MARKED ELEVATION OF BRAIN NATRIURETIC PEPTIDE LEVELS IN PERICARDIAL FLUID IS CLOSELY ASSOCIATED WITH LEFT-VENTRICULAR DYSFUNCTION

Objectives. The purpose of this study was to investigate whether atria l and brain natriuretic peptides (ANP and BNP, respectively) represent autocrine/paracrine factors and are accumulated in pericardial fluid. Background. ANP and BNP, systemic hormones produced by the heart, hav e elevated circulating levels in patients with heart failure. Recent e vidence suggests that the heart itself is one of the target organs for these peptides. Methods. With an immunoreactive radiometric assay, we measured the concentrations of these peptides in plasma and pericardi al fluid simultaneously in 28 patients during coronary artery bypass g raft surgery. Results. The pericardial levels of BNP were markedly ele vated in patients with impaired left ventricular function. We investig ated the correlation of ANP and BNP levels in plasma or pericardial fl uid with left ventricular hemodynamic variables. None of the hemodynam ic variables correlated with ANP levels in plasma or pericardial fluid . Both plasma and pericardial fluid levels of BNP were significantly r elated to left ventricular end-diastolic and systolic volume indexes ( LVEDVI and LVESVI, respectively). In addition, BNP pericardial fluid l evels had closer relations with LVEDVI (r = 0.679, p < 0.0001) and LVE SVI (r = 0.686, p < 0.0001) than did BNP plasma levels (LVEDVI: r 0.56 7, p = 0.0017; LVESVI: r = 0.607, p = 0.0010). BNP levels in pericardi al fluid but not in plasma correlated with left ventricular end-diasto lic pressure (r = 0.495, p = 0.0074). Conclusions. BNP levels in peric ardial fluid served as more sensitive and accurate indicators of left ventricular dysfunction than did BNP levels in plasma. Thus, BNP may b e secreted from the heart into the pericardial space in response to le ft ventricular dysfunction, and it may be a pathophysiologic role in h eart failure as an autocrine/paracrine factor. (C) 1998 by the America n College of Cardiology.