Increased pericardial fluid concentrations of the mature form of adrenomedullin in patients with cardiac remodelling

Background: There is evidence that adrenomedullin has autocrine or paracrine activities that oppose cardiac remodelling. However, it remains unclear whether it exerts those local functions in heart failure patients. Objective: To investigate the relation between plasma and pericardial fluid concentrations of adrenomedullin and left ventricular haemodynamic variables. Design: Samples of plasma and pericardial fluid were obtained from 50 patients undergoing cardiac surgery. They were classified into two groups: group N (n = 27) with a left ventricular end diastolic volume index (LVEDVI) less than or equal to 90 ml/m(2); and group R (n = 23) with LVEDVI > 90 ml/m(2). Plasma and pericordial fluid concentrations of total adrenomedullin (tAM) and mature adrenomedullin (mAM) were measured and related to the preoperative haemodynamic variables. Results: Pericardial fluid concentrations of mAM were much higher than the plasma concentration in both group N and group R (mean (SEM), 10.6 (1.7) v 3.3 (0.2) fmol/ml, p = 0.0001; and 21.2 (2.8) v 3.9 (0.3) fmol/ml, p < 0.0001, respectively). The ratio mAM/tAM in pericardial fluid was significantly higher than in plasma (0.56 (0.02) v 0.28 (0.02), p < 0.0001). Pericardial fluid concentrations of mAM, but not plasma concentrations, were significantly correlated with LVEDVI, left ventricular end systolic volume index, left ventricular ejection fraction, and left ventricular mass index (r = 0.60, 0.63, -0.54, and 0.47, respectively). Conclusions: Raised pericardial fluid concentrations of mAM may reflect the actions of adrenomedullin as a local mediator against cardiac remodelling in patients with left ventricular dysfunction.