Sung Cassandra, Bass John L, Berry James M, Shepard Charles W, Lindgren Bruce, Kochilas Lazaros K
University of Minnesota, Minneapolis, MN, USA.
Children's Hospitals and Clinics of Minnesota, Minneapolis, MN, USA.
Echocardiography. 2017 Sep;34(9):1347-1352. doi: 10.1111/echo.13639. Epub 2017 Aug 22.
Ultrasound imaging of adults with heart failure and increased central venous pressure (CVP) has shown significant thoracic duct (TD) dilation from impedance in lymphatic drainage. Elevated CVP and abnormal lymphatic drainage are implicated in severe Fontan complications, including protein losing enteropathy (PLE) and plastic bronchitis (PB). Systematic studies of TD and lymphatic circulation in children are limited, and their cervical TD normative values have not been established.
Thoracic duct imaging was attempted prospectively during routine echocardiograms performed 7/2014-9/2016 in children 5-21 years old with normal cardiovascular physiology and Fontan palliation. TD insertion to the central venous system (lympho-venous junction) was assessed with an S12-4 MHz transducer. For the first 34 patients, only TD ostia were measured, but ostium shape variability at the lympho-venous junction led to including the TD arch 5-10 mm proximal to the ostium for the remaining cohort.
Seventy-nine total subjects were studied: 58 controls, 13 Fontan patients with normal systemic ventricular ejection fraction (EF) (>50%), and 8 Fontan patients with decreased EF (≤50%). Combined Fontan subjects had larger TD ostial diameters compared to controls when normalized by body surface area (median 2.6 mm/m vs. 2 mm/m ) (P=.04).
To our knowledge, this is the first systematic study of ultrasonographic TD imaging in children. Fontan patients have larger TD diameters, reflecting the impaired lymphatic circulation in patients with this physiology. Further research may provide important associations between sonographic TD features with the functional status of patients with Fontan circulation.
对患有心力衰竭且中心静脉压（CVP）升高的成年人进行超声成像检查发现，由于淋巴引流受阻，胸导管（TD）出现明显扩张。中心静脉压升高和异常淋巴引流与严重的Fontan并发症有关，包括蛋白丢失性肠病（PLE）和塑形支气管炎（PB）。关于儿童胸导管和淋巴循环的系统研究有限，其颈段胸导管的正常参考值尚未确定。
在2014年7月至2016年9月对5至21岁心血管生理正常和接受Fontan姑息手术的儿童进行常规超声心动图检查时，前瞻性地尝试进行胸导管成像。使用S12-4MHz探头评估胸导管与中心静脉系统的连接处（淋巴-静脉交界处）。对于前34例患者，仅测量胸导管开口，但淋巴-静脉交界处开口形状的变异性导致对其余队列纳入开口近端5至10mm处的胸导管弓进行测量。
共研究了79名受试者：58名对照者，13名全身心室射血分数（EF）正常（>50%）的Fontan患者，以及8名EF降低（≤50%）的Fontan患者。按体表面积进行标准化后，Fontan患者组的胸导管开口直径大于对照组（中位数2.6mm/m² 对2mm/m² ）（P = 0.04）。
据我们所知，这是第一项关于儿童超声胸导管成像的系统研究。Fontan患者的胸导管直径较大，反映了具有这种生理状态的患者淋巴循环受损。进一步的研究可能会揭示超声胸导管特征与Fontan循环患者功能状态之间的重要关联。
