Comparisons of skin microvascular changes in patients with primary aldosteronism and essential hypertension

The aim of our cross-sectional study was to evaluate skin microvascular alterations in patients with hypertension secondary to primary aldosteronism (PA) and in subjects with essential hypertension (EH). Skin microcirculation was detected by nailfold videocapillaroscopy (NVC) and laser Doppler perfusion imaging (LDPI), both noninvasive techniques for the evaluation of digital capillaroscopic damage and hand skin blood perfusion. From September 2018 to April 2019, we consecutively enrolled 80 patients, of whom 42 had PA and 38 had EH. A morphological and structural study of cutaneous microcirculation was carried out through NVC, while functional evaluation of the peripheral microcirculation was carried out with LDPI. Using LDPI indices, dermal perfusion gradients were calculated in various regions of interest at the level of the back of the hand (ROI1 and ROI2). No differences between the two groups in NVC parameters were found. In contrast, LDPI showed worse skin perfusion parameters in patients with PA compared with patients with EH (ROI1: 143.9 ± 29.9 pU vs 163.3 ± 35.2 pU, p = 0.01; perfusion gradient ROI1-ROI2: 62.4 ± 28.8 pU vs 79.3 ± 33.5 pU, p = 0.019). Furthermore, the ROI1-ROI2 (proximal-distal) perfusion gradient was negatively correlated with aldosterone plasma levels (r -0.269; p = 0.017). Multivariate analysis showed that aldosterone was significantly associated with the ROI1-ROI2 perfusion gradient (b -0.220; p = 0.044). Patients with PA showed altered skin perfusion and greater microvascular dysfunction compared with the EH group. Our results are consistent with the hypothesis that aldosterone may have a pathophysiological role in microvascular remodeling in patients with PA, with predominant functional dysfunction.