[Recent advances in the investigation of the renin-angiotensin and cardiac natriuretic systems in patients with chronic heart insufficiency].

The renin-angiotensin and cardiac natriuretic systems were studied by measuring plasma renin activity, plasma concentrations of active renin, angiotensinogen, atrial natriuretic hormone and urinary cyclic GMP in 37 patients with moderate to severe cardiac failure. The plasma sodium and osmolality were chosen as markers of hydroelectrolytic imbalance and plasma concentrations of préalbumin and retinol-binding protein as indicators of the degree of hepatocellular dysfunction. Plasma renin activity (PRA) plasma concentration of active renin, atrial natriuretic hormone and urinary cyclic GMP were higher in patients in NYHA Class IV than in those in Classes II-III, whilst plasma sodium, angiotensinogen, prealbumin and retinol-binding protein concentrations were lower in Class IV patients than in patients in Classes II-III. The plasma angiotensinogen concentrations were negatively correlated with PRA (r = -0.41, p less than 0.02), active renin (r = -0.45, p = 0.005), the atrial natriuretic factor (r = -0.36, p less than 0.05) and positively correlated with prealbumin (r = 0.54, p less than 0.001) and retinol-binding protein (r = 0.60, p less than 0.0001). In NYHA Class IV patients the decreased circulating renin substrate led to an underestimation of plasma concentrations of active renin by measurement of PRA. On the other hand, direct radio-immunometric measurement of active renin allows true estimation of circulating active renin, independently of plasma angiotensinogen concentrations and thereby reliably reflects activation of the renin system. The serum sodium was negatively correlated with active renin (r = -0.66, p less than 0.0001) in these patients not receiving converting enzyme inhibitors.(ABSTRACT TRUNCATED AT 250 WORDS)