Atrial fibrillation (AF) is considered the most common human arrhythmia. Around 99\% of thrombi in non-valvular AF are formed in the left atrial appendage (LAA). Studies suggest that abnormal LAA haemodynamics and the subsequently stagnated flow are the factors triggering clot formation. However, the relation between LAA morphology, the blood pattern and the triggering is not fully understood. Moreover, the impact of structures such as the pulmonary veins (PVs) on LA haemodynamics has not been thoroughly studied due to the difficulties of acquiring appropriate data. On the other hand, in-silico studies and flow simulations allow a thorough analysis of haemodynamics, analysing the 4D nature of blood flow patterns under different boundary conditions. However, the reduced number of cases reported on the literature of these studies has been a limitation. The main goal of this work was to study the influence of PVs on left atrium (LA) and LAA haemodynamics. Computational fluid dynamics simulations were run on 52 patients, the largest cohort so far in the literature, where different parameters were individually studied: pulmonary veins orientation and configuration; LAA and LA volumes and its ratio; and flow velocities. Our computational analysis showed how the right pulmonary vein height and angulation have a great influence on LA haemodynamics. Additionally, we found that LAA with great bending with its tip pointing towards the mitral valve could contribute to favour flow stagnation.
翻译:研究显示,异常的LAA血液动力学和随后的静态流动是引发凝块形成的因素,然而,LAA形态学、血液模式和触发作用之间的关系并不完全理解。此外,由于难以获得适当的数据,诸如肺血管(PVs)等结构对LA血浆动力学的影响尚未得到彻底研究。另一方面,在硅基研究和流动模拟中,可以对血液动力学进行透彻分析,分析不同边界条件下血液流动模式的四维性质。然而,LAA的形态学、血液模式和触发作用之间的关系并不完全理解。这项工作的主要目的是研究PVs对LA血浆动力学的影响,因为难以获得适当的数据。另一方面,对血液动力学的抽血动学和流动模拟有助于对血液动力学进行透彻分析,对52个病人进行血液动力学分析,对血液动力学进行最大水平的血液动力学分析,对AA值进行最大幅度的血液流动分析,而LA的血管和血液结构分析显示,LA的深度和血液结构分析表明,LA的深度和深度分析表明,LA的深度结构和深度的深度结构和深度。