[Atrial natriuretic peptide as an indicator of mild postoperative cardiac dysfunction after uncomplicated bypass surgery].

Plasma levels of ANP (pg/ml; radioimmunoassay) as a parameter for postischemic dysfunction and levels of Troponin T (TnT) (ng/ml; ELISA test) as a parameter for postischemic cellular damage were determined in 15 patients with coronary artery disease (CAD) (mean age: 58 +/- 6.1 years; 13 m, 2 w; with no history of myocardial infarction and no signs for congestive heart failure) prior to, during and after extracorporal circulation (ECC). Under standardized conditions during the ECC basic parameters concerning the cardial hemodynamic (heart rate (HR); systolic (RRsys, mmHg), diastolic pressure (RR dia, mmHg) central venous pressure (CVP, mmHg); left atrial pressure (LAP, mmHg); left ventricular enddiastolic pressure (LVEDP, mmHg)) and ECG monitoring blood samples were performed: 1) prior to operation (op); 2) prior to CPB; 3) 1 h CPB; 4) 5 min after CPB; 5) 1 h after CPB; 6) 6 h postoperative (postop); 7) 24 h postop; 8) 48 h postop; 9) 10 days postop. Also the left atrial diameter (LAD, mm) and the left ventricular enddiastolic diameter at Q (LVEDD, mm) pre- and postop were documented with m-mode echocardiography (Echo) and ejection fraction (EF, %) was calculated. The bypass operations were performed with intermittent aortic cross-clamping with open venae cavae (CVP: 0-5 mmHg) and moderate hypothermia. For the determination of ANP levels and TnT levels in arterial and venous blood, a double-antibody (AB) radioimmunoassay and an ELISA test were used. Concerning the patients with CAD there was a maximal increase of ANP from preoperative 90 +/- 10 (M +/- SEM) pg/ml (p < 0.05) up to intraoperative 380 +/- 38 pg/ml. Ten days postop, the ANP level was with 262 +/- 33 pg/ml still increased threefold in comparison to the preoperative level. TnT showed an increase from preoperative 0.02 +/- 0.01 ng/ml up to intraoperative 3.44 +/- 0.47 ng/ml. Ten days postop the TnT concentration was at the preoperative level with 0.13 +/- 0.11 ng/ml. Five minutes after bypass up to 48 h postop, ANP and TnT levels were correlated (p < 0.05, r = 3.4). There was an increase of the LAD from preoperative 42.2 +/- 1.1 mm up to 46.8 +/- 1.2 mm (p < 0.05) 10 days postop as determined by m-mode echo. LVEDD and EF changed from preoperative 51.1 +/- 0.9 mm and 73 +/- 2% to 54.5 +/- 1.2 mm and 65 +/- 4% 10 days postop. The significant increase of TnT (172-fold) indicates the cellular, myocardial injury, caused by the operation without signs in ECG recordings and no signs of congestive heart failure. The significantly increased ANP level up to the 10th day postop indicate sa very sensitive prolonged, postischemic dysfunction, which is not compensated 10 days postop.