Background: Adrenomedullin (AM) is a potent vasodilator peptide. Plasma AM levels are increased in heart diseases and in sepsis. Heart surgery under cardiopulmonary bypass (CPB) induces a systemic inflammatory response.
Methods: We measured plasma AM, cAMP (the second messenger of AM), C-reactive protein (CRP) and haemodynamic parameters in 29 patients undergoing elective open heart surgery, before, during and after anaesthesia and CPB as well as on the first morning after surgery.
Results: Basal AM levels were higher than normal and correlated with systolic pulmonary pressure and pulmonary capillary pressure, but not with other haemodynamic parameters. AM increased during CPB and remained elevated 24 h after the start of surgery. Plasma cAMP increased only at the end of CPB. CRP was increased only in the last sample. At the end of CPB and at the end of surgery AM levels were higher in patients with basal ejection fraction<40% compared with those with ejection fraction >60% [456+/-386 vs 252+/-343 (P<0.03) and 832+/-781 vs 391+/-356 pg/ml (P<0.05), respectively].
Conclusion: We conclude that AM, as inflammation-related cytokines, increases during and after CPB, that cAMP response is unrelated to AM and that AM response is higher in those patients with worse basal ejection fraction.