Numerical investigation of full crimping to 6 mm and deployment in TAVR: coupled influence of implantation depth.

چکیده اصلی

To address the inadequate representation of key physical processes in numerical simulations of transcatheter aortic valve replacement, a high-fidelity mechanical analysis framework that more closely approximates clinical reality has been developed. Based on a comprehensive structural model incorporating the skirt, leaflets, and stent, this framework incorporates the clinically standard 18 Fr crimping dimension and a release mechanism based on axial extraction from the capsule. It systematically investigates the coupled effects of full crimping to clinical standards, deployment strategies, and implantation depth on the mechanical behavior of the valve. The results demonstrate that deployment approaches based on incomplete crimping and radial recoil fail to capture the pronounced spatiotemporal non-uniformity observed in realistic deployment processes. In contrast, the axial pullback mechanism induces multi-stage stress peaks and complex contact evolution, significantly enhancing the anchoring performance between the stent and the vascular wall. Furthermore, implantation depth modulates structural constraint conditions, driving a transition from localized load-bearing to global cooperative load sharing. While this improves overall stability, it also introduces potential physiological risks. Notably, quantitative analysis based on eccentricity reveals a clear correspondence between stent cross-sectional deformation and its geometric configuration. Local geometric features are shown to dominate the post-expansion shape distribution and directly influence the uniformity of radial deformation. Paravalvular leakage exhibits pronounced spatial heterogeneity, with its formation governed by the combined effects of structural interference and contact uniformity. These findings reconstruct the physical picture of the TAVR deployment process from a mechanical perspective, providing new theoretical insights for valve design optimization and patient-specific implantation strategies.

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