By Gustavo S. Oderich, MD
The following quote from David Hartley, FIR, remains true today: “It has become clear that not only the technology but also disease progression plays an important role in the durability of endovascular aortic therapy.”1 Endovascular aneurysm repair (EVAR) has changed the way we manage aortic aneurysms. Although the initial focus was on comparisons with open surgical repair, efforts have more recently been on how to expand the indications of EVAR to the 40% of patients who have inadequate landing zones or involvement of the visceral arteries. In these patients, there has been a push for more liberal indications outside the instructions for use and to shorten the minimum neck to 10 mm or less, including the use of parallel grafts or endoluminal stapling. Although some studies have shown favorable early outcomes with short neck indications, others caution higher rates of failure. Moreover, this change in paradigm is coming at a time when long-term results of the EVAR trials indicate a higher risk of aneurysm rupture for patients treated by EVAR compared to open repair.2,3
In the last decade, we observed a surge of innovative techniques to extend the indications of EVAR with fenestrations, branches, and parallel stent grafts. Fenestrated endografts have widely been used with increasing clinical experience in the last 2 decades. It is estimated that over 20,000 patients have been treated worldwide (Cook Medical, personal communication). In the United States, the Zenith Fenestrated (ZFEN) stent graft (Cook Medical) was approved by the US Food and Drug Administration for commercial use in April 2012. The device is designed with a maximum of three fenestrations and is indicated for patients who are not candidates for infrarenal EVAR because of short necks between 4 to 14 mm.
WHY IT WORKS
Endovascular sealing is based on the principle that a close interaction between the stent graft and the aortic wall is needed to exclude the aneurysm sac. Thrombus, calcification, short length, and gutters violate this principle. Selection of the landing zone has significant ramifications on endovascular repair, because the aorta continues to enlarge adjacent to aneurysmal segments.
The implications of poor neck selection can be noted intraoperatively but are more often evident 3 to 5 years after the procedure.2,3 Majewski et al observed that 60% of patients treated by open repair for juxtarenal aneurysms had enlargement of the aorta above the graft anastomosis.4 Neck dilatation is more prominent with self-expandable stent grafts, which are typically oversized to the normal aortic diameter. Enlargement is > 10 to 15 mm below the renal artery origin and in patients who have proximal necks > 30 mm in diameter.5-7 Neck enlargement continues to progress even in patients who experience a decreasing aneurysm sac and have no evidence of endoleaks.8 This process continues beyond 5 years after the initial procedure.9
The problem of using short neck indications is that treatment of a failed EVAR remains a challenge with significant morbidity and mortality. Several studies have shown that open surgical explantation for failed EVAR is associated with higher morbidity and mortality.10Salvage endovascular procedures (eg, placement of cuff extensions) or chimney grafts are not as effective and may potentially lead to more reinterventions, added cost, and loss of renal function. As for salvage with fenestrated grafts, these are technically more demanding and are associated with lower technical success.11 For these reasons, the first repair needs to be planned with the goal of long-term durability for the lifespan of the patient.
ZFEN AND FUTURE PERSPECTIVES
The United States Zenith Fenestrated trial has shown that the procedure is safe and effective.12 Mortality was low (1.5%) with no conversion, no aneurysm rupture, and with a low rate of renal artery occlusion (4%). Secondary renal stent patency was high (97%). Type Ia endoleak occurred in only one patient at 3 years due to enlargement of the aortic neck. These results have been replicated by systematic reviews, as well as multicenter and single-center experiences.13-16
Two-thirds of patients with complex abdominal aortic aneurysms are not candidates for the ZFEN device due to its design constraints. The maximum of three fenestrations (one nonreinforced) and the use of single-diameter scallops limit the ability to achieve sealing zones above the superior mesenteric artery or celiac axis, making it impractical to treat suprarenal aneurysms while maintaining the very principle of long, healthy sealing zones.
