B-Type Natriuretic Peptide and Tissue Doppler for Predicting Symptoms on Treadmill Exercise in Apparently Asymptomatic Aortic Stenosis

Background and aim of the study: Exercise-induced symptoms are associated with early changes in left ventricular (LV) function. Blood B-type natriuretic peptide (BNP) and tissue Doppler indices (tDi) also reflect early LV dysfunction, and may therefore predict the development of symptoms. The study aim was to compare BNP levels and tDi for predicting symptoms on treadmill exercise in apparently asymptomatic aortic stenosis (AS). Methods: A total of 65 patients (mean age 66 years) with an aortic effective orifice area <1.5 cm(2) who were asymptomatic on formal questioning, underwent transthoracic echocardiography, measurement of blood BNP level, and exercise testing using a modified Bruce protocol. Results: A blood BNP level >58 pg/ml had a sensitivity of 86% and specificity of 64% (AUC = 0.81) for the development of symptoms on exercise testing. The combined tDi index of peak systolic shortening velocity <8 cm/s and E/Ea >15 had a sensitivity of 52% and specificity of 73%. In patients with no symptoms on exercise, 27% with a blood BNP level >58 pg/ml compared to 7% with a level <= 58 pg/ml developed symptoms during follow up. Conclusion: The study results suggested that patients with a blood BNP level <= 58 pg/ml can be seen up to one year, while those with a BNP level >58 pg/ml required exercise testing and a more frequent follow up. The combined tissue Doppler indices gave a similar, but less accurate, stratification.