Department of Cardiothoracic Surgery, Leiden University Medical Center, Leiden, Netherlands.
Department of Cardiology, Biomechanical Engineering, Erasmus MC, Rotterdam, Netherlands.
Eur J Cardiothorac Surg. 2022 Dec 2;63(1). doi: 10.1093/ejcts/ezac522.
To date, it is not known if 16-20-mm extracardiac conduits are outgrown during somatic growth from childhood to adolescence. This study aims to determine total cavopulmonary connection (TCPC) haemodynamics in adolescent Fontan patients at rest and during simulated exercise and to assess the relationship between conduit size and haemodynamics.
Patient-specific, magnetic resonance imaging-based computational fluid dynamic models of the TCPC were performed in 51 extracardiac Fontan patients with 16-20-mm conduits. Power loss, pressure gradient and normalized resistance were quantified in rest and during simulated exercise. The cross-sectional area (CSA) (mean and minimum) of the vessels of the TCPC was determined and normalized for flow rate (mm2/l/min). Peak (predicted) oxygen uptake was assessed.
The median age was 16.2 years (Q1-Q3 14.0-18.2). The normalized mean conduit CSA was 35-73% smaller compared to the inferior and superior vena cava, hepatic veins and left/right pulmonary artery (all P < 0.001). The median TCPC pressure gradient was 0.7 mmHg (Q1-Q3 0.5-0.8) and 2.0 (Q1-Q3 1.4-2.6) during rest and simulated exercise, respectively. A moderate-strong inverse non-linear relationship was present between normalized mean conduit CSA and TCPC haemodynamics in rest and exercise. TCPC pressure gradients of ≥1.0 at rest and ≥3.0 mmHg during simulated exercise were observed in patients with a conduit CSA ≤ 45 mm2/l/min and favourable haemodynamics (<1 mmHg during both rest and exercise) in conduits ≥125 mm2/l/min. Normalized TCPC resistance correlated with (predicted) peak oxygen uptake.
Extracardiac conduits of 16-20 mm have become relatively undersized in most adolescent Fontan patients leading to suboptimal haemodynamics.
目前尚不清楚从儿童期到青春期的身体生长过程中，16-20mm 的心外管道是否会过度生长。本研究旨在确定在休息和模拟运动期间，青少年 Fontan 患者的全腔静脉肺动脉连接（TCPC）血流动力学，并评估管道尺寸与血流动力学之间的关系。
对 51 例使用 16-20mm 心外管道的 Fontan 患者进行了基于特定患者的磁共振成像计算流体动力学模型。在休息和模拟运动期间，量化了功率损耗、压力梯度和归一化阻力。确定了 TCPC 血管的横截面积（CSA）（平均值和最小值），并按流量（mm2/l/min）进行了归一化。评估了峰值（预测）摄氧量。
中位年龄为 16.2 岁（Q1-Q3 14.0-18.2）。与下腔静脉、上腔静脉、肝静脉和左/右肺动脉相比，归一化平均管道 CSA 小 35-73%（均 P < 0.001）。TCPC 压力梯度在休息时为 0.7mmHg（Q1-Q3 0.5-0.8），在模拟运动时为 2.0mmHg（Q1-Q3 1.4-2.6）。在休息和运动时，归一化平均管道 CSA 与 TCPC 血流动力学之间存在中度强的非线性关系。在 CSA≤45mm2/l/min 的患者中，休息时 TCPC 压力梯度≥1.0，模拟运动时 TCPC 压力梯度≥3.0mmHg，在 CSA≥125mm2/l/min 的患者中，在休息和运动时 TCPC 阻力都较小（均<1mmHg）。归一化 TCPC 阻力与（预测）峰值摄氧量相关。
大多数青少年 Fontan 患者的心外管道已变得相对较小，导致血流动力学不佳。
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