| Objective: B-type natriuretic peptide (BNP) is a polypeptide consistingof32amino acids, was first isolated from brain tissue by Sodoh, andsubsequently confirmed that abundantly existed in human cardiomyocytes.When heart failure， ventricular volume expansion and cardiac pressureoverload can lead to cardiomyocyte synthesize and secrete BNP. Itsphysiological function is to increase the excretion of sodium, reduce waterand sodium retention. However, in the failure state, plasma BNP degradequickly, and its physiological effects significantly weakened. The continuousintravenous supplement exogenous BNP can achieve the purpose ofimprovement of heart function, treatment of heart failure.The recombinant human brain natriuretic peptide (rhBNP) has become anew generation of therapeutic agents in the treatment of heart failure.Especially for acute heart failure, the effect is distinct and safe and feasible.The effect of treating chronic heart failure have research confirms its benefits.Multiple studies have shown that the drug can be through expansion of theperipheral vascular resistance, reduce water and sodium retention, thusreducing cardiac preload and cardiac afterload, integrated approach to improveheart function and significantly reduce the clinical symptoms and signs ofpatients with heart failure. So the short-term effect of rhBNP is significant.Plasma BNP levels and heart failure severity is positively correlated.Most studies have shown that plasma BNP levels were correlated with leftventricular pressure and NYHA classification. Therefore, plasma BNP levelscan be used as an index to assess the extent and prognosis of heart failure. Butthe relationship between BNP levels and short-term clinical efficacy of heartfailure remains unknown due to fewer studies at home and abroad. The aim of this research was to investigate the correlation between plasma BNP levelsand short-term clinical efficacy of rhBNP in heart failure patients, andevaluate predictive values of baseline plasma BNP levels for short-termclinical efficacy of rhBNP in heart failure patients，to guide reasonabletreatment and assess healing effect and prognosis of patients with heart failure.Methods: A total of46heart failure patients were selected betweenDecember2012and December2013, including24males and22females, witha mean age of60.26±18.62years. All selected subjects were diagnosed heartfailure (NYHA class Ⅲ to Ⅳ), or acute myocardial infarction (Killip Ⅲ).Appropriate conventional therapies for heart failure were given includingfurosemide and spironolactone diuretics, digitalis and non-digitalis positiveinotropic drugs, angiotensin-converting enzyme inhibitors, or vasodilators.Then patients with poor outcomes received rhBNP with an initial iv. bolus of1.5μg/kg follow by continuous iv. titration of0.0075μg/(kg·min) for3days inaddition to the original treatment.24hours fluid input and output wererecorded before and the first, second，third24hours after drug used. Thedegree of improvement in overall clinical condition was also recorded afterdrug used. Baseline plasma concentrations of BNP were measured beforerhBNP administration. Dopamine, diuretics or other drugs that might affectthe test results during the application of rhBNP were consistent with theprevious administration as far as possible, but for some patients with severeclinical symptoms diuretic dose could be adjusted as appropriate and detailedrecords. Software (SPSS13.0) was used for statistical analysis. Measurementdate showed a normal distribution was expressed as the mean±standarddeviation (SD), and the comparison among groups using analysis of variance.Measurement date showed a skewed distribution was expressed as the median(M) and interquartile range (QR), and comparison among groups usingnonparametric test (rank sum test). Enumeration data was expressed as rate(%), and using Chi-square test. Bivariate correlation analysis, repeatedmeasures analysis of variance and Chi-square test was used for statisticalanalysis. A P value of＜0.05was considered statistically significant. Results: Among46patients, male was24, and female was22, with amean age of60.26±18.62years. The baseline BNP concentrations rangedfrom380pg/ml to5000pg/ml, with a median of1225pg/ml (25th to75thpercentiles,658.5to2347.5pg/ml). Fluid output minus input were（-100.5±767.4）ml,（62.0±1044.3）ml,（230.9±963.0）ml,（156.1±925.9）ml of24hours before drug administration and the first, second，third24hoursafter drug used. It increased after drug administration. There was significantlydifferent among before and the second24hours after drug administration (P＜0.05).Taking quartile BNP levels as the cutoff grouping, the patients weredivided into～658pg/ml group (n=11),659~1225pg/ml group (n=12),1226~2347pg/ml group (n=12),2348～pg/ml group (n=11). The basiccharacteristics, related diseases and drug use of each group were notstatistically significant. The diuretic effect was not significant different amongthe groups.There was a significant inverse correlation between baseline BNP levelsand the diuretic effect of the first24hours (correlation coefficient: r=-0.412，P﹤0.05). A negative correlation trend was found between BNP value and thediuretic effect of the second24hours (correlation coefficient: r=-0.059, P=0.696). The diuretic effect of the third24hours and baseline plasma BNPvalues were negatively correlated (correlation coefficient: r=-0.292, P <0.05).With the increase of baseline plasma levels of BNP, the diuretic effect ofrhBNP appeared a significantly downward trend. And according to the plasmaBNP groups compare the diuretic effect of the first, second，third24hoursafter drug administration respectively show there was a significant differenceamong the different BNP groups in the first24hours (P＜0.05).The degree of improvement in overall clinical status of allpatients: improved significantly,10.9%; improved generally,63%; no change,21.7%; deterioration,4.3%. The degree of improvement in overall clinicalstatus was statistically significant among the BNP groups (P＜0.05). Theoverall clinical condition improved rate of lower BNP levels group is higher than the higher BNP levels group.Conclusion: The diuretic effect of rhBNP is negatively correlated withbaseline plasma BNP levels. The heart failure patients with higher BNP levelshave poor short-term clinical efficacy after rhBNP administration than thepatients with lower BNP levels. Baseline BNP levels can be used to predictthe short-term clinical efficacy of rhBNP in heart failure patients. |
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