Department of Cardiothoracic Surgery, Leiden University Medical Center, Albinusdreef 2, 2333ZA, Leiden, The Netherlands.
Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
J Cardiovasc Magn Reson. 2022 Mar 28;24(1):21. doi: 10.1186/s12968-022-00854-4.
This study explores the relationship between in vivo 4D flow cardiovascular magnetic resonance (CMR) derived blood flow energetics in the total cavopulmonary connection (TCPC), exercise capacity and CMR-derived liver fibrosis/congestion.
The Fontan circulation, in which both caval veins are directly connected with the pulmonary arteries (i.e. the TCPC) is the palliative approach for single ventricle patients. Blood flow efficiency in the TCPC has been associated with exercise capacity and liver fibrosis using computational fluid dynamic modelling. 4D flow CMR allows for assessment of in vivo blood flow energetics, including kinetic energy (KE) and viscous energy loss rate (EL).
Fontan patients were prospectively evaluated between 2018 and 2021 using a comprehensive cardiovascular and liver CMR protocol, including 4D flow imaging of the TCPC. Peak oxygen consumption (VO) was determined using cardiopulmonary exercise testing (CPET). Iron-corrected whole liver T1 (cT1) mapping was performed as a marker of liver fibrosis/congestion. KE and EL in the TCPC were computed from 4D flow CMR and normalized for inflow. Furthermore, blood flow energetics were compared between standardized segments of the TCPC.
Sixty-two Fontan patients were included (53% male, 17.3 ± 5.1 years). Maximal effort CPET was obtained in 50 patients (peak VO 27.1 ± 6.2 ml/kg/min, 56 ± 12% of predicted). Both KE and EL in the entire TCPC (n = 28) were significantly correlated with cT1 (r = 0.50, p = 0.006 and r = 0.39, p = 0.04, respectively), peak VO (r = - 0.61, p = 0.003 and r = - 0.54, p = 0.009, respectively) and % predicted peak VO (r = - 0.44, p = 0.04 and r = - 0.46, p = 0.03, respectively). Segmental analysis indicated that the most adverse flow energetics were found in the Fontan tunnel and left pulmonary artery.
Adverse 4D flow CMR derived KE and EL in the TCPC correlate with decreased exercise capacity and increased levels of liver fibrosis/congestion. 4D flow CMR is promising as a non-invasive screening tool for identification of patients with adverse TCPC flow efficiency.
本研究旨在探讨全腔肺动脉连接（TCPC）中体内 4D 血流心血管磁共振（CMR）衍生血流能量与运动能力和 CMR 衍生肝纤维化/淤血之间的关系。
在单心室患者中，腔静脉直接与肺动脉连接（即 TCPC）的 Fontan 循环是姑息治疗方法。使用计算流体动力学模型已经将 TCPC 中的血流效率与运动能力和肝纤维化联系起来。4D 流动 CMR 可用于评估体内血流能量，包括动能（KE）和粘性能量损耗率（EL）。
2018 年至 2021 年期间，前瞻性评估了 Fontan 患者，使用全面的心血管和肝脏 CMR 方案，包括 TCPC 的 4D 流动成像。使用心肺运动测试（CPET）确定最大摄氧量（VO）。进行铁校正全肝 T1（cT1）映射作为肝纤维化/淤血的标志物。从 4D 流动 CMR 计算 TCPC 中的 KE 和 EL，并按流入量归一化。此外，还比较了 TCPC 标准化节段之间的血流能量。
共纳入 62 例 Fontan 患者（53%为男性，17.3±5.1 岁）。50 例患者获得最大努力 CPET（峰值 VO 27.1±6.2ml/kg/min，预测值的 56±12%）。整个 TCPC（n=28）中的 KE 和 EL 与 cT1（r=0.50，p=0.006 和 r=0.39，p=0.04）、峰值 VO（r=-0.61，p=0.003 和 r=-0.54，p=0.009）和预测峰值 VO 的百分比（r=-0.44，p=0.04 和 r=-0.46，p=0.03）均呈显著相关。节段性分析表明，在 Fontan 隧道和左肺动脉中发现了最不利的血流能量。
TCPC 中不良的 4D 流动 CMR 衍生 KE 和 EL 与运动能力下降和肝纤维化/淤血增加有关。4D 流动 CMR 作为识别 TCPC 血流效率不良患者的非侵入性筛查工具具有广阔的前景。
