Prospective comparison of cisterna chyli ablation to pericardectomy for treatment of spontaneously occurring idiopathic chylothorax in the dog.

OBJECTIVE: Prospective comparison of cisterna chyli ablation (CCA) or pericardectomy (PC) for chylothorax.

STUDY DESIGN: Randomized prospective study. SUBJECT POPULATION: Dogs with idiopathic chylothorax (n= 23).

METHODS: Dogs were treated by thoracic duct ligation (TDL) with either CCA (n = 12) or PC (n = 11). Long-term outcomes, intraoperative central venous pressures (CVPs) and pericardial histology were assessed. Dogs with persistent chylothorax were offered retreatment by the alternative procedure.

RESULTS: Ten (83%) dogs treated by CCA-TDL and 6 (60%) treated by PC-TDL resolved their chylothorax. Retreatment in 4 dogs resulted in resolution in 2 dogs and 2 perioperative deaths. Four dogs developed nonchylous effusions; 2 of which resolved after initiating steroid therapy, 1 of which was unsuccessfully treated by PC, and 1 continues to be managed by thoracocentesis 6.5 years later. CVPs were normal in most dogs and unaffected by PC. On histology, pericardial tissues had extensive external surface fibrosis with mild inflammation. On follow-up (≤ 6.5 years), no recurrence of pleural effusions occurred after initial resolution.

CONCLUSIONS: CCA-TDL appears to offer improved outcomes over historical results with TDL. Results with PC-TDL were more variable for unknown reasons. Venous pressure measurements did not support the hypothesis that venous hypertension was involved in chylothorax or response to therapy in these dogs.