Serum Levels of Adipocyte Fatty Acid-Binding Protein Are Independently Associated With Left Ventricular Mass and Myocardial Performance Index in Obstructive Sleep Apnea Syndrome

Objective: To investigate the cross-sectional association between serum adipocyte fatty acid-binding protein (A-FABP) level and diagnosis or severity of obstructive sleep apnea syndrome (OSAS) and some echocardiographic indices related with cardiac dysfunction. Methods: In this study, plasma A-FABP and high-sensitivity C-reactive protein concentrations were measured, and echocardiography was performed in subjects without any cardiac or pulmonary disease who were referred for evaluation of OSAS. According to the apnea-hypopnea index (AHI), subjects were classified into 3 groups: control group (AHI <5; n = 33), mild to moderate OSAS (30 > AHI >= 5; n = 30), and severe OSAS (AHI >= 30; n = 31). Results: Levels of A-FABP were significantly different between the groups (P < 0.001). After post hoc analyses, all 3 groups were also significantly different from each other. The levels of A-FABP were significantly higher in the patients with severe OSAS (36.4 +/- 13.0 ng/mL) than in the control subjects (9.3 +/- 4.6 ng/mL; P < 0.0001) or in patients with mild-moderate OSAS (24.5 +/- 10.5 ng/mL; P < 0.001). Patients with myocardial performance index (MPI) greater than 0.47 had higher serum A-FABP levels than those with MPI of less than 0.47 (31.8 +/- 13.2 ng/mL vs 10.9 +/- 6.3 ng/mL; P = 0.001). Multivariable regression analyses revealed that increased serum A-FABP concentrations were independently associated with increased left ventricular mass index (beta = 0.195; P = 0.033) and increased MPI (beta = 0.165; P = 0.015). Conclusions: Increased A-FABP levels were found in the patients with OSAS, which were correlated significantly with left ventricular mass index and MPI. Further prospective studies are needed to clarify whether increased serum A-FABP level is a marker or a potential mechanism for left ventricular involvement in patients with OSAS.