What are the current treatment options for patients with large common iliac artery aneurysms and no seal zone above the hypogastric artery?

Current treatment options include covering the origin of the hypogastric artery after preliminary coil embolization or a sandwich technique, which basically puts the branch into the hypogastric artery alongside the common iliac branch that extends down into the external iliac artery. In Europe and other parts of the world, there are integrated iliac branch systems designed for this approach, but in the US, none have been approved yet.

How do the disadvantages of covering the hypogastric artery manifest in patients?

In some patients with abdominal aortic aneurysms, one hypogastric artery may be occluded. In that case, preservation of the contralateral side is paramount. There is the risk of neurologic injury or impotence, as the hypogastric artery supplies the pelvic organs' pericollateral pathways. Oftentimes, when one side is occluded or you have a dominant hypogastric artery that is clearly contributing the bulk of the flow, I think preservation is a smart way to go.

Another possibility is claudication, especially in the gluteal or hip region where collateral flow in certain patients may not be as rich due to profunda disease or other causes. The flow may be adequate in other patients, so claudication would not occur, but there is no way to predict that. So again, I think as a general rule, the more you can preserve the hypogastric arteries, the better.

What are the advantages and disadvantages of the current options for treating these patients while preserving the flow you mentioned?

Option number one of just covering and embolizing the hypogastric artery does not preserve the flow; it treats the aneurysm, but you have to embolize the hypogastric artery so you don't get the transpelvic flow from the other side that would maintain patency and keep the common iliac artery pressurized. A sandwich technique is much more complicated and is clearly something that is not off-the-shelf. You're cobbling together off-the-shelf devices in an unapproved way to do this technique. Rather than having a device system that is designed for your needs, you are forced to cut and paste like an endovascular carpenter to achieve the best possible result.

When you place two devices within another (e.g., the snorkel or chimney technique), there is a possibility of endoleak from the gutters. You're placing the piece that is going down to the external iliac artery to preserve flow to the rest of the limb and the other piece into the hypogastric artery inside a common iliac stent. Those two pieces aren't always going to fit in a perfect geometric fashion.

What percentage of patients might benefit from an offthe- shelf iliac branch endoprosthesis?

Well, I'm not the market maven on this, but clearly I think that this comes up regularly in everyone's practice today. The availability of an off-the-shelf device is very attractive, benefitting around 10% to 20% of patients.

Michael D. Dake, MD, is Thelma and Henry Doelger Professor (III), Department of Cardiothoracic Surgery, Stanford University School of Medicine and Falk Cardiovascular Research Center in Stanford, California. He has disclosed that he is a member of the Scientific Advisory Board for Gore & Associates. Dr. Dake may be reached at mddake@stanford.edu.