Subtyping of Primary Aldosteronism in the AVIS-2 Study: Assessment of Selectivity and Lateralization.

CONTEXT: Adrenal venous sampling (AVS) is the key test for subtyping primary aldosteronism (PA), but its interpretation varies widely across referral centers and this can adversely affect the management of PA patients. OBJECTIVES: To investigate in a real-life study the rate of bilateral success and identification of unilateral aldosteronism and their impact on blood pressure outcomes in PA subtyped by AVS. DESIGN AND SETTINGS: In a retrospective analysis of the largest international registry of individual AVS data (AVIS-2 study), we investigated how different cut-off values of the selectivity index (SI) and lateralization index (LI) affected rate of bilateral success, identification of unilateral aldosteronism, and blood pressure outcomes. RESULTS: AVIS-2 recruited 1625 individual AVS studies performed between 2000 and 2015 in 19 tertiary referral centers. Under unstimulated conditions, the rate of biochemically confirmed bilateral AVS success progressively decreased with increasing SI cut-offs; furthermore, with currently used LI cut-offs, the rate of identified unilateral PA leading to adrenalectomy was as low as <25%. A within-patient pairwise comparison of 402 AVS performed both under unstimulated and cosyntropin-stimulated conditions showed that cosyntropin increased the confirmed rate of bilateral selectivity for SI cut-offs ≥ 2.0, but reduced lateralization rates (P < 0.001). Post-adrenalectomy outcomes were not improved by use of cosyntropin or more restrictive diagnostic criteria. CONCLUSION: Commonly used SI and LI cut-offs are associated with disappointingly low rates of biochemically defined AVS success and identified unilateral PA. Evidence-based protocols entailing less restrictive interpretative cut-offs might optimize the clinical use of this costly and invasive test. (J Clin Endocrinol Metab XX: 0-0, 2020).

Remote ischemic preconditioning to reduce contrast-induced nephropathy: study protocol for a randomized controlled trial.

BACKGROUND: Despite the increasing use of pre- and posthydration protocols and low-osmolar instead of high-osmolar iodine-containing contrast media, the incidence of contrast-induced nephropathy (CIN) is still significant. There is evidence that contrast media cause ischemia-reperfusion injury of the medulla. Remote ischemic preconditioning (RIPC) is a non-invasive, safe, and low-cost method to reduce ischemia-reperfusion injury. METHODS: The RIPCIN study is a multicenter, single-blinded, randomized controlled trial in which 76 patients at risk of CIN will receive standard hydration combined with RIPC or hydration with sham preconditioning. RIPC will be applied by four cycles of 5 min ischemia and 5 min reperfusion of the forearm by inflating a blood pressure cuff at 50 mmHg above the actual systolic pressure. The primary outcome measure will be the change in serum creatinine from baseline to 48 to 72 h after contrast administration. DISCUSSION: A recent pilot study reported that RIPC reduced the incidence of CIN after coronary angioplasty. The unusual high incidence of CIN in this study is of concern and limits its generalizability. Therefore, we propose a randomized controlled trial to study whether RIPC reduces contrast-induced kidney injury in patients at risk for CIN according to the Dutch guidelines. TRIAL REGISTRATION: Current Controlled Trials ISRCTN76496973.

Plasma metanephrine for assessing the selectivity of adrenal venous sampling.

