Quantitative comparison of blood flow patterns from in silico simulations and 4D flow data before and after left atrial occlusion

Casademunt, Paula; Morales Ferez, Xabier; Cepas-Guillen, Pedro L.; Doltra, Ada; Mill, Jordi; Saiz-Vivó, Marta; Flores-Umanzor, Eduardo; Sanchis, Laura; Freixa, Xavier; Camara, Oscar

Quantitative comparison of blood flow patterns from in silico simulations and 4D flow data before and after left atrial occlusion

Citation

Casademunt P, Morales X, Cepas-Guillén P, Doltra A, Mill J, Saiz-Vivó M, et al. Quantitative comparison of blood flow patterns from in silico simulations and 4D flow data before and after left atrial occlusion. In: Camara O, Puyol-Antón E, Sermesant M, Suinesiaputra A, Zhao J, Wang C, et al., editors. Statistical atlases and computational models of the heart. 15th International Workshop, STACOM 2024; 2024 Oct 10; Marrakesh, Morocco. Cham: Springer; 2024. p 75-86. DOI: 10.1007/978-3-031-87756-8_8

Abstract

Atrial fibrillation (AF), the most common cardiac arrhythmia, increases the risk of thrombus, especially in the left atrial appendage (LAA). LAA occlusion (LAAO) reduces stroke risk in AF patients by isolating the LAA from the left atrium (LA). Computational fluid dynamics (CFD) simulations, offering superior resolution than current imaging techniques, are proposed to assess thrombus risk, but require validation. Emerging imaging techniques like 4D flow MRI provide in-vivo flow measurements supporting CFD credibility. Our dataset includes 4D flow magnetic resonance imaging (MRI), cardiac computational tomography (CT), and Doppler ultrasound (US) of the mitral valve for four patients (pre- and post-LAAO). We developed patient-specific CFD simulations from CT and US data, comparing blood flow patterns with 4D flow MRI. The analysis was focused on thrombus formation indicators, such as particle deposition, LAA washout, and endothelial cell activation potential (ECAP). Results from both data and simulations were within similar ranges but showed limited patient-wise agreement. Post-LAAO hemodynamic changes assessed by 4D flow MRI and CFD data agreed on reduced thrombogenic indices such as ECAP, flow stasis and vorticity. This study highlights the need for computational model validation, comparing CFD models with 4D flow MRI, being the first to quantitatively analyze 4D flow MRI data with implanted LAAO devices.