Nearly 1.6 million Americans suffer from clinically significant tricuspid heart valve leakage. A first critical step toward successfully treating these patients is to fully understand and characterize the complex mechanics of the valve. To achieve this elusive goal we have built the first and fully subject-specific computer models of human tricuspid valves. To this end, in an organ preservation system, we reperfuse beating healthy donor hearts and over multiple cardiac cycles record tricuspid annulus dynamics using sonomicrometry, in addition to hemodynamics on a loaded right ventricle. Upon arresting the hearts, we then excise the tricuspid valve complex, image the leaflets, and digitize their geometry. Next, we recreate the 3D annulus from sonomicrometry data onto which we non-rigidly transform the leaflet geometries. Subsequently, we use imaging data to assign chordal insertions and rebuild the valve in-silico. Additionally, we characterize material properties and microstructural information of the leaflets and chordae through in-vitro planar biaxial and uniaxial testing, respectively, and 2-Photon microscopy. We then impose boundary conditions through annular displacement fields and transvalvular pressure gradients as measured in the beating hearts. Finally, we simulate the dynamics of the tricuspid valve over one full cardiac cycle in Abaqus/Explicit. The tricuspid valve models faithfully capture leaflet geometry and coaptation as validated against 2D echo scans of the same beating hearts. In the future, our models may be used to virtually implant repair devices on the tricuspid valve and optimize surgical procedures at a patient-specific level.
