JS-NG-7: ASSOCIATION BETWEEN PLASMA ALDOSTERONE CONCENTRATION AND AMBULATORY BLOOD PRESSURE PROFILE IN PATIENTS WITH PRIMARY ALDOSTERONISM

Abstract

Background: Primary aldosteronism (PA) is a major cause of curable hypertension with its morbidity rate 5–10% in hypertensive patients reported, and thus is highly prevalent in patients with hypertension, a cause of resistant hypertension, and closely associated with target organ damage compared with essential hypertension. Although an altered circadian blood pressure (BP) rhythm estimated by ambulatory blood pressure monitoring (ABPM) has been highlighted as a major contributor of CVD in essential hypertension, there would be very few reports investigating clinical significance of ABPM in PA patients. Therefore, we aimed to examine a possible association between plasma aldosterone concentration (PAC) and ABPM profile in PA patients. Methods: Consecutive 27 PA patients, who had been diagnosed by the functional tests and underwent adrenal venous sampling (AVS) from April 2015 to March 2020, were included in this study. All clinical indexes including 24-hour ABPM were measured during the hospitalization, and all participants received dietary salt restriction with 6 g/day of salt. The 24-hour ABPM was performed from the first day of hospitalization to the next day, and AVS was performed on the third day in the morning. Regarding PAC measurement, we collected blood samples during AVS. After resting for 30 minutes in a supine position, blood samples were collected from inferior vena cava by catheterization. During AVS, we also performed ACTH stimulation, and blood samples were collected essentially 1 hour after the stimulation. Results: We firstly analyzed a correlation between PAC and ABPM profile and found that PAC measured after ACTH stimulation (post-PAC) was negatively correlated with nocturnal dipping rate in both systolic and diastolic BPs (SBP and DBP) (R = -0.430, P = 0.025, and R = -0.431, P = 0.025, respectively), while PAC measured before ACTH stimulation (pre-PAC) was not. Thus, according to the median of post-PAC, we divided participants into lower PAC and higher PAC groups and compared clinical characteristics between the two groups. Compared to the lower PAC group, nocturnal SBP and DBP dipping rates and serum potassium levels were significantly decreased in the higher PAC group (SBP dipping 10.3 ± 6.4 vs 3.5 ± 7.7 %, P = 0.02; DBP dipping 13.6 ± 7.7 vs 5.5 ± 6.3 %, P = 0.01; serum potassium 4.1 ± 0.3 vs 3.7 ± 0.4 mEq/L, P = 0.03). Conclusions: In this cross-sectional study, higher PAC was significantly associated with a non-dipper circadian BP profile characterized by lower nocturnal BP dipping rates in PA patients. Prospective longitudinal study is warranted to seek for a causal relationship between hyperaldosteronism and ABPM profile.