**4. Mitral regurgitation**

**Figure 3.** A and B. Printing process and the flexible 3D aorta model; C and D: deployment of an aortic stent graft into an aortic model, serving as educational resource for training vascular surgeons; E: model positioned on measuring

350)—Instituto Nacional de Tecnologia—Laboratório de Modelos Tridimensionais—Ministério da Ciência, Tecnologia

**Figure 4.** A–D. Sequence of the development of a 3D flexible model of aorta from CT scanner files; E: 3D printed flexi‐

"Tango black" flexible resin on OBJET Connex 350)—Instituto Nacional de Tecnologia—Laboratório de Modelos Tridi‐ mensionais—Ministério da Ciência, Tecnologia e Inovação.; F: variant colored rigid 3D printed model of aorta (3D printed in thermoplastic ABS—Stratasys U-Print-Fused Deposition Modeling)—Núcleo de Experimentação Tridimen‐

), damaged after tests (3D Printed in

ble model of aorta positioned on measuring scale table (scale reference: 1 cm2

); F: model damaged after tests. (3D printed in flexible clear resin on OBJET Connex

scale table (scale reference: 1 cm2

sional—NEXT PUC-Rio.

e Inovação.

116 New Trends in 3D Printing

The mitral valve prolapse, the well-known entity, in some specific cases may be associated with mitral regurgitation. When mitral regurgitation reaches a high level, a large volume of blood returns to the left atrium during ventricular systole. In these cases, there may be important symptoms culminating with left ventricular dysfunction. When this occurs, a mitral regurgitation correction procedure is indicated. One surgical technique, already established for this condition, is the Quadrangular Resection. When a severe mitral regurgitation is caused by prolapse of the posterior leaflet, the Quadrangular Resection can be performed. In this surgical technique, part of valve leaflet tissue is excised, besides the confection of a suture in the mitral annulus. The objective of this procedure is to enable the full coaptation of the leaflets during ventricular systole, preventing blood regurgitation into the left atrium [7].

**Figure 5A** presents, in three projections, the mitral valve leaflets of a patient with prolapse of the posterior leaflet, which cause no coaptation and a regurgitant orifice. Again, as a step to plan the surgical procedure, a virtual simulation of Quadrangular Resection was performed in the digital file using Rhinoceros 5.0 (McNeel North America, USA). In this simulation, the amount of tissue that would be needed to be excised from the posterior mitral leaflet can be estimated (**Figure 5B**).

**Figure 5.** 3D virtual models of Quadrangular Resection in mitral valve repair—Núcleo de Experimentação Tridimen‐ sional—NEXT PUC-Rio.

**Figure 6.** A–D. 3D printed model of mitral valve prolapse from 3D ultrasound (3D US)—printed in poliamide—(EOS P110)—Instituto Nacional de Tecnologia—Laboratório de Modelos Tridimensionais—Ministério da Ciência, Tecnolo‐ gia e Inovação.

This file is also used for making the physical model, which can be seen from different angles in **Figure 6A**–**D**. The digital file of the mitral valve leaflets was generated by performing a 3D Echocardiography with Vivid E9 (GE Healthcare, USA).
