Transcardiac gradients of N-terminal B-type natriuretic peptide in aortic valve stenosis

Background: Plasma B-type natriuretic peptide (BNP), as well as the N-terminal part of the prohormone (Nt-BNP), are frequently elevated in aortic valve stenosis (AS). Yet, their release from the heart into the circulation has never been directly studied in AS. Aim: To assess the release of Nt-BNP in AS with focus on the identification of its main determinants. Methods: We studied 49 adult patients undergoing preoperative cardiac catheterization for isolated AS. Blood was sampled from the aortic root and the coronary sinus for Nt-BNP determination by immunoassay. Results: The mean (+/- S.E.) transcardiac Nt-BNP step-Lip averaged 79 +/- 53 pmol/l in 11 control patients free of structural heart disease, 75 +/- 32 pmol/l in 31 AS patients frec of heart failure (HF), 236 +/- 62 pmol/l in 8 AS patients with diastolic HF (ejection fraction >= 50%, pulmonary wedge pressure > 14 mm fig) and 469 +/- 66 pmol/l in 7 AS patients with systolic HF (ejection fraction < 50%, wedge pressure > 14 mm Hg) (p < 0.001). The transcardiac Nt- BNP gradient was independently associated with left ventricular (LV) end-diastolic pressure (beta=0.47, p < 0.001) and ejection fraction (beta=-0.29, p < 0.019) and with co-existent coronary artery disease (beta=0.23, p=0.050). Conclusion: LV diastolic and systolic dysfunction along with coronary artery disease are likely to be the key determinants of cardiac Nt-BNP release in AS. The transcardiac Nt-BNP gradient increases on average three-fiold with the development of diastolic HF and six-fold in systolic HF. (c) 2004 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.