Data from: Toward translating near-infrared spectroscopy oxygen saturation data for the non-invasive prediction of spatial and temporal hemodynamics during exercise

Image-based computational fluid dynamics (CFD) studies conducted at rest have shown that atherosclerotic plaque in the thoracic aorta (TA) correlates with adverse wall shear stress (WSS), but there is a paucity of such data under elevated flow conditions. We developed a pedaling exercise protocol to obtain phase contrast magnetic resonance imaging (PC-MRI) blood flow measurements in the TA and brachiocephalic arteries during three-tiered supine pedaling at 130, 150, and 170 % of resting heart rate (HR), and relate these measurements to non-invasive tissue oxygen saturation [Formula: see text] acquired by near-infrared spectroscopy (NIRS) while conducting the same protocol. Local quantification of WSS indices by CFD revealed low time-averaged WSS on the outer curvature of the ascending aorta and the inner curvature of the descending aorta (dAo) that progressively increased with exercise, but that remained low on the anterior surface of brachiocephalic arteries. High oscillatory WSS observed on the inner curvature of the aorta persisted during exercise as well. Results suggest locally continuous exposure to potentially deleterious indices of WSS despite benefits of exercise. Linear relationships between flow distributions and tissue oxygen extraction calculated from [Formula: see text] were found between the left common carotid versus cerebral tissue [Formula: see text] and the dAo versus leg tissue [Formula: see text]. A resulting six-step procedure is presented to use NIRS data as a surrogate for exercise PC-MRI when setting boundary conditions for future CFD studies of the TA under simulated exercise conditions. Relationships and ensemble-averaged PC-MRI inflow waveforms are provided in an online repository for this purpose.

既往基于图像的计算流体动力学（computational fluid dynamics, CFD）研究表明，静息状态下胸主动脉（thoracic aorta, TA）内的动脉粥样硬化斑块与不良壁面切应力（wall shear stress, WSS）存在关联，但血流升高状态下的此类数据仍较为匮乏。本研究构建了蹬车运动方案，以在静息心率（resting heart rate, HR）的130%、150%及170%强度下的三级仰卧蹬车过程中，获取胸主动脉及头臂动脉的相位对比磁共振成像（phase contrast magnetic resonance imaging, PC-MRI）血流测量数据，并将这些测量结果与同一运动方案中通过近红外光谱法（near-infrared spectroscopy, NIRS）获取的无创组织氧饱和度[Formula: see text]相关联。通过计算流体动力学对壁面切应力指标进行局部量化后发现，升主动脉外曲率及降主动脉（descending aorta, dAo）内曲率处的时间平均壁面切应力（time-averaged WSS）随运动强度增加而逐渐升高，但头臂动脉前壁的时间平均壁面切应力仍维持在较低水平。主动脉内曲率处观察到的高振荡壁面切应力（oscillatory WSS）在运动过程中亦持续存在。研究结果提示，尽管运动具有诸多益处，但局部区域仍持续暴露于潜在有害的壁面切应力指标。通过[Formula: see text]计算得到的血流分布与组织氧提取率之间存在线性相关关系：左侧颈总动脉与脑组织[Formula: see text]间、降主动脉与腿部组织[Formula: see text]间均呈现此类关联。据此我们提出了一套六步流程，旨在在未来模拟运动状态下胸主动脉的计算流体动力学研究中，以近红外光谱法数据作为替代参数用于设定边界条件。为此，本研究已将上述相关关系及集合平均的PC-MRI流入波形上传至在线仓库以供使用。