OR02-6 Importance of Basal and Post ACTH Aldosterone Levels and Contralateral Aldosterone Suppression during Bilateral Simultaneous Adrenal Venous Sampling in Primary Aldosteronism

Program: Abstracts - Orals, Poster Previews, and Posters
Session: OR02-Renin-Angiotensin-Aldosterone - Bench to Bedside
Basic/Translational
Friday, April 1, 2016: 11:45 AM-1:15 PM
Presentation Start Time: 1:00 PM
Room 156 (BCEC)

Outstanding Abstract Award
Nada El Ghorayeb*1, Tania L Mazzuco1, Isabelle Bourdeau1, Eric Thérasse1 and André Lacroix2
1Centre de Recherche du Centre hospitalier de l’Université de Montréal, Montreal, QC, Canada, 2Centre de Recherche du Centre hospitalier de l’Université de Montréal, Montreal, QC, Canada
Background: Adrenal vein sampling (AVS) is required to preoperatively identify lateralized source in Primary Aldosteronism (PA).
Objectives: To evaluate the postoperative outcomes of patients undergoing unilateral adrenalectomy (UA) according to AVS lateralization ratios (LR) of aldosterone to cortisol of dominant side to the opposite side (A/C)DOM/(A/C)OPP ≥2 for basal and/or ≥4 post 250 μg bolus ACTH. To compare pre-op and post-op clinical and biochemical parameters according to various basal contralateral aldosterone (CL) suppression ratios.
Methods: 171 successful simultaneous bilateral AVS in a single referral center were retrospectively studied. Further analyses were performed on the 66/80 patients who underwent UA and had evaluable outcome data. CL suppression was determined by the ratio of basal aldosterone of opposite side/periphery AOPP/AP and compared to the ratio of (A/C)OPP/(A/C)P. Clinical improvement (CI) of PA was defined as achieving at least 2 criteria: BP <140/90, decrease in number of antihypertensive medications by ≥50%, normokalemia without need for supplements; clinical cure (CC) as BP <140/90 and normokalemia without any medications and biochemical cure (BC) by normalization of aldosterone/renin ratio.
Results: Using a post ACTH LR≥4 criteria, 33.8% displayed bilateral disease, 28.7% lateralized to the right and 37.6% to left. A discordance of lateralization between basal (LR≥2) and post-ACTH (LR≥4) values was observed in 28% of cases. Of the 66 patients who underwent UA, 26% achieved CC, 61% BC, 17% both, and 58% CI with significant change in post-op BP, K, PAC, renin and number of medications (p<0.001). In the subgroup (85% of UA patients) lateralizing basally (LR≥2) and post ACTH (LR≥4): 27% achieved CC, 55% BC, 16% both, and 55% CI. Among the 8 patients who lateralized only basally:  7 achieved BC, 6 CI, and 2 CC. The 2 patients lateralizing only post ACTH achieved BC and CI but not CC. 77% of UA patients displayed CL suppression using (A/C)OPP/(A/C)P <1.5. vs 30% only when using the AOPP/AP at the same cut-off. Patients in the group with CL suppression had more severe form of PA ie higher BP and PAC with lower pre-op K compared to non-suppressed group (p=0.02).  Absence of CL suppression was associated with lower rate of response to UA in terms of clinical and biochemical parameters with difference in CI (35% vs 67% p=0.01), CC (55% vs 13% p=0.0003) and overall cure (35% vs 9% p=0.0003) using AOPP/AP. In contrast, no difference noted for CC or BC when using (A/C)OPP/(A/C)P.
Conclusions: Although ACTH stimulation is useful to improve selectivity of AVS, it can modify interpretation of lateralization in 28% of cases; therefore basal ratios are as important as post ACTH ratios to set an indication of UA. CL suppression is a valuable tool in AVS interpretation and helps predict post-op outcomes and potential cure from PA. AOPP/AP provided superior results compared to (A/C)OPP/(A/C)P

Nothing to Disclose: NE, TLM, IB, ET, AL

*Please take note of The Endocrine Society's News Embargo Policy at https://www.endocrine.org/news-room/endo-annual-meeting/pr-resources-for-endo

Sources of Research Support: CIHR grant 201209NMD to AL & IB; Novartis Canada partially supports NEG fellowship.