title: Myocardial ischaemia is associated with an elevated brain natriuretic pepide level even in the presence of left ventricular systolic dysfunction.
abstract: OBJECTIVE
  Plasma BNP and high-sensitivity cardiac troponin-T (hs-TnT) are elevated by both ischaemia and LV systolic dysfunction (LVSD). As a result, it is unknown whether BNP and/or hs-TnT could be useful biomarkers to identify ischaemia in the presence of LVSD.
  
  
  RESULTS
  Three separate patient populations were studied. Study A (n = 500) involved consecutive patients undergoing clinically indicated myocardial perfusion scintigraphy, study B (n = 100) included patients with vascular disease but no known cardiac disease, and study C (n = 300) recruited primary prevention patients with controlled risk factors. Levels of BNP and hs-TnT were measured prior to the stress testing to detect myocardial ischaemia. The prevalence of myocardial ischaemia was 28.2, 28, and 6.3% in study A, B, and C, respectively. For BNP, area under curve (AUC) values to identify ischaemia in the presence and absence of coincidental LVSD were: 0.73 vs. 0.63 (study A), 0.90 vs. 0.81 (study B), and 0.83 vs. 0.80 (study C). Equivalent figures for hs-TnT were: 0.64 vs. 0.60 (study A), 0.75 vs. 0.68 (study B), and 0.53 vs. 0.68 (study C). BNP and hs-cTnT, when combined together, performed better with an AUC of 0.75 vs. 0.65 (study A), 0.91 vs. 0.92 (study B), and 0.84 vs. 0.83 (study C).
  
  
  CONCLUSIONS
  In three separate populations a consistent finding is that BNP is increased further by myocardial ischaemia even in the presence of LVSD. A disproportionately high BNP for the degree of LVSD might be due to (unsuspected) ischaemia, and a disproportionately low BNP could be useful as a 'rule out' test for ischaemia even in the presence of LVSD.
authors.affiliation: Division of Cardiovascular and Diabetes Medicine, University of Dundee, Dundee, UK.
authors.forename: M Adnan
authors.initials: MA
authors.lastname: Nadir
authors.forename: Eleanor
authors.initials: E
authors.lastname: Dow
authors.forename: John
authors.initials: J
authors.lastname: Davidson
authors.forename: Norman
authors.initials: N
authors.lastname: Kennedy
authors.forename: Chim C
authors.initials: CC
authors.lastname: Lang
authors.forename: Allan D
authors.initials: AD
authors.lastname: Struthers
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000097:blood* / Q000150:complications / Q000000981:diagnostic imaging; D055414:Myocardial Perfusion Imaging; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D011379:Prognosis; D012307:Risk Factors; D013599:Systole; D020107:Troponin T / Q000097:blood; D018487:Ventricular Dysfunction, Left / Q000097:blood / Q000150:complications* / Q000503:physiopathology
chemical_list: D015415:Biomarkers; D020107:Troponin T; D020097:Natriuretic Peptide, Brain
keywords: Biomarkers; Ischaemia; Natriuretic peptides; Troponin