Impact of mixed valvular disease on coarctation hemodynamics using patient-specific lumped parameter and Lattice Boltzmann modeling

The optimal course of intervention for patients with coexisting coarctation of the aorta (COA) and mixed valvular disease (combinations of aortic and mitral valve pathologies, MVD) is an area of contention and uncertainty. To effectively evaluate risk status and create guidelines for intervention aimed at minimizing the progression of cardiovascular disease, precise diagnostic information, which hinges on the quantification of aortic fluid dynamics, is required. For this purpose, we developed an innovative patient-specific computational-mechanics framework that integrates the local hemodynamics with the global circulatory cardiovascular system using the 3-D Lattice Boltzmann method along with a patient-specific lumped parameter model to investigate the impact of COA and MVD on aortic fluid dynamics in patients with COA and MVD. The computational framework was validated against clinical cardiac catheterization data and four-dimensional flow magnetic resonance imaging. Our results demonstrate that MVD interacts with COA fluid dynamics, amplifying irregular flow patterns especially downstream of COA and may contribute to speed up the progression of the disease. More specifically, aortic regurgitation and mitral regurgitation, when coexistent with COA, substantially lead to significant progression of the disease at the COA region. We concluded that not only the severity of the COA, but also the presence and the severity of the MVD should be considered in the evaluation of risks in patients with COA. The results suggest that some more aggressive surgical approaches may be required as regularly chosen current surgical techniques may not be optimal for patients with both COA and MVD.