In Silico Modeling and Validation of Post-Dilation in TAVI Patients.

PURPOSE (STATING THE MAIN PURPOSES AND RESEARCH QUESTION): The purpose of this study is to develop and validate a balloon post-dilation model into patient-specific transcatheter aortic valve implantation (TAVI) simulations, addressing the current lack of numerical models capable of reproducing this procedural step. METHODS: A finite element model of a TrueTM Dilatation (BD, Tempe, Arizona) balloon was reconstructed and discretized. Balloon material properties were calibrated and validated through experimental tensile and inflation tests, respectively. The balloon model was then integrated into the final configurations of four TAVI simulations to reproduce the post-dilation phase. Model predictions were quantitatively compared with post-operative computed tomography (CT) images to assess the reliability of the final device configuration. Additionally, simulations performed with and without post-dilation phase were compared to evaluate differences in prediction error and to quantify the impact of post-dilation on agreement with clinical imaging. RESULTS: The calibrated balloon model accurately reproduced experimental inflation behavior around the nominal working pressure, and post-dilation was simulated in all cases. Quantitative comparison with post-operative CTs demonstrated high predictive accuracy of the final stent configuration. The average percentage error in orifice area was 1.55 ± 1.26%, while eccentricity error at the left ventricular outflow tract level was 1.54 ± 1.08. Inclusion of post-dilation reduced prediction errors by 53% for orifice area and 80% for eccentricity. CONCLUSION: The integration of balloon post-dilation significantly improves the accuracy and clinical relevance of patient-specific TAVI simulations. Incorporating this step is essential to reliably predict final stent configuration and support the development of robust in silico tools for personalized TAVI planning and risk assessment.