Dynamic Patient-Specific Three-Dimensional Simulation of Mitral Repair

Abstract

<jats:sec><jats:title>Objective</jats:title><jats:p> Planned mitral repair strategies are generally established from preoperative echocardiography; however, specific details of the repair are often determined intraoperatively. We propose that three-dimensional printed, patient-specific, dynamic mitral valve models may help surgeons plan and trial all the details of a specific patient's mitral repair preoperatively. </jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p> Using preoperative echocardiography, segmentation, modeling software, and three-dimensional printing, we created dynamic, high-fidelity, patient-specific mitral valve models including the subvalvular apparatus. We assessed the accuracy of 10 patient mitral valve models anatomically and functionally in a heart phantom simulator, both objectively by blinded echocardiographic assessment, and subjectively by two mitral repair experts. After this, we attempted model mitral repair and compared the outcomes with postoperative echocardiography. </jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p> Model measurements were accurate when compared with patients on anterior-posterior diameter, circumference, and anterior leaflet length; however, less accurate on posterior leaflet length. On subjective assessment, Likert scores were high at 3.8 ± 0.4 and 3.4 ± 0.7, suggesting good fidelity of the dynamic model echocardiogram and functional model in the phantom to the preoperative three-dimensional echocardiogram, respectively. Mitral repair was successful in all 10 models with significant reduction in mitral insufficiency. In two models, mitral repair was performed twice, using two different surgical techniques to assess which provided a better outcome. When compared with the actual patient mitral repair outcome, the repaired models compared favorably. </jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p> Complex mitral valve modeling seems to predict an individual patient's mitral anatomy well, before surgery. Further investigation is required to determine whether deliberate preoperative practice can improve mitral repair outcomes. </jats:p></jats:sec>

Three-dimensional printing for cardiovascular diseases: from anatomical modeling to dynamic functionality

“…3 Functional 3D models and their coupling with a mock circulatory system. Images in the figure are from the literature [72][73][74] same two materials to create aortic valve complexes, and confirmed their feasibility for ultrasound imaging. Biglino et al [72] made a blood vessel model using TangoPlus, and demonstrated its suitability for fabricating arteries, although its mechanical properties might not be suitable for modeling softer blood vessels.…”

“…Scanlan et al [73] compared 3D models of the tricuspid valve obtained by the two methods, and reported that both closely replicated the patient's anatomy, while the silicone model was better at simulating the texture of cutting and stitching. Based on the ultrasound images, a mitral valve prolapse model created by Olivia et al [74] using Echoflex 00-30 also had good fidelity to the preoperative three-dimensional echocardiogram. Such materials are promising for the production of low-cost functional 3D cardiovascular models.…”

“…Pantalos et al [77] placed a silicone ventricle in a chamber full of compressed gas to control its rhythmic contraction and relaxation. Olivia et al [74] used compressed gas to drive pneumatic pistons, which were connected to contractile loops around different levels of a ventricle model, to simulate the movement of different ventricular segments.…”

“…Although the above studies to a certain extent simulated the motion of normal and pathological mitral valves and in vivo hemodynamic characteristics, due to the lack of systematic resistance in the device, the anterior velocity and pressure gradient generated by the ventricle during systole were not sufficient, and the results were not satisfactory. Olivia et al [74] created 3D models of 10 patients with mitral valve regurgitation, and set up a pipe about 0.85 m high in a mock circulatory system to simulate the hydrostatic pressure generated by the aorta in vivo. The device could generate 107 mmHg pressure during systole, more accurately reflecting the in vivo hemodynamic state.…”

Multimodality imaging for the quantitative assessment of mitral regurgitation

“…Recent developments in the assessment of MR with potential future value include (I) the 'average pixel intensity' (API) method (92), a novel digital quantification of the CW pixel intensity in grading MR severity; (II) 4D-flow CMR (93), which allows correction for MV motion; (III) real-time 3D TOE-based 4-dimensional MV models (94), which allow excellent morphological visualization and a comprehensive quantitative analysis of MV annulus and leaflets during the entire cardiac cycle; and (IV) 3D printing of MV (95,96), where the anatomy of a patient-specific MV can be accurately modeled to improve pre-operative planning of complex surgical interventions.…”