Rapid Cortisol Assay during Adrenal Vein Sampling in Patients with Primary Aldosteronism

Adrenal Vein Sampling for Primary Aldosteronism: Recommendations From the Australian and New Zealand Working Group

Adrenal vein sampling (AVS) is the current recommended procedure for identifying unilateral subtypes of primary aldosteronism (PA), which are amenable to surgery with the potential for cure. AVS is a technically challenging procedure usually undertaken by interventional radiologists at tertiary centres. However, there are numerous variations in AVS protocols relating to patient preparation, sampling techniques and interpretation which may impact the success of AVS and patient care. To reduce practice variations, improve the success rates of AVS and optimise patient outcomes, we established an Australian and New Zealand AVS Working Group and developed evidence-based expert consensus recommendations for the preparation, performance and interpretation of AVS. These recommendations can be used by all healthcare professionals in a multidisciplinary team who look after the diagnosis and management of PA.

Unilaterally Selective Adrenal Vein Sampling for Identification of Surgically Curable Primary Aldosteronism

BACKGROUND

Adrenal venous sampling is recommended for the identification of unilateral surgically curable primary aldosteronism but is often clinically useless, owing to failed bilateral adrenal vein cannulation.

OBJECTIVES

To investigate if only unilaterally selective adrenal vein sampling studies can allow the identification of the responsible adrenal.

METHODS

Among 1625 patients consecutively submitted to adrenal vein sampling in tertiary referral centers, we selected those with selective adrenal vein sampling results in at least one side; we used surgically cured unilateral primary aldosteronism as gold reference. The accuracy of different values of the relative aldosterone secretion index (RASI), which estimates the amount of aldosterone produced in each adrenal gland corrected for catheterization selectivity, was examined.

RESULTS

We found prominent differences in RASI values distribution between patients with and without unilateral primary aldosteronism. The diagnostic accuracy of RASI values estimated by the area under receiver operating characteristic curves was 0.714 and 0.855, respectively, in the responsible and the contralateral side; RASI values >2.55 and ≤0.96 on the former and the latter side furnished the highest accuracy for detection of surgically cured unilateral primary aldosteronism. Moreover, in the patients without unilateral primary aldosteronism, only 20% and 16% had RASI values ≤0.96 and >2.55.

CONCLUSIONS

With the strength of a large real-life data set and use of the gold reference entailing an unambiguous diagnosis of unilateral primary aldosteronism, these results indicate the feasibility of identifying unilateral primary aldosteronism using unilaterally selective adrenal vein sampling results.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT01234220.

Screening for unilateral aldosteronism should be combined with the maximum systolic blood pressure, history of stroke and typical nodules

To determine factors associated with lateralization in primary aldosteronism (PA). The clinical data for PA patients hospitalized at the First Affiliated Hospital of Guangxi Medical University from October 2016 to March 2021 were included in this study. They were classified according to results derived from computed tomography (CT): bilaterally normal nodules (no typical nodules were found in either adrenal glands, only changes in unilateral adrenal hyperplasia thickening or bilateral adrenal hyperplasia thickening), unilateral nodules (typical nodule appears in unilateral adrenal gland, and there are no abnormalities in the contralateral adrenal gland or only thickening of unilateral adrenal hyperplasia) and bilateral nodules (typical nodule like changes in bilateral adrenal glands). Multivariate logistic regression and receiver operating characteristic (ROC) were used to analyze the factors associated with lateralization of PA and consistencies between adrenal CT images and adrenal venous sampling (AVS) results. A total of 269 patients with PA were recruited, with an average age of 46 years and 112 cases had typical nodules. Results from CT scans revealed that there were 49 bilateral normal cases, 177 cases were unilateral abnormal and 43 cases were bilateral abnormal. In all of the PA patients, multifactorial logistic regression analysis showed that the maximum systolic blood pressure (OR = 1.03, P < .001), history of stroke (OR = 2.61, P = .028), and typical nodules (OR = 1.9, P = .017) were all relevant factors in unilateral primary aldosteronism (UPA). In the unilateral nodule group, multivariate logistic regression analysis suggested that maximum systolic blood pressure (OR = 1.03, P < .001) and typical nodules (OR = 2.37, P = .008) were the related factors for UPA. However, the consistency between adrenal CT and AVS was only 40.68%, while maximum systolic blood pressure (OR = 1.02, P < .001) and plasma aldosterone renin ratio (OR = 1.001, P = .027) were the relevant consistent factors between AVS and CT results. Maximum systolic blood pressure, typical nodules, and history of stroke are important factors to consider when screening for UPA. It is recommended to combine medical history and imaging findings when looking at different subgroups before a clinical decision is made. Patients with PA in the absence of lesions or bilateral lesions on CT should be diagnosed by AVS as far as possible.

Effect of Intraprocedural Cortisol Measurement on ACTH-stimulated Adrenal Vein Sampling in Primary Aldosteronism

Context

Adrenocorticotropin (ACTH) loading is used to increase the success rate of adrenal vein sampling (AVS).

