ARTICLE | doi:10.20944/preprints202301.0276.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: FFR; Blood Flow Simulation; SimVascular; coronal stenosis; cCTA
Online: 16 January 2023 (08:29:37 CET)
A novel physiologically based algorithm (PBA) for fast CFD computation of Flow Fractional Reserve (FFR) in Coronary Artery Trees (CATs) is proposed and developed, which, unlike traditional methods, is based on the extension of the Murray’s law for blood vessels at the outlets and extra inlet conditions prescribed alternatively and iteratively. The PBA is then implemented in both SimVascular and Ansys CFD for testing and validation. For validation purpose, 3D models of CATs are built by using their CT images and computational meshes generated for mesh convergence study. Results obtained are then compared with Invasive Coronary Angiographic (ICA) data for validation and evaluation of its accuracy and computational efficiency. It is found that discrepancies between experimental and calculated values of pressure and flow rate at the inlet were less than 0.1% at the end of the 10th round of iteration or less. Further validation shows that the difference between estimated and experimental FFR agree with each other with a maximum difference of 1.62% after convergence is achieved. The PBA is found to be a robust patient-specific and physiologically sound method that can be a good alternative to the existing Lumped Parameter Model (LPM) which is based on empirical scaling correlations using limited population-averaged data and requires nonlinear iterative computation for convergence.
ARTICLE | doi:10.20944/preprints202301.0201.v1
Subject: Biology And Life Sciences, Biophysics Keywords: FFR, Blood Flow Simulation, coronal stenosis, Coronary Computed Tomography Angiography (CCTA), OpenFOAM
Online: 11 January 2023 (11:56:16 CET)
A novel physiologically based algorithm (PBA) for the computation of fractional flow reserve (FFR) in coronary artery trees (CATs) using computational fluid dynamics (CFD) is proposed and developed. The PBA is based on the extension of Murray's law and additional inlet conditions prescribed iteratively, and is implemented in OpenFOAM for testing and validation. 3D models of CATs are created using CT scans and computational meshes, and the results are compared to in-vasive coronary angiographic (ICA) data to validate the accuracy and effectiveness of the PBA. The discrepancy between calculated and experimental FFR is within 2.33-5.26% in steady-state and transient simulations, respectively, when convergence is reached. The PBA is a reliable and physiologically sound technique compared to the current lumped parameter model (LPM), which is based on empirical scaling correlations and requires nonlinear iterative computing for conver-gence. The accuracy of the PBA method is further confirmed using the FDA nozzle, which demonstrates good alignment with CFD-validated values.
ARTICLE | doi:10.20944/preprints202310.0692.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: iodixanol; cardiac ct; coronary ct; ccta; contrast media; intravenous contrast media; computed tomography; iodixanol; cardiac catheterization; contrast induced nephropathy
Online: 13 October 2023 (03:23:31 CEST)
ABSTRACT: Iodixanol is an iso-osmolar nonionic dimeric hydrophilic contrast agent with a higher viscosity than the monomeric agents. It is the only Food and Drug Administration (FDA)approved isoosmolar agent in the United States, and it is the only contrast agent with an FDA-approved indication for use in cardiac computed tomographic angiography (CCTA), to assist in the diagnostic evaluation of patients with suspected coronary artery disease. In clinical studies, it has been noted to have fewer side effects and similar image quality when compared to low osmolar contrast media. This can be attributed to the pharmacological properties of iodixanol. In the field of cardiology, iodixanol among other intravenous contrast media is used for coronary computed tomography angiography and cardiac catheterization. In this article, the use, tolerability and efficacy of iodixanol in the field of cardiology are reviewed, specifically evaluating the use for CCTA and coronary angiography, including outcome studies, randomized trials and comparisons to other contrast agents.
ARTICLE | doi:10.20944/preprints202305.0354.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: CCTA; cardiac CT; Coronary artery disease; CAD; Coronary Computed Tomography Angiography; Transcatheter aortic valve implantation; TAVI; Pacemaker; PMK; Percutaneous coronary intervention; PCI
Online: 5 May 2023 (10:42:41 CEST)
Introduction: The aim of our study was to assess the role of ECG-gated Coronary CT Angiography (CCTA) in the diagnosis, imaging follow-up, and treatment guidance in post-procedural/surgical interventions of the heart and thoracic aorta (PTCA, TAVI, PMK/ICD placement, CABGs).