Development of a 0D digital twin for assessment of the impact of vascular graft on ex-vivo porcine aortas

In patients affected by a thoracic aortic aneurysm, the gold standard treatment consists of surgically replacing the pathological portion with a synthetic graft. The implicit increase in arterial stiffness induced by the prosthetic graft leads to altered biomechanics. Different technical approaches can be adopted to predict vessel alteration: in vitro or computational approaches. The in vitro approach can couple physiological and pathological working conditions with the realism of ex vivo tissues. Nevertheless, operator dependency and the use of animal samples limit reproducibility. The computational approach, which is based on constructing realistic 3D models from patient-specific images, has proven effective in predicting post-operative biomechanics; however, the complexity of the numerical algorithms and high computational costs limit clinical adoption. In this scenario, we propose to develop a 0D lumped parameter model that acts as a pre- and post-operative digital twin of porcine aortas. The simplified model was coupled with a mock circulatory loop for experimental validation. Applied to sixteen ex-vivo models, the digital twin is designed to simulate the impact of the grafting procedure on aortic biomechanics. The simplified numerical model can predict post-operative vascular stiffening, with a deviation of less than 10 % compared to experimental data. Furthermore, this approach has the capability to predict a progressive reduction in the vessel Windkessel mechanical response due to the presence of various polymeric grafts. Therefore, due to its very low computational cost, the proposed numerical model could serve as a pilot tool for planning patient-specific surgical procedures.