Postoperative Lymphatic Complications in Congenital Heart Disease: A MR Lymphangiography Case Series

Description of Clinical Presentation: Complex congenital heart disease (CHD) patients, especially those who have received palliative care, such as Glenn and Fontan procedures, frequently develop lymphatic complications. These may represent significant clinical impact, including chylothorax, ascites, plastic bronchitis, and protein-losing enteropathy. In our institution, we observed a wide spectrum of postoperative manifestations. Findings ranged from a patent and normal-caliber thoracic duct to distal stenosis, tortuosity, diffuse ectasia, and exuberant collateral vessels. Clinical presentation included persistent effusions, respiratory compromise, and signs of lymphatic dysfunction, which prompted advanced diagnostic investigation.

Diagnostic Techniques and Their Most Important Findings: Twelve patients evaluated at our institution between 2022 and 2025 underwent magnetic resonance lymphangiography (MRL) using T2-weighted sequences and, if warranted, dynamic contrast-enhanced protocols. Three patients demonstrated dilation and tortuosity of the thoracic duct, a phenomenon associated with central venous hypertension after Fontan surgery. Four patients showed normal duct caliber and in two patients the duct was not visualized, probably due to collateral vessels redistribution. Cervical, supraclavicular, mediastinal and abdominal lymphatic collaterals were also identified in six cases. Patterns of diffuse lymphatic congestion with subcutaneous edema, ascites, and bilateral pleural effusions were also found in three patients, consistent with central drainage failure and major systemic repercussions. Non-visualization of the cisterna chyli was observed in two cases, which could be associated with anatomical variant of the central lymphatic system or with abdominal collaterals.

Learning Points from this Case: MRL is an imaging method of significant clinical relevance in the evaluation of CHD patients with late lymphatic complications. This non-invasive technique provides diagnostic information based on comprehensive analysis of the lymphatic system anatomy, which is not available through conventional modalities. Findings observed in this case series, albeit limited by a small sample size, are consistent with previously reported studies, emphasizing the growing role of MRL in risk stratification, clinical decision-making, and individualized management of patients after complex congenital procedures.

Coronal T2 weighted-SPACE MR image shows a tortuous thoracic duct with mild dilation and significant distal stenosis
Coronal T2 weighted-SPACE MR image shows diffuse lymphatic congestion after Tetralogy of Fallot repair.
Coronal T2 weighted-SPACE MR image shows diffuse lymphatic congestion after Fontan procedure