| BackgroundAcute coronary syndromes (ACS) encompass a continuum of cardiac ischemic events, ranging from unstable angina pectoris with no biochemical evidence of myocardial necrosis to ST-elevation acute myocardial infarction(AMI). The common denominator of ACS is a pathophysiologic process characterized by rupure of an atherosclerotic plaque, altered coronary vasomotor tone, platelet aggregation, and thrombosis. The prognosis of patients with ACS varies widely, and clinical, electrocardiographic, and biochemical markers of adverse prognosis have been used to identify hight risk patients who need aggressive intervention. Recently, cardiac biochemical markers, including troponin and B-type natriuretic pepetide (BNP), were well studied and might promise to identify high-risk patients with ACS.BNP is a cardiac neurohormone that is synthesized in ventricular myocardium and released in response to increased ventricular wall stress. It diverse actions include natriuresis, vasodilation, inhibition of the rennin-angiotensin-aldosterone system (RAS), and inhibition of sympathetic nerve activity. Recently, BNP has been shown to provide valuable prognostic information in patients with AMI. Specifically, when measured between one and four days after presentation with transmural myocardial infarction, and elevated plasma concentration of BNP was associated with increased mortality risk, independently of left ventricular function. However, few studies were done to look at whether early plasma concentration ofBNP, which was measured at the beginning of ACS presentation to the hospital, was associated with adverse prognosis of ACS.It is important to know whether plasma concentration of BNP at the beginning of ACS presentation to the hospital (i.e. emergency room) is associated with adverse prognosis. So that patients with ACS can be stratified earlier and given aggressive intervention to improve prognosis. Consequently, this study was designed to look at the prognostic and therapeutic value of early plasma concentration of BNP in patients with ACS.METHODS1 Study Population.A total of 960 consecutive individuals with ACS, who presented to the Cardiac Center of the National Guard Hospital, Saudi Arabia, were enrolled between Jan.1 to Dec.31,2001. Eligible criteria as following:(1) Nationality of Saudi Arabia;(2) Age > 18 years old, but <80 years old;(3) Working diagnosis of acute coronary syndromes:1) Unstable angina episode within the preceding 24 hours;2) AMI with at least 2 of following criteria:a. Persistent chest pain >20 minutes;b. ST elevation in at least 2 corresponding leads (>0.05mV), or with new onset of complete left bundle block;c. Elevation of cardiac enzymes or markers;d. New regional wall motion abnormality on echocardiography.2 Data Collection.2.1 All demographic data, CAD risk factors and clinical features of CAD were obtained from the database in Cardiac Science, which include nationality,gender, age, smoking, obesity, hyperlipidemia, DM, hypertension, classification of angina, ACS, heart function (NYHA), and lab results.2.2 End points.Each enrolled individual was followed up closely in the cardiac clinic according to the special protocol for 6 months for the development of following recurrent clinical events, including:a. Death from any cause;b. New or recurrent myocardial infarction;c. Rehospitalization for ACS;d. New or worsening congestive heart failure.2.3 BNP testing.Blood samples were obtained at enrollment by trained study personnel, and were analyzed by biosite assays at bedside.2.4 cTnl testing.Blood samples were obtained at enrollment by trained study personnel every 6 hours for 4 times, and were analayed using ACS: 180 Chemiluminescence cTnI Immunoassay method.2.5 12-lead-EKG.12-lead-EKG. were done at enrollment by an EKG technician, reports were available within 10 minutes.2.6 Echocardiography.Echocardiography data were obtained within 30 minutes after en...
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