The Significance Of Brain Natriuretic Peptide In Early Risk Stratification And Prognosis Of Acute Coronary Syndromes

BackgroundAcute coronary syndromes(ACS)is the commonnest cause of admission to thecoronary care unit and accounts for 60-70％of all admissions. Risk stratification ofpatients with ACS is fundamental in determining prognosis and choosing appropriatecare. Patients with the highest risk of subsequent events usually have the largestbenefit of an intensified pharmaceutical treatment and early mechanical intervention.Early risk stratification is usually performed by the use of clinical backgroundfactors,the changing of electrocardiography. Brain natriuretic peptide (BNP),another member of natriuretic peptide system, is synthesised and released fromcardiac ventricular myocardium., the levels of BNP are more closely related to leftventricular pressure and volume indices.Its roal in diagnosis of heart failure isconfirmed,but the implication in risk stratification and prognosis of ACS is few.ObjectiveTo explore the variation and significance of BNP level independently andcombined with cTnI,high sensitivity C reactive protin(hsCRP),blood white cell(WBC) level in patients between ACS and Stable angina(SA),and in the subgroupof ACS.MethodsThe study included 67 ACS patients and 20 SA patients(control group) withnormal heart function. ACS patients was divided into ST elevated myocardialinfarction group (STEMI)(27),non-ST elevated myocardial infarction group(NSTEMI)(20)and unstable angina group (UA) (20). And the rapid bedsidemeasurements of BNP,cTnI were performed within 24 hours and at 5th day.At thesame time, hs CRP and the sum of WBC were detected. Electric cadiogram(ECG),Ultrasound cardiogram (UCG) were examined and Coronary angiography (CAG) operation was done among the ACS patients. By following up outpatients,the majoradverse cardiac events(MACE) within 30 days and 3 month were observed among theACS patients.Results1. The BNP level in ACS group is higher than those in SA group,(559.59±735.16pg/ml vs 23.28±11.69pg/ml, P＜0.05),also,in the subgroups ofACS,BNP level is different in every group(1050.59±932.31 pg/ml vs 357.65±263.48pg/ml,98.69±96.99 pg/ml P＜0.05).2. The BNP level is inversely with LVEF(r=-0.76).3. The BNP level in group of 3-vessel disease is higher than only 1-vessel disease(972.54±224.05 pg/ml vs 249.29±192.10pg/ml, P＜0.01)4. The BNP level in group of the left descending anterior branch(LAD) vesselinvolved is higher than other vessel involved(789.76±944.85 pg/ml vs 336.20±332.94 pg/ml, P＜0.01);5. The BNP level in group of anterior MI is higher than other part MI(806.35±973.23 pg/ml vs 347.10±327.00 pg/ml, P＜0.01).6. In predicting the 30th motality with BNP, the AUC is 0.89, (95％CI为0.81-0.97; P＜0.05), when plasma BNP concentration is higher than 100pg/ml,thesensitivity is 75％,the specificity is 97％,the accuracy is 81％;in predicting the MACEduring 3 month, the AUC is 0.79, (95％CI为0.67-0.90; P＜0.05), when plasma BNPconcentrations is higher than 100pg/ml,the sensitivity is 84％,the specificity is69％,the accuracy is 64％7. The cTnI,hsCRP,WBC level in ACS group is higher than those in SA grouprespectively, (16.06±13.15 ng/ml vs0.05±0 ng/ml,40.86±42.22mg/lvs4.61±4.12mg/l,9.04±3.39×10~9个/l vs 5.63±0.97×10~9个/l, P＜0.05).8. There is a good relationship between BNP and cTnI(r=0.55, P＜0.001),hsCRP (r=0.46, p＜0.001).9. When BNP,cTnI,hsCRP and WBC is positive respectively, the prediction ofMACE is 56.5％,55.0％,51.0％,75.0％,while combined together, is 80.0％.The sameto it, the prediction of the 30th mortality is 13.2％,14.9％,12.1％,23.8％and 25.0％。10. In group STEMI,the BNP concentrations of high risk,intermedia-low risk were1536.77±1157.31 pg/ml and 599.14±214.99 pg/ml, P＜0.05;In group NSTEACS,theBNP concentrations of high risk,intermedia risk and low risk were446.75±234.89pg/ml vs 224.33±179.98 pg/ml,84.584±138.33 pg/ml, P＜0.05.11. According to the BNP concentration of the begining,it was divided into fourgrades,when it was in the second grade,the risk estimation of STEMI incidence is2.07 higher than that of NSTEACS,when in the third,is3.00;when in the fourth, is17.00.ConclusionsPlasma BNP concentrations were associated with the severity of the disease.Thehigher of the BNP level,the more of anterior MI,the more of vessels involved,thehigher stratification of KILLIP and the more severe heart faliure(HF).Elevations inBNP concentrations were associated with a higher incidence of MACE, the BNPconcentrations are higher in the high risk ACS group,and with the BNP gradehigher, the risk of STEMI incidence is higher. It might serve as a strong independentpredictor of the early risk stratification and prognosis of ACS. When combined withthe other biomarkers,such as cTnI,hs CRP,WBC,it provides an even better riskstratification concerning mortality in ACS patients.