Adrenal vein sampling is used to establish the origins of excess production of adrenal hormones in primary aldosteronism. Correct catheter positioning is confirmed using adrenal vein measurements of cortisol, but this parameter is not always reliable. Plasma metanephrine represents an alternative parameter. The objective of our study was to determine the use of plasma metanephrine concentrations to establish correct catheter positioning during adrenal vein sampling with and without cosyntropin stimulation. We included 52 cosyntropin-stimulated and 34 nonstimulated sequential procedures. Plasma cortisol and metanephrine concentrations were measured in adrenal and peripheral venous samples. Success rates of sampling, using an adrenal to peripheral cortisol selectivity index of 3.0, were compared with success rates of metanephrine using a selectivity index determined by receiver operating characteristic curve analysis. Among procedures assessed as selective using cortisol, the adrenal to peripheral vein ratio of metanephrine was 6-fold higher than that of cortisol (94.0 versus 15.5; P<0.0001). There were significant positive relationships between adrenal to peripheral vein ratios of cortisol and metanephrine for cosyntropin-stimulated samplings but not for nonstimulated samplings. Receiver operating characteristic curve analysis indicated a plasma metanephrine selectivity index cutoff of 12. Using this cutoff, concordance in sampling success rates determined by cortisol and metanephrine was substantially higher in cosyntropin-stimulated than in nonstimulated samplings (98% versus 59%). For the latter procedures, sampling success rates determined by metanephrine were higher (P<0.01) than those determined by cortisol (91% versus 56%). In conclusion, metanephrine provides a superior analyte compared with cortisol in assessing the selectivity of adrenal vein sampling during procedures without cosyntropin stimulation.

Percutaneous radiofrequency ablation of osteoid osteomas with use of real-time needle guidance for accurate needle placement: a pilot study.

PURPOSE: To evaluate the accuracy and technical success of positioning a radiofrequency ablation (RFA) electrode in osteoid osteomas by use of a new real-time needle guidance technology combining cone-beam computed tomography (CT) and fluoroscopy. MATERIALS AND METHODS: Percutaneous RFA of osteoid osteomas was performed in five patients (median age 18 years), under general anesthesia, with the use of cone-beam CT and fluoroscopic guidance for electrode positioning. The outcome parameters were technical success, meaning correct needle placement in the nidus; accuracy defined as the deviation (in mm) from the center of the nidus; and clinical outcome at follow-up. RESULTS: In all five cases, positioning was possible within 3 mm of the determined target location (median nidus size 6.8 mm; range 5-10.2 mm). All procedures were technically successful. All patients were free of pain at clinical follow-up. No complications were observed. CONCLUSION: Real-time fluoroscopy needle guidance based on cone-beam CT is a useful tool to accurately position radiofrequency needles for minimally invasive treatment of osteoid osteomas.

In-vivo imaging of changes in abdominal aortic aneurysm thrombus volume during the cardiac cycle.

PURPOSE: To evaluate in-vivo thrombus compressibility in abdominal aortic aneurysms (AAAs) to hopefully shed light on the biomechanical importance of intraluminal thrombus. METHODS: Dynamic electrocardiographically-gated computed tomographic angiography was performed in 17 AAA patients (15 men; mean age 73 years, range 69-76): 11 scheduled for surgical repair and 6 under routine surveillance. The volumes of intraluminal thrombus, the lumen, and the total aneurysm were quantified for each phase of the cardiac cycle. Thrombus compressibility was defined as the percent change in thrombus volume between diastole and peak systole. Continuous data are presented as medians and interquartile ranges (IQR). RESULTS: A substantial interpatient variability was observed in thrombus compressibility, ranging from 0.4% to 43.6% (0.2 to 13.5 mL, respectively). Both thrombus and lumen volumes varied substantially during the cardiac cycle. As lumen volume increased (5.2%, IQR 2.8%-8.8%), thrombus volume decreased (3.0%, IQR 1.0%-4.6%). Total aneurysm volume remained relatively constant (1.3%, IQR 0.4-1.9%). Changes in lumen volume were inversely correlated with changes in thrombus volume (r = -0.73; p = 0.001). CONCLUSION: In-vivo thrombus compressibility varied from patient to patient, and this variation was irrespective of aneurysm size, pulse pressure, and thrombus volume. This suggests that thrombus might act as a biomechanical buffer in some, while it has virtually no effect in others. Whether differences in thrombus compressibility alter the risk of rupture will be the focus of future research.