Use of N-terminal pro-B-type natriuretic peptide to detect myocardial ischemia

Purpose To evaluate the utility of plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels to detect myocardial ischemia. Methods We conducted a prospective observational study in 260 consecutive patients with suspected myocardial ischemia referred for rest/ergometry myocardial perfusion single-photon emission computed tomography. Levels of NT-proBNP were determined before and immediately after symptom-limited bicycle ergometry. Results Inducible myocardial ischemia on perfusion images was detected in 129 patients (49.6%). Baseline NT-proBNP and exercise induced increase in NT-proBNP (ΔNT-proBNP) were significantly higher in patients with myocardial ischemia (median baseline NT-proBNP 155 pg/mL vs 91 pg/mL, P<.001; ΔNT-proBNP 15 pg/mL vs 7 pg/mL, P = .002). Compared with patients in the lowest ΔNT-proBNP quartile, those in the highest quartile of ΔNT-proBNP had three times the risk of inducible ischemia (relative risk, 2.9; 95% confidence interval, 1.4 to 6.0; P = .003). Overall, the accuracy of baseline NT-proBNP and ΔNT-proBNP in the detection of myocardial ischemia were similar to that of the exercise electrocardiogram (ECG). Combining exercise ECG and baseline NT-proBNP or ΔNT-proBNP slightly increased the accuracy of exercise ECG only. Conclusion The NT-proBNP level at rest as well as ΔNT-proBNP during exercise stress testing is associated with inducible myocardial ischemia. NT-proBNP levels may have incremental value in the diagnosis of myocardial ischemia.