Effects of routine heparin therapy on plasma aldosterone concentration.

Changes in plasma aldosterone, plasma renin activity, plasma cortisol, serum sodium and potassium concentrations were studied in 9 patients with thromboembolic diseases treated with heparin. Heparin was administered at doses of 700-1000 units/h for 7-10 days. Plasma aldosterone decreased from 239 +/- 33 to 114 +/- 25 pmol/l during heparin therapy and returned to basal levels after discontinuation of the therapy. In addition, responses to a low sodium intake (3 g/day) and ACTH were examined in 5 patients during and 2 weeks after heparin therapy. The increase in plasma aldosterone caused by low sodium intake was significantly attenuated during heparin therapy (124 +/- 5% increase from baseline) as compared with that 2 weeks after heparin therapy (148 +/- 7%, p less than 0.05). On the other hand, ACTH stimulated plasma aldosterone similarly during and at 2 weeks after heparin therapy (increase from baseline: 190 +/- 20% vs 193 +/- 9%). These results suggest that heparin decreased plasma aldosterone owing to attenuation of the angiotensin II-induced aldosterone production.