneurysm (20). Endoleaks are related to the graft itself or other factors such as the presence of large patent lumbar arteries (21). The presence of an endoleak increases the chance of rupture. Diagnostic imaging plays an important role in the detection of endoleaks intraprocedural angiograms, surveillance CT scans, or duplex ultrasounds. 

Type I endoleak is caused by failure to achieve a circumferential seal at either the proximal (type lA) or distal end (type IB) of the stentgraft. Type IC endoleak is due to non-occluded iliac artery in patients with aorto-mono-iliac stent and femoral-femoral bypass. With type I endoleak, the aneurysm is perfused directly from the aorta or the iliac arteries (inflows). The leak usually communicates through a channel (sometimes multiple channels) with the aneurysmal sac. There are several outflow vessels, mainly lumbar arteries and inferior mesenteric artery (IMA) that communicate with the channel and or the sac (Figs. 14.1,14.2). The pressure within a type I leak is systemic. The tension on the aortic wall remains high. 

A type II endoleak corresponds to the retrograde filling of the aneurysm mainly from lumbar arteries and/or IMA but also in rare situations from sacral, gonadal or accessory renal artery (Figs. 14.3,14.4). 

Fig. 14.5a,b. Type III endoleak due to a hole in the fabric, a Aortogram demonstrates the endoleak (large black arrow) with IMA (small black arrow) and a lumbar artery (white arrow) acting as an outflow vessel, b The wire is passed through the hole in the aortic aneurysm (arrow)... 

Fig. 14.6a-c. Type III endoleak due to incomplete seal at the junction between components, a Angiogram from left groin demonstrates a type III endoleak (white arrow) and a lumbar artery (black arrow), b Palmaz stent placement inflated to 12 mm.c Control angiogram shows no more endoleak... 

The occlusion of the iliac artery is usually sufficient to treat the leak. However, in cases of long-term type IC endoleak, many outflow vessels may have developed and the leak may communicate with multiple lumbar arteries and the IMA. These enlarged vessels might be source of late type II endoleak. Thus, we usually embolize both the outflow vessels and the sac before occluding the iliac artery. Another attractive technique to achieve the occlusion of the common iliac artery is to perform an endovascular internal to external iliac artery bypass using stentgraft. This technique can allow the exclusion of the common iliac preserving the internal iliac artery. 

Schmid R, Gurke L, Aschwanden M, et al (2002) CT-guided percutaneous embolization of a lumbar artery maintaining a Type II endoleak. J Endovasc Ther 9 198-202... 

Occasionally, communications between branches of an uninvolved IIA and distal lumbar arteries can create type-II endoleaks (Fig. 15.1). This can be a more technically challenging situation and embolization of the distal branches should be attempted only if growth of the aneurysm sac has been documented (see Sect. 15.2.1). 

Fig. 15.1. a Contrast. enhanced CT of abdomen shows an abdominal aortic aneurysm with patent lumbar and inferior mesenteric arteries. Patient developed a type 11 endoleak after endograft placement, b Non-contrast CT shows glue embolization of the lumbar arteries and the sac through a branch of the internal iliac artery... 

Occasionally, communications between various branches of the IIA and the lumbar arteries may cause retrograde flow into the sac of an aortic aneurysm creating a type-II endoleak. Microcatheter traversal of the entire length of these conununications may not always be possible. Under such circumstances, liquid embolic agents have been employed to occlude the feeder arteries. As mentioned above, this practice may cause ischemic radiculopathy if the targeted vessels are either lateral sacral or iliolumbar arteries. It may be more prudent to coil embo-lize these arteries and use alternative approaches to deal with the possible residual type-II endoleak (see Chap. 14). 

Fig. 23.9. a Type II endoleak after EVAR of an abdominal aortic aneurysm, with a bifurcation graft. The endoleak is filled from a retrograde flow out of a lumbar artery (arrow), b Type III endoleak after EVAR of an abdominal aneurysm. The graft is ruptured (arrowhead), leading to this type of endoleak... 

---