Validation of Fenestrations Positioning by Numerical Simulation in Fenestrated Endovascular Repair of Abdominal Aortic Aneurysms

Fenestrated endovascular repair (FEVAR) is nowadays a recognized option to treat juxtarenal, pararenal or suprarenal abdominal aortic aneurysms in patients at high risk for conventional repair. The technique consists in deploying a custom-made stent-graft (SG) inside the patient aorta. Part of the customization involves cauterizing a hole in SG fabric and reinforcing it with a Nitinol stent ring, thereby creating a fenestration for each corresponding collateral artery. For this reason, preoperative planning is crucial to determine adequate positions of fenestrations, in order to obtain perfect alignment with the collateral arteries of the patient. Inadequate positioning may result in failure to catheterize a collateral artery and subsequent organ damage, increased catheterizing time, increased irradiation dose, endoleaks... The current process of fenestrations positioning for fenestrated anacondaTM SG involves: (i) anatomical measurements on patient preoperative CT-scan by case planners using dedicated sizing software; (ii) designing an initial custom device scheme with its positioned fenestrations, created by engineers with CAD software using the above cited measurements and (iii) validation of fenestrations position by in vitro testing using a SG prototype deployed inside a transparent anatomy model (3D-printed model of patient aorta and collateral arteries). The main limitations of this process are the costs and long SG delivery time.