Division of Cardiology, 6567Children's Hospital of Philadelphia, Philadelphia, PA, USA.
Department of Cardiothoracic Surgery, 11297Aarhus University Hospital, Aarhus, Denmark.
World J Pediatr Congenit Heart Surg. 2022 Nov;13(6):737-744. doi: 10.1177/21501351221119394.
The Fontan circulation challenges the lymphatic system. Increasing production of lymphatic fluid and impeding lymphatic return, increased venous pressure may cause lymphatic dilatation and decrease lymphatic contractility. In-vitro studies have reported a lymphatic diameter-tension curve, with increasing passive stretch affecting the intrinsic contractile properties of each thoracic duct segment. We aimed to describe thoracic duct occlusion pressure and asses if thoracic duct dilation impairs contractility in individuals with a Fontan circulation and lymphatic failure.
Central venous pressure and thoracic duct measurements were retrospectively collected from 31 individuals with a Fontan circulation. Thoracic duct occlusion pressure was assessed during a period of external manual compression and used as an indicator of lymphatic vessel contractility. Measurements of pressure were correlated with measurements of the thoracic duct diameter in images obtained by dynamic contrast-enhanced MR lymphangiography.
The average central venous pressure and average pressure of the thoracic duct were 17 mm Hg. During manual occlusion, the thoracic duct pressure significantly increased to 32 mm Hg. The average thoracic duct diameter was 3.3 mm. Thoracic duct diameter correlated closely with the central venous pressure. The rise in pressure following manual occlusion showed an inverse correlation with the diameter of the thoracic duct.
Higher central venous pressures are associated with increasing diameters of the thoracic duct. When challenged by manual occlusion, dilated thoracic ducts display a decreased ability to increase pressure. Dilatation and a resulting decreased contractility may partly explain the challenged lymphatic system in individuals with a Fontan circulation.
Fontan 循环对淋巴系统构成挑战。淋巴液产量增加和淋巴回流受阻，静脉压升高可导致淋巴管扩张和淋巴收缩力下降。体外研究报告了淋巴管直径-张力曲线，随着被动拉伸增加，影响每个胸导管段的固有收缩特性。我们旨在描述胸导管闭塞压，并评估在 Fontan 循环和淋巴功能衰竭的个体中，胸导管扩张是否会损害收缩性。
回顾性收集了 31 名 Fontan 循环患者的中心静脉压和胸导管测量值。在外部手动压缩期间评估胸导管闭塞压，并将其作为淋巴管收缩性的指标。压力测量值与动态对比增强磁共振淋巴造影术获得的图像中胸导管直径的测量值相关。
平均中心静脉压和胸导管平均压分别为 17mmHg。在手动闭塞期间，胸导管压力显著增加到 32mmHg。平均胸导管直径为 3.3mm。胸导管直径与中心静脉压密切相关。手动闭塞后压力升高与胸导管直径呈负相关。
较高的中心静脉压与胸导管直径的增加有关。当受到手动闭塞的挑战时，扩张的胸导管显示出增加压力的能力降低。扩张和由此导致的收缩性降低可能部分解释了 Fontan 循环个体中受到挑战的淋巴系统。
