[Value of adrenal venous sampling in the subtype diagnosis of primary aldosteronism].

Abstract

To assess the diagnostic value of adrenal venous sampling (AVS) in the subtype diagnosis of primary aldosteronism (PA). The diagnosis of PA was made in 36 patients based on an elevated ratio of plasma aldosterone (ALD) to plasma rennin activity (PRA) (ARR) and confirmed tests (saline infusion or captopril challenge) in recent 3 years. All PA patients underwent adrenal computed tomographic scan (CT) and AVS. The diagnostic accuracy of CT and AVS in the subtype differentiation of PA were evaluated by comparing the differences of CT findings, AVS results and clinical outcomes. Fifteen of 36 patients (42%) had a final diagnosis of aldosterone-producing adenoma (APA) and another 21 patients (58%) with bilateral adrenal hyperplasia (BAH). The level of ALD was significantly higher in APA group than that in BAH group (298.9 ± 91.0 vs 226.3 ± 59 ng/L, P < 0.05). PRA (ng×ml(-1)×h(-1)) in APA patients were markedly lower than that in BAH counterparts (0.18 ± 0.14 vs 0.28 ± 0.29 ng×ml(-1)×h(-1), P < 0.01). Consequently, ARR in APA group was evidently higher than that in BAH group (2444.7 ± 1405.2 vs 1550.0 ± 1059.8, P < 0.05). Plasma potassium in APA patients was lower than that in those with BAH (2.71 ± 0.57 vs 3.17 ± 0.40 mmol/L). But there was no statistic significance (P > 0.05). The CT findings were discordant with the AVS results in 27.8% of patients (10/36). The accuracy of adrenal CT scan was only 72.2% in the subtype diagnosis of PA, provided AVS was the gold standard for distinguishing between APA and BAH. Reliance on CT findings could lead to inappropriate management in 25% of PA patients. Conversely, the AVS results were concordant with the clinical outcomes in 94.4% of all patients. CT scan is not a reliable method of differentiating primary aldosteronism. Compared with CT, AVS is more accurate in establishing a correct diagnosis of primary aldosteronism. AVS should be performed routinely before operation in PA patients opting for adrenalectomy.