Changes Of The Brain Natriuretic Peptide Levels During Perioperative Period In Patients With Cardiac Valve Replacement And Its Clinical Significance

Objective To investigate the changes of serum brain natriuretic peptide(BNP) levels during perioperative period in patients accepted cardiac valve replacement, and study its clinical significance.Methods Plasma BNP were determined with immunofluorescence diagnostics in 35 patients with rheumatic heart disease who accepted cardiac valve replacement. The plasma BNP concentrations were measured before cardiac surgery, 6h, 24h, 48 h, 72h and 7days after operation. The correlation between the BNP level and the grade of heart function according to the NYHA classification was analyzed. We also investigate the relationship between BNP and the left ventricular ejection fraction(LVEF) in these patients before cardiac surgery. The plasma BNP levels were observed in those patients who were afflicted by severe ventricular arrhythmias early after operation.Results BNP levels before cardiac surgery in NYHA class II, III and IV were (233.70±141.13)ng/L, (535.78±208.73)ng/L,(1078.50±353.4 )ng/L ,respectively (p<0.01).There was a positive correlation between BNP level and the grade of heart function(NYHA), but no correlation between BNP level and LVEF(r=0.22,p=0.204>0.05)。BNP levels increased 24h later and reached to a peak value 24-48h after operation, then the BNP level began to decrease, but 7 days later, the BNP level was still higher than that before operation(p=0.02>0.05).There was obvious difference between the patients who had severe ventricular arrhythmias and the control group at several time points: before operation, 24h and 7 days after operation, respectively (p<0.05).Conclusion The perioperative plasma BNP level can reflect the patients perioperative cardiac function who accepted cardiac valve replacement. The higher the BNP level , the poorer the cardiac function . The BNP level increased in the early time after operation , reached a peak value after 24-48h , then gradually decreased in the late phase after operation. BNP level had the clinical significance in evaluating the patient's cardiac condition before operation, It was useful for us to make decision if the patient was appropriate for cardiac surgery, and help us to prognosticate if severe ventricular arrhythmias happened by observing the change of BNP dynamically early after operation.