**3. Aortic aneurysms**

**Figure 1.** A. 3D model of human heart from CT scanner with "arduino" electronic board controlling led inside the model to allow the visualization of different densities of the heart positioned on measuring scale table (scale reference:

Aortic valve can be affected by many diseases that culminate with the necessity of a heart surgery, for aortic valve replacement. In this surgical procedure, the native aortic valve, dysfunctional, is excised and a biological or metallic prosthesis is implanted in the aortic annulus. After this surgery, several complications may occur. When the suture fixing the prosthetic valve in the aortic annulus breaks, a hole is formed between the prosthetic ring and the aortic annulus, a process named as paraprosthetic leak. With this complication, during ventricular diastole, blood present in the aortic root returns to the left ventricle, causing volume

**Figure 2A** presents a physical model, in full scale, of a heart segment in which there is a paraprosthetic leak around a biological aortic valve prosthesis. This hole measures approxi‐ mately 1 cm. This model was carried out with the purpose of planning the percutaneous procedure that would be done to fix this abnormality. In **Figure 2B** and **C**, the implantation process of an occluder may be noted within the paraprosthetic leak. In this case, the physical model can help the physician to detect the spatial location of the defect to be corrected before the procedure is started. Besides that, the physical model can be used to test many types and sizes of percutaneous occluders. The digital archive of heart images was generated by performing an angio-CT scan, Somatom Sensation 64 × 0.6 mm (Siemens Inc., Germany).

overload that can result with a severe left ventricular dysfunction.

)—(3D printed in photosensible resin—PROJET 3510 HD Plus—3D Systems)—Núcleo de Experimentação Tridi‐ mensional—NEXT PUC-Rio; B: Same 3D file printed in two parts to allow the visualization of the internal structures (3D printed in polyamide at EOS P110)—Instituto Nacional de Tecnologia—Laboratório de Modelos Tridimensionais

1 cm2

114 New Trends in 3D Printing

—Ministério da Ciência, Tecnologia e Inovação.

In the field of vascular surgery, particularly in the case of aortic stent grafting of the treatment of aortic aneurysms, there is already a commercially available product in which the stent graft is custom-made for each patient with unusual complex anatomy relaying on the 3D printing technology. To provide the surgeon with training, he receives in advance a prototype of the custom-made stent graft and a 3D model of the patient's aorta. If needed, modifications can be suggested until there is agreement between the engineering and the medical team [12, 13].

The evolving technology allows for flexible and malleable models that are fairly realistic in its shape (**Figure 3A** and **B**). Another practical application already in use is medical training itself, in which the training vascular surgeon can learn the so-called endovascular techniques by deploying stents and stent grafts in 3D artery models (**Figure 3C** and **D**). These techniques are normally learned during hundreds of hours of "hands-on" training under staff supervision, which carry along, for both patients and surgeons, extra doses of radiation, required to perform these interventional radiology procedures. The current underdeveloping 3D training models do not require radiation and give the training surgeon a 3D hands-on feeling and vision of the devices itself, since we can print transparent flexible models, while the actual endovascular procedures provide only with the regular 2D images of the monitor screen (**Figure 4**).

**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 scale table (scale reference: 1 cm2 ); F: model damaged after tests. (3D printed in flexible clear resin on OBJET Connex 350)—Instituto Nacional de Tecnologia—Laboratório de Modelos Tridimensionais—Ministério da Ciência, Tecnologia e Inovação.

**Figure 4.** A–D. Sequence of the development of a 3D flexible model of aorta from CT scanner files; E: 3D printed flexi‐ ble model of aorta positioned on measuring scale table (scale reference: 1 cm2 ), damaged after tests (3D Printed in "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‐ sional—NEXT PUC-Rio.
