Computer simulation model may prevent thoracic stent-graft collapse complication
Objective
Endovascular repair of aortic arch aneurysms is a valuable option for patients at high risk for open surgery. However, accurately predicting how a stent-graft will behave in complex arch anatomies remains a challenge, and current planning relies only on CT-scan imaging reconstruction.
A key limitation is that these tools cannot show the mechanical interaction between the aortic wall and the stent-graft. The objective of this case report is to show whether patient-specific finite element simulation could have predicted a severe device collapse complication before the intervention.
Methods
We report the case of a 71-year-old man with a 60 mm aortic arch aneurysm and no adequate proximal sealing zone, treated with a custom-made double-branch Relay device (Terumo Aortic).
Anatomic data from the pre-operative CT-scan, together with the mechanical and geometric characteristics of the double-branch device, were used to simulate stent-graft deployment.
The simulation used finite element technology based on proprietary algorithms (PrediSurge) and the Abaqus/Explicit solver, and the predicted result was compared with the post-operative CT-scan.
Results
After deployment, the patient developed severe complications, and the post-operative CT-scan revealed a collapse of the device just distal to the branch fenestration zone β deemed the main cause of the complications.
The simulation reproduced this collapse at the exact same location in the fabric. It predicted the failed deployment and major deformation of the same three stent rings distal to the valley, matching the shapes seen on the post-operative CT-scan.
Conclusion
Patient-specific finite element simulation was able to reproduce a serious stent-graft collapse that occurred in a complex aortic arch case.
This shows the potential of computer simulation to anticipate device behavior during pre-operative planning β helping improve patient selection, stent-graft choice, and testing of different designs, and potentially reducing intra operative and post-operative complications.