Prof. L. Canaud: "the simplicity of the procedure significantly reduces manipulations in the aortic arch. It takes us around 60 minutes to complete the procedure"

Professor Canaud works as a thoracic and vascular surgeon at CHU Montpellier.

He has published numerous papers on the modification of endografts to treat aortic arch pathology. He has described a personal technique for modification and implantation with a large number of cases and excellent short- and mid-term results. He currently leads the Evergreen study (prospective multcnetric study with core lab analysis) to study the outcomes of his technique.

Javier Río: We welcome our audience to a new interview today. We have the honor of interviewing one of the world's most experienced surgeons in the treatment of the aortic arch using Physician Modified EndoGrafts (PMEG´s). Good morning, Professor Canaud. First, let me ask you, what inspired you to start performing fenestrations in the aortic arch?

Ludovic Canaud: At the Montpellier University Hospital (CHU de Montpellier), we have long been performing a significant number of emergency endovascular procedures at the thoracic level. For certain patients for whom a subclavian surgical revascularization was not feasible, we carried out emergency stent grafts. In 2014, in an effort to improve our patient care, we began to create large scallops to maintain the patency of the left subclavian artery. Given the initial success, we advanced to performing single fenestrations, which we catheterized via a retrograde approach. Subsequently, we progressed to combining the transposition of supra-aortic trunks with single fenestrations.

In 2017, the idea of double fenestrations emerged for patients requiring landing in zone 0 to perform complete endovascular repairs without manipulating the carotid arteries. Initially, we thought the number of eligible patients would be very limited. However, in reality, more than 90% of isolated aortic arch lesions (without extension to the ascending aorta) are eligible.

J.R.: In your extensive experience modifying PMEGs for the aortic arch: what type of patient would be ideal for your technique?

L.C.: It is difficult to define the ideal patient. One key criterion is the urgency or the inability to wait for a custom-made prosthesis.

Regarding the use of the double fenestration technique, the ideal lesions are those located in the inner part of the aortic arch or lesions in zone 1. It is crucial for the patient to have a healthy ascending aorta with a diameter of less than 42 mm. Another very important criterion is the absence of thrombus in the aortic arch to minimize the risk of stroke as much as possible

J.R.: Unfortunately, not all cases are "ideal." What type of anatomical feature would be the most limiting when performing your technique?

L.C.: There are essentially three key criteria that contraindicate this practice.

Firstly, lesions located on the outer curve of the aortic arch. The use of fenestration does not allow for the treatment of these lesions.

Secondly, the diameter of the ascending aorta to avoid the risk of retrograde dissection. It must not exceed 42 mm.

And thirdly, the presence of thrombus in the aortic arch. These patients are at high risk for stroke.

Finally, there is the criterion of accessibility, due to the need to use large-diameter introducer sheaths for the stent-graft.

J.R.: Considering the entire process (measurement-modification-implantation), which step, or technical detail would you consider the most critical?

L.C.: The critical point in this technique is the modification of the stent-graft. We have discovered many tips through our practice after numerous errors. The resheathing of the graft must maintain the alignment of the fenestrations and avoid any torsion of the stent-graft. Additionally, it is important to ensure that the preloaded guidewire does not get blocked during the resheathing of the stent-graft.

J.R.: Having read your articles, the answer seems quite obvious: what is your favorite endograft for your technique? And most importantly, what advantages does it offer over other devices?

L.C.: The stent-graft we use is the Valiant Captivia by Medtronic. It offers numerous advantages. The tension of the graft in relation to the stent allows for the complete opening of the fenestrations. Its radial strength also ensures that the alignment of the fenestrations is maintained, even in cases of significant aortic tortuosity. The tight stitching of the fabric to the stent prevents the creation of traps for the preloaded guidewire, which is often an issue with other grafts. Additionally, it is easy to modify and resheath.

J.R.: According to your results, the use of your technique implies a lower risk of stroke compared to company-manufactured devices. What do you think accounts for this difference?

L.C.: I believe there are two key factors. First, this technique does not require any manipulation of the carotid arteries. The alignment of the proximal landing zone is automatically achieved by the subclavian stent. Second, the simplicity of the procedure significantly reduces manipulations in the aortic arch. In general, it takes us around 60 minutes to complete the procedure.

J.R.: As a final question: we are seeing a rise in the use of PMEG´s both in the thorax and abdomen with good published outcomes. Do you think we are getting closer to being able to modify an endograft within the device's instructions for use?

L.C: I believe that the increase in this type of procedure is related to the growing expertise of surgeons in complex abdominal aortic pathologies. On the other hand, the manufacturing timelines, costs, and the lack of solutions that deliver the expected results are pushing surgeons to develop these techniques and seek to compensate for the absence of innovation or for innovations that are likely not the best. In the USA, there are licenses for performing modifications of stent-grafts. This allows for a framework that ensures the technique is reproducible and facilitates patient follow-up. Establishing guidelines for these practices will shift them from off-label to on-label use.