Background: B-type natriuretic peptide (BNP) and left ventricular ejection fraction (LVEF) are both increasingly used in the clinical management of patients with suspected coronary artery disease (CAD). Unfortunately, there is very limited data regarding the association between BNP and LVEF.
Methods: BNP and LVEF were measured in 260 consecutive patients with suspected myocardial ischemia referred for rest/ergometry myocardial perfusion single-photon emission computed tomography (SPECT). The correlation between BNP and LVEF was studied using Spearman's correlation test.
Results: Median LVEF was 57% (IQR, 50 to 64), and median BNP level was 53 pg/ml (IQR, 24 to 109). LVEF and BNP levels showed a statistically significant, but overall weak correlation (r=0.274, p<0.001). The correlation seemed to depend on the presence of a myocardial scar, which was detected in 104 patients (40%), including 89 men (49% of men) and 15 women (20% of women). The correlation between BNP and LVEF was moderate in patients with a myocardial scar (r=-0.540, p<0.001), but very weak in patients without a scar (r=0.185, p=0.025). Moreover, the correlation between BNP and LVEF was moderate in men (r=-0.503, p<0.001), but not existent at all in women. In the overall cohort, BNP was not an accurate test to detect left ventricular systolic dysfunction. The area under the ROC curve was 0.643 (95% CI, 0.563-0.723).
Conclusions: The BNP level and LVEF show only a weak correlation in patients with suspected myocardial ischemia. Neurohormonal and morphologic assessments provide different windows to the heart.