Background: Exertional change in brain natriuretic peptide (BNP) has recently been proposed as a biomarker of myocardial ischemia. However, in patients with abnormal left ventricular (LV) filling, BNP is frequently increased. Therefore, we studied the relationship of exertional changes in atrial and brain natriuretic peptides (ANP and BNP) with resting and exercise-induced changes of LV systolic function and filling pattern.
Methods: LV function at rest and peak exercise was assessed in 140 patients (mean age 65 years, 78 men) during symptom-limited exercise echocardiography for evaluation of suspected coronary artery disease. ANP and BNP were measured at rest and 5 min after exercise.
Results: ANP and BNP increased with exercise. The increase in BNP was significantly greater in the 65 patients with than in the 76 patients without ischemia [14.7 pg/ml (5.7-19.6) vs. 4.9 pg/ml (2.1-9.2), p<0.0001]; there was no difference in increase of ANP [340 pg/ml (176-729) vs. 424 pg/ml (249-648), p=0.54]. The exertional rise in BNP was also greater in patients with abnormal LV filling at rest [10.5 pg/ml (4.9-19.6) vs. 4.1 pg/ml (2.0-6.7), p<0.0001]. By multivariate linear regression, exertional change in wall motion score index (beta=0.23, p<0.001), baseline BNP (beta=0.71, p<0.001), abnormal LV filling pattern (beta=0.24, p<0.001) and age (beta=-0.15, p=0.02) were predictors of change in BNP.
Conclusions: In patients with suspected coronary artery disease, exertional changes of BNP are related not only to ischemia, but also to the LV filling pattern at rest.