Extracorporeal circulation influence on plasma atrial natriuretic peptide concentration in cardiac surgery patients.

An attempt was made to clarify the change of plasma human atrial natriuretic peptide (hANP) concentration before, during, and after cardiac surgery in heart failure with extracorporeal circulation. Plasma hANP concentration did not significantly decrease during total aortic cross clamping (ACC) with complete clamping of the superior and inferior vena cavae. This finding may be explained by the suppression of endopeptidase activities and the response of hANP receptors due to the low body temperature. Plasma hANP concentration strongly increased from 56.6 +/- 8.4 to 208.9 +/- 40.7 pg/ml (n = 5) by the release of total ACC. This strong increase of hANP in the plasma may occur due to the rapid increase of atrial pressure from zero to 12.5 mm Hg caused by releasing the total ACC. The molecular form of plasma hANP obtained after the release of total ACC was alpha-hANP alone, which was estimated by gel permeation chromatography and reverse HPLC.