How would you summarize the current unmet needs in endovascular aneurysm repair (EVAR) for patients with abdominal aortic aneurysms (AAAs)?

There are two areas where there is definitively a need for improvement. One area of importance is challenging infrarenal neck anatomy. This includes short, wide, angulated, tapered, calcified, or thrombus-laden infrarenal necks.

Another area there is a need for improvement is in patients with challenging access anatomy. This is related to narrowed, severely calcified, and tortuous iliac and common femoral arteries.

What would you say are the benefits of low profile delivery? What types of patients can benefit from this approach, and to roughly what percentage of the population does this apply?

Almost all of the companies that are currently involved in producing EVAR devices have a goal to reduce the profile of their delivery systems to accommodate patients with challenging access anatomy. Obviously, the purpose is to offer their products to a larger spectrum of patients and to reduce the incidence of vascular complications. Some of them have already significantly reduced the profile of these devices. For instance, the first-generation EVAR devices were 22 to 24 F in profile, and some even had a 27 F outer diameter profile. Until 2010, a great majority of EVAR devices were > 20 F in profile. Since 2010, some of the manufacturers now offer devices that are 16 F, or even 14 F, in profile. This advancement is particularly important when treating patients with severely diseased iliac arteries and when performing the procedures via percutaneous approach with local anesthesia.

What are some of the possible tradeoffs in making a current stent graft platform into a lower profile device?

Originally, the technology was not there, and compromises were made by some manufacturers to design lower profile devices. They found later that these devices frequently failed, and therefore, they are no longer available. More recently, several companies have made significant technological improvements in their products, and now they are producing third- or fourth-generation devices, which have resolved most of the concerns encountered with the first-generation products. Several issues that have plagued the first-generation devices, such as material fatigue, loss of structural integrity, high permeability, migration, modular component separation, and others, have been resolved.

To what degree can long-term data be applied from one iteration of a device platform to the next?

I think that is a question that should be addressed and seriously looked into by all current manufacturers of EVAR devices. In the United States, the FDA takes this issue very seriously, and based on our experience over the last 2 decades, several strict testing requirements are mandatory before the first-in-man procedure is performed or a clinical trial is initiated. I think that at the present time, due to these changes, there is definitively less risk involved for unexpected complications that might occur with the newer-generation devices than what was encountered with the older-generation endografts.

What would be the value of having the GORE® EXCLUDER® Device delivered via a lower profile without changing the durability of the graft?

We have been waiting very patiently for this improvement to happen. The previous-generation GORE® EXCLUDER® Device (Gore & Associates, Flagstaff, AZ) required the use of 18 and 20 F sheaths. Iliac arteries are too narrow and too diseased to accommodate the use of 20 F sheaths, and this poses a serious problem. Obviously, if all GORE® EXCLUDER® Devices can be delivered via a smaller 18 F sheath, this would be a significant improvement. This was achieved with the latest-generation GORE® EXCLUDER® Device, without compromising the durability of the endograft. This lower profile device was designed with the intention in mind to lower the risk of vascular complications and to treat patients who have very narrow and diseased femoral and iliac arteries.

What future progress do you anticipate in low profile delivery from Gore in this platform?

I believe that in the near future, there will probably be an even lower profile expanded polytetrafluoroethylene endograft that will be as durable as the already well-tested current-generation GORE® EXCLUDER® Device.

What are the specific challenges that are posed by large neck aneurysms, both in the placement phase and down the road when you're looking at follow-up?

We have been using the GORE® EXCLUDER® Device for a long period of time—over a decade—and have had excellent long-term results, with an extremely low risk of complications, such as migration, type I or type III endoleaks, or thrombosis.

What was missing, until a few years ago, was the ability to make small adjustments during the positioning of the device and before the final deployment in the desired location. Accurate deployment of an endograft is particularly important in patients with challenging infrarenal neck anatomy. This was resolved with the introduction of the GORE® C3® Delivery System. This improvement allows the device to be repositioned if necessary and redeployed more accurately below the renal arteries, which is very important in patients with challenging infrarenal neck anatomy.

How does the availability of a 35 mm trunk graft affect your ability to match device to anatomy?

The latest development, the 35 mm GORE® EXCLUDER® Device trunk (and 36 mm cuff without any scallops on the top), is a great improvement that will expand the opportunities to treat patients with wide infrarenal necks and other challenging infrarenal neck anatomies that were not candidates for EVAR with previous-generation devices. Another significant achievement with this device is that it can be delivered through an 18 F sheath as any other GORE® EXCLUDER® Device.

Zvonimir Krajcer, MD, is Peripheral Vascular Intervention Fellowship Program Director at the Texas Heart Institute and St. Luke's Episcopal Hospital in Houston, Texas. He has disclosed that he is a consultant to and speaker for Gore. Dr. Krajcer may be reached at (713) 790-9401; zkrajcer@leachmancardiology.com.