The next generation of ZFEN devices is being designed to address these limitations and will include features that help to facilitate technical aspects of the procedure. These improvements in device design will also allow for extending the repair to the supraceliac aorta, even for short-necked infrarenal aneurysms, if there is concern with progression of aortic disease. Recent clinical experience with three- or four-vessel fenestrations demonstrates high technical success and low morbidity and mortality, with lower rates of type Ia endoleaks long term as compared to one- or two-vessel fenestrated endografts.12-16
SUMMARY
The ZFEN device represents an initial step forward in achieving durable sealing zones in patients with what has been considered “unfavorable” neck anatomy for infrarenal EVAR. Cook continues to advance this technology forward with improvements in device design, implantation techniques, and adjunctive maneuvers to decrease mortality and morbidity, with the long-term goal of achieving the most durable repair possible.
Gustavo S. Oderich, MD
Professor of Surgery
Vascular and Endovascular Surgery
Mayo Clinic
Rochester, Minnesota
oderich.gustavo@mayo.edu
Disclosures: Consultant to Gore & Associates and Cook Medical; research grants from Gore & Associates, Cook Medical, and GE Healthcare; all consulting fees and grants were paid to Mayo Clinic.
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- Hartley D, Eagleton, M, Roeder B. Proximal abdominal aortic aneurysm necks. Endovasc Today. 2014;13(supp):4-9.
- Schermerhorn ML, Buck DB, O’Malley AJ, et al. Long-term outcomes of abdominal aortic aneurysm in the Medicare population. N Engl J Med. 2015;373:328-338.
- Patel R, Sweeting MJ, Powell JT, Greenhalgh RM. Endovascular versus open repair of abdominal aortic aneurysm in 15-years’ follow-up of the UK endovascular aneurysm repair trial 1 (EVAR trial 1): a randomised controlled trial. Lancet. 2016;388:2366-2374.
- Majewski W, Stanisic M, Pawlaczyk K, et al. Morphological and mechanical changes in juxtarenal aortic segment and aneurysm before and after open surgical repair of abdominal aortic aneurysms. Eur J Vasc Endovasc Surg. 2010;40:202-208.
- Rodway AD, Powell JT, Brown LC, Greenhalgh RM. Do abdominal aortic aneurysm necks increase in size faster after endovascular than open repair? Eur J Vasc Endovasc Surg. 2008;35:685-693.
- Oberhuber A, Buecken M, Hoffmann M, et al. Comparison of aortic neck dilatation after open and endovascular repair of abdominal aortic aneurysm. J Vasc Surg. 2012;55:929-934.
- Arthurs ZM, Lyden SP, Rajani RR, et al. Long-term outcomes of Palmaz stent placement for intraoperative type Ia endoleak during endovascular aneurysm repair. Ann Vasc Surg. 2011;25:120-126.
- Kaladji A, Cardon A, Laviolle B, et al. Evolution of the upper and lower landing site after endovascular aortic aneurysm repair. J Vasc Surg. 2012;55:24-32.
- Tsilimparis N, Dayama A, Ricotta JJ. Remodeling of aortic aneurysm and aortic neck on follow-up after endovascular repair with suprarenal fixation. J Vasc Surg. 2015;61:28-34.
- Turney EJ, Steenberge SP, Lyden SP, et al. Late graft explants in endovascular aneurysm repair. J Vasc Surg. 2014;59:886-892.
- 11.Katsargyris A, Yazar O, Oikonomou K, et al. Fenestrated stent-grafts for salvage of prior endovascular abdominal aortic aneurysm repair. Eur J Vasc Endovasc Surg. 2013;46:49-56.
- Oderich GS, Greenberg RK, Farber M, et al; Zenith Fenestrated Study Investigators. Results of the United States multicenter prospective study evaluating the Zenith fenestrated endovascular graft for treatment of juxtarenal abdominal aortic aneurysms. J Vasc Surg. 2014;60:1420-1428.
- Mastracci TM, Eagleton MJ, Kuramochi Y, et al. Twelve-year results of fenestrated endografts for juxtarenal and group IV thoracoabdominal aneurysms. J Vasc Surg. 2015;61:355-364.
- British Society for Endovascular Therapy and the GLOBALSTAR Registry. Early results of fenestrated endovascular repair of juxtarenal aortic aneurysms in the United Kingdom. Circulation. 2012;125:2707-2715.
