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Treatment of penetrating aortic ulcers (PAUs) has been swayed by recent advances in endovascular aneurysm repair (EVAR). Anecdotally, the majority of diagnosed PAUs are treated by endovascular techniques rather than by open surgery, and the minimally invasive approach is yielding encouraging results.1 In this arena, the BeGraft aortic stent from Bentley (Hechingen, Germany)—a balloon-expandable covered stent—shows promise, addressing issues of “overtreatment,” says Nikolaos Tsilimparis, director of vascular surgery at Ludwig-Maximilian University Hospital in Munich, Germany.
Tsilimparis has extensive experience treating PAUs, and here speaks to Vascular News on how balloon-expandable covered stents have changed his approach to the indication. Previously, he states, treatment with large diameter covered grafts was “too much for too small a lesion,” whereas the BeGraft aortic is more tailored to the unique characteristics of a PAU, thereby providing “the right tool” for this distinct pathology.
Before using balloon-expandable covered stents, how did you treat patients with PAU disease?
Previously, we would treat PAU patients with either standard infrarenal devices, iliac limbs (if the diameters were appropriate), or with conventional repair. Essentially, we were overtreating a very localised lesion in the aorta. We started to use balloon-expandable covered stents and noticed that the BeGraft aortic addresses the issue of overtreatment, thanks to its ability to be dilated to different diameters, allowing the physician to adjust the degree of therapy in order to match the extent of the disease.
Before we used this particular stent, one of the main challenges with this procedure was that standard infrarenal bifurcated grafts are designed to be used in large aneurysmatic aortas. Aortas with PAUs often have diameters of between 14 and 18mm, whereas self-expandable aortic stent grafts are made for large diameters of around 24mm.
Another issue was that an aortic aneurysm has more space to accommodate the bifurcation of the stent graft, whereas this is not the case in PAUs. In these patients, using iliac limbs of 12 or 16mm diameters in a narrow aortic bifurcation makes it very prone to occlusions. These were both challenges that have now been eliminated thanks to the BeGraft aortic.
Which anatomical conditions are needed in order for a balloon-expandable covered stent to provide good outcomes?
A basic condition is the ability to reach a healthy aortic segment. In addition, one needs to have a very localised lesion, as balloon-expandable stent grafts are not very long.
One should be aware of a tapered aorta. This is not an exclusion criterion, but one has to be cautious not to cause a rupture with a balloon-expandable stent due to extreme oversizing of the lower part of the aorta.
What made you decide to try out the BeGraft aortic for this indication?
I always thought that we were doing too much for too small a lesion. Drawing on my experience with this balloon-expandable stent in other indications and getting to know it as a very reliable stent graft that can be inserted with a low-profile system of 9–11Fr, I thought it would be worth trying for PAUs. After the first few cases, we realised that it is an excellent solution for this indication.
What are the main advantages and limitations of using a balloon-expandable covered stent in a PAU?
I think the balloon-expandable covered stent offers very accurate positioning and also flexibility in terms of how much of the lesion you want to cover. In addition, it has a big advantage in terms of the sizes that are on offer.
It must be taken into account that one needs to develop techniques for how to deal with the challenges of using balloon-expandable covered stents in the aorta. We always use the lowest diameter of the aorta to start with and then, if we need to put in two stent grafts, we taper them instead of putting the bigger diameter stent into a smaller aorta. We do not measure to the proximal or largest diameter, but instead the distal, smaller diameter, and then balloon the proximal part, in order to get the proximal seal.
What are the long-term outcomes in patients you have treated?
The long-term reliability of a balloon-expandable stent in an aorta that degenerates over time is a big concern. However, the pathology is a little bit different with PAUs than with the typical atherosclerotic aortic aneurysm that will evolve and develop. PAU patients have a very localised plaque rupture or have a local dissection—indications that require treatment, but these patients still have a relatively stable aorta. Nevertheless, I would always follow these patients extensively, especially at the beginning of our experience, with a standard protocol that is similar to the one we use for infrarenal aortic aneurysms.
A multicentre study led by our institution, which is now in the publishing process, found that use of the BeGraft aortic for the treatment of infrarenal PAU produces excellent results with low complications.2
How many patients do you see with a typical PAU and how often do you treat them with an endovascular approach?
The indications for treating PAUs are not yet well defined, so while we are currently not treating a lot of patients, we are still seeing quite a few. In terms of approach, I was previously very cautious about treating a patient with a small aortic ulcer or a local dissection by using an aortoiliac stent graft, because I thought it to be an overtreatment. However, with localised, minimally invasive surgery, it is just like putting a covered stent in the iliac arteries, but instead you put it in the aorta. I now feel much more comfortable offering endovascular therapy to patients that present with these findings.
What are your key messages for treating PAU patients with this endovascular approach?
My main message is that we are able to treat a disease of its extent with the right tool, which is appropriate for the pathology. We no longer overtreat just because we do not have the right tools.
In addition, there are many centres that have now decided to use this technique, which shows how useful it is, and it is interesting to note that different centres have developed different tactics and strategies in order to deal with or to treat these patients with the BeGraft aortic. I think that it is an excellent tool and technique for this indication, and I believe that the more we learn from our experience, the better we will be able to understand the pathology and the further we will be able to extend the treatment options available.
- Taher F, Assadian A, Strassegger J, et al. Pararenal aortic ulcer repair. Eur J Vasc Endovasc Surg 2016; 51: 504–510.
- Stana J, Tsilimparis N, et al. Multicenter experience with large diameter balloon-expandable stent grafts for the treatment of infrarenal penetrating aortic ulcers. Journal of Endovascuar Therapy, under review.
DISCLAIMER The usage of the BeGraft aortic is an off-label indication for the treatment of PAU.