Assessment of Postoperative Chylothorax Volume Threshold Associated with Failed Conservative Management

N. Lin¹, N. Kapula¹, B. Wallen², J. Kim³, P. Manapat³, D. Kamtam¹, B. Guenthart⁴, I. Elliott⁵, N. Lui⁶, L. Backhus⁷, J. Shrager¹, M. Berry⁶, D. Liou^1
1Stanford University School of Medicine, Stanford, California ²Stanford Medical School, Stanford, California ³Stanford University School of Medicine, Palo Alto, California ⁴Stanford Health Care, San Jose, California ⁵Stanford, Stanford, California ⁶Stanford University, Stanford, California ⁷Stanford University, Dept. of Cardiothoracic Surgery, Stanford, California

Purpose: Management of postoperative chylothorax typically involves a stepwise strategy of initial conservative management followed by lymphangiography and re-operation when conservative management fails. This study tested the hypothesis that high-volume chylothorax drainage over the first 48 hours is associated with failure of conservative management.

Methods: Our institutional database was queried for patients who developed postoperative chylothorax following lung, foregut, or mediastinal surgery and underwent initial conservative management between 2009 to present. Postoperative chylothorax was confirmed by pleural triglyceride level >=110 mg/dL. Patients were stratified according to whether the chylothorax resolved with conservative management versus intervention with lymphangiography and/or re-operation. Daily thoracostomy tube drainage was evaluated, and a 48-hour chylothorax volume cut-off point associated with failure of conservative management was calculated by using the Youden’s index from the receiver operating characteristic (ROC) curve. Predictors of failed conservative management was estimated using multivariable logistic regression.

Results: Seventy-seven patients experienced postoperative chylothorax during the study period, including 43 (56%) after lung resection, 22 (29%) after esophagectomy or benign foregut surgery, and 12 (16%) after mediastinal surgery. Forty-eight (62%) patients were successfully managed conservatively while 29 (38%) patients required intervention with lymphangiography or re-operation. Patients requiring intervention had a higher proportion of esophageal surgery (41% vs. 21%, p=0.05) and open surgery for the index operation (41% vs. 19%, p=0.031) compared to the conservative management group. Daily chylothorax drainage was significantly lower in patients who required only conservative management compared to those who required intervention (Figure). The area under the ROC curve (AUC) was 0.75 (0.64, 0.86), and the 48-hour chylothorax volume cut-off point was 1,110 mL based on the Youden’s index. In multivariable logistic regression analysis, chylothorax drainage >1,100 mL over the first 48 hours was associated with nearly 4-fold increased risk of failed conservative management (AOR 3.84, p=0.023) (Table). Patients who required intervention had longer median hospital stay (16 vs. 7 days, p< 0.001) and lower incidence of discharge to home (76% vs. 94%, p=0.026).

Conclusion: Patients who develop postoperative chylothorax with drainage >1,100 mL over the first 48 hours should be considered for early intervention with lymphangiography or re-operation given the likelihood of failing conservative management.

Identify the source of the funding for this research project: n/a