Image-based computational fluid dynamics to compare two mitral valve reparative techniques for the prolapse

Objective Nowadays, the treatment of mitral valve prolapse involves two distinct repair techniques: chordal replacement (Neochordae technique) and leaflet resection (Resection technique). However, there is still a debate in the literature about which is the optimal one. In this context, we performed an image-based computational fluid dynamic study to evaluate blood dynamics in the two surgical techniques. Methods We considered a healthy subject (H) and two patients (N and R) who underwent surgery for the prolapse of the posterior leaflet and were operated with the Neochordae and Resection technique, respectively. Computational Fluid Dynamics (CFD) was employed with prescribed motion of the entire left heart coming from cine-MRI images, with a Large Eddy Simulation model to describe the transition to turbulence and a resistive method for managing valve dynamics. We created three different virtual scenarios where the operated mitral valves were inserted in the same left heart geometry of the healthy subject to study the differences attributed only to the two techniques. Results We compared the three scenarios by quantitatively analyzing ventricular velocity patterns and pressures, transition to turbulence, and the ventricle ability to prevent thrombi formation. From these results we found that both the operated cases were able to restore almost physiological blood dynamic conditions, with some differences due to the reduced mobility of the Resection posterior leaflet. Conclusions: Our findings suggest that the Neochordae technique developed a slightly more physiological flow with respect to the Resection technique. The latter gave rise to a different direction of the mitral jet during diastole increasing the turbulence that is associated with ventricular effort and hemolysis, with also a larger ability to washout the ventricular apex preventing from thrombi formation.