Vol 9, No 4 (2005)
Original paper
Published online: 2005-08-05
Prevalence and characteristic of adrenal glands’ abnormalities assessed by computed tomography in hypertensive patients with elevated plasma aldosterone to renin activity ratio
Nadciśnienie tętnicze 2005;9(4):252-260.
Abstract
Background The plasma aldosterone to renin activity
(ALDO/PRA) ratio over 50 in hypertensive patients is
widely recognized as a cut-off value for identification of
primary hyperaldosteronism (especially in patients without
hypokalaemia). The aim of this study was to evaluate
prevalence and characteristic of adrenal glands’ abnormalities
in hypertensive patients with an elevated plasma
aldosteron to plasma renin activity ratio.
Material and methods In 1367 subsequent adult patients with arterial hypertension plasma renin activity was estimated twice: first in patients receiving normally salted diet (100–120 mmol sodium per day) after 8 hours of recumbent position (PRA1) and a second time after 3 days of sodium restriction (10–20 mmol sodium per day) and 3 hours of upright position (PRA2). Plasma aldosterone concentration was assessed only in patients with low PRA1 (< 1 ng/ml/h) and without or only marginal reaction of PRA to salt restriction and upright position (PRA2/PRA1 < 1.5). Plasma aldosteron concentration was assessed also twice on normally salted diet and after sodium retriction (ALDO1 and ALDO2). In patients with ALDO/PRA ≥ 50 a CT scan of adrenal glands and a saline infusion test were performed.
Results ALDO/PRA ≥ 50 was found in 36 patients (2.6% of the entire hypertensive group). In that subgroup frequency of hypokaliaemia (< 3,5 mmol/l) was significantly higher than in hypertensive patients with a lower ALDO/PRA ratio. Computed tomography was performed in 34 out of these 36 patients. The scans revealed no abnormalities in 44.1% (n = 15). The most frequent abnormalities were: isolated adrenal tumour and bilateral adrenal enlargement. Saline infusion test was performed in 24 patients. A positive result was obtained in 15 cases. The ROC analysis revealed, that a ALDO/PRA ratio over 147 is connected with adrenal abnormalities in 66.7% of patients and only 21.1% changes remain unrevealed.
Conclusions 1. The prevalence of primary hyperaldosteronism in general population of hypertensive patients estimated according to the raised plasma aldosterone to plasma renin activity ratio (≥ 50) is 2.6%. 2. The ALDO/PRA ratio is especially useful in diagnosis of Conn syndrome in hypertensive patients without elevated serum aldosterone concentration. 3. The ALDO/PRA over 147 is highly specific for patients with morfological changes observed in computed tomography.
Material and methods In 1367 subsequent adult patients with arterial hypertension plasma renin activity was estimated twice: first in patients receiving normally salted diet (100–120 mmol sodium per day) after 8 hours of recumbent position (PRA1) and a second time after 3 days of sodium restriction (10–20 mmol sodium per day) and 3 hours of upright position (PRA2). Plasma aldosterone concentration was assessed only in patients with low PRA1 (< 1 ng/ml/h) and without or only marginal reaction of PRA to salt restriction and upright position (PRA2/PRA1 < 1.5). Plasma aldosteron concentration was assessed also twice on normally salted diet and after sodium retriction (ALDO1 and ALDO2). In patients with ALDO/PRA ≥ 50 a CT scan of adrenal glands and a saline infusion test were performed.
Results ALDO/PRA ≥ 50 was found in 36 patients (2.6% of the entire hypertensive group). In that subgroup frequency of hypokaliaemia (< 3,5 mmol/l) was significantly higher than in hypertensive patients with a lower ALDO/PRA ratio. Computed tomography was performed in 34 out of these 36 patients. The scans revealed no abnormalities in 44.1% (n = 15). The most frequent abnormalities were: isolated adrenal tumour and bilateral adrenal enlargement. Saline infusion test was performed in 24 patients. A positive result was obtained in 15 cases. The ROC analysis revealed, that a ALDO/PRA ratio over 147 is connected with adrenal abnormalities in 66.7% of patients and only 21.1% changes remain unrevealed.
Conclusions 1. The prevalence of primary hyperaldosteronism in general population of hypertensive patients estimated according to the raised plasma aldosterone to plasma renin activity ratio (≥ 50) is 2.6%. 2. The ALDO/PRA ratio is especially useful in diagnosis of Conn syndrome in hypertensive patients without elevated serum aldosterone concentration. 3. The ALDO/PRA over 147 is highly specific for patients with morfological changes observed in computed tomography.
Keywords: plasma aldosterone to plasma renin activity ratioprimary hyperaldosteronismarterial hypertensionsuprarenal glandscomputed tomography