A Study Of The Diagnostic Efficacy Of The Sitting Saline Test For Primary Aldosteronism

SEATED SALINE SUPPRESSION TESTING IS COMPARABLE TO CAPTOPRIL CHALLENGE TEST FOR THE DIAGNOSIS OF PRIMARY ALDOSTERONISM:A PROSPECTIVE STUDYObjective: Saline Suppression Testing(SST)and captopril challenge test(CCT)are commonly used confirmatory tests for primary aldosteronism(PA).Seated SST is reported to be superior to recumbent SST.Whether SSST is better than CCT remain unclear.We aimed to compare the diagnosis of accuracy of SSST and CCT in a prospective study.Methods: Hypertensive patients with high risk of PA were consecutively included.Patients with aldosteronism-renin ratio ?1.0ng.dl^-1/u IU.ml^-1 were asked to complete SSST,CCT and fludrocortisone suppression test(FST).Using FST as the reference standard(plasma aldosterone concentration [PAC] post-FST?6.0ng/dl),area under the receiver-operator characteristic curves(AUC),sensitivity and specificity of SSST and CCT were calculated,and multiple regression analyses were conducted to identify potential factors for false diagnosis.Result: A total of 196 patients diagnosed as PA and 73 as essential hypertension completed the study.Using PAC post-SSST and PAC post-CCT to confirm PA,SSST and CCT had comparable AUCs(AUCSSST 0.87 [95%CI(0.82,0.91)] vs.AUCCCT 0.88 [95%CI(0.83,0.95)],P=0.646).Setting PAC post-SSST and post-CCT at 8.5ng·dl^-1 and 11.0ng·dl^-1,respectively,the sensitivity and specificity of SSST [0.72(0.65,0.78)and0.86(0.76,0.93)] and CCT [0.73(0.67,0.80)and 0.85(0.75,0.92)] were not statistically different.In the multiple regression analyses,1SD increment of sodium intake resulted in 40% lower risk of false diagnosis in SSST.Conclusions: SSST and CCT have comparable diagnostic accuracy.Insufficient sodium intake decreases the diagnostic efficiency of SSST,not CCT.Since the CCT is simpler and cheaper,it is preferable to the SSST.IMMUNOHISTOCHEMICAL,GENETIC AND CLINICAL CHARACTERIZATION OF UNILATERAL PRIMARY ALDOSTERONISM WITH COMPUTED TOMOGRAPHY IMAGE NEGATIVEObjective: Computed tomography(CT)is often used to classify subtype of primary aldosteronism.Howerver,CT has a detection limit in small adrenal mass lesion.Immunohistochemical,genetic and clinical characterization of unilateral primary aldosteronism(UPA)with CT positive(defined as diameter of adrenal nodules more than or equal to10mm)have been reported,but it has been seldomly reported on immunohistochemical,genetic and clinical characterization of unilateral primary aldosteronism with CT negative.To investigate the genetic mutation rate,clinical and immunohistological characteristics of patients with CT negative UPA in a Chinese cohort.Method: A total of 60 UPA patients with CT negative and 204 UPA patients with CT positive were included retrospectively.All patients underwent unilateral adrenalectomy and achieved complete biochemical success after surgery.Adrenal specimens of 30 UPA patients with CT negative and 12 UPA patients with CT positive were collected.The tumor specimens were stained by Aldosterone Synthase(CYP11B2)and the staining were quantified by Mc Carty's H-score system.Somatic mutations of KCNJ5,ATP1A1,ATP2B3 and CACNA1 D gene were studied in 47 UPA patients with CT negative and 189 UPA patients with CT positive.Results: Potassium is higher in CT negative UPA than in CT positive UPA [3.34±0.54 vs.3.03±0.6mmol/l,P<0.05];Plasma aldosterone level in CT negative UPA is lower [27.1(20.4,35.8)vs.34.5(23.6,51.7)ng/dl,P<0.05].H-Score of CYP11B2 in CT negative group is higher than that in CT positive group,the score is 197(165,230)and 162(150,185),respectively(P<0.05).the number of APCC is 4(3,8)and 2(0,4)between two groups(P<0.05).30 cases with CT negative were classified as unilateral multiple adrenalcortical micronodules(UMN),single adrenalcortical micronodule and multiple aldosterone-producing cell cluster(APCC)based on CYP11B2 immunohistochemistry.No difference is found in blood pressure,potassium,plasma aldosteronism level in three subgroups.Somatic mutation is detected in 31 patients in 47 CT negative group,and 159 patients in 189 CT positive group;the prevalence of KCNJ5 mutation is 55%(27 cases)and 82%(155 cases)between two groups,ATP1A1 mutation is 4.3%(2 cases)and 1%(2 cases);ATP2B3 is 6.4%(3cases)and 1%(2 cases);No CACNA1 D mutation is detected.Compared with CT positive UPA patients,CT negative UPA patients have a lower mutation rate[65.9% vs.84%,P<0.05].Conclusion: Compared with UPA with CT positive,UPA patients with CT negative have a milder clinical characteristics.The increase of APCC is an important pathological features in CT negative UPA.