Preservation of Internal Iliac Arterial Flow during Endovascular Aortic Aneurysm Repair Using the “Sandwich” Technique

Conventional endovascular aneurysm repair (EVAR) of an abdominal aortic aneurysm (AAA) requires adequate graft seal proximally in the infrarenal aorta and distally in the common or external iliac arteries. When possible, sealing in the common iliac artery is performed to maintain perfusion to the internal iliac artery. Approximately 40% of AAAs have associated common iliac artery aneurysms that would require an external iliac seal zone and ipsilateral internal iliac artery embolization to prevent a type II endoleak. Concurrent or staged internal iliac artery occlusion may result in pelvic ischemia, which commonly manifests as buttock claudication or, in men, impotence. Uncommon but more serious consequences include colonic and spinal artery ischemia. Coverage or embolization of a single internal iliac artery is generally well tolerated. There is a varied incidence (20 to 50%) of clinically significant buttock claudication that tends to improve over time resulting in ∼10% incidence of buttock claudication at 1 year with single hypogastric artery embolization.

Published case series and individual reports of bilateral internal iliac artery embolization demonstrate that bilateral hypogastric occlusion appears safe, although there is an increased risk of serious complications that may be life threatening. Most physicians attempt to preserve flow to a single internal iliac artery whenever possible. Various methods have been described to preserve internal iliac artery flow during EVAR. Investigational iliac branched devices (not currently approved by the Food and Drug Administration [FDA]), hybrid surgical revascularization of the internal iliac artery, physician modification of existing endografts, and, more recently, parallel endografting with the “sandwich” technique are some of the ways flow can be preserved to the hypogastric artery.

The sandwich endograft technique involves placing two endografts side by side into an existing iliac limb to create an off-the-shelf bifurcated component to preserve flow to both the internal iliac and external iliac arteries. This technique has been gaining acceptance as a viable method for preservation of flow to at least a single internal iliac artery allowing for expansion of anatomy suitable for EVAR with the use of commercially available endograft components, albeit in an off-label manner. The sandwich technique is applicable to a variety of endograft designs, although the steep bifurcation of most endografts requires axillary or brachial artery access to deliver a stent into the preserved internal iliac artery. The bifurcation-sparing nature of the Endologix AFX (Endologix, Irvine, CA) endograft allows for this technique to be performed from an entirely femoral approach and has become our preferred approach for internal iliac preservation during EVAR when the anatomy is appropriate.

• Suggested Readings

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