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International Journal of Bioprinting Evaluation of advanced visual computing solutions for the left atrial appendage occlusion

All meshes and images were uploaded to VRIDAA identify consistent technology-related biases. At the end of
before the practical session with participants. In VRIDAA, the case analysis, they were asked to make a final decision
the centerline was not selected by the user; each case had a with all knowledge gathered from all technologies. Finally,
centerline previously generated in the web-based VIDAA they answered the SUS questionnaire and open questions
platform, as well as the measurements and the proposed for a global assessment of each employed technology.
devices, which were transferred into the VR platform. The order to present the technologies in the practical
Thus, if the system is already calibrated, the only required session is as follows (going from the most available to
step for using the VR platform was the transfer and upload the most sophisticated technologies): CT medical images
of the files to the VRIDAA system, making the workflow (optional), VIDAA, 3D printing, VRIDAA, and simulations.
quite fast and straightforward. Initially, we offered the possibility of visualizing the raw CT

2.3.4. In silico flow simulations medical images of each patient. Afterward, the web-based
VIDAA platform followed, since it is similar to some of the
The participants were presented with the visualization most advanced software solutions commercially available in
of in silico fluid simulations in the studied LA anatomies the market (e.g., 3mensio). Next, 3D printing and VRIDAA
and any possible LAAO device to be implanted, using the were presented to incorporate data visualization with
Ansys Discovery Live (ANSYS Inc., USA) software, under enhanced depth perception, starting with 3D printing since
the Academic License (i.e., free of charge). It includes most physicians are more familiar with it. Finally, the in silico
a GPU-based Lattice Boltzmann method that allows simulations were shown in the Ansys Discovery Live software
almost real-time simulations, once each case was set-up. to include functional information complementary to the
Therefore, the participants could manually choose a given structural knowledge provided by the other technologies.
device (i.e., type and size) and place it in each position to
analyze resulting blood flow patterns, which can be iterated 2.4.1. CT imaging
as many times as desired. The visualization of CT medical images was optional since
The volumetric meshes required for the fluid some of the physicians do not work on their daily basis
simulations were generated from the 3D surface models with CT measurements. Although it was not assessed in
using the Gmsh 4.5.4 software (https://gmsh.info/). SUS questionnaire, CT visualization was offered since it is
The final meshes were around 800 thousand elements the gold standard technique to explore LA anatomy, thus
for all cases. The PC used to run the simulations was useful to plan LAAO interventions. Moreover, there were
the one used for VR. The blood flow was treated as a questions related to CT use in the general questionnaire.
3
Newtonian fluid, with a density of 1060 kg/m and a Physicians could explore the CT medical images with the
viscosity of 0.0035 Pa/s. The boundary conditions in Open-Source ITK-Snap software (http://www.itksnap.
the inlets and outlets of the 3D LA model of the LA org/) to: (1) browse through the CT slices for inspecting
were chosen as in our most recent LAA fluid simulation the LAA shape and other anatomical landmarks such as
study [39] , but without dynamic movement of the mitral the circumflex or the ostium and (2) take measurements of
ring plane since it was not allowed in the employed these anatomical landmarks.
software. Basically, they were the same for all patients,
which were extracted from Doppler echo, and pressure 2.4.2. Web-based VIDAA platform
measurements of an AF patient are different from the Initially, after opening the 3D LA geometry in the VIDAA
ones processed in this study: A velocity profile in the platform, participants were asked to select a point to create
outlet (i.e., the mitral valve) and a pressure wave at the the optimal LAA centerline. Then, the contour diameters
pulmonary veins. The set-up for each simulation case perpendicular to the LAA centerline were automatically
included 30 min for meshing and building, accounting computed (less than 30 s), as well as the selection
for 21.6 hours in total (with 13 devices per five patients). of recommended LAAO devices. Next, participants
interactively explored the LAA geometry, observing the
2.4. Practical session contour diameters and looking for the best position and
Before the practical session, the participants received device for each case. In addition, physicians could select
a tutorial on the different technologies, approximately among the different (recommended or not) LAAO devices
lasting 1 h, demonstrating their features. During the and move them freely to decide.
practical session, data from five typical LAAO patients
(i.e., not particularly complicated LAA geometries) were 2.4.3. 3D printing
presented to the physicians. For each case and technology, The 3D-printed model of the LA of each studied case was
the participants chose the optimal device settings to offered to the physician to manipulate with their hands,

Volume 9 Issue 1 (2023) 264 https://doi.org/10.18063/ijb.v9i1.640