Adiponectin Paradox in Coronary Artery Bypass Graft Patients: A Comparative Analysis of Pericardial Fluid and Plasma Levels.

Background Adiponectin is an anti-inflammatory and cardioprotective adipokine involved in the regulation of glucose and lipid metabolism. Although it has been extensively studied in blood, data on its concentrations in pericardial fluid remain scarce. Objectives This study aimed to assess adiponectin levels in plasma and pericardial fluid of patients undergoing coronary artery bypass grafting (CABG) and to evaluate their clinical significance in comparison with healthy individuals. Methodology Pericardial fluid and plasma samples were obtained from 50 patients who underwent CABG, while plasma samples were collected from 50 healthy controls. Adiponectin levels were measured using the enzyme-linked immunosorbent assay (ELISA) method. Results In the patient group, the plasma adiponectin level was 7.68±1.76 ng/mL (median: 7.70), while the pericardial fluid level was 8.70±3.16 ng/mL (median: 8.56). The plasma level in the healthy control group was 5.25±0.77 ng/mL (median: 5.20), significantly lower than that in the patient group (p<0.001). No significant difference was observed between patient plasma and pericardial fluid levels (p=0.070). The receiver operating characteristic (ROC) analysis revealed a high discriminative power of plasma adiponectin levels in distinguishing patients from controls, with an area under the curve (AUC) value of 0.901. Conclusion Elevated adiponectin levels in both plasma and pericardial fluid of CABG patients suggest regulation by systemic and local mechanisms, possibly via epicardial adipose tissue. This pattern aligns with the "adiponectin paradox," where increased levels may reflect a compensatory response or cardiac stress in advanced disease. Pericardial fluid assessment provides novel insights into the cardiac microenvironment with potential diagnostic and prognostic value.