Experimental and computational investigation of mechanical function as influenced by shape and material properties in native and surgically modified heart valves

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Objectives of the proposed research program:***The current predictions from structural engineering models are not yet trustworthy enough to be factored into the patient-specific surgical planning of heart valve repairs. As a result, in cases of aortic and mitral valve leakage, where restoration of functionality in the native defective valve (repair) is generally more desirable than the replacement with a prosthesis, cardiac surgeons must single-handedly master the complex interplay of geometry and material properties to fix the valve. The proposed research program aims to address the deficit in relevance and reliability of structural engineering models for the surgical repair of heart valves. The specific objectives are: 1) the acquisition of new experimental data to establish more accurate engineering models, 2) the development of new validation methods for computer simulations, and 3) the expansion of existing engineering simulation tools to handle cases of high surgical relevance. The resulting simulations are ultimately meant to provide actionable information that can be further evaluated in clinical trials (a logical next step not included in this proposal).******Summary of scientific approach:***The scientific approach will consist in a series of mostly interconnected projects mixing experiments at the tissue and organ levels, computional modeling, and synthesis between experiments and modeling. Specifically, new experimental data will be collected on human valvular tissues for accurate engineering modeling; physical models of normal and diseased heart valves will be developed and validated for the controlled testing of surgical procedures in the lab; finite element simulations will be thoroughly validated against experimental data at the tissue and organ levels; and new metrics will be developed to evaluate the discrepancies in the dynamic function of heart valves between computational simulations and clinical imaging, to rationalize and ease the process of model validation.******Novelty and anticipated significance of the work:***The proposed program will break new ground regarding engineering simulations for heart valve repair surgeries. It will directly improve basic science and engineering knowledge, as well as bring useful, relevant, engineering tools closer to the bedside in concrete and quantifiable ways, while providing advanced training to at least eight HQP. In addition to the anticipated progress regarding engineering models and methods, the proposed program is especially relevant because the number of patients with valvular disease keeps growing due to the aging of the population in Canada and elsewhere. Overall, this Canadian program will reinforce the position of the applicant's group on the international scene as a leader in cardiovascular biomedical engineering research.