Objectives To compare plasma concentrations of biomarkers of endothelial dysfunction between primary aldosteronism (PA) and essential hypertension (EH), and to determine whether elevated levels of these biomarkers predict development of early organ damage.

Methods Thirty-six cases with PA and 39 controls with EH individually matched for age, sex, blood pressure and duration of hypertension were assessed in this study. Plasma levels of biomarkers reflecting endothelial dysfunction (von Willebrand factor [vWF], soluble intercellular adhesion molecule 1 [sICAM-1], and oxidised low density lipoprotein [ox-LDL]) were detected and compared between cases with PA and their matched controls. Left ventricular mass index (LVMI) determined by echocardiography, 24-hour urinary protein quantitative determination and urinary albumin excretion rate (UAER) were adopted to evaluate early organ damage. Left ventricular hypertrophy was defined as LVMI > 125 g/m² in men and > 120 g/m² in women, and microalbuminuria was defined as UAER of between 20 µg/min and 200 μg/min.

Results The biomarkers of endothelial dysfunction (vWF and sICAM-1), as well as ox-LDL, LVMI, 24-hour urinary protein quantitation (24h UPQ) and UAER, were significantly higher in PA cases than in EH controls (vWF [%], 122.3 ± 53.8 vs 113.1 ± 68.3; sICAM-1 [ng/mL], 401.0 ± 74.1 vs 300.9 ± 87.0; ox-LDL [U/L], 13.6 ± 10.0 vs 8.1 ± 5.9; LVMI [g/m²], 124.7 ± 33.6 vs 109.1 ± 25.7; 24h UPQ [g], 0.17 ± 0.10 vs 0.09 ± 0.04 and UAER [µg/min], 25.9 ± 7.7 vs 9.7 ± 5.9, all P values < 0.05). Elevated plasma vWF, sICAM-1 levels and plasma aldosterone concentration independently predicted incident microalbuminuria in multiple regression models; whereas, elevated plasma vWF and ox-LDL levels, plasma aldosterone concentration and systolic blood pressure independently predicted left ventricular hypertrophy.

Conclusions Patients with PA have greater endothelial dysfunction reflected by multiple biomarkers and early organ damage than with EH, and plasma aldosterone concentration and multiple endothelial dysfunction biomarkers predict early organ damage independently.