EXPLANATION

Lymphatic complications after congenital heart surgery may arise from thoracic duct injury, venous obstruction, or elevated central venous pressure. Impaired lymphatic drainage and the development of collateral pathways can manifest as chylothorax, plastic bronchitis, protein-losing enteropathy, or generalized lymphedema. These conditions can lead to respiratory failure, anasarca, immunosuppression, and increased mortality. Management has historically centered on medical therapies aimed at reducing lymph production, although new interventional and surgical strategies are emerging with the goal of definitive treatment.¹

The thoracic duct is the body’s largest lymphatic vessel and transports chyle from the lower extremities, retroperitoneum, and intestines. It originates from the cisterna chyli, anterior to the second lumbar vertebrae, and ascends through the mediastinum to terminate at the junction of the left subclavian and jugular veins. Along its course, it receives lymphatic drainage from tributaries draining the pulmonary parenchyma and parietal pleura.¹

Patients with thoracic duct obstruction and multisystemic lymphatic failure are often critically ill and do not respond to medical therapy. In this population, a surgically created thoracic duct-to-azygous vein lymphovenous anastomosis (TDA-LVA) may restore effective lymphatic drainage. Prior to surgery, patients undergo detailed lymphatic imaging to identify the distal patent thoracic duct location and a nearby vein, commonly the azygous vein, suitable for anastomosis. The procedure begins with percutaneous access of the thoracic duct by an interventional cardiologist, who places a catheter to aid surgical localization. A thoracotomy is then performed, and the thoracic duct and azygous vein are dissected. Under a high-powered operating microscope, the surgeon creates an end-to-side or end-to-end anastomosis between the thoracic duct and target vein. After confirming anastomotic patency, the chest is closed. Throughout both imaging and surgery, general anesthesia with neuromuscular blockade and controlled ventilation is required to prevent patient movement.²

In 2025, The Children’s Hospital of Philadelphia reported initial outcomes of TDA-LVA in eight neonates and infants with multisystem lymphatic failure. All patients were high-risk surgical candidates with significant anasarca and required mechanical ventilation, with a median preoperative peak airway pressure of 28 mmHg. The surgery had a median length of five hours, requiring lateral positioning, and lung compression for surgical visualization. Although intraoperative vitals and ventilatory parameters are not described, the authors report that all patients tolerated the intraoperative course well. Six of eight patients (75%) survived to hospital discharge, and all six remained alive at last follow-up, a median of 165 days after discharge.²

In this patient, percutaneous selective lymphatic duct embolization would not be effective because the thoracic duct is interrupted, resulting in numerous large lymphatic collaterals. This technique is best suited for patients with a patent thoracic duct, elevated central venous pressures, and a single dominant lymphatic collateral. Similarly, the surgical innominate vein turndown procedure would not be successful, as it does not address thoracic duct interruption. This procedure would be most effective in single ventricle patients with chronically elevated central venous pressures and multisystem lymphatic failure, where it diverts lymphatic return from the higher pressure systemic venous circulation to the lower pressure common atrium.¹

REFERENCES

1. Ramirez-Suarez KI, Tierradentro-Garcia LO, Biko DM, et al. Lymphatic anomalies in congenital heart disease. Pediatr Radiol. 2022 Sep;52(10):1862-76.

2. Smood B, Maeda K, Hwang R, et al. Thoracic Duct-to-Azygous vein lymphovenous anastomosis for lymphatic decompression: initial experience and early outcomes. Ann Thorac Surg Short Reports. 2025, Sept 13. In press.