Abstract: Objective To investigate the efficacy of B-type natriuretic peptide (BNP) in patients with severe heart failure. Methods Forty-four patients with severe congestive heart failure of New York Heart Association cardiac function class IV were treated with recombinant human B-type natriuretic peptide (rh-BNP) on the basis of basic anti-heart failure therapy, and the changes of heart rate, blood pressure, in/out volume, central venous pressure, renal function, plasma BNP level, left ventricular end-diastolic diameter (LVEDD) and left ventricular ejection fraction (LVEF) were observed. The efficacy of BNP was observed. Results Forty of the 44 patients showed significant improvement in heart failure symptoms, with an overall efficiency of 90.9%. After treatment, urine output increased significantly, heart rate, central venous pressure and plasma BNP levels decreased significantly compared with those before treatment, left ventricular end-diastolic diameter decreased, and left ventricular ejection fraction increased compared with those before treatment. Conclusion The measurement of plasma BNP level can reflect the degree of heart failure of patients, and the application of exogenous recombinant BNP can significantly improve the symptoms of heart failure of patients. It is safe and reliable in the treatment of severe heart failure. Zhai Hongxia, Department of Geriatrics, The First Affiliated Hospital of the General Hospital of the Chinese People’s Liberation Army Keywords: heart failure, recombinant B-type natriuretic peptide Chronic cardiac insufficiency is a clinical critical condition and is the regression of most heart diseases. Patients with EF <25% have a 1-year mortality rate of 50% and a 5-year mortality rate of 76.8%, while patients with EF 25-39% have a 1-year mortality rate of 32.3% and a 5-year mortality rate of 73.1% [1]. BNP is a recently discovered physiologically active substance with pro-sodium, diuretic and vasodilator effects secreted mainly by ventricular myocytes, and studies have shown that it has a significant correlation with the severity of heart failure [2]. Currently, it is mostly used in the diagnosis of clinical heart failure. In this study, BNP was applied to the treatment of severe heart failure and acute exacerbation of chronic heart failure to observe the efficacy and provide experience for the treatment of heart failure patients. 1, Data and methods 1.1 General data 44 patients with severe heart failure hospitalized in our hospital from July 2006 to October 2008, with EF values of 25-35(28±3.5)% and plasma pro-BNP levels of 319~35000(6453±2346)ng/ml as determined by echocardiography. 25 cases were male and 19 cases were female, aged 26~91(72±11.6)ng/ml. 91(72±11.6) years old. Cardiac function was graded as Class IV according to the American New York Society of Cardiology. Including coronary artery disease, old myocardial infarction, ischemic cardiomyopathy in 37 cases and dilated cardiomyopathy in 7 cases. 1.2.1 Treatment of patients with heart failure All 44 patients with cardiac insufficiency were treated out-of-hospital with standard anti-heart failure therapy, including ACEI or ARB analogues, β-blockers, diuretics, aldosterone antagonists, and other oral drugs. After admission to the hospital, nitroglycerin, uradil or sodium nitroprusside were given on top of this, and some of the critically ill patients still could not effectively relieve heart failure, and were treated with small doses of dobutamine. Still cannot completely relieve heart failure and cannot lie down at night. Blood pressure can be maintained above the level of 90/60mmHg, that is, to start to give the application of new livein (lyophilized recombinant human B-type natriuretic peptide produced by Chengdu Nordicom Biopharmaceutical Co., Ltd.) treatment, after starting to give 1.5ug/kg loading dose of intravenous shock, at 0.0075ug/kg/min continuous intravenous pumping, a total of 7 days of application. 1.2.2 Observation indexes and methods The changes of cardiac function classification, heart rate, blood pressure, in/out volume, central venous pressure, plasma BNP level, plasma creatinine level, endogenous creatinine clearance level, left ventricular end-diastolic diameter and left ventricular EF value were observed before BNP application, on day 3 and day 8 of drug administration, respectively. Determination of plasma BNP: Venous blood was taken with heparin anticoagulation tubes on an empty stomach, and BNP levels in whole blood specimens were determined by applying the chemiluminescence method using the Elecsys 2010 instrument manufactured by Roche. 1.3 Statistical analysis Statistical analysis was performed using SPSS 11.5 software, and the notational data were expressed as mean ± standard deviation. Paired t-test was used before and after treatment, and P<0.05 was statistically significant. 2, Results Among 44 patients, 37 patients had a significant increase in urine output on the first day of medication, and clinical symptoms improved significantly. 3 patients had improved symptoms from the second day of medication and could sleep flat at night. Cardiac function improved by 1-2 grades. 