3-dimensional printing for the diagnosis of left ventricular outflow tract obstruction after mitral valve replacement.

The objective of this study was to evaluate the use of the generation of 3D models and 3D prints of complex cases for physicians at the example of an intricate left ventricular outflow tract obstruction (LVOTO). LVOTO is a known complication of mitral valve surgery. A 38-year-old female patient with increasing dyspnoea after mitral valve replacement was referred to our centre. Echocardiography showed a strut of the bioprosthetic heart valve protruding into the left ventricular outflow tract. However, the diagnosis of a LVOTO was difficult based on echocardiography alone. Therefore, we fabricated a physical model of the left ventricular outflow tract, the mitral valve, the aortic valve and the left ventricle. With this physical model in hand, we were able to visualize the LVOTO and to discuss potential therapeutic options. Moreover, we were able to plan the subsequent redo surgery in detail using the model. This case shows the benefit of 3D printing technologies for surgeons and patients, not only for analysis, but also during the decision-making and pre-operative planning process.

Patient-Specific Instrument with a Cutting Template for Mitral Valve Repair by Resection.

Mitral valve regurgitation is one of the most common heart valve diseases and mitral valve repair is the favored therapy, in which a part of the mitral valve is resected. To improve preoperative planning of this challenging surgery, patient-specific mitral valve replicas have been developed on which the repair can be simulated. However, there is no possibility yet to transfer the planning from the replica to the surgery of the patient. To solve this problem, we developed a patient-specific instrument with a cutting template, intraoperatively visualizing the part of the mitral valve to be resected as planned on the replica. To realize this instrument, the surgeon first simulates mitral valve repair by resection on a patient-specific mitral valve replica. This postoperative mitral valve replica is then digitalized and from it and a preoperative mitral valve model the instrument with cutting template is automatically designed and then 3D printed. An expert heart surgeon successfully tested the functional principle of the instrument on a pig mitral valve.