SIMulation of tools / tissues interactions for the PLanning of Endovascular devices implantation.
Patient specific and predictive numerical simulation for decision support in the planning of cardiovascular interventions
Coordinator: Pascal Haigron – LTSI Laboratoire Traitement du Signal et de l’Image
Principal Investigator: Claire Dupont – LTSI
Other CAMI Partners: LTSI (Rennes), ISIR (Paris), TIMC-IMAG (Grenoble)
Started: January 2nd, 2017
Motivations and objectives:
Among mini-invasive surgical techniques, endovascular treatment consists in accessing the lesion through intravascular way to interact with pathological tissues . These techniques have developed in recent years to become the reference therapy for several pathologies (aneurysm, stenosis …) . However, the introduction of delivery tools through arteries and the deployment of implantable devices can have major consequences due to interactions between endovascular devices and tissues. Nowadays, the anticipation of complications mainly relies on the surgeon’s experience. Because of the regular development of more and more complex endovascular devices, the practitioners face difficulties to anticipate treatment outcome and to gain experience. To improve the planning of the treatment and optimize the interventional strategy, there is a need for new decision support tools compatible with the clinical workflow. Software tools for planning endovascular treatment already exist but mainly focus on pre-operative imaging. Beyond preoperative image analysis, explicit modelling of endovascular devices and of their interactions with tissues could be used to propose an augmented decision process by predicting possible complications .
Several studies about modelling and numerical simulation have been reported in the context of cardiovascular diseases. However, issues related to patient-specific simulation for endovascular treatment planning have been little addressed so far. The prediction of the mechanical equilibrium between the vascular structure and endovascular device from preoperative patient data remains a challenge.
The main objectives of the project SIMPLE are to propose and develop patient-specific and predictive numerical methods to simulate endovascular treatments and to investigate their integration in the clinical decision process. Application context focuses on some endovascular interventions that share common features (e.g. delivery tools and access pathways): endovascular abdominal aneurysm repair (EVAR), transcatheter aortic valve implantation (TAVI), percutaneous transluminal angioplasty (PTA) and access to supra aortic trunks, especially in case of active catheterization.
To develop patient- specific and predictive simulation, the proposed approach is based on the joint exploitation of patient image data and biomechanical models. Intended work more specifically deals with the simulation of delivery tools insertion, vascular deformations, prosthesis and stent deployment, and active catheterization.
Main results and on-going work:
SIMPLE project is carried out in strong interaction with clinicians integrated in the team. First results have been obtained in the context of endovascular abdominal aneurysm repair. Ongoing work is extending to other endovascular applications in surgery, interventional cardiology and radiology.
The finite element (FE) method developed by  showed efficacy in predicting vascular deformation in the context of endovascular aortic aneurysm repair. However, its computational cost is a limitation to its integration into the clinical workflow. To reduce significantly the computational cost, a reduced order model (ROM) is being developed at LTSI in collaboration with ANSYS and Therenva companies. The approach consists in applying machine learning techniques to reference FEM simulation results obtained from several hundred of cases.
Reduced order modelling of vascular deformation.
The first results show that the reduced order model could be used to estimate the vascular deformation due to the insertion of a stiff guidewire in a few seconds and can be more easily integrated into the clinical workflow. Further ssessments are underway.
A numerical method has been developed to simulate stent-graft deployment in abdominal aortic aneurysm considering the vascular deformation due to the insertion of the delivery tools. First results were presented at SURGETICA’2017 conference .
Starting from preliminary results obtained in collaboration with ANSYS and other academic teams (LaMCos, Lyon; CIS, Saint Etienne)  , experiments were conducted at LTSI to adapt FE method developed for EVAR to simulate the guidewire insertion during TAVI, assuming deformable vascular structures. Work has also been initiated to address the problem of patient-specific simulation of device – tissue interactions in transluminal angioplasty (balloon, stent), where the prediction of calcified plaque behaviour remains a challenging issue.
In order to extend simulation based decision support to active catheterization recently proposed by ISIR and Basecamp Vascular start-up, issues related to the analysis of intra-operative observations are also being addressed by ISIR. The objective is to estimate the pose and to characterize the behaviour of this new kind of devices from fluoroscopic images, more specifically when accessing supra aortic trunks. The work planned at TIMC deals with the development of an experimental bench, integrating fluids flow dynamics, compatible with intra-operative X-ray rotational imaging. The evaluation and the study of the influence of the blood flow on catheter navigation are then possible. This will allow analysing the validity of different hypotheses eligible for catheterization simulation.
 Thompson M. M., Morgan R. A., Matsumura J. S., Sapoval M., and Loftus I. M. Endovascular Intervention for Vascular Disease: Principles and Practice. CRC Press, 2007.
 Wilbring M., Rehm M., Ghazy T., Amler M., Matschke K., Kappert U. Aortic Arch Mapping by Computed Tomography for Actual Anatomic Studies in Times of Emerging Endovascular Therapies. Annals of Vascular Surgery 2016;30:181–91.
 Kaldji A., Daoudal A., Gindre J., Lalys F., Cardon A., Haigron P., Lucas A. Numeric simulation predicts iliac complications during the implantation of an aortic stentgraft. Annals of Vascular Surgery 2017 ; 44:2.
 Gindre J., Bel-Brunon A., Kaladji A., Duménil A., Rochette M., Lucas A., Haigron P., Combescure A. Finite element simulation of the insertion of guidewires during an EVAR procedure: example of a complex patient case, a first step toward patient specific parameterized models: FE Simulation of the Insertion of Endovascular Guidewires. Int J Numer Method Biomed Eng. 2015 , 31, e02716.
 Gindre J., Bel-Brunon A., Rochette M., Lucas A., A. Kaladji, Haigron P. and Combescure A. Patient-specific finite element simulation of the insertion of guidewire during an EVAR procedure: Guidewire position and curvature prediction validation on 28 cases. IEEE Trans Biomed Eng. 2017 ; 64(5) :1057-1066.
 Dupont C., Kaladji A., Gindre J., Lucas A., Haigron P. Patient speciﬁc ﬁnite element simulation of stent-graft deployment in EVAR procedure. SURGETICA’2017. Strasbourg, France. Nov. 20-22 2017.
 P. Vy, V. Auffret, M. Castro, P. Badel, M. Rochette, P. Haigron, S. Avril. Patient‐specific simulation of guidewire deformation during transcatheter aortic valve implantation. Int J Numer Method Biomed Eng. 2018.