Seated saline infusion test in predicting subtype diagnosis of primary aldosteronism

Abstract

Context:Although saline infusion test is widely used as a confirmatory test for primary aldosteronism (PA), it is reportedly less sensitive in patients in whom aldosterone is responsive to the upright position by performing it in recumbent position.Based on a single-centre experience, seated saline infusion test (SSIT) has been reported to be highly sensitive and superior to recumbent testing in identifying both unilateral and bilateral forms of PA. However, due to limited participants number, the utility of SSIT needs to be validated in other series.Objective: This study aimed to evaluate the accuracy of SSIT in determining the PA subtypes compared with adrenocorticotropic hormone stimulation test under dexamethasone suppression (Dex-AT). Patients and Setting: Sixty-four patients with PA who underwent both SSIT and Dex-AT were included. Subtype diagnosis of PA was determined by adrenal venous sampling (AVS) (16 unilateral and 48 bilateral forms). Main Outcome Measure: Plasma aldosterone concentrations (PACs) were measured after SSIT and Dex-AT. Results:The area under the receiver operating characteristic (ROC) curve for diagnosing unilateral PA was greater in SSIT than that in Dex-AT (0.907 vs. 0.755; P = .023).ROC curve analysis predicted optimal cut-off PACs of 13.1 ng/dL (sensitivity, 93.8%; specificity, 79.2%) for SSIT and 34.2 ng/dL (sensitivity, 75.0%; specificity, 68.8%) for Dex-AT.Conclusions: Seated saline infusion test has superior accuracy in subtype diagnosis of PA compared with Dex-AT. SSIT can be a sensitive test for determining patients who require AVS prior to surgery. K E Y W O R D Sadrenal cortex function tests, adrenocortical adenoma, aldosterone, cosyntropin, hyperaldosteronism, hypertension, renin-angiotensin system

Use of peripheral plasma aldosterone concentration and response to ACTH during simultaneous bilateral adrenal veins sampling to predict the source of aldosterone secretion in primary aldosteronism

“…Also, these three comparative studies were done in Asian populations with PA which can have differences in ion channel mutations and MC2R expression in the tumours. A recent study in a Japanese population found that PAC following seated saline infusion test is more predictive (sensitivity, 93.8%; specificity, 79.2%) for lateralization than PAC following ACTH stimulation test under dexamethasone suppression (sensitivity, 75.0%; specificity, 68.8%) . A previous study in a predominant Caucasian population did not report the cut‐off for maximal peripheral PAC following ACTH associated with 90% specificity to discriminate lateralized PA from nonlateralized PA …”

Reassessment of Urinary Aldosterone Measurement After Saline Infusion in Primary Aldosteronism

“…All patients were diagnosed with PA according to the guidelines of the Japan Endocrine Society [ 13 ] and Japanese Society of Hypertension [ 14 ], including case detection and confirmatory tests. Case detection and confirmatory tests of PA and AVS were performed and evaluated as previously described [ 6 ]. Before the diagnosis, antihypertensive drugs were generally changed to calcium channel blockers and/or α-adrenergic blockers.…”

“…SSIT was performed as previously described in a hospitalized setting [ 6 ]. Briefly, patients remained in the sitting position during the transvenous infusion of 2 L of 0.9% saline, which contains 18 g sodium chloride, over 4 hours starting at 0900 am (Day 2).…”

“…We and others previously showed that plasma aldosterone concentrations (PAC) after seated saline infusion test (SSIT) are useful in predicting subtype diagnosis of PA [ 6 , 7 ]. However, aldosterone secretion is not constant; aldosterone is secreted in a pulsatile manner throughout the day [ 8 ].…”

Recent Development toward the Next Clinical Practice of Primary Aldosteronism: A Literature Review

“…Reassessment of the cut-off values for confirmatory tests also brought an additional meaning in subsequent subtyping. With relatively small number of PA patients, a Japanese group revealed another aspect of SIT as a subtyping tool [ 137 ]. Based on the analysis of the receiver operating characteristic curve, they proposed an optimal cut-off value of PAC after seated saline infusion as 13.1 ng/dL for subtype prediction, which had a sensitivity of 0.94 and a specificity of 0.79 for unilateral PA [ 137 ].…”