Baseline plasma N-terminal pro-B-type natriuretic peptide is associated with the extent of stress-induced myocardial ischemia during dobutamine stress echocardiography.

OBJECTIVE

To determine the relationship between baseline plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels and the presence and extent of myocardial ischemia during dobutamine stress echocardiography (DSE).

METHODS

NT-proBNP was measured in 170 consecutive patients prior to DSE. Rest wall motion abnormalities (RWMAs) and new wall motion abnormalities (NWMAs) were scored using a 5-point, 17-segment model. Kruskal-Wallis tests were applied to study differences in NT-proBNP levels between patients with normal DSE, RWMAs but no NWMAs, and NWMAs, and (in patients with NWMAs) between those with 1-2, 3-4 and >4 ischemic segments. Univariate and multivariate regression analyses were used to determine the value of NT-proBNP in predicting NWMAs.

RESULTS

The median NT-proBNP level was 110 ng/l (interquartile range: 42-389 ng/l). Median NT-proBNP was 59, 321 and 440 ng/l in patients with normal DSE, with RWMAs but no NWMAs, and with NWMAs, respectively (P<0001). Among patients with NWMAs, median NT-proBNP was associated with the number of ischemic segments: 364, 710 and 2376 ng/l in patients with 1-2, 3-4 and >4 ischemic segments, respectively (P<0.001). Elevated NT-proBNP levels were significantly associated with NWMAs (odds ratio per 100 ng/l increase: 1.14, 95% confidence interval: 1.1-1.2) in a multivariate analysis of clinical baseline variables and RWMAs.

CONCLUSION

Elevated baseline levels of NT-proBNP are associated with the presence and extent of myocardial ischemia during DSE, independent of the presence of RWMAs.