Biomechanical Engineering Comparison of Four Leaflet Repair Techniques for Mitral Regurgitation Using a Novel 3D-Printed Left Heart Simulator

ABSTRACT OBJECTIVE Mitral valve repair is the gold standard treatment for degenerative mitral regurgitation; however, a multitude of repair techniques exist with little quantitative data comparing these approaches. Using a novel ex vivo model, we sought to evaluate biomechanical differences between repair techniques. METHODS Using porcine mitral valves mounted within a custom 3D-printed left heart simulator, we induced mitral regurgitation utilizing an isolated P2 prolapse model by cutting primary chordae. Next, we repaired the valves were repaired in series using the edge-to-edge technique, neochordoplasty, nonresectional remodeling, and classic leaflet resection. Hemodynamic data and chordae forces were measured and analyzed using an incomplete counterbalanced repeated measures design with the healthy pre-prolapse valve as a control. RESULTS With the exception of the edge-to-edge technique, all repair methods effectively corrected mitral regurgitation, returning regurgitant fraction to baseline levels (baseline 7.8±1.0%, edge-to-edge 17.9±7.4%, nonresectional 9.4±2.1%, neochordal 9.0±3.4%, resection 9.9±3.7%, p=0.04). Forces on the primary chordae were minimized using the neochordal and nonresectional techniques (0.11±0.06 N and 0.11±0.05 N) whereas the edge-to-edge and resectional techniques resulted in significantly elevated forces (0.16±0.04 N and 0.16±0.06 N, p CONCLUSIONS While multiple methods of degenerative mitral valve repair are utilized clinically, their biomechanical properties vary significantly. Nonresectional techniques, including leaflet remodeling and neochordal techniques, appear to result in lower chordal forces in this ex vivo technical engineering model.