Haggerty Christopher M, Whitehead Kevin K, Bethel James, Fogel Mark A, Yoganathan Ajit P
Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia.
Division of Pediatric Cardiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
Ann Thorac Surg. 2015 Mar;99(3):911-7. doi: 10.1016/j.athoracsur.2014.10.043. Epub 2015 Jan 22.
Single ventricle lesions are associated with gradual attrition after surgical palliation with the total cavopulmonary connection (TCPC). Ventricular dysfunction is frequently noted, particularly impaired diastolic performance. This study seeks to relate TCPC hemodynamic energy losses to single ventricle volumes and filling characteristics.
Cardiac magnetic resonance (CMR) data were retrospectively analyzed for 30 single ventricle patients at an average age of 12.7 ± 4.8 years. Cine ventricular short-axis scans were semiautomatically segmented for all cardiac phases. Ventricular volumes, ejection fraction, peak filling rate, peak ejection rate, and time to peak filling were calculated. Corresponding patient-specific TCPC geometry was acquired from a stack of transverse CMR images; relevant flow rates were segmented from through-plane phase contrast CMR data at TCPC inlets and outlets. The TCPC indexed power loss was calculated from computational fluid dynamics simulations using a validated custom solver. Time-averaged flow conditions and rigid vessel walls were assumed in all cases. Pearson correlations were used to detect relationships between variables, with p less than 0.05 considered significant.
Ventricular end-diastolic (R = -0.48) and stroke volumes (R = -0.37) had significant negative correlations with the natural logarithm of a flow-independent measure of power loss. This power loss measure also had a significant positive relationship to time to peak filling rate (normalized to cycle time; R = 0.67).
Flow-independent TCPC power loss is inversely related with ventricular end-diastolic and stroke volumes. Elevated power losses may contribute to impaired diastolic filling and limited preload reserve in single ventricle patients.
单心室病变与采用全腔静脉肺动脉连接术（TCPC）进行手术姑息治疗后的逐渐衰退有关。经常会出现心室功能障碍，尤其是舒张功能受损。本研究旨在探讨TCPC血流动力学能量损失与单心室容积及充盈特征之间的关系。
对30例平均年龄为12.7±4.8岁的单心室患者的心脏磁共振（CMR）数据进行回顾性分析。对所有心动周期的电影心室短轴扫描进行半自动分割。计算心室容积、射血分数、峰值充盈率、峰值射血率和峰值充盈时间。从一系列横向CMR图像中获取相应的患者特异性TCPC几何形状；从TCPC入口和出口处的平面相位对比CMR数据中分割出相关流速。使用经过验证的自定义求解器通过计算流体动力学模拟计算TCPC指数功率损失。所有情况下均假设为时间平均流动条件和刚性血管壁。采用Pearson相关性分析来检测变量之间的关系，p值小于0.05被认为具有统计学意义。
心室舒张末期容积（R = -0.48）和每搏量（R = -0.37）与与流量无关的功率损失测量值的自然对数呈显著负相关。该功率损失测量值与峰值充盈率时间（归一化至心动周期时间；R = 0.67）也呈显著正相关。
与流量无关的TCPC功率损失与心室舒张末期容积和每搏量呈负相关。功率损失升高可能导致单心室患者舒张期充盈受损和前负荷储备受限。
