Model reduction methodology for computational simulations of endovascular repair

Abstract

Endovascular aneurysm repair (EVAR) is a current alternative treatment for thoracic and abdominal aortic aneurysms, but is still sometimes compromised by possible complications such as device migration or endoleaks. In order to assist clinicians in preventing these complications, finite element analysis (FEA) is a promising tool. However, the strong material and geometrical nonlinearities added to the complex multiple contacts result in costly finite-element models. To reduce this computational cost, we establish here an alternative and systematic methodology to simplify the computational simulations of stent-grafts (SG) based on FEA. The model reduction methodology relies on equivalent shell models with appropriate geometrical and mechanical parameters. It simplifies significantly the contact interactions but still shows very good agreement with a complete reference finite-element model. Finally, the computational time for EVAR simulations is reduced of a factor 6–10. An application is shown for the deployment of a SG during thoracic endovascular repair, showing that the developed methodology is both effective and accurate to determine the final position of the deployed SG inside the aneurysm.

Keywords:

• EVAR
• finite element analysis
• model reduction
• Robust Design Method
• stent-graft deployment

Acknowledgments

The authors would like to acknowledge the French National Research Agency (ANR) for funding the Endosim project (grant ANR-13-TECS-0012). The authors are also grateful to the European Research Council for grant ERC-2014-CoG BIOLOCHANICS.