Division of Cardiology, Heart Institute, Children's Hospital Colorado, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA.
Department of Radiology, Children's Hospital Colorado, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA.
Int J Cardiovasc Imaging. 2020 Apr;36(4):691-700. doi: 10.1007/s10554-019-01764-w. Epub 2020 Jan 6.
Aortopathy is a recognized comorbidity of Tetralogy of Fallot (TOF). Aortic flow in children with repaired TOF is abnormal despite normal aortic valve anatomy and early surgical repair that results in aortic size normalization. The purpose of this study was to investigate the flow hemodynamics inside the left ventricle (LV) of children with repaired TOF using 4D-Flow MRI derived vorticity. Vorticity is the spatial derivative of flow velocity and is sensitive to anatomic and geometric variations. Vorticity was calculated inside the LV of children with repaired TOF having normal aortic size (n = 14) and normal controls (n = 10) during systolic ejection phase. All subjects underwent comprehensive biventricular analysis including the MRI based feature-tracking based LV strain analysis and mechanical dyssynchrony. Right ventricular (RV) volumetric indices along with LV mechanical indices were correlated with LV vorticity. All TOF patients had supraphysiologic helical flow in the ascending aorta. The generated peak systolic vorticity integrated over the LV volume was elevated in TOF group compared to control (median: 1344 vs. 858 s, P < 0.001). TOF patients had increased LV mechanical dyssynchrony (47 ± 11 vs. 32 ± 7 ms, P < 0.001) and reduced LV global circumferential strain (19 ± 2 vs. 21 ± 2%, P = 0.020). In the TOF group, LV systolic vorticity was independent of RV size and LV mechanical indices. Pathologic aortic flow in children with repaired TOF is associated with abnormal ejection flow patterns inside the LV. Increased systolic vorticity was not associated with LV mechanical dyssynchrony and RV dilation, suggesting that systolic flow inside the LV is independent of impaired LV contractile mechanics and inter-ventricular interactions.
主动脉病是法洛四联症（TOF）的一种公认的合并症。尽管主动脉瓣解剖结构正常且早期手术修复导致主动脉大小正常化，但修复后的 TOF 患儿的主动脉血流仍然异常。本研究旨在使用 4D-Flow MRI 衍生的涡度研究修复后的 TOF 患儿左心室（LV）内的血流动力学。涡度是流速的空间导数，对解剖和几何变化敏感。在收缩射血期，对主动脉大小正常的修复后的 TOF 患儿（n=14）和正常对照（n=10）的 LV 内计算涡度。所有患者均接受了全面的双心室分析，包括基于 MRI 的基于特征追踪的 LV 应变分析和机械不同步。右心室（RV）容积指数与 LV 机械指数与 LV 涡度相关。所有 TOF 患者的升主动脉均存在超生理螺旋血流。与对照组相比，TOF 组的 LV 容积内生成的收缩期峰值涡度积分升高（中位数：1344 对 858 s，P<0.001）。TOF 患者的 LV 机械不同步增加（47±11 对 32±7 ms，P<0.001），LV 整体环向应变降低（19±2 对 21±2%，P=0.020）。在 TOF 组中，LV 收缩期涡度与 RV 大小和 LV 机械指数无关。修复后的 TOF 患儿病理性主动脉血流与 LV 内异常射流模式有关。收缩期涡度增加与 LV 机械不同步和 RV 扩张无关，表明 LV 内的收缩期血流独立于受损的 LV 收缩力学和室间相互作用。
