title: Serum to urinary sodium concentration ratio is an estimate of plasma renin activity in congestive heart failure.
abstract: We investigated the relationship between plasma renin activity (PRA) and serum ([sNa(+)]) and urinary ([uNa(+)]) sodium concentrations in 124 congestive heart failure (CHF) patients (II-IV NYHA class) and 20 healthy subjects. According to PRA (> or <3 ng ml(-1) h(-1)) and [sNa(+)] (> or <135 mEq l(-1)), patients were classified as Group A (normal PRA and normal [sNa(+)], n=39), Group B (increased PRA and normal [sNa(+)], n=62) and Group C (low [sNa(+)], n=23). Measurements were performed at rest and, in 26 cases, after extracorporeal ultrafiltration (UF). At rest, [sNa(+)] and [uNa(+)], and their difference ([sNa(+)]-[uNa(+)]), were linearly correlated with PRA, but the values did not allow differentiation of control subjects from patients or differentiation of patients with from those without renin-angiotensin system (RAS) activation. Conversely, the [sNa(+)]/[uNa(+)] ratio showed the best correlation with PRA (r=0.79, P<0.0001). UF-induced PRA changes were linearly correlated with [sNa(+)]/[uNa(+)] ratio changes (r=0.67, P=0.002), but not with those of [sNa(+)], [uNa(+)] and [sNa(+)]-[uNa(+)]. In CHF, the [sNa(+)]/[uNa(+)] ratio best correlates with PRA and reflects the basal activity as well as the rapid changes (as those induced by UF) of the RAS. Therefore, it can be considered a strong and easily available marker of PRA.
authors.affiliation: Centro Cardiologico Monzino, IRCCS, Institute of Cardiology, University of Milan, via Parea 4, 20138 Milan, Italy. giancarlo.marenzi@cardiologicomonzino.it
authors.forename: GianCarlo
authors.initials: G
authors.lastname: Marenzi
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Lauri
authors.forename: Emilio
authors.initials: E
authors.lastname: Assanelli
authors.forename: Marco
authors.initials: M
authors.lastname: Grazi
authors.forename: Jeness
authors.initials: J
authors.lastname: Campodonico
authors.forename: Gabriella
authors.initials: G
authors.lastname: Famoso
authors.forename: Piergiuseppe
authors.initials: P
authors.lastname: Agostoni
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood / Q000652:urine; D001794:Blood Pressure / Q000502:physiology; D001806:Blood Urea Nitrogen; D003404:Creatinine / Q000097:blood; D004232:Diuretics / Q000008:administration & dosage; D005260:Female; D005665:Furosemide / Q000008:administration & dosage; D006333:Heart Failure / Q000097:blood* / Q000628:therapy / Q000652:urine*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D012083:Renin / Q000097:blood* / Q000187:drug effects; D012720:Severity of Illness Index; D012964:Sodium / Q000097:blood* / Q000652:urine*; D013223:Statistics as Topic; D016896:Treatment Outcome; D014462:Ultrafiltration / Q000379:methods
chemical_list: D015415:Biomarkers; D004232:Diuretics; D005665:Furosemide; D012964:Sodium; D003404:Creatinine; D012083:Renin; D009638:Norepinephrine