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.


OBJECTIVE
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-up averaged 79+/-53 pmol/l in 11 control patients free of structural heart disease, 75+/-32 pmol/l in 31 AS patients free of heart failure (HF), 236+/-62 pmol/l in 8 AS patients with diastolic HF (ejection fraction > or = 50%, pulmonary wedge pressure > 14 mm Hg) 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).


CONCLUSIONS
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-fold with the development of diastolic HF and six-fold in systolic HF.
Kupari
Markku
M
Division of Cardiology, Department of Medicine, Helsinki University Central Hospital, 00029 HUS, Helsinki, Finland. markku.kupari@hus.fi
Turto
Heikki
H
Lommi
Jyri
J
Mäkijärvi
Markku
M
Parikka
Hannu
H
D000368:Aged; D001024:Aortic Valve Stenosis / Q000097:blood* / Q000000981:diagnostic imaging; D006328:Cardiac Catheterization; D005260:Female; D006801:Humans; D007118:Immunoassay; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D014463:Ultrasonography
D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain