Dr. Sherif Sultan Explored the Latest Treatments for Aortic Aneurysm at the Veith Symposium 2011

Q: What makes thoracoabdominal aortic aneurysms such a surgical challenge in need of other treatment technologies?

A: The problem is dealing with complex anatomy and the availability of a stent graft that can handle this anatomy. What we’re trying to do is adapt a technology that has fewer complications. The idea is to try to see why a patient has an aneurysm and treat it on this basis. Of all the grafts available now, a multilayer flow modulator stent actually treats the aneurysms rather than excluding the aneurysm.

Q: What made you decide to use a multilayer flow modulator (MFM) stent to treat these patients?

A: In December 2009, when the mother of a vascular surgeon I knew developed a very large aneurysm, he came to me to see what we could do for the situation. We were faced with either doing nothing or trying open surgery. She was the first person I treated in this way and she is currently still alive and well. I am very proud of this patient, in particular, because she opened the book.

Q: What are the benefits of MFM having “off the shelf” availability?

A: If you have an aneurysm in the hospital in need of treatment, you need to design the graft tailored for the patient for a fenestrated or branch graft. With a MFM, you have all of the sizes right next to you on the table. We went from using lots of different guides, balloons, etc. and now only use a single modulated device.

It has made things so simple. Some people say that it’s too good to be true but like anything, this is a new technology and will evolve.  What I’m doing currently is creating the first global registry so that I can better understand the whole science behind it. Currently there are 172 cases that have been done and this is only currently available in Europe but they are working on getting this FDA-approved for the U.S. now.

Q: Were there any unexpected side effects?

A: Out of 172 cases, there were 2 ruptures, but these were technically fault of the operator rather than the technology itself. In the first case, the operator should have gone from nomal aorta to nomal aorta, but that did not happen. In the second case, the device used was too small for the area so it allowed blood flow around the stent. The rupture rate was still less than it was with a covered stent graft in these cases. There is also zero paraplegia, which is a bonus to such technology. There are issues with stent foreshortening, which necessitated  secondary interventions for two patients in my practice. Although the concept is revolutionary and the technology has massive potential, the stent itself is still only a first generation device and undoubtedly in need of on-going research and development.

Q: What were the limitations of the study?

A: All of these are complex cases. Of the cases we studied, 70% were acute patients, 67% were redo patients, and almost 75% of them were ASA IV cases.

Q: What are the patient benefits of this technology over the traditional open surgical repair? Were there any unexpected pleasant findings?

A:  There were several patient benefits found. The patient gets in and out on the same day with quick turnover and recovery. The procedure is cost effective and provides a higher quality of life for patients because there are no issues with ischemia, bowel replacement, and paraplegia. It is also performed under local anesthesia rather than general anesthesia.

Q: What is your success rate and have patients been satisfied and safer with your treatment?

A: We have 100% delivery to the target area and no loss of area to the side branches. We have also had no paraplegia or stroke complications.

Q: What is the next phase of the study?

A: Currently research and development efforts are focusing on improvements in stent design in terms of material properties, variability in sizing and stent configuration. In particular the different stent properties required to treat individual aortic pathologies, i.e. aneurysm vs. dissection, and the variability in acute and chronic states are being investigated. This technology has been used in the ascending thoracic aorta, having been successfully deployed just above the aortic valve. The unique requirements for the ascending compared to the descending aorta are also being addressed.

Q: Is there anything further that you would like to add that hasn’t been mentioned yet?

A: The finite element analysis shows that we are not measuring a diameter. We are studying the flow and how to treat an aneurysm rather than exclude it. This is going to change a lot of views on how to treat arterial aneurysms.

Dr. Sherif Sultan is a consultant vascular and endovascular surgeon and honorary senior lecturer at NUI Galway, Galway, Ireland.