Dr. Michael J. Tullis Shares His Experience in Using a New AAA Stent Graft

Q: Tell me about your motivations in using the new Endurant II AAA Stent Graft.

A: My patient was a 70-year-old gentleman with two issues that made him an excellent candidate to consider for aortic endografting. The first was that he had a hostile abdomen secondary to a previous Whipple procedure and multiple subsequent laparotomies for small bowel obstructions. This would have made an open repair very difficult. The second issue was that the patient had significant calcific iliac occlusive disease. The question was whether or not we could deliver an endograft through his iliac arteries to exclude his aneurysm and avoid an open repair.

After discussing the case with Michael Stumpf, a Medtronic representative, we both felt that this would be a perfect case for the Endurant II because of the benefits and changes made to the device. As soon as it became available, we went ahead with the procedure.

Q: What makes this graft better than other options currently available?

A: The Endurant II has a couple of unique qualities. It’s the first AAA stent graft that Medtronic developed internally with physicians instead of buying other technology and using it. By getting input from hundreds of physicians who have performed aortic endografting, they developed a graft that met a lot of needs, incorporating the best of all grafts at the time. The Endurant graft was a leap forward in terms of endografting technology, but the Endurant II is certainly an improvement over the original.

This particular patient needed a 28 mm graft so we needed a delivery system that could get that size graft through very narrow blood vessels and into position. Typically on the Endurant system and on most other systems, it is delivered through a 20 Fr or greater sheath depending on the company. The Endurant II has now taken the 28 mm graft and put that in an 18 Fr delivery system. They increased the hydrophilic coating on that delivery system by more than 50%, which makes it slicker and easier to pass through the tortuous iliac arteries. The diameter is smaller and it’s slippery so we were able to deliver the graft to this patient in the appropriate position without having to do much to his iliac arteries.

Another improvement is the longer limb lengths. Often, you need to use two main components and then additional pieces if the patient has longer anatomy. They’ve actually increased the length of their limbs such that you don’t need to use as many pieces. Less parts and pieces means less dye that you have to give the patient, less time, less x-ray exposure time, and less blood loss. Also, when you have narrow iliac arteries, if you have to put in multiple pieces, those pieces overlap so you have double the material and potential constriction due to multiple layers. Ultimately, fewer components equal less cost and fewer complications.

Q: Do you use any other devices for similar procedures?

A: There are other devices out there, but for me, this is the best one. The two improvements that I discussed give it features that the others don’t have at the moment. Additionally, the Endurant II now has better markers on the device, which make it easier for the physician to see during the procedure.

Q: What are the next steps for studying this graft? How will you track your results with this device?

A: The typical follow-up involves obtaining a CT scan after 1 month to look at the graft. If everything looks okay after 1 month, there’s no significant endoleak, and the graft is in good position, we follow-up with regular x-rays and ultrasound studies to monitor the diameter of the aorta. The Endurant II won’t change our follow-up protocol, but hopefully these changes on the graft will help patients have fewer complications over time.

Q: Are there any limitations that you found in this graft?

A:  This device is very good for treating the vast majority of infrarenal AAAs. However, it does not address the smaller percentage of aneurysms that involve the renal or mesenteric arteries. That is an area of continuing device development by multiple manufacturers.

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Michael J. Tullis, MD, FACS, is a vascular surgeon at St. Luke’s Cardiothoracic and Vascular Associates, in Boise, Idaho. He graduated from the University of Wisconsin in Madison and earned his medical degree from the University of Chicago Pritzker School of Medicine. He completed his training in general surgery at the University of Wisconsin Hospitals and Clinics, and specialized in vascular surgery at the University of Washington Medical Center in Seattle. Dr. Tullis served as an assistant professor of surgery at the University of New Mexico in Albuquerque, and is a member of the Society of Vascular Surgery, International Society of Endovascular Specialists, Peripheral Vascular Surgery Society, Pacific Northwest Vascular Society, Idaho Medical Association, and Ada County Medical Society. Dr. Tullis joined Cardiothoracic and Vascular Associates in 2000.