Changes Of Nt-probnp In Patients Suffering Eplacement Of Mitral Valve In Beating Hearts With Mild Hypothermic And Its Significance

objective:To study the changes of N-terminal pro-brain natriuretic peptide (NT-proBNP)levels in patients suffering replacement of mitral valve in beating heans with mild hypothermic, Explore the clinical significance of NT-proBNP during perioperative period in patients after Cardiopulmonary bypass, research the myocardial protective effect of mitral valVe replacement in beating hearts with mild hypothermic.Methods:Forty patiems with rheumatic heart disease undergoing mitral valve replacement were randomly diVided into2groups:experimental group(beating heart with mild hypothermic group,n=20)and control group(arrested heart with median hypothermic group,n=20).All of the patients graded heart function according to the cardiac function standard of New York Heart Association, measured left yentricular ejection fraction (LVEF) and lefc ventricular end-diastolic diameter(LVEDD)by Doppler echocardiography before the operatiOn.The serum level of NT-proBNP were measured by ELISA before CPB, at the end of CPB,6h after CPB,24h aRer CPB,48h after CPB,72h after CPB. To monitor the injection rate of dopamine hydrochloride. the assisted breathing time and the length of time the ICU after surgery.Results:1.There was a positive correlation between preoperative NT-proBNP level and New York heart association heart function classification (r=0.809＞P＜0.05), but no correlation between preoperative NT-proBNP level and left ventricular ejection fraction, left ventricular end-diastolic diameter (r=-0.053,0.193, P＞0.05)2. Two groups of NT-proBNP levels no obvious rise at the end of CPB (P＞0.05), obvious rise in6h after surgery,24h after surgery and reached to a peak. In48h after surgery,72h after surgery, NT-proBNP level was significantly higher than its original level before surgery (P＜0.05). The serum level of NT-proBNP at6h after surgery,24h after surgery,48h after surgery,72h after surgery in the experimental group was lower than in the control group(P＜0.05).3. The level of NT-proBNP at24h after surgery correlated significantly with the injection rate of dopamine hydrochloride(r=0.660, p=0.000, p＜0.05), however, it did not correlate with the assisted breathing time and the length of time the ICU (r=-0.053,0.193, P＞0.05).The injection rate of dopamine hydrochloride after surgery in the experimental group was lower than in the control group(P＜0.05). But, the assisted breathing time and the length of time the ICU after surgery was not statistically significant between two groups (P>0.05).Conclusion:1.The concentration of NT-proBNP before surgery correlated significantly with New York heart association heart function classification. The concentration of NT-proBNP can objective reflects the state of patients’cardiac functions. Detect the NT-proBNP level can reflect the changes of patients’ cardiac function in the perioperative period.2. The plasma NT-proBNP concentration Increased after cardiopulmonary bypass. The patients’cardiac functions in postoperative decreased than preoperative level after cardiopulmonary bypass blow. The Postoperative NT-proBNP levels of patients suffering replacement of mitral valve in beating hearts with mild hypothermic lower than which suffering replacement of mitral valve in arrested heart with median hypothermic, and its injection rate of dopamine hydrochloride after surgery was lower. Its cardiac function Impaired lighter, the mitral valve replacement in beating hearts with mild hypothermic has a better myocardial protective effect.