Fast image-based mitral valve simulation from individualized geometry

Clinical Impact of Computational Heart Valve Models

This paper provides a review of engineering applications and computational methods used to analyze the dynamics of heart valve closures in healthy and diseased states. Computational methods are a cost-effective tool that can be used to evaluate the flow parameters of heart valves. Valve repair and replacement have long-term stability and biocompatibility issues, highlighting the need for a more robust method for resolving valvular disease. For example, while fluid-structure interaction analyses are still scarcely utilized to study aortic valves, computational fluid dynamics is used to assess the effect of different aortic valve morphologies on velocity profiles, flow patterns, helicity, wall shear stress, and oscillatory shear index in the thoracic aorta. It has been analyzed that computational flow dynamic analyses can be integrated with other methods to create a superior, more compatible method of understanding risk and compatibility.

Automatic extraction of the mitral valve chordae geometry for biomechanical simulation

PURPOSE

Mitral valve computational models are widely studied in the literature. They can be used for preoperative planning or anatomical understanding. Manual extraction of the valve geometry on medical images is tedious and requires special training, while automatic segmentation is still an open problem.

METHODS

We propose here a fully automatic pipeline to extract the valve chordae architecture compatible with a computational model. First, an initial segmentation is obtained by sub-mesh topology analysis and RANSAC-like model-fitting procedure. Then, the chordal structure is optimized with respect to objective functions based on mechanical, anatomical, and image-based considerations.

RESULTS

The approach has been validated on 5 micro-CT scans with a graph-based metric and has shown an [Formula: see text] accuracy rate. The method has also been tested within a structural simulation of the mitral valve closed state.

CONCLUSION

Our results show that the chordae architecture resulting from our algorithm can give results similar to experienced users while providing an equivalent biomechanical simulation.

Pediatric Mitral Regurgitation: Standardized Repair-Oriented Strategy With Leaflet Plication

To introduce a standardized strategy and reproducible procedures of mitral repair for mitral regurgitation in the pediatric population with leaflet plication as a principal technique. Consecutive patients who had undergone mitral repair by our standardized repair-oriented strategy in our institution from January 2016 to December 2019 were included retrospectively. The standardized repair strategy included 3-step inspections and repair from the subvalvular to leaflet, and then to the annular level. The main surgical techniques included chordae detachment, papillary muscle splitting, leaflet plication, and posterior annuloplasty. The indication for leaflet plication was that the distance between 2 adjacent chordae tendineae was greater than 4 mm. A total of 113 patients were enrolled. During 22.6-month (range, 2-50 months) follow-up period, primary endpoint was documented in 15 (13.3%) patients, including 1 (0.9%) death, 0 transplantation, and 14 (12.4%) functional mitral failure. Freedom form primary endpoints at 6 months, 1 year, and 3 years was 94.7%, 94.7%, and 82.3%, respectively. Significant independent predictors of functional mitral valve failure were younger age (hazard ratio [HR], 0.28; 95% confidence interval [CI], 0.04-0.72; P = 0.037) and ischemic mitral regurgitation (MR) (HR, 24.34; 95% CI, 4.52-47.33; P < 0.001). Leaflet plication was significantly associated with well-functioned mitral valve (HR, 7.42; 95% CI, 2.35-30.54; P = 0.004). Compared with nonischemic MR group, ischemic MR group was noted with higher occurrence of primary endpoint events (11/28 vs 4/85, P < 0.001). The short- to mid-term outcomes of standardized mitral repair technique with leaflet plication were favorable, among which, however, repair for mitral regurgitation with ischemic lesions is comparatively challenging.