Search

Aldosterone secretion in primary aldosteronism (PA) is often regulated by adrenocorticotropic hormone (ACTH) in addition to its autonomous secretion. However, the clinical characteristics and risk of cardiovascular and cerebrovascular (CCV) events in PA patients with aldosterone responsiveness to ACTH stimulation remain unclear. This study aimed to investigate the prevalence of CCV events in PA patients with high aldosterone responsiveness to ACTH stimulation. A retrospective cross-sectional study was conducted as part of the Japan Primary Aldosteronism Study/Japan Rare Intractable Adrenal Disease project. PA patients with adrenal venous sampling (AVS) between January 2006 and March 2019 were enrolled. The ACTH-stimulated plasma aldosterone concentration (PAC) of the inferior vena cava during AVS was used to evaluate aldosterone responsiveness to ACTH. We analyzed the relationship between responsiveness and previous CCV events. Logistic regression analysis demonstrated that the ΔPAC (the difference between the PAC measurements before and after ACTH stimulation) significantly increased the odds of previous CCV events in PA patients after adjusting for classical CCV event risk factors, baseline PAC and duration of hypertension (relative PAC: odds ratio [OR], 2.896; 95% confidence interval [CI], 0.989-8.482; ΔPAC: OR, 2.344; 95% CI, 1.149-4.780; ACTH-stimulated PAC: OR, 2.098; 95% CI, 0.694-6.339). This study clearly demonstrated that aldosterone responsiveness to ACTH is closely related to previous CCV events. The responsiveness of the PAC to ACTH could be useful in predicting CCV event risk.Registration Number in UMIN-CTR is UMIN000032525.

Hyperkalemia is developed in a part of patients with aldosterone-producing adenoma (APA) after adrenalectomy, suspected to be due to the insufficiency of aldosterone secretion. The purpose of this study is to determine the frequency and characteristics of prolonged postoperative hypoaldosteronism (PPHA) using chemiluminescent enzyme immunoassay (CLEIA). We studied 58 patients with APA with long time after adrenalectomy and whose PAC was measured using a CLEIA kit. The PAC value measured using CLEIA was significantly lower than that of using RIA between two consecutive visits before and after the shift of measuring method of PAC (median [interquantile range], 123.0 [99.8-164.0] vs. 39.5 [15.8-64.2] pg/mL, p < 0.01). PAC was below the minimum limit of quantification (4.0 pg/mL) of the CLEIA kit at least once in nine patients (15.5%) who had PPHA. The PPHA group were older (mean ± standard deviation, 61.3 ± 8.5 vs. 50.5 ± 10.1 years, p < 0.01) and had lower eGFR (60.3 ± 14.0 vs. 82.3 ± 22.8 mL/min/1.73 m 2 , p < 0.01) than the non-PPHA group. The frequency of postoperative hyperkalemia (maximum serum potassium >5.5 mEq/L) was higher in the PPHA group than in the non-PPHA group (55.6% vs. 8.2%, p < 0.01). In conclusion, a few patients with APA long time after adrenalectomy had unmeasurable PAC using CLEIA. PPHA is likely to develop in patients with APA after adrenalectomy who are older and have impaired renal function. Additionally, PPHA is related to the occurrence of postoperative hyperkalemia.

In Japan, the standard method for measuring plasma aldosterone concentration (PAC) for primary aldosteronism (PA) diagnosis was changed from radioimmunoassay (RIA) to a novel chemiluminescent enzyme immunoassay (CLEIA). The purpose of this study is to simulate the possible impact of the change on PA diagnosis. This retrospective study assessed 2,289 PA patients. PACs measured by conventional RIA were transformed to estimated PACs (CLEIA) as follows: RIA (pg/mL) = 1.174 × CLEIA (pg/mL) + 42.3. We applied the estimated PAC (CLEIA) to the conventional cut-off of aldosterone-to-renin activity ratio ≥200 for screening and captopril challenge test (CCT) and PAC ≥60 pg/mL for saline infusion test (SIT). Application of the estimated PAC to screening and confirmatory tests decreased the number of PA diagnoses by 36% (743/2,065) on CCT and 52% (578/1,104) on SIT (discrepant cases). Among the discrepant cases, 87% (548/628) of CCT and 87% (452/522) of SIT were bilateral on adrenal venous sampling (AVS). Surgically treatable aldosterone-producing adenomas (APAs) were observed in 6% (36/579) and 5% (23/472) of discrepant cases on CCT and SIT, respectively; most were characterized by hypokalemia and/or adrenal nodule on CT imaging. Application of the PAC measured by the novel CLEIA to conventional cut-offs decreases the number of PA diagnoses. Although most discrepant cases were bilateral on AVS, there are some APA cases that were characterized by hypokalemia and/or adrenal tumor on CT. Further studies which evaluate PACs measured by both RIA and CLEIA for each patient are needed to identify new cut-offs for PAC measured by CLEIA.