Postoperative constrictive pericarditis caused rupture of lymphatic collaterals: a rare etiology of chylothorax.

Background: Chylothorax after cardiovascular surgery is primarily caused by direct injury to the thoracic duct or its branches, and occurs in early postoperative period. In the present case, we describe a rare case of chylothorax manifesting three months after surgery secondary to constrictive pericarditis.

Case Presentation: A 71-year-old man underwent mitral valve replacement, tricuspid valve annuloplasty, and the maze procedure. He developed acute perioperative myocardial infarction on postoperative day one due to plaque rupture in the left anterior descending artery and underwent percutaneous coronary intervention. Although the patient was discharged on postoperative day 36, he required readmission on postoperative day 83 because of right side chylothorax associated with constrictive pericarditis. Lymphangiography revealed thoracic duct interruption and development of lymphatic collateral vessels via the right hilum. Single-photon emission computed tomography revealed abnormal tracer accumulation in the right hilum, suggesting a lymphatic leakage site. A catheter study indicated biventricular dip and plateau patterns with a reduced cardiac index (1.6 L/min/m) and elevated central venous pressure (18 mmHg). Conservative treatment for chylothorax, including a low-fat diet and continuous drainage with chest tube, was unsuccessful. Drainage of chyle at approximately 500 mL/day continued. On hospitalization day 50, complete pericardiectomy via median sternotomy was performed because the patient's cardiac function deteriorated. The central venous pressure dramatically decreased, and the chylothorax gradually subsided. There was no recurrence of symptoms 1 year postoperatively.

Conclusions: Chylothorax associated with constrictive pericarditis subsequent to cardiac surgery is extremely rare. Although conservative management failed, the present case was successfully treated via pericardiectomy alone and did not require any additional precedures, such as thoracic duct ligation via a right thoracotomy.