Key result
Atrial fibrillation resulted in lower blood flow velocity and higher relative residence time in the left atrial appendage compared to sinus rhythm, indicating a substantially increased risk of thrombosis.
Why the study?
Identifying patients with high risk of thrombosis is crucial for advanced stroke warning, motivating investigation into the mechanism behind thrombus formation in the LAA.
Does atrial fibrillation increase the biomechanical risk of thrombosis in chicken wing shape left atrial appendages compared to sinus rhythm?
Does atrial fibrillation increase the biomechanical risk of thrombosis in chicken wing shape left atrial appendages compared to sinus rhythm?
Computational fluid dynamics modeling demonstrates that atrial fibrillation significantly increases blood residence time and decreases wall shear stress in chicken-wing left atrial appendages, providing a biomechanical mechanism for increased thrombotic risk.
Computational LAA flow modeling in AF may identify thrombosis predictors; hypothesis-generating pending prospective clinical validation.
Atrial fibrillation (AF) is a common and life-threatening disease. For the patients with AF, more than 90% of the thrombi are formed in the left atrial appendage (LAA), thrombus dislodgement can cause vascular embolism, making them is becoming a high-risk group for stroke. Therefore, identifying the patients with high risk of thrombosis is crucial for advanced stroke warning. To better investigate the mechanism behind thrombus formation in the LAA, this study reconstructed the 3-D Left Atrium (LA) models of six AF volunteer patients by corresponding Computed Tomography (CT) images. Combine the advantages of Computational Fluid Dynamics (CFD), the blood flow field in LA both in AF and sinus heart rate states were studied. The risk of thrombus was evaluated based on the blood viscosity, shear rate thrombus prediction model and Time Average Wall Shear Stress (TAWSS), Oscillatory Shear Index (OSI), and Relative Residence Time (RRT) values. The results showed that the left atrium had lower blood flow velocity and TAWSS values at the LAA in both AF and sinus rhythm, thus the LAA is the most thrombogenic region in the LA. Besides, the RRT value of LAA was generally higher in AF than in sinus rhythm. Therefore, AF carries a higher risk of thrombosis.
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Yang et al. (2022) studied Atrial fibrillation with chicken wing shape left atrial appendage (n=6). Atrial fibrillation (simulated state) vs. Sinus rhythm (simulated state) was evaluated on Risk of thrombus evaluated by blood viscosity, shear rate, Time Average Wall Shear Stress (TAWSS), Oscillatory Shear Index (OSI), and Relative Residence Time (RRT). Atrial fibrillation resulted in lower blood flow velocity and higher relative residence time in the left atrial appendage compared to sinus rhythm, indicating a substantially increased risk of thrombosis.
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