Q&A with Frank R. Arko, III, MD; Halim Yammine, MD; and Jocelyn K. Ballast, BA
Abdominal aortic aneurysms with short proximal necks are a challenging anatomical condition to treat. The creation of the ANCHOR registry in 2012 has led to the collection a great deal of data on the use of EndoAnchors in treatment of short proximal necks. In this Q&A, Frank R. Arko III, MD, and colleagues discuss experiences using EndoAnchors and offer tips for operators early in the learning curve. Dr. Arko is the Chief of Vascular and Endovascular Surgery at the Carolinas HealthCare System in Charlotte, North Carolina. He is also a guest course director for the International Symposium on Endovascular Therapy (ISET), which took place from February 3-7, 2018 in Hollywood, Florida. Dr. Arko spoke about EndoAnchors and other topics at ISET.
What are some of the latest approaches in EndoAnchors for short proximal neck?
My group began using the EndoAnchors as part of the ANCHOR registry. We’re one of the leading enrollers in the ANCHOR registry, and have been part of the trial since 2011. I was skeptical of their utility initially but withheld judgment until there were data to evaluate. At this point, my early skepticism has changed into enthusiasm based on our own results and what we’ve seen from the ANCHOR registry data. We have incorporated EndoAnchors into our practice even in patients who are not candidates for the registry, and have had excellent results.
We perform a variety of repairs at our institution and handle a large volume of aortic disease. Patients are often referred here for FEVAR, parallel grafting, and branch grafting, and we still perform these complex procedures. However, upon examination, many of these patients have very large aneurysms and are not able to tolerate those procedures from a physiologic and anatomic standpoint. With EndoAnchors, we can provide another strategy to treat these patients.
The use of EndoAnchors and an endograft essentially simulates an open surgical repair in patients who are unable to tolerate such a procedure. When doing an open surgical repair, most people just clamp above the renal arteries and then sew to that tissue. When placing an endograft, we would usually need to do a fenestrated graft, parallel graft, or branch graft to extend the length of the proximal neck to get to healthy tissue. With EndoAnchors, we can put the graft right below the renal arteries, just like with an open repair.
We’ve utilized the EndoAnchors with endografting for relatively short necks, in the range of 3-4 mm to 5-6 mm, and we’ve had good results. In fact, Medtronic recently was approved for their Endurant graft with a 4 mm neck, and that approval was derived from the ANCHOR registry. My group was part of the FDA audit that looked at the outcomes of those patients, and it went very smoothly and successfully.
Are there any new areas of research emerging from the ANCHOR registry data?
My group will be looking at the short-neck indication and publishing the ANCHOR registry data. Other researchers are studying prevention of aortic neck dilatation with the placement of EndoAnchors, and there have been some early positive reports from that line of inquiry. The ANCHOR registry itself is trying to reach approximately 2,000-3,000 patients, so it will be interesting to see what results emerge as that registry continues to collect data.
We also have recently examined our own data on the use of EndoAnchors in conjunction with parallel grafting to shut off or prevent gutters from forming, which is a frequent frustration with parallel grafting. EndoAnchors have also been successful in patients who present at a later date with evidence of a type 1 endoleak.
What are the benefits for patients?
EndoAnchor procedures are much quicker than the alternatives, and the patient is exposed to less radiation. This benefit also extends to the interventionalist, as less radiation exposure can improve our long-term health and reduce the risk of radiation-induced cancers.
Are there any complications that happen during repair that people need to be prepared to handle?
We have found EndoAnchors to be reliable and easy to use. We haven’t encountered many complications, even in the early learning curve.
Do you have any recommendations for people in the learning stages of using EndoAnchors?
EndoAnchors are best utilized in the short-neck indication, but it might be preferable to start in less challenging patients. These could be cases in which the neck is longer but the patient is young and there is a concern about a proximal neck dilatation in the future. As you start to treat necks that are progressively shorter, then you should be ready to proceed with great accuracy.
Placement is important. When we use EndoAnchors, we put them in the top ring, ie, the first 5 mm of the neck. Some operators put one EndoAnchor at the top ring and then several down below, but I try to simulate open surgical repair and get the device in the healthy tissue of aorta, as close to the renal arteries as possible.
It’s important to have a 90-degree position of the sheath itself, and then make sure that you see the stent graft move and then feel the reactionary. If you’re pushing out, you’ll feel the force pushing back on the catheter. And when you have that, then you know that you should go through the graft, through the aorta, and then through the adventitia.
Occasionally, if you are treating a patient with an angulated neck, it’s helpful to use both the right and left access sites. Sometimes I find it easier to reach one side if I’m approaching from the contralateral side.
Lastly, while the delivery sheath is its own sheath, I typically use a longer, 35 cm sheath. This upsizes the hole a little bit, but usually no bigger than the sheath used for the stent graft. I like to put the delivery sheath through another sheath all the way up and above the flow divider, which allows me to torque the device itself through that sheath in order to avoid worrying as much about tortuosity.
I recommend that new operators start by using them in the abdominal aorta. If operators then want to increase their capabilities with EndoAnchors, I recommend they go to the distal thoracic where there can be problems with retrograde migration of thoracic stent grafts in the long term. However, it’s more challenging placing EndoAnchors there than in the infrarenal component. And then finally, going up into the arch. Although my group has done this successfully, it’s important for a new user to work through the progression of infrarenal aorta and then descending thoracic before working with the arch or proximal thoracic aorta.
Are there any cases that are gray areas or tough decisions in terms of whether to use an EndoAnchor?
Most of our clinical decision-making and strategies for repairs are based on the patient’s anatomy, physiology, life expectancy, and potential for long-term surveillance. We’ve used EndoAnchors both on-label and off-label because we felt their use was appropriate.
We’ve used EndoAnchors in dissections, which is an off-label use, but it worked out well. We have utilized them to anchor new proximal extensions and then anchor the bottom end to a graft that has been migrating in order to prevent further migration. We’re not sure what the results will be in the long term, but this approach, though off-label, simulates what we would do with an open surgical repair.
When I do place an endograft, or when I clip two grafts together, I also re-line the inner portion so that if there is a tear in the future it has already been managed with the graft on the inside.
The uses I mentioned are certainly gray areas. They have worked well for my group, but I don’t have enough data to comment on outcomes. However, we have not had any complications in the small number of patients we’ve treated.
Are there any objections to using the device?
Certainly, some surgeons are opposed to the EndoAnchor. I had similar thoughts initially, but the registry data have been convincing. Based on the data that we have, I think it’s short-sighted to assume that the device is ineffective without ever having tried it. The gold standard is open surgical repair. If we can simulate open surgical repair with the placement of an endograft and EndoAnchors, then it is hard to argue against the use of the device because you are essentially arguing against open surgery.
Secondly, cost is a potential point of contention. However, although the cost is an add-on to the traditional endograft, that cost is offset in many ways because the use of an EndoAnchor means operators can avoid using other devices that are necessary in a more complex repair such as parallel grafting or fenestrated grafting.
Are there cases in which EndoAnchors should be avoided?
You cannot use EndoAnchors for every repair. Some patients need a fenestrated graft or parallel stent grafting, and you would not use EndoAnchors. There has to be some neck below the renal arteries in order to use EndoAnchors. However, EndoAnchors can be beneficial in patients with a 4 to 6 mm or even a 10 mm neck. If we can show that the data are comparable to that of a fenestrated or parallel graft, it’s a quicker and easier procedure to use the EndoAnchors, which, again, reduces the amount of radiation to which the patient is exposed. We’re always focused on what is best for the patient.