Tomasulo CE, Chen JM, Smith CL, Maeda K, Rome JJ, Dori Y. Ann Thorac Surg. 2020 Dec 26:S0003-4975(20)32169-X. doi: 10.1016/j.athoracsur.2020.10.058. PMID: 33373590
Take Home Points:
- Congenital heart disease can lead to significant lymphatic complications such as chylothorax, plastic bronchitis, protein losing enteropathy and ascites.
- Recent improvements in lymphatic imaging and the development of new lymphatic procedures can help alleviate symptoms and improve outcomes.
- In addition to optimization of the cardiac circulation and medical management, new minimally invasive lymphatic interventional procedures and lymphatic directed surgical procedures are now available and should be utilized to treat patients with these disorder.
Commentary from Dr. Manoj Gupta (New York, USA), section editor of Pediatric & Fetal Cardiology Journal Watch: Magnetic resonance lymphangiography is an important imaging modality for both the peripheral and central lymphatic systems. It can be used as a screening tool for lymphatic abnormalities and has good spatial resolution.
T2-weighted MR lymphangiography has demonstrated differences in the lymphatic systems of patients after cavopulmonary anastomoses compared to patients with non-single ventricle CHD. After single ventricle palliation, T2 imaging has shown Thoracic Duct dilation, lymphangiectasia, lymphatic collateralization and tissue edema. After Fontan procedure, patients who developed PLE or plastic bronchitis appear to have statistically significantly larger Thoracic Duct compared to those without such complications.
Lymphatic abnormalities were classified into 4 types (Figure 1).
Figure 1: Classification of T2 Thoracic Lymphatic Abnormalities
(A) Type 1: no significant T2 abnormality in mediastinum or neck.
(B) Type 2: increased abnormal signal within bilateral supraclavicular region.
(C) Type 3: extension into mediastinum.
(D) Type 4: further extension into interstitium of lungs.
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The higher-grade types had significantly longer postoperative hospital stays and duration of effusions, mortality, orthotopic heart transplant (OHT), ECMO, plastic bronchitis and acute Fontan takedown only occurred in patients with type 4, indicating a poor prognosis for patients in this group. This imaging should be used as a screening tool for thoracic lymphatic abnormalities in all single ventricle patients prior to the Fontan operation.
Noncontrast magnetic resonance lymphangiography
Intrahepatic Dynamic contrast magnetic resonance lymphangiography is a new imaging modality designed to assess liver lymphatic anatomy and flow and is the modality of choice for patients with PLE and ascites, Intranodal Dynamic contrast magnetic resonance lymphangiography is one of the more recent imaging techniques and is the modality of choice for central lymphatic flow disorders and Intramesenteric Dynamic contrast magnetic resonance lymphangiography is another new imaging modality that is now available for certain forms of PLE.
In all patients with suspected lymphatic abnormalities, cardiac catheterization should be performed to assess hemodynamics and determine reversible causes of lymphatic failure, such as SVC or branch pulmonary artery stenosis. Single ventricle patients after the Fontan procedure with no obstruction through the Fontan pathway can undergo creation or recreation of a Fontan fenestration to help reduce pressures. Lymphatic interventions can be separated into those that serve to decompress the lymphatic system, such as lymphovenous anastomosis (LVA), surgical or percutaneous thoracic duct decompression, and those that target exclusion of the abnormal lymphatic channels, including selective lymphatic duct embolization, placement of covered stents in the thoracic duct, ethiodized oil lymphatic embolization, liver lymphatic embolization, and thoracic duct embolization or ligation.