Diagnostic Significance Of Aldosterone Gradient Within Left Adrenal Vein Of Adrenal Venous Sampling In Primary Aldosteronism Subtyping

Background:Previous studies have shown that the aldosterone gradient within left adrenal vein(referred to as the left-sided gradient)can be used to diagnose left-sided dominant secretion in patients with primary aldosteronism(PA).However,there is currently no research on the use of left gradient in diagnosing left-sided dominant secretion in PA patients during adrenal vein sampling(AVS)without adrenocorticotropic hormone(ACTH)stimulation.Objective:To explore the value of left-sided gradient in the diagnosis of left dominant secretion of PA in AVS without ACTH stimulation.Methods:This study enrolled patients with PA who visited the Department of Cardiology at the Second Affiliated Hospital of Nanchang University from January 1,2018,to December 31,2021,and had successful AVS at three blood draw sites(right adrenal vein,left adrenal common trunk vein,and left adrenal central vein).Left-sided gradient was calculated using the ratio of aldosterone/cortisol(A/C)between the common trunk vein and the central vein.The data with successful AVS at both left and right adrenals veins were used as the gold standard for subtype diagnosis.Receiver operating characteristic curve(ROC)was used to analyze the sensitivity and specificity of left-sided gradient in diagnosing left-dominant secretion in patients with PA.Results:A total of 97 patients with PA were included.The plasma aldosterone concentration(PAC)and plasma cortisol concentration(PCC)in the left adrenal common trunk vein were both lower than those in the central vein(P<0.001),but there was no statistically significant difference in A/C and lateralization index(LI)between the two sampling sites(P=0.89).In the overall population,the area under the receiver operating characteristic curve(AUC)of left-sided gradient for diagnosing left-sided dominant secretion in patients with PA was 0.699(95% CI: 0.595-0.804).The cutoff value of left-sided gradient for diagnosing left-sided dominant secretion in patients with PA at the highest specificity was 3,with a specificity of 95.74% and a sensitivity of 14.00%.In typical populations,including those PA with hypokalemia,left adrenal adenoma and both,the AUCs of left-sided gradient for diagnosing left-sided dominant secretion in patients with PA were 0.776(95% CI: 0.623-0.929),0.946(95% CI: 0.838-1.000),and 1.000(95% CI: 1.000-1.000),respectively;the cutoff values of left-sided gradient for achieving a specificity of 100% were 2.000,1.762,and 1.611,respectively;and the corresponding sensitivities were 40.91%,81.82%,and 100%.Conclusion:1)The left-sided gradient may be a useful tool for identifying left-sided dominant secretion in patients with PA who have successful left AVS,and for subtyping cases with difficulty in right AVS,especially those with aldosterone combined with hypokalemia,left adenoma,and both.2)The PAC and PCC in the left adrenal common trunk vein were both lower than those in the central vein,but there was no statistically significant difference in A/C and LI between the two sampling sites.