Objective

We aimed to determine the effect of intraprocedural cortisol measurement (ICM) on ACTH-stimulated AVS (AS-AVS) owing to a lack of reliable data on this topic.

Methods

This multicenter, retrospective, observational study took place in 28 tertiary centers in Japan. Among 4057 patients enrolled, 2396 received both basal AVS (B-AVS) and AS-AVS and were divided into 2 groups according to whether ICM was used. The effect of ICM on AS-AVS was measured.

Results

In patients who underwent both AVS procedures, the ICM group had significantly higher success rates for both B-AVS and AS-AVS than the non-ICM group did. However, the probability of failure of AS-AVS after a successful B-AVS and the probability of success of AS-AVS after a failed B-AVS were not significantly different in the 2 groups. For subtype diagnosis, propensity-score matching revealed no significant difference between the 2 groups, and the discrepancy rate between B-AVS and AS-AVS for subtype diagnosis was also not significantly different.

Conclusion

ICM significantly increased the success rate of B-AVS and AS-AVS in protocols in which both AVS procedures were performed and had no effect on subtype diagnosis. However, in protocols in which both AVS procedures were performed, the results suggest ICM may not be necessary when performing AS-AVS if ICM is used only when B-AVS is performed. Our study suggests that ICM during AVS plays an important role and should be recommended.

Rapidity and Precision of Steroid Hormone Measurement

Steroids are present in all animals and plants, from mammals to prokaryotes. In the medical field, steroids are commonly classified as glucocorticoids, mineralocorticoids, and gonadal steroid hormones. Monitoring of hormones is useful in clinical and research fields for the assessment of physiological changes associated with aging, disease risk, and the diagnostic and therapeutic effects of various diseases. Since the discovery and isolation of steroid hormones, measurement methods for steroid hormones in biological samples have advanced substantially. Although immunoassays (IAs) are widely used in daily practice, mass spectrometry (MS)-based methods have been reported to be more specific. Steroid hormone measurement based on MS is desirable in clinical practice; however, there are several drawbacks, including the purchase and maintenance costs of the MS instrument and the need for specialized training of technicians. In this review, we discuss IA- and MS-based methods currently in use and briefly present the history of steroid hormone measurement. In addition, we describe recent advances in IA- and MS-based methods and future applications and considerations.

Adrenal Vein Sampling in Primary Aldosteronism: A Pictorial Essay for Optimal Left-Side Sampling

Primary aldosteronism (PA) is a curable cause of hypertension. Recent studies have revealed that the actual prevalence of PA is higher than previously recognized. Adrenal vein sampling (AVS) is an essential diagnostic procedure for revealing the cause of PA and determining the treatment plan. The success of AVS is confirmed by comparing cortisol levels between the samples from each adrenal vein and peripheral vein. The failure rate of the procedure is reported to be high in the right adrenal vein, which is directly connected to the inferior vena cava, while that in the left adrenal vein is relatively low; however, this has rarely been reported. In this review, we introduce and analyze cases of failure in left adrenal vein sampling.

Utility of semi-quantitative quick cortisol assay with low-dose adrenocorticotropic hormone infusion adrenal vein sampling

BACKGROUND

Adrenal vein sampling (AVS) is integral to identifying surgically remediable unilateral primary aldosteronism (PA). However, right adrenal vein (AV) cannulation can be challenging, limiting its success. Intra-procedural cortisol assays can improve the reliability of AVS. The aim of this study was to validate the use of semi-quantitative cortisol estimates obtained utilizing a quick cortisol assay (QCA) during AVS procedures at our institution.

METHODS

Retrospective review of results of AVS procedures before and after the introduction of the QCA. Twenty-three AVS procedures were performed with the provisional success determined by intra-procedural QCA. Successful AV cannulation was defined by an AV to peripheral vein cortisol ratio ≥ 4.0 (the selectivity index) from laboratory measurements. The control cohort consisted of 23 consecutive procedures prior to introduction of the QCA.

RESULTS

QCA correctly predicted all AV cannulation attempts. Successful bilateral AV cannulation increased from 52% to 91% of procedures when performed with the QCA (P = 0.01) and adequate cannulation of the right AV increased from 61% to 91% (P = 0.03). There was no increase in procedural time, number of AV cannulation or sampling attempts.

CONCLUSIONS

Point-of-care, semi-quantitative cortisol estimates can be performed accurately during AVS with QCA, facilitating improvements in AVS success rates without increasing procedural time.

Reduction of Radiation Exposure in Adrenal Vein Sampling: Impact of the Rapid Cortisol Assay

PURPOSE

 To determine radiation exposure associated with adrenal vein sampling and its reduction by implementing the rapid cortisol assay and modification of the sampling protocol.