4 patients were ineffective, and the total effective rate was 90.9%. Patients' heart rate decreased significantly after BNP application, and there was no significant change in blood pressure. On day 3, the outgoing volume was significantly greater than the incoming volume in negative balance, and the central venous pressure also decreased significantly. Plasma BNP levels increased on day 3 and decreased significantly 1 day after discontinuation. Plasma creatinine level and creatinine clearance did not change significantly. The left ventricular end-diastolic diameter decreased, but did not reach statistical significance, and the left ventricular EF was significantly increased. Detailed results are shown in the following table. Comparison of indicators before and after heart failure treatment Before medication 3 days after medication 8 days after medication Heart rate (beats/min) 102±12 86±9* 65±6# Blood pressure (mmHg) 120±23/75±18 118±22/73±19 121±25/72±20 Outflow (ml/24h) 350±54 -620±80# -420±46 # Central venous pressure (cmH20) 18±3 16±3 12±2 # Plasma BNP (ng/ml) 6453±2346 8251±3249 2356±2197 # Plasma creatinine (umol/L) 98±24 96±27 91±28 Creatinine clearance (ml/min) 60±13 61±14 60±12 Left ventricular end-diastolic diameter (mm) 67±11 66±12 62±10 Left ventricular EF (%) 28±4 30±5 33±3* Compared with pre-dose,* P<0.05, #P<0.01 3 , Discussion BNP is a peptide compound with 32 amino acids, secreted mainly by the ventricles, and its release is directly related to ventricular pressure overload or volume expansion. It is a more sensitive and specific indicator of ventricular malfunction in heart failure, therefore, it is mostly used in the diagnosis of heart failure and the judgment of the efficacy after treatment [3-6], BNP can also predict the prognosis of patients, the higher the plasma BNP level, the worse the prognosis [7]. angiotensin-aldosterone system. It can be used in the treatment of heart failure. In this study, based on the above results, patients with clinically severe, refractory systolic insufficiency who could not effectively relieve heart failure despite the application of conventional, basic anti-heart failure drug therapy were given BNP continuous intravenous pumping to observe the therapeutic effect, and the results showed that most patients could see a significant diuretic effect on the first day of drug administration, with a significant increase in urine volume resulting in a negative balance of in and out volume and a significant The results showed that most of the patients saw a significant diuretic effect on the first day of treatment. The heart rate of the patients gradually decreased after the drug, and the heart rate basically returned to the basal level on day 8. Blood pressure did not change much after the drug was administered, and some patients with low blood pressure did not decrease further after the drug was administered, and blood pressure levels increased as cardiac function improved. Central venous pressure levels gradually decreased with prolonged dosing, which was considered to be related to the reduction of cardiac load. Studies have shown that plasma BNP levels decrease after heart failure treatment, but do not return to normal levels [5-6]. In this study, plasma BNP levels were measured to be higher on day 3 of drug administration compared to before treatment, considering that current assays cannot completely distinguish between endogenous BNP and exogenous BNP. after 1 day of drug discontinuation, exogenous BNP had completely disappeared, so plasma BNP levels showed a significant decrease. BNP is metabolized in the kidneys, and in patients with renal insufficiency, plasma BNP levels are higher. After the application of BNP treatment, patients showed a trend of decreasing plasma creatinine levels, but it did not reach statistical significance because of the small number of cases. However, patients did not show an increase in endogenous creatinine clearance after treatment, indicating that BNP did not have a significant effect on patients' renal function. BNP has the ability to dilate blood vessels, inhibit vascular smooth muscle growth, promote water and sodium excretion, antagonize the renin-angiotensin-aldosterone system, reduce the excitability of the sympathetic nervous system, inhibit the release of endothelin and pituitary pressor, and inhibit ventricular remodeling. In this study, a decrease in the left ventricular end-diastolic diameter and an increase in left ventricular EF were observed in patients after drug administration. Because of the short duration of the patient's dosing, the patient's left ventricular reduction and improvement in cardiac function were considered to be mainly due to its powerful function of promoting water and sodium excretion. Because exogenous BNP has a short half-life, requires continuous intravenous administration, and no oral drug therapy is available, studies on the effects of its long-term application on the improvement of cardiac function and the prognosis of heart failure cannot be performed at this time.