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Towards Experimental and Computational Investigations of Balloon Angioplasty and Stenting in Human Femoropopliteal Arteries
Device-artery interactions play an important role in arterial healing and repair effectiveness, but they remain insufficiently understood due to lack of experimental data. A better understanding of device-artery interactions can lead to improved patency and reduced healthcare costs through better device design and patient-specific use. This is particularly important for endovascular treatments of the femoropopliteal artery (FPA) that are notorious for their high failure rates. Current work presents an experimental analysis of FPA tissue characteristics under supraphysiologic loads experienced during balloon angioplasty. A constitutive model that accounts for the nonlinear anisotropic inelastic behavior of human FPAs is proposed, and its constitutive parameters describing biaxial damage initiation and progression in specimens of different ages are presented. We then describe the results of an imaging study investigating the interaction between the angioplasty balloon and the arterial wall in FPA specimens with different calcium severity using μCT, and report on different patterns of calcium cracking during balloon angioplasty, demonstrate that higher calcium burdens are not associated with lower luminal gains but have soft tissue damage, and show a high prevalence of arterial dissections after balloon treatment that require a stent. Experimental FPA evaluations are then followed by the investigation of stents used to treat peripheral arterial disease (PAD). These stents are made of a superelastic shape memory alloy Nitinol, and we have used bench-top experimental evaluation and inverse computational analysis to determine its material properties in 11 commercial PAD stents. We report significant differences in Nitinol across devices, and present data that can be used directly in device-artery computational simulations. Finally, we describe a parametric finite element approach to developing a new PAD stent that can accommodate limb flexion-induced compression, bending, and torsion of the FPA while limiting arterial wall stresses and pinching and maximizing apposition to the arterial wall. Overall, the presented results improve understanding of balloon angioplasty and stenting procedures in human FPAs, which can guide the development of better devices for endovascular PAD treatments.
Biomedical engineering|Surgery|Health sciences|Physiology|Biomechanics
Anttila, Eric David, "Towards Experimental and Computational Investigations of Balloon Angioplasty and Stenting in Human Femoropopliteal Arteries" (2021). ETD collection for University of Nebraska - Lincoln. AAI28646880.