Abstract 19331: The Adrenal Vein Sampling International Study-2: Results in 1636 Primary Aldosteronism Patients

Abstract

Background: Guidelines recommend Adrenal vein sampling (AVS) for the subtyping of primary aldosteronism (PA), the most common curable cause of arterial hypertension. How this recommendation is implemented in practice remains uncertain. Hence, in 2011 upon completion of the AVIS-1 Study we launched the AVIS-2 Study to determine: 1) the success rate of the AVS studies performed in major referral centers worldwide; 2) the impact of AVS results on the clinical decision making and on outcome of the patients at follow-up. Methods: All the AVIS-1 Study centers were invited to join the AVIS-2 by entering the individual PA patients AVS and clinical data in an ad hoc predefined web-based database. Data were analyzed according to use of cosyntropin unstimulated or -stimulated protocols. Results and Conclusions: Sixteen centers in Europe, North America and Asia recruited a total of 1656 PA patients (age 50 years ± 10; 39.5% females). The AVS success rate was examined as a function of the Selectivity Index (SI) cutoffs. Among unstimulated AVS (n = 1307), the rate of bilaterally selective tests fell from 86% to 53% and 45% with cut off values of 1.10, 2.00 and 3.00, respectively; for adrenalectomized patients (49% of total), the decision was based on bilateral selective AVS in 71%, 56% and 43% of cases, respectively. Among cosyntropin-stimulated AVS, 85%, 80%, 76% and 72% were bilaterally selective, with a cut-off of 2.00, 3.00, 4.00, and 5.00, respectively; the rate of adrenalectomy based on AVS data fell from 47% with a cut-off = 2.00 to 40% with a cut-off = 5.00. The lateralization index value did not improve by comparing those with SI bilaterally > 2.0 (baseline) and > 5.0 after cosyntropin (3.8 [median, 1.6-12.7 IQR] vs 3.7 [1.5-14.0]). Conclusions: Only a minority of PA submitted to AVS have bilaterally selective studies if high cutoffs for the SI are used. Moreover, in even less patients AVS eventually led to adrenalectomy. These intriguing results from the largest dataset of AVS studies provide compelling evidence for the need of further prospective studies in this field.