Purpose: Pericardial fluid (PF) contains biologically active substances, such as the L-arginine and its methylated derivative asymmetric dimethylarginine (ADMA). L-arginine is the substrate of nitric oxide synthase (NOS) producing NO, which has been implicated in cardiac remodeling, whereas ADMA interferes with NO bioavailability. Thus we hypothesized that L-arginine and ADMA present in PF of patients undergoing coronary artery bypass graft (CABG) or valve replacement (VR) surgery, and their levels correlate with the morphology of the heart.
Methods L-arginine and ADMA concentrations were determined in plasma and PF of patients undergoing CABG (n=26) or VR (n=23) surgery. Morphological parameters of the chambers of the heart were examined by 2-D echocardiography.
Results: In both groups, the levels of both plasma and PF L-arginine were higher than that of ADMA (CABG, plasma: 74.7±4.6 μmol/L vs. 0.7±0.1 μmol/L, PF: 76.1±4.7 μmol/L vs. 0.7±0.0 μmol/L; VR, plasma: 58.4±5.4 μmol/L vs. 0.8±0.0 μmol/L, PF: 75.1±5.3 μmol/L vs. 0.9±0.0 μmol/L; p<0.05). The PF ADMA was higher in the VR than CABG group (0.9±0.0 μmol/L vs. 0.7±0.0 μmol/L; p<0.05). The thickness of interventricular septum (IVS) and the posterior wall (PW), as well as the right ventricular (RV) and right atrial (RA) and the left atrial (LA) areas were higher in VR compared to CABG group. In addition, the left ventricular mass (LVM) was higher in the VR compared to the CABG group. In the VR group, we found a positive correlation between the level of PF ADMA and the left ventricular end-systolic diameter (Ds), the left ventricular end-diastolic diameter (Dd), the RV, and the LVM.
Conclusions: The elevated concentration of ADMA in the pericardial fluid indicates a reduced level of NO, which may be responsible for the development of cardiac hypertrophy, especially in patients with valve replacement. Thus ADMA could be an additional biomarker of cardiac hypertrophy.