Correlation Between Plasma Level Of Brain Natriuretic Peptide And Cardiac TroponinⅠ In Patients With Unstable Angina Pectoris

Objective:To investigate the clinical significances of difference of plasma level of N-terminal ProB-type natriuretic peptide (NT-proBNP) between Unstable angina pectoris(UAP) and Stable angina pectoris(SAP) in normal heart function and correlation between plasma cardiac troponin I (cTnI) and NT-proBNP in patients with UAP. Methods: a total of 116 patients(male81, female35)with angina pectoris were enrolled in this study, including54 SAP (male37, female17, average age 58.48±10.91), 62 UAP (male44, female18, average age 57.47±9.08). The UAP patients were divided into 32 cases whose cTnI were positive (male 28, female 4, average age 56.75±10.07) and 30 cases whose cTnI were negative (male16, female14, average age58.23±7.97), and 52 healthy persons were selected as control (male44, female11, average age55.54±9.54). measure the serum glucose, triglyceride, total cholesterol, low density lipoprotein and high density lipoprotein of all cases, and checked with ultrasonic echocardiogram. The left ventricular ejection fraction (LVEF) in patients with angina pectoris were > 45% , measure the plasma NT-proBNP and cTnI concentration of all cases, the difference of plasma levels of NT-proBNP in the three groups and the correlation between cTnI and NT-proBNP in cTnI (+)group were analyzed. Results:Plasma levels of NT-proBNP were 146.55(53.65, 772.55) pg/ml, 47.50(19.23, 87.35)pg/ml, 33.70(17.58,68.43) pg/ml in the patients with UAP , SAP and normal control respectively, the level of NT-proBNP was significantly higher in UAP than that in SAP or control(χ~2=40.53,P < 0.01, P < 0. 01); there were no significant difference in NT-proBNP level between SAP and control( P > 0. 05). Plasma levels of NT-proBNP were 646.86(127.85,1181.63) pg/ml , 91.50(26.54,45.83)pg/ml in the patients with UAP whose cTnI (+) and UAP whose cTnI (-) respectively, the level of NT-proBNP was significantly higher in UAP whose cTnI (+) than in UAP whose cTnI (-) (P < 0.01), NT-proBNP level were positively correlated with cTnI in UAP(rs 0.57, P<0.05). Conclusions:The plasma NT- ProBNP level in UAP is increased and it positively correlated with cTnI; NT-ProBNP is one of the significant stimulating factor of myocardial ischemia, NT- ProBNP were associated with the severity of myocardial ischemia; all of the patients with coronary heart disease (CHD) should measure the plasma NT-proBNP to find the patients with CHD at the high risk, whose heart function is normal, for receive the early intervention, and reduce the incidence of cardiovascular risk.