Individual Research Project 10

Tissue characterization and endovascular aortic repair in a circulatory mock loop

Francesco Bardi – ESR 10

The aim of this ESR programme is to develop a mock loop for in-vitro testing and in-silico model for ascending thoracic aortic aneurysm treatment to (i) validate the endovascular procedure and (ii) to analyse the effect of endograft implant in the fluid-dynamic environment by CFD. For the achievement of the objectives, 4 phases of the research activities are planned: mechanical characterization of aneurysmatic vessel tissue for ascending thoracic aortic district, morphological assessment of patient specific models for aneurysms, in-vitro simulation of the surgical implant with fluid-dynamic characterization through the mock loop and in-silico simulation of the surgical implant. For the first phase an ex-vivo fresh specimen is gathered from patient undergoing selective surgical procedure according to the best clinical practice, then a mechanical characterization (uniaxial/biaxial traction tests) is achieved and experimental data extraction and fitting via constitutive model with particular attention to anisotropic behaviour is carried. The second phase foresees a patient-specific images and data extraction from clinical FTGM Database, image post-processing and segmentation for morphology definition and additive manufacturing of patient-specific models (rigid in a first step and then compliant according to experimental data). For the third phase the simulation of the implant deployment is carried and the evaluation of the implant performances on the patient-specific model by extracting the resulting experimental data (pressures, flows, etc.) is achieved. Last phase is completed by carrying CFD Simulations before, after and during endograft deployment and validating and comparing numerical results with experimental data from in-vitro simulation..

Expected Results

• Integration between patient-specific clinical data and engineering approaches to evaluate the delicate issue of endograft deployment in the treatment of ascending thoracic aortic aneurysms..

• Coordinated adoption of in-silico and in-vitro approaches, fundamental for comparisons and deeper validations.

• Analysis coupling mechanical and fluid simulation for the evaluation of implant performances, especially in terms of device conformability and fluid-dynamics.