B-type natriuretic peptide (BNP) has been found to be inversely
related to peak oxygen consumption (peak VO2) in various patient
populations. However, in these studies, circulating plasma BNP, i.e.
the net effect of release and elimination, rather than cardiac BNP
release has been measured. We assessed the relationship between the
transcardiac BNP gradient [ΔBNPCS-A, i.e. the difference
between BNP in coronary sinus (BNPCS) and arterial (BNPA) plasma]
and peak VO2 in healthy subjects with a view to better understanding
the regulation of cardiac BNP release in humans.
We studied 10 asymptomatic subjects (age 64±11 years, two
females) with preserved left ventricular function (left ventricular
ejection fraction 62±5%, averaged early diastolic mitral
annular velocity 9±3cm/s) and low BNP (BNP in venous plasma
[BNPV] <100ng/l). Subjects underwent measurement of BNPA and
BNPCS for the calculation of ΔBNPCS-A, maximal cardiopulmonary
exercise testing, echocardiography and resting and submaximal
exercise right heart catheterisation.
The median (range) BNPV, BNPA, BNPCS, and ΔBNPCS-A were 62
(14, 82), 60 (13, 79), 110 (25, 157), and 44 (1, 103) ng/l. The
median peak VO2 during cardiopulmonary exercise testing was 21.5
(18, 54) ml/min/kg. There was an inverse correlation between higher
ΔBNPCS-A and lower peak VO2 (r=-0.84; p=0.002) and oxygen
pulse (r=-0.64, p=0.049). There was a trend towards an inverse
correlation between ΔBNPCS-A and the exercise arteriovenous
oxygen content difference (r=-0.58; p=0.08).
In healthy humans, there is an inverse association between
myocardial BNP release and peak VO2, which may be due to cardiac and