Combination of Aldosterone to Renin Ratio and Plasma Aldosterone Concentration Is Useful in Detecting Unilateral Subtype of Primary Aldosteronism

Presentation Number: LB SAT 66
Date of Presentation: April 1st, 2017

Yui Shibayama*1, Norio Wada1, Hironobu Umakoshi2, Takamasa Ichijo3, Yuichi Fujii4, Kohei Kamemura5, Tatsuya Kai6, Ryuichi Sakamoto7, Atsushi Ogo7, Yuichi Matsuda8, Tomikazu Fukuoka9, Mika Tsuiki2, Tomoko Suzuki10 and Mitsuhide Naruse2
1Sapporo City General Hospital, Sapporo, Japan, 2National Hospital Organization Kyoto Medical Center, Kyoto, Japan, 3Saiseikai Yokohamashi Tobu Hospital, Yokohama, Japan, 4Hiroshima General Hospital of West Japan Railway Company, Hiroshima, Japan, 5Akashi Medical Center, Akashi, Japan, 6Sakurakai Hospital, Japan, 7Kyushu Medical Center, Fukuoka, Japan, 8Sanda City Hospital, Sanda, Japan, 9Matsuyama Red Cross Hospital, Matsuyama, Japan, 10Kitasato University

Abstract

Objectives: In primary aldosteronism (PA), although aldosterone/renin ratio (ARR) has been utilized as the most reliable screening test of PA, very low plasma renin activity (PRA) could cause a false positive result even if plasma aldosterone concentration (PAC) is not increased. Previous studies reported patients with low PAC were rarely diagnosed as APA. Some investigators included a minimum PAC of 150pg/ml for the screening criteria. Others indicated 100pg/ml to reduce the risk of missing APA. The aim of this study is to investigate the significance of PAC added on ARR for diagnosis of unilateral disease by adrenal venous sampling (AVS).

Patients and Methods: This study was conducted as a part of multi-center collaborative study on AVS in Japan (WAVES-J study). Data of 449 patients (198 men, 251women, mean age 54.3 ± 11.1 y) from 9 centers with basal ARR >200 and at least one positive result of confirmatory testing, including the captopril challenge test, the upright furosemide-loading test and the saline loading test were studied. All patients underwent AVS. PRA, PAC and ARR were evaluated using the basal values at diagnosis. We divided the patients into the following four groups, PAC≦100pg/ml (Low PAC group, n=54), PAC 100-120pg/ml (Normal PAC group, n=39), PAC 120-150pg/ml (High normal PAC group, n=81), and PAC>150pg/ml (High PAC group, n=275). Unilateral disease in AVS was determined by both lateralization index (LI) >4 and contralateral ratio (CR) <1 after ACTH stimulation.

Results: Ninety-seven (22%) patients were determined as unilateral disease in AVS. The minimal value of basal PAC in the patients determined as unilateral disease was 95pg/ml. One (1.9%, 1/54) patient in Low PAC group, 1 (2.6%, 1/39) patient in Normal PAC group, 5 (6.2%, 5/81) patients in High normal group and 90 (32.7%, 90/275) patients in High PAC group had unilateral disease in AVS. The prevalence of the patients with unilateral disease was significantly higher in high PAC group than that in other three groups (p<0.001). When we set the cut-off value of 120pg/ml, we could detect 98% patients with unilateral disease.

Conclusions: In screening for PA, the combination of ARR (>200) and PAC can not only reduce false positive cases, but also find efficiently cases with unilateral subtype in AVS who are possibly cured by unilateral adrenalectomy. Considering the cut-off value of PAC from the viewpoint of preventing to miss the cases with unilateral subtype in AVS, PAC 150pg/ml is a reasonable criterion and PAC 100pg/ml or 120pg/ml are strict criteria. It can become a new rationale of case detection for PA.

 

Disclosure: MT: Investigator, ONO-Pharma. Nothing to Disclose: YS, NW, HU, TI, YF, KK, TK, RS, AO, YM, TF, TS, MN