Short neck AAAs: “Choosing what is best for the patient”

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Ross Milner at CIA 2023

Navigating cases of abdominal aortic aneurysm (AAA) with short neck anatomy pose a serious challenge to vascular surgeons, but the list of potential options available to carry out repairs are numerous—and decision-making can be optimised by using a bespoke algorithm.

That was the message delivered by Ross Milner (University of Chicago Medicine, Chicago, USA) in a session on endovascular aneurysm repair (EVAR) controversies at the Critical Issues America (CIA) annual meeting (10–11 February, Miami, USA).

Milner outlined the four core pathways open to surgeons when they are confronted with short necks—defined as greater than 4mm and less than 10mm: open repair, fenestrated EVAR (FEVAR) or physician-modified endografts (PMEGs), off-label chimney EVAR (ChEVAR), and endosuture aneurysm repair (ESAR).

In short, he said, the treatment ultimately elected should be dictated by the individual patient.

“I think in the past you have seen a lot of talks that are designed as debates between one of these techniques, and we commonly joke about different techniques not working well,” he told CIA 2023. “The reality is, when you are looking at each one of your patients, and you are sitting in the office, and trying to make a decision, I think we incorporate all of these options.”

Milner uses his algorithm, or decision tree, in order to help establish which approach is going to best serve the patient in front of him. This includes figuring out the patient’s physiologic risk, the level of urgency of a procedure, durability based on risk profile/age, the direction of the renal arteries and the state of the aortic arch anatomy.

“When I look at the anatomy, the things I look at from an anatomic standpoint are: how do the renal arteries come off the aorta?” he said. “At least in my hands, I find that for chimney approaches, downward-going renal arteries are easier. For upward-going, fenestrated is easier. But again, in different people’s hands, it is probably different. I also look at the anatomy of the neck and the tortuosity. If you are going to think about ChEVAR, you look at the aortic arch.”

Open repair can be valuable in the right set of patients, Milner continued, but is “highly invasive” and “the risk of renal failure with open surgery is greater than with complex EVAR, and likely to leads to worse outcomes.”

In his practice, Milner and colleagues do not perform procedures with PMEGs but rather on-label FEVARs. “It is FDA approved, it is all transfemoral, it is indicated for 4mm neck, but it can be limited by anatomy, and sometimes the device just cannot be made,” he explained.

ChEVAR, meanwhile, has performed “relatively well” for his team in the treatment of complex anatomy, Milner said. “Its limitations are gutter leaks and stroke risk.”

Then there is short neck ESAR, he added, which incorporates EndoAnchors with an Endurant stent graft (Medtronic).

Overall, said Milner, his decision tree breaks down to, first, physiologic risk. “If it is low, consider open surgery,” he said. “If high, go with an endovascular approach. For FEVAR, I look at iliac access, the direction of the renals, the neck tortuosity, the urgency of the procedure;

for ChEVAR, again, iliac access, the direction of the renals, neck tortuosity and the aortic arch anatomy; for ESAR, calcification and thrombus, and reverse taper of the neck.”

Responding to skepticism over the ESAR procedure, Milner acknowledged controversy centres on a central question: “What is the true neck? And all of us know that a 4mm neck is exceptionally challenging to use EndoAnchors on. I know that this is written as an indication, but that is hard to do,” he said, concluding: “Many options exist; choose what is best for your patient.”


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