Troponin T and N-terminal pro B-Type natriuretic peptide and presence of coronary artery disease

Abstract

Background. We tested the effects of exercise intensity, sampling intervals, degree of coronary artery stenosis, and demographic factors on circulating N-terminal pro B-Type natriuretic peptide (NT-pro-BNP) and cardiac Troponin T (cTnT) in subjects suspected of coronary artery disease (CAD). Materials and methods. A total of 242 subjects referred for diagnostic evaluation of possible CAD had blood samples obtained before, 5 min after, and again 20 h after a symptom-limited exercise test. Results. Totally 40 subjects had CAD with ≥ 50% stenosis, 115 subjects had no stenosis and 87 subjects served as controls. In univariate analysis CAD-subjects had higher median baseline NT-pro-BNP-levels (85.3 ng/L) compared with non-CAD-subjects (41.3 ng/L) and controls (40.1 ng/L), both p < 0.001, but the association disappeared in multivariate analysis adjusted for age and gender. NT-pro-BNP increased similarly after exercise in CAD-subjects, non-CAD-subjects, and controls (median increase 8.14 ng/L) and the increase was positively associated with baseline NT-pro-BNP but not presence of CAD. Median baseline cTnT was 6.25 ng/L in CAD-subjects and 3.00 ng/L in non-CAD-subjects as well as controls, both p < 0.0001. Median ΔcTnT (baseline to 20 h after exercise) was higher in CAD-subjects than non-CAD-subjects and controls (0.62 ng/L vs. 0.0 ng/L, p < 0.001). A linear relationship between ΔcTnT and ‘percent of predicted maximal heart rate achieved’ was found in subjects with ≥ 70% stenosis (n = 24, r = 0.4067 p = 0.046). Conclusions. Baseline cTnT and ΔcTnT were found to be independently associated with CAD and also with exercise intensity in stable chest pain subjects. These properties were not identified for NT-pro-BNP.

Key Words::

• Angina pectoris
• atherosclerosis
• biological markers
• troponin
• exercise test

Acknowledgements

The study was supported by the Danish Heart Foundation 07-10-R61-A1807-B859-22396F, Th. Maigaards Eftf. Fru Lily Benthine Lunds Fond, Direktoer Kurt Boennelycke og hustru Fru Grethe Boennelyckes Fond, Fru Gudrun Elboth mindelegat, Jens Anker Andersen Fonden, Henry og Astrid Moellers Fond, Grosserer Chr. Andersen og hustru Ingeborg Ovidia Signe Andersen Legat, Beckett Fonden, Snedkermester Sophus Jacobsen og hustru Astrid Jacobsens Fond, Krista og Viggo Petersens Fond, Alfred Helsteds og Eli Moellers legat, Murermester Laurits Peter Christensen og hustru Kirsten Sigrid Christensens Fond, Arvid Nielssons Fond, Else og Mogens Wedell-Wedellsborg Fond, and Axel Muusfeldts Fond.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Supplementary material available online

Supplementary Figures A and B.