Chylothorax Following Coronary Artery Bypass Graft - The Masked Effusion

Introduction. Chylothorax is a rare but serious complication following coronary artery bypass grafting (CABG). It is associated with malnutrition, immunosuppression, and prolonged hospitalization. Management strategies remain non-standardized due to the low incidence of this complication. Aim. To describe two low-output chylothoraces post-OPCAB with divergent timings, exploring LIMA-linked pathophysiology and conservative efficacy in resource-limited South India. Case description. We describe two patients who developed low-output chylothorax after off-pump CABG with left internal mammary artery grafting. One presented three months postoperatively with cough, orthopnea, and left pleural effusion, while the other presented on postoperative day three with dyspnea and a large left chylous effusion. In both cases, pleural fluid fulfilled biochemical criteria for chylothorax, and patients were managed conservatively with intercostal drainage and a low-fat, medium-chain fatty acid diet, resulting in progressive reduction of drain output and complete resolution. Discussion. These cases illustrate that chylothorax after CABG can present from days to months after surgery and may occur despite different LIMA harvesting techniques, possibly involving injury to mediastinal or thymic lymphatics or variant thoracic duct anatomy. Conclusion. Chylothorax following CABG should be recognized across a wide postoperative window. Conservative management with drainage and dietary modification is an effective first-line approach for low-output cases, particularly in resource-limited settings.