Vascular stent placement for palliation of mass-associated chylothorax in two dogs

CASE DESCRIPTION 2 dogs with chylothorax were identified to have cardiac mass lesions obstructing the return of venous blood from the cranial vena cava. Chylous effusion was presumed to have been a result of an increase in cranial vena cava pressure affecting flow of chyle through the thoracic duct. CLINICAL FINDINGS Both dogs had tachypnea and pleural effusion requiring therapeutic thoracocentesis. Fluid analysis confirmed chylothorax. A heart-base mass was identified via echocardiography in each dog, and CT-angiographic findings confirmed obstruction to venous return in the cranial vena cava in both dogs and compression of the pulmonary artery in 1 dog. TREATMENT AND OUTCOME Each dog was anesthetized, and self-expanding endovascular stents were placed with fluoroscopic guidance. In both dogs, the site of stent placement was the cranial vena cava, and in 1 dog, an additional stent was positioned in the pulmonary artery. Chylous effusion resolved successfully in both dogs after surgery, with postoperative survival times exceeding 6 months. Complications included periprocedural arrhythmias in both dogs and eventual obstruction of the stent with tumor extension and fluid reaccumulation in 1 dog. CLINICAL RELEVANCE Endovascular stent placement may provide a useful palliative treatment for chylothorax secondary to vascular compression by a heart-base mass in dogs.