Plasma adrenomedullin in cardiac surgery with extracorporeal circulation

The influence of cardiac surgery with extracorporeal circulation (ECC) on secretion of adrenomedullin (AM) was investigated in association with hemodynamic parameters. Plasma samples for measurement of AM and hemodynamic parameters were collected in nine patients undergoing cardiac surgery; coronary artery bypass graft (CABG) in seven, CABG; and aortic valve replacement (AVR) in one, and AVR and mitral valve replacement (MVR) in one. Plasma AM was measured by immunoradiometric assay. Plasma AM was significantly altered following discontinuation of ECC. The plasma AM concentration was not affected by surgical procedures such as lung lobectomy, gastrectomy, and laparoscopic cholecystectomy. Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), in vitro stimulators of AM production, were not detected throughout this study. The ratio of decrease in systemic vascular resistance index (SVRI) 10min after weaning from ECC to that at preoperation was significantly correlated with the ratio of increase in the value of plasma AM 60min after weaning from ECC to that at preoperation. We conclude that in cardiac surgery with ECC, the secretion of endogenous AM can be attributed to hemodynamic changes induced by ECC.