永存动脉干的流体力学

中文摘要 AI 辅助

永存动脉干（TA）是一种罕见且严重的先天性心脏病，其特点是心脏发出的两根主要动脉在子宫内未能分离，导致形成单一的动脉干和动脉干瓣膜，输送混合的含氧血和脱氧血。约25%的患者拥有四叶式动脉干瓣膜，该瓣膜易发生反流和再次干预。尽管流体力学对瓣膜性能和血液混合至关重要，但TA中的流体力学机制仍知之甚少。基于TA修复前后的CT影像，进行了患者特异性流固耦合模拟。四叶式瓣膜采用基于弹性的设计构建，利用从超声心动图提取的患者游离缘长度和几何高度。血液与瓣膜之间的相互作用通过浸没边界法进行模拟。边界条件根据患者数据进行调整。含氧血和脱氧血的混合及血流分流通过拉格朗日相干结构（LCS）和拉格朗日粒子追踪（LPT）进行评估。在整个心动周期中，单侧肺动脉（PAs）内的低压、前向血流和流向涡旋影响了瓣叶运动，导致不对称关闭和反流。全舒张期主动脉血流反向为肺动脉血流和反流射流提供供应。LCS和LPT显示，含氧血从左心室（LV）到主动脉以及脱氧血从右心室（RV）到肺动脉存在有利的分流。动脉干手术后，正常血流动力学得以恢复。这是首项关于TA流体力学的研究。通过定性和定量血流分析，我们识别了由单侧肺动脉引起的术前血流动力学紊乱，并展示了修复后正常血流动力学如何重建。有利的分流被证明与患者报告一致。因此，在完全混合性病变中，有利分流是可能的，患者特异性建模可能有助于其检测。

英文摘要

Truncus arteriosus (TA) is a rare, severe congenital heart disease in which the two main arteries exiting the heart fail to separate in utero resulting in one truncus and truncal valve, carrying mixed oxygenated and deoxygenated blood. About 25% of patients have a quadricuspid valve, which is prone to regurgitation and re-intervention. Despite its relevance for valve performance and mixing, fluid mechanics in TA are poorly understood. Patient-specific fluid-structure interaction simulations were performed based on CT imaging before and after TA repair. The quadricuspid valve was constructed using elasticity-based design with the patient's free edge length and geometric height extracted from echocardiography. Interaction between blood and valve was simulated with the Immersed Boundary Method. Boundary conditions were tuned to the patient's data. Mixing of oxygenated and deoxygenated blood and streaming were assessed via Lagrangian Coherent Structures (LCS) and Lagrangian Particle Tracing (LPT). Low pressures, forward flow and streamwise vortices in the one-sided pulmonary arteries (PAs) throughout the cardiac cycle affected leaflet motion, leading to asymmetric closure and regurgitation. Holodiastolic aortic flow reversal supplied PA flow and the regurgitant jet. LCS and LPT indicated favorable streaming of oxygenated blood from the LV to the aorta and deoxygenated blood from the RV to the PAs. After truncal surgery, normal hemodynamics were restored. This is the first study of fluid mechanics of TA. Using qualitative and quantitative flow analysis, we identified disrupted preoperative hemodynamics caused by one-sided PAs and showed how normal hemodynamics were re-established after repair. Favorable streaming was demonstrated aligned with patient reports. Thus, favorable streaming is plausible in total mixing lesions and patient-specific modeling may aid in its detection.

发表机构

• Stanford University（斯坦福大学）

机构由 AI 辅助整理，请以论文原文为准。