Dr. Fillinger is director of vascular surgery training programs and professor of surgery at Geisel School of Medicine in Dartmouth, New Hampshire. Dr. Fillinger reports no disclosures related to the content herein.
The Aorfix stent graft (Lombard Medical) is designed for use in place of more invasive open surgery in patients who have an abdominal aortic aneurysm (AAA). The device received US Food and Drug Administration approval in 2013. At the 2014 VEITHsymposium, Vascular Disease Management spoke with Mark F. Fillinger, MD, about 2-year results of the Aorfix PYTHAGORAS trial, for which he served as principal investigator.
Q: Could you start by telling us a little about the Aorfix device and how it’s applied?
A: The Aorfix device is a soft, very conformable, flexible device that was designed to treat highly angulated aortic necks. It’s been used in Europe for a number of years with excellent result and because of that, I got involved with the US PYTHAGORAS study, which treated aneurysm patients with highly angulated necks for the majority of the patients in the trial. So this is the first trial to look at 60-degree to 90-degree angulated necks. It’s the first trial to take the difficult anatomy and not make it just a subset of a trial of mostly normal anatomy but rather take a trial of mostly extreme difficult anatomy that had never been treated in a trial before.
Q: What were the goals of the study and the inclusion and exclusion criteria?
A:The inclusion/exclusion criteria were fairly typical of most studies with one or two key differences. One is that in this case, the normal anatomy was used as a lead-in before treating the extremely challenging anatomy. So the patients with normal anatomy formed the minority of patients in the trial, and sites were not allowed to enroll normal anatomy patients after their leading patients. The other thing that was different is that the neck lengths required a 15 mm center line neck length, which sounds fairly typical but because the necks were highly angulated, the seals on the inner curve was actually much less than would be typical in studies of less angulated necks with a similar type of neck length.
Q: Could you describe some of the key points from the 2-year data?
A: The data actually go out past 2 years but we reported the 2 year data at the VEITH meeting because we now have the large majority of patients out to 2 years and so we feel comfortable presenting. The data are extremely solid out to that point. The data are good out to 5 years as well, it’s just that we don’t have the majority of patients out that far yet. The things that we look for as we get out to longer and longer-term data is the durability, because as this is the first trial to treat such extreme anatomy, we worry that we got a good acute result but don’t know what is going to happen down the road. Will the device continue to conform to the anatomy and conform to the aneurysms shrinking?
Many of us have experience with other devices off-label getting an acute result, but then having to do a lot of secondary interventions and that sort of thing to try and maintain a good result. It can be an issue for this extreme anatomy. So we were happy to see that so far as the longer term results, there has not been an increase in secondary interventions. Type 1 3 endoleak was zero from year 1 to year 2. The secondary intervention rate is still less than 10%. Inclusive from implant to 2 years, things like that, the results seem to be holding up and very durable and there are no worrisome issues as we extend out on the follow-up.
Q:And they seem to be holding that way up to 5 years?
A: They do. It’s just I’m fairly conservative in that, so I like to have every large cohort out to that point before getting too carried away. But certainly, the data from Europe would suggest that as well because they have a very large cohort of patients out to that time point because it had CE Mark in Europe well before it was available publicly in the United States.
Q:Given the positive results that you see so far, how do you think this could change clinical decision making for vascular clinicians?
A: The big difference is that we now have a good on-label option for patients that have highly-angulated necks. In the past, we were torn between giving them open repair or doing observation in people who are higher risk, a lot of the patients, as you may have seen from the presentation, as the neck angle gets more and more severe, you have a higher and higher percentage of females and a higher and higher percentage of elderly patients. They’re the ones who have the highest neck angles, they are also the ones who have the highest risk for open repairs. So, that makes for some very difficult decision making now with a less invasive option, it gives us another solution. It’s not necessarily something that’s used for everybody, but it gives us a much better option in almost all patients than just watching them and treating them medically.
Q: Are there other data you think that needs to be collected in the future?
A: We still want to continue to follow patients to get that majority all the way out to 5 years and we’re just about to start a postmarket surveillance study in conjunction with the FDA so that now that it’s released commercially on a very wide scale, we’ll be following those patients consecutively enrolled in a commercial database in conjunction with the SVS and the FDA to see what the real-world results look like with the device.
Q:Is there anything else that I might have missed that you think is important for vascular specialists to know?
A: I think the only other thing that’s probably notable is that in general when you get highly angulated aortic necks, you very frequently have very tortuous iliac anatomy as well and the device also handles that type of anatomy very well. It basically has to — we’ve seen a lot of that in the trial and the limbs are also very flexible so it’s not just handling the very high angulation of the proximal end it also handles the very sharp angulations that you frequently see at the distal end as well. It handles it very nicely without some of the kinks and frequent limb occlusions and that sort of thing that we saw with earlier generation devices.