Primary aldosteronism: Higher volume load, cardiac output and arterial stiffness than in essential hypertension

Abstract

Background. The diagnostics of primary aldosteronism (PA) are usually carried out in patients taking antihypertensive medications. We compared haemodynamics between medicated PA, medicated essential hypertension (EH), never-medicated EH and normotensive controls (n = 130 in all groups). Methods. The hypertensive groups were matched for age (53 years), sex (84 male/46 female) and body mass index (BMI) (30 kg m À2); normotensive controls had similar sex distribution (age 48 years, BMI 27 kg m À2). Haemodynamics were recorded using whole-body impedance cardiography and radial pulse wave analysis, and the results were adjusted as appropriate. Radial blood pressure recordings were calibrated by brachial blood pressure measurements from the contralateral arm. Results. Radial and aortic systolic and diastolic blood pressure was similar in PA and never-medicated EH, and higher than in medicated EH and normotensive controls (P ≤ 0.001 for all comparisons). Extracellular water balance was~4% higher in PA than in all other groups (P < 0.05 for all), whilst cardiac output was~8% higher in PA than in medicated EH (P = 0.012). Systemic vascular resistance and augmentation index were similarly increased in PA and both EH groups when compared with controls. Pulse wave velocity was higher in PA and never-medicated EH than in medicated EH and normotensive controls (P ≤ 0.033 for all comparisons). Conclusions. Medicated PA patients presented with corresponding systemic vascular resistance and wave reflection, but higher extracellular water volume, cardiac output and arterial stiffness than medicated EH patients. Whether the systematic evaluation of these features would benefit the clinical diagnostics of PA remains to be studied in future.

Haemodynamics of primary aldosteronism associated with adrenocortical adenoma: insights from bioimpedance cardiography measurements

“…Another important finding of the present study is the increased cardiac index (~8%) observed in medicated PA patients compared to treated EH subjects, despite similar use of beta-blockers [5]. This result is in agreement with most previous studies in which methods different from those employed by Choudhary et al [7] were used to assess the cardiac performance.…”

“…Extracellular water (ECW) balance, recorded using whole-body impedance cardiography, was~4% higher in PA than in all other groups (P < 0.05 for all) [5]. This result is largely expected given that mineralocorticoids excess leads to fluid retention and may increase intravascular volume [2,6], even if a more extensive use of thiazides in medicated EH and greater use of insulin in PA patients might have amplified the difference regarding ECW [5].…”

“…Extracellular water (ECW) balance, recorded using whole-body impedance cardiography, was~4% higher in PA than in all other groups (P < 0.05 for all) [5]. This result is largely expected given that mineralocorticoids excess leads to fluid retention and may increase intravascular volume [2,6], even if a more extensive use of thiazides in medicated EH and greater use of insulin in PA patients might have amplified the difference regarding ECW [5]. By using radioisotope dilution techniques, Chobanian et al in 1961 already described slight increases in exchangeable sodium and extracellular fluid volume in a very small group of PA patients in comparison to EH subjects and normal controls [6], and similar results were obtained in subsequent investigations [7].…”

“…This is the reason why, despite continued aldosterone excess and hypervolemia, oedema does not develop in PA (2, 7). Choudhary et al observed in PA subjects' values of systemic vascular resistance index (SVRI) similar to those of EH patients, although the former showed mean radial and aortic pressures greater than the latter [5]. The greater use of vasodilators such as calcium antagonists or alpha-blockers, in PA patients compared to EH subjects, may have hidden a real difference between groups regarding this parameter.…”

“…In the current issue of Journal of Internal Medicine is published one of the largest studies regarding haemodynamics of PA. Choudhary et al compared the haemodynamic features of medicated PA, medicated EH, never-medicated EH and normotensive subjects (n = 130 in all groups), adding a new piece of evidence in the pathophysiological scenario of PA [5].…”