Aims: Both raised plasma levels of B-type natriuretic peptide (BNP) and an abnormal exercise response predict adverse clinical outcomes in aortic stenosis (AS). This study examines the relationship between the response to treadmill exercise and plasma levels of BNP in AS.
Methods and results: 34 asymptomatic patients with moderate or severe AS (mean valve area 0.96+/-0.3 cm(2)) and 15 age matched controls underwent echocardiography, treadmill exercise testing, and BNP analysis. Compared to control subjects, AS patients had a higher left ventricular mass index, (133+/-50 vs 106+/-24 g/m(2), p=0.03), higher E/E' ratio, (10.6+/-3.6 vs 6.7+/-1.8, p=<0.0001), higher ejection fraction, (65+/-6 vs 59+/-6%, p=0.03), elevated resting BNP (11.4+/-6.5 vs 7.4+/-4.0 pmol/L, p=0.03) and shorter exercise duration (8.2+/-3.0 min vs 10.9+/-2.6 min, p=0.002). AS patients with an increase in systolic BP of <or=20 mmHg during exercise (n=18) had higher plasma levels of BNP than patients with an increase in systolic BP >20 mmHg (13.8+/-6.1 vs 8.6+/-6.0 pmol/L, p=0.003). The BNP measured at peak exercise was also associated with the BP response (p=0.003). The area under the receiver operator curve to predict an abnormal BP response to exercise was 0.82 for BNP measured at rest but only 0.46 for aortic valve area. There was a modest association between raised BNP and lower exercise capacity.
Conclusion: In patients with AS there is an association between BNP and an abnormal BP response to exercise. Further study is needed to determine the incremental prognostic value of BNP and exercise testing in asymptomatic AS.