The lymphatic system plays crucial roles in immune regulation, transport of macromolecules for nutrition, and fluid balance. The thoracic duct (TD) is the central conduit for lymphatic fluid which it receives from various sources, including the peripheral tissues, liver, mesentery, and lungs1. Dysfunction of normal lymphatic circulation, termed as lymphatic conduction disorder, can manifest as lymphatic leaks in various body compartments and produce significant morbidity. In the thorax, these disorders produce chylothorax, plastic bronchitis, and chylopericardium2, 3, 4. In the abdomen, leak of fluid into bowel produces protein-losing enteropathy (PLE) and chylous ascites if into the peritoneal cavity5,6 (Figure 1).

Lymphatic conduction disorders may be categorized as primary or secondary (Figure 2). Primary disorders have a variety of genetic associations and are marked by lymphatic hyperplasia with disorganized/dysplastic architecture7. Secondary disorders are more common and often develop after palliation of single-ventricle congenital heart disease (CHD) as a result of increased central venous pressure (CVP), which increases afterload of the TD and produces upstream lymphatic dilation and collateralization8, 9, 10. If collateral lympho-venous anastomoses are insufficient, lymphatic leak may result11. Secondary disorders may also result from trauma (including iatrogenic), lymphatic obstruction by tumors, chronic infection, and filariasis.

Management of lymphatic leaks includes drainage and supportive measures, including low-fat diet and medications such as diuretics, pulmonary vasodilators and steroids12. Surgical interventions include TD ligation, lympho-venous anastomosis, pleurodesis, and innominate vein turn-down13,14. Importantly, percutaneous techniques, covered in this article, are well-suited for treatment of these disorders, and such lymphatic interventions comprise an important therapeutic modality15. These include lymphatic embolization and balloon dilation or stenting of duct obstruction16. TD externalization can also be offered to relieve severe symptoms of TD obstruction. Percutaneous TD decompression or Fontan take-down are additional considerations for single-ventricle patients to decrease CVP and is covered elsewhere in this issue17,18.