CARDIOVASCULAR COMPLICATIONS FOLLOWING TRANSCATHETER AORTIC VALVE REPLACEMENT: QUANTIFICATION AND SYSTEMATIC DIFFERENTIATION USING CLINICAL MEASUREMENTS AND IMAGE-BASED PATIENT-SPECIFIC IN SILICO MODELING

Abstract

The success of TAVR procedure hinges on quantifications of the global hemodynamics (heart function metrics and workload), and the local hemodynamics (3-dimensional flow dynamics in left ventricle, aortic root, and coronary arteries). In this study, we developed an image-based framework that can quantify local and global hemodynamics for TAVR assessment. The proposed framework uses fluid-structure interaction method and lumped-parameter modeling that only needs routine non-invasive clinical patient data. The computational framework was validated against clinical cardiac catheterization data and Doppler echocardiographic measurements. One of the challenging aspects of TAVR is its common association with complex valvular, ventricular, and vascular diseases (C3VD). Treatment strategies for these patients are quite uncertain and, on a case-by-case basis. In order to examine long term risk factors and create guidelines for intervention aimed at minimizing the progression of cardiovascular disease, the impact of C3VD on ventricle fluid dynamics in patients who underwent TAVR was investigated in this thesis. Our results showed that interactions of C3VD with TAVR fluid dynamics may amplify adverse hemodynamic effects that limit the benefits of TAVR and might contribute to speed up disease progression. The results suggest that some other interventions in addition to TAVR, such as mitral valve intervention and percutaneous coronary intervention, might be required as regularly chosen current surgical techniques might not be optimal for patients with C3VD who undergo TAVR. Post-TAVR complications including paravalvular leakage, thrombosis and coronary obstruction remain as the main Achilles heels of TAVR. While coronary artery disease (CAD) is present in approximately half of TAVR candidates, correlation of post-TAVR complications such as paravalvular leakage (PVL) or misalignment with CAD are not fully understood. To effectively evaluate risk status and create guidelines for intervention, precise quantification of aortic root and coronary artery hemodynamics is required. We used a patient-specific multiscale computational-mechanics framework in both pre and post TAVR states to investigate the effect of TAVR complications such as PVL and misalignments on the coronary arteries and aortic root hemodynamics. The proposed framework could provide a platform for testing the intervention scenarios and evaluating their influences on the hemodynamics.