Clinical Research Of Relationship Between Level Of B-type Natriuretic Peptide And Prognosis Of Acute Coronary Syndrome

鈽匒cute coronary syndrome (ACS) is a series of cardiovascular emergencies based on the pathological findings ranging from the rupture of atheromatous plaques to acute thrombosis in coronary arteries, which poses great threats on the health of human being. It is urgent to develop a detection method with higher sensitivity and specificity to assess the severity and short-term prognosis of ACS in clinical practice. B-type natriuretic peptide/brain natriuretic peptide (BNP) was approved as a serum marker for diagnosis of heart failure by FDA in 2000．In recent years, many studies have aimed at identifying BNP as an independent predictor of short-term/medium-term risk stratification and cardiovascular events in ACS and some have achieved fruitful results. Foreign researches suggested that plasma BNP levels increased in patients with various types of ACS. However, the differences in prognosis among different patients and the associations between BNP and myocardium enzymes, LVEF, CRP are not fully elucidated. The objective of this study was to investigate the role of BNP in assessing the short-term prognosis of ACS and its associations with above-mentioned factors, thus providing theoretical evidences for clinical practice. 鈽?銆? Subjects鈽?1) Patients: Forty-one inpatients diagnosed as having acute coronary syndrome in Department of Cardiovascular Diseases of PLA No. 463 Hospital from March 2006 to January 2007．According to the diagnostic criteria, these patients were divided into two groups:鈶?acute myocardial infarction: 21 patients including 16 men and 5 women with a mean age of (64．24卤11．24) years;鈶?unstable angina pectoris: 20 patients including 13 men and 7 women with a mean age of (65．75卤8．08) years.鈽?2) Healthy controls: 21 outpatients in our hospital including 14 men and 7 women with a mean age of (65．1卤10．41) years.鈽?銆?Research methods鈽?1) General data: detailed case history, smoking status, history of hypertension, diabetes mellitus and old myocardial infarction, complete physical examination and measurement of serum glucose and lipid.鈽?2) Sample collection and measurement: 6ml of blood in median cubital vein were collected from all the patients in the early morning on an empty stomach within 48 hours after the onset of chest pain, among which 2 ml were used to directly measure BNP concentration by double antibody sandwich immumofluorescence method using triage instrument manufactured by US Biosite Corporation, while the remaining 4 ml were stored at room temperature for 30 minutes, then centrifuged to collect serum to be detected by fully automatic biochemistry analyzer.鈽?3) Cardiac events evaluation: All the adverse cardiac events occurring during hospital stay and within 3 months after discharge, including cardiac death, recurrent myocardial infarction, intractable angina, heart failure.鈽?4) Statistical analysis: All the data were processed by SPSS 11．5 for windows.The measurement data were expressed by mean卤standard deviation ((?)卤S) and the group comparison was performed by two-sample, non-paired data t test. The numeration data were compared by Chi square test. The correlation of cardiac events was analyzed by Logistic regression model. If P value was less than 0．05, the difference was considered statistically significant.鈽匯esults鈽?. Measurement of BNP in acute myocardial infarction group, unstable angina pectoris group and control group: BNP value was higher in acute myocardial infarction group than that in unstable angina pectoris group, while BNP value in unstable angina pectoris group was higher than that in control group. The difference in BNP value was significant between acute myocardial infarction group and unstable angina pectoris group (t=2．106, P=0．043) , and BNP value of all the 41 patients in acute myocardial infarction group and unstable angina pectoris group was significantly different from that in control group (t=6．294, P=0．000) . The percentage of patients with high BNP value in acute myocardial infarction group was higher than that in unstable angina pectoris group, but the difference was non-significant (P=0．11) . However, the percentage of patients with high BNP value in acute myocardial infarction group and unstable angina pectoris group was markedly higher than that in control group.鈽?. According to BNP level, 41 patients in acute myocardial infarction group and unstable angina pectoris group were redivided into high BNP (BNP>100pg/ml) group comprising 26 patients and normal BNP (BNP鈮?00pg/ml) group comprising 15 patients. There were no statistically significant differences in general clinical data between two groups, such as age, gender, smoking status, hypertension, diabetes mellitus, hyperlipoidemia and old myocardial infarction.鈽?. The relationship between BNP level and short-term cardiac events incidence in patients with acute coronary syndrome: There were eleven cardiac events in high BNP group, including three cases of cardiac death, one recurrent myocardial infarction, three intractable angina and four heart failure. There were only two cardiac events in normal BNP group, including one case of intractable angina and one heart failure. The incidence of cardiac events in high BNP group was higher than that in normal BNP group with significant differences in total cases (P<0．05) , demonstrating that patients with high BNP level were liable to cardiac events.鈽?. Analysis of Factors related to cardiac events: With cardiac events as the dependent variable and gender, age, BNP value, CK-MB value, CRP value, smoking, diabetes mellitus, hypertension, hyperlipoidemia and old myocardial infarction as independent variables, Logistic regression analysis showed that BNP>100pg/ml, CRP>0．8mg/dL and gender were most strongly associated with cardiac events (P<0．05) , and increasing BNP was an independent risk factor of cardiac events with an estimated relative risk of 9．837(P=0．002) .Discussion鈽匓ecause of the ascending tendency of incidence and the high rate of mortality and morbility of ACS nowadays, It's very improtant for us to take measures diagnosing ACS from early stage and treating it reasonably(properly). The multiple clinical circumstances and the relatively complicated diagnosis and treatment of ACS has attracted more and more concerns.鈽匫ur research found that the levels of BNP in the AMI group and UAP group were significantly higher than that of the control group.The results testify that BNP may used as a marker of the degree and severity of ischemia, it can also indicate the level of the potential left ventrical damage from a clinical point of view.鈽匱he level of BNP in serum is of great significance predicting the prognosis of ACS patients in the near future. We found in our experiment that the overall incidence of recent heart attack in group of BNP>100pg/ml was higher than group of BNP<100pg/ml, there was significant deviation between two groups, also no significant deviation was found in single heart attack, maybe it is because of rare samples.