angiotensinogen and Hypernatremia

To compare the determination of plasma renin activity (PRA) and the direct measurement of active renin by immunoradiometric assay (IRMA) as methods of assessing the renin system in patients with congestive heart failure.. The status of the renin-angiotensin system in congestive heart failure was assessed by measuring the plasma renin substrate concentration, PRA, and plasma concentration of active renin in 37 patients with mild to severe congestive heart failure. Natremia and plasma levels of atrial natriuretic factor (ANF) were determined as biologic indexes of the severity of heart failure, and concentrations of prealbumin and retinol-binding protein were used as indexes of liver dysfunction.. The PRA and the concentrations of active renin and ANF were markedly higher in patients with New York Heart Association class IV heart failure than in patients with class II to III heart failure, while natremia and the concentrations of renin substrate, prealbumin, and retinol-binding protein were markedly lower in the class IV patients than in the class II to III patients. Plasma renin substrate concentration was negatively correlated with active renin concentration (n = 37, r = -0.45, p = 0.005), and positively related to natremia (r = 0.56, p less than 0.0005), prealbumin (r = 0.54, p less than 0.001), and retinol-binding protein (r = 0.60, p less than 0.0001).. Low levels of plasma renin substrate can be considered as an indirect index of the severity of heart failure that reflects both the high level of circulating active renin and the decrease in hepatic protein output. In patients with class IV heart failure, low levels of renin substrate led to a marked underestimation of active renin concentration from measurements of PRA. In contrast, direct IRMA of active renin measures the true plasma active renin concentration, independent of plasma renin substrate, and closely reflects renin secretion.

Topics: Adult; Aged; Aged, 80 and over; Angiotensinogen; Atrial Natriuretic Factor; Female; Heart Failure; Humans; Hypernatremia; Immunoradiometric Assay; Liver; Male; Middle Aged; Prealbumin; Renin; Renin-Angiotensin System; Retinol-Binding Proteins; Retinol-Binding Proteins, Plasma; Severity of Illness Index