Further Development of the “Frozen Elephant Trunk Technique” with a Side-Branch Stent for the Left Subclavian Artery (FET-SSB): A Feasibility Study in a Human Anatomical Model

Objectives: The frozen elephant trunk technique (FET) has emerged as an important treatment strategy for operations of complex aortic arch aneurysms and dissections. Long circulatory arrest times and difficult anastomoses distal to the left subclavian artery (LSA), however, are associated with this operation. Therefore, specialized centers are performing the distal anastomosis between the left carotid and the subclavian artery (zone 2) followed by extra-anatomic bypass grafts or the challenging separate reimplantation of the LSA. The purpose of this experimental work was to test the feasibility of implantation of an FET-prosthesis with a subclavian artery side branch (FET-SSB) in the human anatomical setting.

Methods: An FET-prosthesis with a side branch stent graft for the LSA was conceptualized by our group and developed by Jotec (Hechingen, Germany). In addition, a side-branch prosthesis for distal aortic perfusion, as well as a Y-Graft, for separate reimplantation of the innominate artery and the left common carotid artery were part of this new design.

In 2019, the FET-SSB prosthesis was implanted in two human cadavers at the Anatomical Institute of the Medical University Clinic of Graz. The hybrid prosthesis was deployed into the proximal descending aorta with the side branch located at the take-off of the LSA. After accomplishment of the distal anastomosis in zone 1 or 2 of the aortic arch, the left common carotid artery and the innominate artery were anastomosed. A guide wire was advanced from the brachial artery into the LSA and into the open aortic arch prosthesis. In an antegrade fashion, a covered stent (Advanta V12) was inserted and deployed into the subclavian side arm, in order to complete endovascular treatment of the subclavian artery. Thereafter, the proximal anastomosis with the ascending aorta was performed.

Results: Accurate deployment of the prosthesis with placement of the short side-branch stent into the take-off of the LSA was feasible in both cases. In addition, we managed intraoperative stenting of the left subclavian artery with an additional covered stent. FET anchoring in zone 1 or 2 facilitates and potentially accelerates the performance of the distal anastomosis, thereby reducing circulatory arrest time in the clinical setting.

Conclusion: This initial study in human anatomical bodies could demonstrate the feasibility of implantation of a frozen elephant trunk prosthesis with a side branch for the left–subclavian artery. This evolution of the FET technique has the potential to simplify aortic arch surgery by reducing operative time and procedure complexity.