[Plasma aldosterone concentration in patients with primary aldosteronism in the last decade]

We analyzed the chronological variation of plasma aldosterone concentration (PAC) in 27 surgically confirmed patients with primary aldosteronism (PA) during the period from 1975 to 1984. PAC values in PA-patients were significantly higher than those in 82 age-matched patients with essential hypertension (EHT). However, although average PAC in the PA-patients declined consistently in recent years, no chronological trend of PAC was observed in the EHT-patients. Therefore, the distributions of PAC in the two groups of patients overlapped in the last few years. Such chronological variations of PAC in the PA-patients were not related to serum potassium concentration, blood pressure level on admission, duration of hypertension, or diameter of the adrenal adenomas. In some recently observed cases of PA, not only was the basal PAC relatively low, PAC also responded to either salt depletion or salt loading. These findings could not be explained simply by the change of methodology for PAC determination but rather by the technological advance of diagnostic radiology. As a result, PA might be diagnosed in the early stages or before becoming fullblown. Further study should be necessary to clarify the exact mechanism.