BCs for LCA and RCA on a cardiovascular model

[Jessica Blair]

Hello,
I was hoping to get some help on my Boundary conditions for my model. I am currently creating models and simulations for ten cardiac modes, and have been having issues with the simulation. I tried using the values, one at a time, for the boundary conditions from the coronary project that I downloaded from SimVascular, but every time I convert the files for ParaView the simulation turns yellow, meaning something is wrong. Whenever I change to coronary boundary condition type and use the values from the project, the simulations third column has primarily high numbers. I was hoping to get help to figure out the correct boundary conditions for my model, as I believe that is what is affecting my simulation. I watched tutorial nine on YouTube, but was having trouble getting the correct conditions. I can post my project if need be, or screenshots of my model. Thank you in advance.

[Weiguang Yang]

If the nonlinear residual values in histor.dat blew up, I would check if the inlet and outlets are correctly labeled and assigned BCs in the svpre file and solver.inp You can also use your simulation results to check if 1. inflow is correctedly prescribed. 2. no slip condition is correctly imposed (I assume you used a rigid wall.) If you find nothing wrong, instead of coronary BCs, apply zero pressure boundayr conditions to your outlets or use some simple BCs such as resistance and see if flow looks normal and residuals decrease with time. If nothing is wrong, maybe you can upload/share your simulation files via a download link.

[Jessica Blair]

Hello,

Thank you for the insight. I found that the simulation looks a lot better when I use Resistance instead. The simulation is not exactly looking how I would like it to, any other on how to get the correct BCs, or which ones should be changed to look more like a correct simulation? Thank you in advance.

[Weiguang Yang]

Can you confirm you can run the SV coronary project without any issue? Compared to the demo model, do your model size, cardiac output and the number of coronary arteries differ significantly? If they are quite similar, the BCs taken from the demo may work for your model. Otherwise, instead of using the values from the demo directly, you may need to calculate BCs for your model following the procedure outlined in the tutorial.

[Jessica Blair]

Hello,

I can run the Coronary Project simulation, but sometimes the files seem to intermix and when I run my own simulation, BAV70, and try the Coronary Project after that, the results in ParaView portray the wrong model. I have also noticed the pressure will come out low on the Coronary Project, despite not changing anything once downloaded from this website.
Also, I have noticed that when I run my own simulation and the model comes out correctly on ParaView, the pressure is extremely low.
To answer your question, yes, compared to the demo model the sizes, output, and number of coronary arteries, my model differs. I have included photos of my model, on ParaView and on SimVascular for reference.
As a note, when doing a simulation, I create data files, then export the data, which I then upload to SimVascular Gateway, wait for the results, download the file, put this back into SimVascular under the "Cover Results" tab under "Simulation", and click on "Convert...", so I do not know why the pressure is so low.
With the help of Justin, I have different mesh sizes for the aorta versus coronary arteries, and calculated the resistance to be split between the outflow of the aorta, left coronary artery, right coronary artery, and left coronary artery x. I also use the "scaled_pulse_flow.flow" file for the inflow of the aorta.
For reference, the third photo (blue model) is the model I created, called BAV70. This model has extremely low pressure, as seen.
The second photo is directly from the Coronary Project, where the pressure is also low.
The first photo is another attempt at creating a correct simulation of BAV70, my model, and getting better results, but the model shown is from Coronary Project. I also cannot see the pressure, as the drop down box on ParaView only has three options, pressure not being one of them.
Another colleague of mine seems to be having the same issue with their pressure results.
Please let me know if you need anymore files, screenshots, or etc. and thank you for your help!

[Weiguang Yang]

I just ran the coronary project pulsatile simulation. The average pressure is ~ 100 mmHg and flow looks normal to me. I am surprised that the pressure was not correct in the demo case you ran. Do other demo cases work on your machine?

[Jessica Blair]

Hello,

I had to delete previous files so I believe they had skewed data and that was affecting the coronary project pressure issue. I posted my current pressure issue to SimVascular on another post, if you are able to help.
Thank you for your time.

[Weiguang Yang]

Yes, we can take a look at your data. Please make sure that the coronary demo case can run and produce physiologic pressure/flow on your desktop.