Use of changes in B-type natriuretic peptides to detect ischemia in selected patients

BACKGROUND: There is accumulating evidence that transient exercise-induced ischemia triggers the release of B-type natriuretic peptide (BNP) and N-terminal pro-B-type natriuretic peptide (NT-proBNP). The aim of this study was to either confirm or refute a previous investigation suggesting that myocardial ischemia can reliably be detected by exercise-induced changes in BNP or NT-proBNP levels in selected patients. METHODS: A total of 139 consecutive patients with normal left ventricular function and normal resting BNP and NT-proBNP levels referred for rest/stress myocardial perfusion single-photon emission computed tomography (SPECT) were analyzed. Levels of BNP and NT-proBNP were determined before and immediately after symptom-limited bicycle ergometry. RESULTS: Inducible myocardial ischemia on perfusion images was detected in 46 patients (33%). Median exercise-induced increases in BNP (DeltaBNP) and NT-proBNP (DeltaNT-proBNP) were similar in patients with and without inducible ischemia (DeltaBNP 12.7 pg/ml vs. 9.4 pg/ml, p=0.109; DeltaNT-proBNP 7 pg/ml vs. 6 pg/ml, p=0.309). The area under the receiver operating characteristic curve for the ability to detect myocardial ischemia was 0.583 (95% CI, 0.479-0.688) for DeltaBNP, and 0.553 (95% CI, 0.450-0.656) for DeltaNT-proBNP. CONCLUSIONS: Exercise-induced changes in BNP and NT-proBNP do not reliably detect myocardial ischemia in selected patients.