Systemic and renal effects of atrial natriuretic peptide in patients with heart failure treated with angiotensin-converting enzyme inhibitor or in acute saline solution loading.
BACKGROUND
Our purpose was to study the effects of atrial natriuretic peptide (ANP) on cardiorenal functions when it is used to manage patients with heart failure who are receiving an angiotensin-converting enzyme inhibitor (ACEi) or in acute saline solution loading.


METHODS
Seventeen patients with mild to moderate heart failure were entered into protocol 1 or 2. Protocol 1 was ANP (30 ng/kg/min) infused before and after treatment with ACEi (n = 9). Protocol 2 was acute saline loading with or without coadministration of ANP (n = 8). In both protocols cardiorenal hemodynamics and urinary sodium excretion were assessed before and after each intervention.


RESULTS
Protocol 1: Although ANP infusion significantly increased urinary sodium excretion to a similar extent before and after ACEi treatment, the infusion increased the glomerular filtration rate (75 +/- 16 --> 82 +/- 15 mL/min, P <.05) and renal blood flow (390 +/- 123 --> 438 +/- 140 mL/min, P <.05) only before ACEi treatment. Protocol 2: Acute saline solution loading decreased plasma renin activity (P <.05) but did not affect ANP level. Coadministration of ANP with saline solution load enhanced the increase of urinary sodium excretion (75% +/- 34% increase) compared with the acute saline solution load alone (49% +/- 33% increase) (P <.05) but had no affect on renal hemodynamics.


CONCLUSIONS
When ANP is used in patients with mild to moderate heart failure who are on combined ACEi treatment or in acute saline solution loading, the vasodilatory effect of ANP is blunted while the natriuretic effect of ANP is preserved. The renin-angiotensin system seems to modulate the vasodilatory effect of ANP.
Third Department of Internal Medicine, Division of Cardiology, Teikyo University Ichihara Hospital, 3426-3 Anezaki, Ichihara, Chiba, Japan 299-0111. h-tomiya@med.teikyo-u.ac.jp
H
H
Tomiyama
G
G
Watanabe
M
M
Abe
R
R
Okazaki
H
H
Yoshida
N
N
Doba
D000328:Adult; D000368:Aged; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D018592:Cross-Over Studies; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006321:Heart / Q000187:drug effects*; D006333:Heart Failure / Q000188:drug therapy* / Q000503:physiopathology*; D006801:Humans; D007262:Infusions, Intravenous; D007668:Kidney / Q000187:drug effects*; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D012084:Renin-Angiotensin System / Q000187:drug effects* / Q000502:physiology; D012964:Sodium / Q000652:urine; D014664:Vasodilation / Q000187:drug effects
D000806:Angiotensin-Converting Enzyme Inhibitors; D009320:Atrial Natriuretic Factor; D012964:Sodium