Atrial natriuretic peptide response to postural changes and upright exercise in patients with venous valvular insufficiency.

To investigate the effects of postural changes and upright exercise on atrial natriuretic peptide release and renin-angiotensin-aldosterone system behavior in patients with venous valvular insufficiency, plasma ANP, plasma renin activity and aldosterone were measured in 11 patients with venous disease and in 11 age-matched controls. In patients with large varicose veins and venous valvular dysfunction, standing was associated with a greater fall in circulating ANP levels (p < 0.05) and upright exercise was accompanied by a smaller rise in ANP concentrations (p < 0.05) as compared with controls. A significant (p < 0.001) inverse relationship was found between the number of venous segments with reflux and both upright and exercise plasma ANP concentrations (r = -0.91; r = -0.84, respectively). In the two groups the response of the renin-angiotensin-aldosterone system to upright position and physical stress was similar. These results suggest that a decreased atrial stretch, due to a reduced venous return, could account for the blunted ANP response to erect posture and exercise in patients with venous valvular incompetency.