Association between elevated B-type Natriuretic Peptide levels with extent of coronary artery disease in patients with unstable angina and NSTEMI.

The study was undertaken to find out the correlation of elevated B-type Natriuretic Peptide (BNP) levels with the severity of coronary artery disease in patients with unstable angina and NSTEMI. This cross sectional analytical study was carried out in the department of cardiology, National Institute of Cardiovascular Diseases, Dhaka during a period of August 2011 to June 2012. A total of 100 consecutive patients with unstable angina and NSTEMI undergoing coronary angiography were included in the study. BNP assay was done by Architect system, a chemo luminescent microparticle immunoassay (CMIA). CAG was done by conventional method within 14 days of index hospital admission. Study patients were divided into two groups on the basis of BNP levels. In Group I, BNP Levels were ≤80pg/ml and in Group II, BNP levels were elevated >80pg/ml. with 50 patients in each group. Angiographic severity of CAD was assessed by vessel score and Friesinger score. Vessel score showed single vessel was involved in 21(47.7%) patients while multi vessel in 23(52.3%) patients was found in Group I. On the contrary 11(22.4%) single vessel patients and 38(77.6%) multivessel patients were found in Group II. There was significant association between vessel involvement (p=0.01). Friesinger score revealed that less severe CAD was found in 22(44%) patients and significant severe CAD in 28(56.0%) patients in Group I. On the contrary 7(14.0%) less severe CAD patients and 43(86.0%) severe CAD patients were found in Group II. There was significant difference between severity of CAD among the study groups (p=0.01). There was linear correlation between BNP pg/ml and coronary artery disease severity in terms of Vessel score (r=0.38, p=0.01) and Friesinger score (r=0.51, p=0.01). The present study concluded that increased BNP level >80pg/ml was significantly associated with the presence and severity of CAD in patient with UA and NSTEMI.