- Nordon IM, Hinchliffe RJ, Holt PJ, et al. Modern treatment of juxtarenal abdominal aortic aneurysms with fenestrated endografting and open repair—a systematic review. Eur J Vasc Endovasc Surg, 2009;38:35-41.
- Oderich GS, Ribeiro M, Hofer J, et al. Prospective, nonrandomized study to evaluate endovascular repair of pararenal and thoracoabdominal aortic aneurysms using fenestrated-branched endografts based on supraceliac sealing zones. J Vasc Surg. 2017;65:1249-1259.
Jesse Manunga, MD, is a vascular surgeon at Abbott Northwestern Hospital in Minneapolis, Minnesota. Dr. Manunga shares his thoughts on getting experience with FEVAR as a new attending and building a team to support the procedure.
How did you start your FEVAR program when you first got into practice?
I had interest. I knew that I wanted to do endovascular and open complex aortic work. But my first emphasis was endovascular. I interviewed at a number of places and had several job offers, and I made sure everywhere I interviewed that they were supportive of my vision. I was coming out of fellowship a year after ZFEN was approved, and a lot of people were still doing back table stuff. In fellowship, we had participated in or had seen at least 50 fenestrated cases done. Most of us who came from Mayo knew what it entailed and wanted to continue this work. Decision to take the job in Minneapolis was based on the community need and the desire of the institution to start a fenestrated program.
How did you go about building your team when you got to Abbott Northwestern?
This can be a daunting task, because you are walking right into a mature practice. I was joining straight out of fellowship as the sixth or seventh surgeon in a group. These guys were very accomplished and as a young surgeon you come out and say, “Hey, I’m going to start doing this new procedure.” I think it starts by building trust. Building trust starts by doing easy things. I knew the volume was there. It started with me being on call and getting ruptured aneurysms, and being able to do them both open and endovascularly—open for those who didn’t have a neck or endovascular for those who had a neck, and patients survived them. We got really lucky where we got no mortality and no complications early in experience.
When I started, I made this presentation on fenestrated stent grafts, and gave it to my partners. I kept on showing them what’s possible and what other people are doing, and I kept on saying “A bigger healthcare system like this cannot survive without this program. We need it—our patients need it.”
From there, I went on to giving talks on the topic to nurses, anesthesia team and Cath Lab techs. I started to see people growing in interest saying “We need to do this.” And yet, I still did not have an ideal patient for this. It wasn’t until one of my partners actually referred a patient like, “Hey, this patient has a juxtarenal aneurysm, but he does not want an open repair. How about that fenestrated thing you were talking about?” The patient came and saw me in the clinic and I said, “We can do this.” And he said, “How many have you done?” And I said, “Zero here. But I trained at the Mayo Clinic and I saw a lot of these and I feel comfortable doing this.” And it so happened that we had two patients that needed fenestrated stent grafts on the very first day. I scheduled them on the very first day. I was eager to get a proctor in, and get these signed off. I was confident that I could do these cases. We finished the first case in ninety minutes I think, and the second case took us even less, I think forty-five minutes and we were done. We stented both cases. I had good support from the interventional radiologist who was my partner— Andy Craig—and he had very good wire and catheter techniques. He and my boss – Tim Sullivan – really helped support my vision and me. I knew that I had the support and that proved to be really helpful.
What is your team like now? How do you train your team?
To date, there is one assistant and me that work together on these cases all the time. If the other surgeons get a fenestrated case, I believe in training everyone, so everyone has to learn. Fenestrated stent grafting is not for everybody. There are some surgeons who say, “No, I don’t want to do that.” Our practice has so many young people who want to get involved in the program. If they want to do a case, it’s okay. They just need to have someone with experience there and I make myself available to them.
As far as the team, that was a challenge, it became very clear, very quickly that to produce the best results we needed to establish a dedicated team. We trained a core group of people and a lead tech who is with us on every single fenestrated case we’ve done. Then once the hospital noticed that we are serious, and we showed them our results and our results are good, we started asking them “Okay, we need fusion CT, and we need TerraRecon.” They didn’t have this stuff when I started. I had to go back and show them that I’m an investment to them.
