Prior to endovascular aortic repair (EVAR), make sure of the patency of superior mesenteric artery (SMA) as inferior mesenteric artery (IMA) will be blocked by the graft. If SMA is not patent, this can lead to compromise of bowel vasculature.
A good CT imaging prior to the EVAR procedure can avoid a digital subtraction angiography (DSA) with marker pigtail and the consequent contrast load. Renal artery can be delineated by injection from a catheter introduced through the left radial route. Stent graft has to be positioned below the renals. If the renals have to be covered by the graft, they can be preserved by upward directed chimney stenting. Similarly, internal iliacs can be preserved by downward directed chimney stenting. But if the chimney stents are not covered well by the graft, it can lead to type I endoleaks.
Chance of paraplegia following a thoracic EVAR (TEVAR) is 2-6% and that for a surgical repair is 4 to 20%.
Internal iliac artery can be a source of endoleak for EVAR reaching upto the external iliac. In such situations, internal iliac has to be coiled off, after making sure that the opposite internal iliac is patent. Opposite internal iliac can be protected by a wire inside to avoid it being covered by the corresponding iliac limb of the stent graft.
Types of endoleaks after EVAR
I – Proximal or distal attachment site
II – Branch vessel
III – Modular disconnection and fabric tear
IV – Graft porosity
V – Endo tension