Morphology display and hemodynamic testing using 3D printing may aid in the prediction of LVOT obstruction after mitral valve replacement

Aims: Left ventricular outflow tract(LVOT) obstruction after mitral valve replacement can be life-threatening once occur. We simulated mitral valve replacement preoperatively using dynamic, three-dimensional(3D) printed models to help predict LVOT obstruction in this study.

Methods: 56 patients who underwent mitral valve replacement were included. Prediction of LVOT obstruction in vitro was based on the data from 4 sources: digital, anatomical, flexible, and dynamic model. Digital 3D models were designed based on computed tomography (CT) image dataset and printed with photopolymer resin to create a 3D anatomical model, which contributed to the morphology display. Then, flexible models were made from specialized silicone, which is similar to cardiac tissue in terms of its softness and elasticity. Dynamic function was achieved by coupling flexible models to a mock circulatory system (MCS). Besides, surgery simulation and hemodynamic testing was done using dynamic 3D printed model and patients were regrouped based on hemodynamic change. Finally, different methods for prediction of LVOT obstruction as well as classification based on two-dimensional image data and dynamic model were compared with surgical results as golden standard.

Results: (1)Qualitatively, the prediction of LVOT obstruction using the dynamic 3D model was the most accurate and was consistent with clinical outcomes. In the four patients who developed LVOT obstruction after surgery, only two were at a high risk based on the other three models. (2)Quantitatively, the area of neo-LVOT predicted by the digital, anatomical, and flexible models was higher compared with the dynamic models and in-vivo after surgery. (3)Classification based on traditional criteria(two-dimensional image data) was different from surgical results. While the difference between dynamic model and surgical results was not statistically different.

Conclusions: After coupling the flexible model with the mock circulatory system, the dynamic 3D model predicted LVOT obstruction more accurately with hemodynamic testing compared with morphological evaluation. 3D printing can assist surgeons to better plan mitral valve replacement than traditional image data.