It takes a team. I look at Gustavo Oderich and the way he does it. Number one, he has same team over and over again. But how he does it, I can never give him too much credit. It is so important to have the support of other physicians, to have the same team over and over again. Results don’t happen in a vacuum. They happen because you have a great team.
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Jesse Manunga, MD, is a paid consultant of Cook Medical.
Mathew Wooster, MD, is in his fifth and final year of the integrated residency program at the University of South Florida in Tampa. Dr. Wooster shares his experience with FEVAR as a fellow and how it has impacted his job search.
How did you get involved with fenestrated cases as a fellow?
Getting involved initially as a fellow is pretty straightforward. Basically, your attendings book a case and you figure out you have to learn how to do it. I already had a basic understanding of the procedure from going to a bunch of different meetings, so I was very curious about it and talked to my faculty about it. And when we got it here, I just jumped at the first case they were doing to try to start being involved—double scrubbing because at that time I was a junior resident. And then as I got more senior, planning the cases and doing the cases independently with the attendings.
What would you tell other fellows to help them get more exposure and experience with FEVAR techniques?
I don’t know that there’s anything anybody can do to get more exposure other than having the cases be available to them. It’s really a matter of knowing that the technology is there and whenever you see a patient with an aneurysm, you have to assess them and decide, is this patient a candidate? And if they are, advocate for it. It’s the only on-label technology we have right now for juxtarenal aneurysms and it certainly has the best data behind it. Obviously, there’s a lot of proponents for snorkels and we do our fair share here, but this is the only thing that’s actually on label to treat this pathology. Tell your faculty that you’d like to try it and that the data supports doing it over an open aneurysm repair with the appropriate patient selection. Getting after it that way is the only way to do it, really.
As you get ready to go into practice, how has learning these skills impacted your decision on where to go?
It’s helped in the sense that I have a pre-formed understanding of what I want to do. I want to have a fair amount of aortic work in my practice and so I was looking for a facility where that would be supported and encouraged as well as a facility that was going to both support and encourage fenestrated repairs.
And in terms of finding the right fit, I found that. I’m going to be going into university practice. They have a fairly large aortic experience right now. They have one of the larger fenestrated experiences in the country. The person who was doing most of those happened to be leaving, so I’ll slide right in as another person to help fill that role.
Did FEVAR make you more marketable coming out of fellowship?
Definitely. It was definitely very much sought after to know that you had somebody coming in who could offer really any level of endovascular or open experience. Being able to have the full array of treatments is crucial. There’s a lot of practices that have predominately older surgeons still, and they’re looking to bring in somebody younger who can offer this to patients. There’s other practices that have some younger people who are doing it, and they just want help. The reality is that a fenestrated case is at least a two-physician case. You need two sets of hands in addition to a tech. There are some practices where they just need a second person who knows what they’re doing with this stuff to be able to technically accomplish it. So knowing that I had that ability definitely made me more marketable to people.
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Mathew Wooster, MD, is an independent physician with no financial ties to Cook Medical.
Martyn Knowles, MD, practices vascular surgery at UNC Rex Hospital in Raleigh, North Carolina. He shares his advice for establishing a FEVAR practice in a community setting.
What is your practice like in Raleigh?
Our group practices at a 650-bed, private hospital in Raleigh that is a part of the University of North Carolina Healthcare system. I have six partners, four vascular surgeons and two vascular medicine specialists. We work closely with the academic vascular surgery group in Chapel Hill and collaborate in education, clinical care, and research. We practice a broad spectrum of vascular surgery with a strong emphasis on peripheral artery disease, aortic disease, venous disease, dialysis access, and DVT/PE management.
How did you go about establishing a FEVAR practice at your facility?
