Association Of Plasma Brain Natriuretic Peptide Levels With The Severity Of Coronary Artery Disease In Patients With Non-ST Elevation Myocardial Infarction, Stable And Unstable Angina

Objective:To evaluate plasma BNP levels in patients with stable angina, unstable angina or non-ST elevation myocardial infarction, and to study the relationship between the BNP levels and the severity and extent of involved coronary vessels.Methods:81 patients with coronary artery disease (CAD) were recruited, 56 men (69.1%) and 25 women (30.9%) (mean age 60±11 years). According to clinical manifestation, electrocardiography and the levels of biochemical markers of myocardial necrosis, they were classified into 3 groups: group 1 (stable angina group, n＝24), group 2 (unstable angina group, n=33) and group 3 (non-ST elevation myocardial infarction group, n=24). We compared these groups with 20 age- and gender- matched cases who complained of chest pain and with negative CAG result (group 0). All recruited patients underwent coronary angiographic examination (CAG) and echocardiographic evaluation. Blood samples for BNP were drawn before CAG from the peripheral veins. No patients had heart failure, previous myocardial infarction, or electrocardiographic ST elevation. The patients with other organ disease were also excluded.Results:1. A significant increase in BNP levels was observed in group 3 compared with the other groups (P＜0.001). BNP demonstrated a significant correlation with troponin I (TnI) level (mean 7.07±7.42ng/ml) in group 3 (r=0.765, P＜0.001). group 1 and group 2 had higher BNP levels than group 0 (27.86pg/ml, 39.30pg/ml vs. 9.26pg/ml; P＜0.001). Compared with BNP Values in group 1, there were a increased tendency to those in group 2 (P=0.078).2. BNP levels in patients with 3-vessel disease were higher than those with 1- and 2-vessel disease (121.0pg/ml vs. 19.8pg/ml, P＜0.001; vs. 39.0pg/ml, P＝0.018).3. Patients with left anterior descending (LAD) involvement had higher BNP levels than those patients with involvement in the others (65.4pg/ml vs. 15.1pg/ml, P＜0.001). When the analysis was limited to the 1-vessel disease group (n=29), BNP levels had an elevated tendency in patients with LAD compared with those in patients with left coronary circumflex disease and right coronary artery disease (P＝0.29).4. In patients with＞75% LAD stenosis, a proximal LAD lesion location was associated with higher BNP level compared with a mid-/ distal LAD lesion location (159.0pg/ml vs. 60.0pg/ml, P=0.011; vs. 29.1pg/ml, P=0.028). But there no difference between a middle LAD lesion location and a distal LAD lesion location (P=0.61).5. BNP was higher in patients with(?)75% stenosis of LAD than in those with 50-75% stenosis of LAD (86.4 pg/ml vs. 33.2 pg/ml; P=0.021).6. TIMI flow showed a significant negative correlation with plasma BNP levels (r＝-0.402, P＜0.001). For the patients with BNP＞80 pg/ml, most of them were with NSTEMI or multivessel disease.Conclusion:Plasma BNP levels elevate in patients with coronary atherosclerotic heart disease (CAD). Elevated BNP levels can estimate the severity of involved coronary vessels. Patients with UA/NSTEMI have higher plasma BNP levels than patients with SA. Plasma BNP levels can evaluate the risk of CAD.