Pleural Effusion After Endoscopic-Assisted, Minimally Invasive Off-Pump Bypass Grafting.

Postoperative pleural effusion (PE) is a common finding after endoscopic-assisted, minimally invasive coronary bypass surgery (Endo-CAB). This study evaluated its postoperative course, defined a threshold for clinically significant PE, and identified associated risk factors. Between May 2021 and January 2026, 727 patients were retrospectively analyzed. A total of 3141 postoperative chest X-rays obtained during hospitalization and follow-up were reviewed to quantify PE. Clinically significant PE was defined as ≥25% on radiographic assessment. Baseline characteristics and postoperative outcomes were analyzed, and logistic regression was used to identify independent risk factors. All patients received oral diuretics for two weeks after discharge as standard protocol. PE occurred in 86.1% of patients, typically developing within the first two postoperative days, with a median maximum of 13% [5-21%]. By the third postoperative week, PE had resolved to 0% [0-0%] in most cases. Adjustment of diuretic therapy was required in 18.3%, while 5.1% underwent thoracocentesis. Clinically significant PE occurred in 15.4% and was associated with longer hospital stay and increased blood transfusion rates. Independent risk factors included age, body mass index, continuation of dual antiplatelet therapy, and blood transfusion. Overall, PE is frequent but usually self-limiting after Endo-CAB.