My interest in FEVAR was developed during residency and fellowship, so I had a clear interest coming in. During training, I had extensive training in FEVAR under Carlos Timaran at UT Southwestern, and honed those skills when I stayed on as a faculty member prior to moving to North Carolina. With an interest and a knowledge base, it was an easy transition once I got to my new practice. An important aspect of successfully setting up a FEVAR practice is either having experience and translating it into your practice or learning ways to absorb it and incorporate it into the practice.
As FEVAR was already being done here at our hospital, it was already somewhat set up, but the goal was to try and build the program. The administration and the hospital were on board. What I really focused on was getting the team up to speed and getting them comfortable with the procedures—what devices, what ancillary equipment, and what the patients would need to best carry out the procedures in the most expedient and safe fashion. The goal as always was to provide a safe repair option, with a minimal amount of radiation.
The procedure team is a very important aspect of a fenestrated program because you really have to have trust in them and they have to have trust in you. That way, they know exactly what you’re going to need so they’re not running around spending a huge amount of time trying to find everything that you could potentially need. That does come with some experience, and having a discussion with team members prior to the case and subsequently a debrief can help avoid and prevent issues.
Specifically, going over the case in depth with the team ahead of time is prudent to anticipate what devices, catheters, wires, and then potentially bail-outs would be needed or available in case there is an issue.
The next part was letting everybody in the hospital know that this is something we would be doing. This involved making the ICU intensivists and other physicians comfortable with the care of these patients. Furthermore, we educated physicians out in community from primary care all the way up to vascular surgeons about the procedure. We tried to encourage the vascular surgeons to involve us in the care of some of the patients that had been deemed poor surgical candidates with short neck aneurysms.
Why did you feel that it was important to integrate FEVAR into your practice?
I think the first and most important aspect of integrating FEVAR is a belief in the platform and the durability of the repair. FEVAR is a safe and effective procedure for these patients. It’s been well-tested, with thousands of implants domestically and internationally, and we know the results are excellent. In my practice, it’s a very successful, safe device for the repair of juxtarenal or short neck aneurysms. The data is clear that these patients don’t do as well with infrarenal repair and FEVAR is an excellent option to the repair, and specifically, using an FDA approved device. Cases that are not candidates for a FEVAR repair are assessed for open repair, or sent to UNC and placed into Dr. Mark Farber’s IDE if they are deemed candidates. We have a collaborative approach to these patients that allows them the most advanced care under a carefully scrutinized program.
With that being said, because there’s a belief in knowing that the device performs well, it was an easy thing to want to incorporate. I believe it’s the best thing for the patients. It’s minimally invasive, and often allows them to get back to life without much of a change in their quality of life afterwards. Importantly, we established a set of guidelines for the follow-up of the patients to provide the best care moving forward after repair and to identify any ongoing issues.
I do think it’s also important to be efficient in the skills required for FEVAR because fenestrated technology is the first step in the future of vascular surgery. There are so many other devices and improvements upon this platform coming down the pipeline, and if you don’t understand or embrace this, I think you’re going to get left behind as it becomes more complex and more difficult moving forward.
Another important component of building a FEVAR practice is that you’re looking for a way to stick out and add something that other physicians in the area don’t do or don’t have experience with. FEVAR can provide you some leadership within the community for the repair of these complex aneurysms.
What advice do you have for physicians who want to establish the same type of program?
The most crucial parts are creating a team that you trust, and knowing what you’re looking for and what you’re trying to accomplish. I think working on a referral program and involving referring physicians, especially vascular surgeons, in the care of these patients is important. There are a lot of procedures performed, using devices not meant for this pathology with mixed results. Educating those around your area to FEVAR is in the best interest for patients.
From an advice standpoint: plan, plan, plan for these cases. For me, that means not just planning the case initially, but making sure you have a plan A, B, C, and D to anticipate the potential problems that may arise. Optimally, I try to think about these cases in so many different ways, and I’ve overthought it to such a degree that I try to eliminate the possibility that there’s anything during the case that’s unexpected. The more cases you see, the more pitfalls and problems you can avoid. Additionally, always thinking about FEVAR allows you to identify a large number of patients who would be outside IFU for an infrarenal repair.
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Martyn Knowles, MD, is a paid consultant of Cook Medical.