Influence of cardiopulmonary bypass (CPB) on the natriuretic peptides ANP and BNP. A comparison between long and short duration of CPB and off pump surgery

Abstract

Plasma atrial and brain natriuretic peptide (ANP and BNP) are cardiac hormones secreted mainly due to cardiac overload. The study was designed to assess plasma concentrations of ANP and BNP in patients undergoing coronary bypass grafting (CABG) with long and short duration of cardiopulmonary bypass (CPB) and without CPB (off-pump surgery). We studied 45 patients scheduled for elective CABG. Patients were allocated in three groups: group A received CPB with a duration less than 60 minutes, group B more than 60 minutes and patients without CPB were allocated in group C. ANP and BNP were measured after induction of anaesthesia (T0), at the end of surgery (T1), 4 hrs. (T2), 24 hrs. (T3) and 120 hrs. postoperatively (T4). In all groups, ANP-levels increased from T0 to T4 (group A: from 3.7 +/- 2.1 to 8.9 +/- 8.0; group B: from 3.3 +/- 1.7 to 8.0 +/- 6.0; group C: from 3.0 +/- 1.6 to 5.3 +/- 2.3 pg/ml), but there were no significant differences between the groups. BNP-concentrations increased also from T0 to T4 (group A: from 34 +/- 18 to 234 +/- 164; group B: from 33 +/- 26 to 219 +/- 182; group C: from 33 +/- 24 to 77 +/- 55 pg/ml). Furthermore we measured significant higher BNP-levels in group B compared to group C at T3 and T4. No significant differences between group A and B were found. CPB influenced BNP, but not ANP plasma concentrations. An influence of the duration of CPB on ANP and BNP was not seen.