NT-proBNP and the diagnosis of exercise-induced myocardial ischaemia

BACKGROUND: Amino terminal pro-B-type natriuretic peptide (NT-proBNP) is a sensitive marker of ventricular dysfunction. Exercise causes an increase in the secretion of NT-proBNP, and with myocardial ischaemia the increase is more pronounced. This increase has been found to improve the diagnostic sensitivity of the stress ECG in diagnosing myocardial ischaemia in subjects with normal ventricular function. OBJECTIVE: To assess whether the change in NT-proBNP can be used to diagnose effort-induced myocardial ischaemia in an unselected population. METHODS: We enrolled a total of 51 consecutive patients, referred for exercise stress (99m)Tc-sestamibi SPECT MPI (single-photon emission computed tomography myocardial perfusion imaging) to diagnose inducible myocardial ischaemia. NT-proBNP was determined at rest and 30 minutes after cessation of exercise. RESULTS: Of the 51 patients, 28 had normal perfusion scans, seven had scans with fixed perfusion defects (previous myocardial infarction with no inducible ischaemia) and 16 had reversible perfusion defects (inducible ischaemia). There was no correlation between ischaemia and resting NT-proBNP, post-stress NT-proBNP or the change in NTproBNP (delta-NT-proBNP). CONCLUSION: In an unselected population the change in NT-proBNP cannot be used to diagnose effort-induced myocardial ischaemia.