Marie-Josée Desrochers, Matthieu St-Jean, Nada El Ghorayeb, Isabelle Bourdeau, Benny So, Éric Therasse, Gregory Kline, and André Lacroix
Unilateral aldosteronomas should suppress renin and contralateral aldosterone secretion. Complete aldosterone suppression in contralateral adrenal vein sample (AVS) could predict surgical outcomes.
To retrospectively evaluate the prevalence of basal contralateral suppression using Aldosterone (A)contralateral(CL)/Aperipheral(P) as compared to (A/Cortisol(C)CL)/(A/C)P ratio in primary aldosteronism (PA) patients studied in two Canadian centers. To determine the best cut-off to predict clinical and biochemical surgical cure. To compare the accuracy of ACL/AP to the basal and post-ACTH lateralization index (LI) in predicting surgical cure.
In total, 330 patients with PA and successful AVS were included; 124 lateralizing patients underwent surgery. Clinical and biochemical cure at 3 and 12 months were evaluated using the PASO criteria.
Using ACL/AP and (A/C)CL/(A/C)P at the cut-off of 1, the prevalence of contralateral suppression was 6 and 45%, respectively. Using ROC curves, the ACL/AP ratio is associated with clinical cure at 3 and 12 months and biochemical cure at 12 months. (A/C)CL/(A/C)P is associated with biochemical cure only. The cut-offs for ACL/AP offering the best sensitivity (Se) and specificity (Sp) for clinical and biochemical cures at 12 months are 2.15 (Se: 63% and Sp: 71%) and 6.15 (Se: 84% and Sp: 77%), respectively. Basal LI and post-ACTH LI are associated with clinical cure but only the post-ACTH LI is associated with biochemical cure.
In lateralized PA, basal contralateral suppression defined by ACL/AP is rare and incomplete compared to the (A/C)CL/(A/C)P ratio and is associated with clinical and biochemical postoperative outcome, but with modest accuracy.
Jessica Boyd, Alexander A Leung, Hossein SM Sadrzadeh, Christina Pamporaki, Karel Pacak, Timo Deutschbein, Stephanie Fliedner, and Gregory A Kline
Determine rate of high plasma normetanephrine or metanephrine (PNM-PMN) in a large sample of patients according to PNM-PMN posture and age-adjusted references.
Retrospective re-analysis of PNM-PMN from a Canadian reference laboratory (n = 5452), 2011–2015; most were in seated position (n = 5112) rather than supine (n = 340). An international PPGL database demonstrated expected distribution of supine PNM-PMN in PPGL patients.
All PNM-PMN from a tertiary referral laboratory were reviewed. Any PNM-PMN result greater than 2× upper reference limit (URL) was considered likely true PPGL. Results 1–2× URL were uncertain, requiring additional testing/follow-up despite most being false positive given the rarity of PPGL. The rate of results in the 1–2× URL category were calculated for each group according to collection posture and differing published URL: seated, supine or supine age adjusted.
When collected and interpreted by seated URL, 19.6% of PNM required additional testing; only 4.6% being >2× URL. For patients over age 50 years, the abnormal rate was 24.9%. When collected supine, interpreted by supine age-adjusted URL, only 5.3% of PNM were mildly elevated. Possible false positives may be even lower when considering PMN or plasma methoxytyramine which were commonly high in true PPGL despite mild PNM elevations.
In a general medical population, seated PNM has a high rate of abnormal results, far exceeding expected prevalence. Supine measurement with supine, age-adjusted interpretation is strongly preferred prior to costly or invasive PPGL investigations.
Review of 5452 plasma normetanephrine measurements showed 20% to be high, likely false positives for most. Supine, age-adjusted measures were half as likely to be elevated.