Atrial natriuretic peptide plasma levels during cardiac surgery.

In this investigation, the hypothesis was tested that patients with valvular heart disease have higher atrial natriuretic peptide (ANP) plasma levels than patients with coronary artery disease during cardiac surgery. Six patients scheduled for valve replacement (group V) and seven scheduled for coronary artery bypass grafting (CABG) (group C) were studied. ANP plasma levels and hemodynamic measurements were obtained at several times during surgery. ANP levels were elevated in both groups compared to those measured in healthy volunteers; and ANP levels in valvular patients were found to be higher than in the CABG patients. In addition, isotonic fluid loading, rewarming during cardiopulmonary bypass, and weaning from cardiopulmonary bypass increased ANP from baseline in group C. Mean arterial pressure and ANP levels correlated in group C. Ejection fraction, pulmonary artery diastolic pressure, and right atrial pressure did not correlate with ANP levels in either group. In conclusion, patients with valvular heart disease have higher ANP levels during surgery compared to patients with coronary artery disease. This difference probably relates to different pressure and volume loads on atrial tissue.