MATERIALS AND METHODS

 A single-center retrospective study of adrenal vein sampling performed between August 2009 and March 2020 revealed data from 151 procedures. Three subgroups were determined. In group I, a sampling protocol including sampling from the renal veins without the rapid cortisol assay was applied. In group II, blood was sampled using the same protocol but applying the rapid cortisol assay. In group III, a modified sampling protocol was used, in which the additional sampling from the renal veins was dispensed with, while the rapid cortisol assay was retained. Primary endpoints were radiation exposure parameters with dose area product, fluoroscopy time, and effective dose. As secondary endpoints, procedural data including technical success, lateralization, the correlation between patient BMI and radiation exposure, and concordance of lateralization with cross-sectional imaging were investigated. Furthermore, the correlation of aldosterone-cortisol ratios between the adrenal and ipsilateral renal vein was calculated to assess the benefit of sampling from the renal veins.

RESULTS

 For all procedures performed in the study collective, the median dose area product was 60.01 Gy*cm² (5.71-789.31), the median fluoroscopy time was 14.90 min (3.27-80.90), and the calculated median effective dose was 12.60 mSv (1.20-165.76). Significant differences in radiation exposure parameters between the study subgroups could be revealed. Dose area product resulted in reductions of 57.94 % after implementation of the rapid cortisol assay and a further 40.44 % after revision of the sampling protocol. Fluoroscopy time was reduced by 40.48 % after integration of the rapid cortisol assay and a further 40.47 % after protocol refinement. Radiation doses were increased in cases of resampling (dose area product 51.31 vs. 118.11 Gy*cm², fluoroscopy time of 12.48 vs. 28.70 min). A strong correlation between patient BMI and procedural dose area product could be found. After the introduction of the rapid cortisol assay, successive improvement of the technical success rate could be found (33.33 % in group I, 90.22 % in group II and 92.11 % in group III). The correlation of aldosterone-cortisol ratios between adrenal and renal veins was poor.

CONCLUSION

 The introduction of the rapid cortisol assay significantly decreased the radiation exposure and increased the technical success rate. Renal vein sampling did not provide further benefit in the evaluation of primary aldosteronism subtype and its omission resulted in a further reduction of radiation dose.

KEY POINTS

· The rapid cortisol assay significantly reduces the procedure-related radiation dose in adrenal vein sampling and increases the procedural technical success.. · Since additional sampling from the renal veins offers no further diagnostic benefit, a refinement of the sampling protocol can enable a further reduction of radiation dose.. · Resampling, technical unsuccessful procedures, and higher patients' BMI are associated with higher radiation exposures..

CITATION FORMAT

· Augustin A, Dalla Torre G, Fuss CT et al. Reduction of Radiation Exposure in Adrenal Vein Sampling: Impact of the Rapid Cortisol Assay. Fortschr Röntgenstr 2021; 193: 1392 - 1402.

Adrenal venous sampling in primary hyperaldosteronism: correlation of hormone indices and collimated C-arm CT findings

PURPOSE

To evaluate the feasibility and effect of an approach to adrenal venous sampling (AVS) analysis by combining established selective cortisol and aldosterone indices with the acquisition of a collimated C-arm CT(CACT_Coll).

METHODS

Overall, 107 consecutive patients (45f,62 m; 54 ± 10 years) undergoing 111 AVS procedures without hormonal stimulation from 7/13 to 2/20 in a single institution were retrospectively analysed. Hormone levels were measured in sequential samples of the suspected adrenal veins and right iliac vein, and selectivity indices (SI) computed. Stand-alone SI_Cortisol and/or SI_Aldosterone ≥ 2.0 as well as SI_Cortisol and/or SI_Aldosterone ≥ 1.1 combined with positive right-sided CACT_Coll of the adrenals (n = 80; opacified right adrenal vein) were defined as a successful AVS procedure. Radiation exposure of CACT was measured via dose area product (DAP) and weighed against an age-/weight-matched cohort (n = 66).

RESULTS

Preliminary success rates (SI_Cortisol and/or SI_Aldosterone ≥ 2.0) were 99.1% (left) and 72.1% (right). These could be significantly increased to a 90.1% success rate on the right, by combining an adjusted SI of 1.1 with a positive CACT_Coll proving the correct sampling position. Sensitivity for stand-alone collimated CACT (CACT_Coll) was 0.93, with 74/80 acquired CACT_Coll confirming selective cannulation by adrenal vein enhancement. Mean DAP_{Coll_CACT} measured 2414 ± 958 μGyxm², while mean DAP_{Full-FOV_CACT} in the matched cohort measured 8766 ± 1956 μGyxm² (p < 0.001).

CONCLUSION

Collimated CACT in AVS procedures is feasible and leads to a significant increase in success rates of (right-sided) selective cannulation and may in combination with adapted hormone indices, offer a successful alternative to previously published AVS analysis algorithms with lower radiation exposure compared to a full-FOV CACT.

Computed tomography image fusion, Coaxial guidewire technique, Fast intraprocedural cortisol testing technique improves success rate and decreases radiation exposure, procedure time, and contrast use for adrenal vein sampling

BACKGROUND

Adrenal vein sampling (AVS) is recommended for discriminating patients with unilateral primary aldosteronism from bilateral disease. However, it is a technically demanding procedure that is markedly underused. We developed a computed tomography image fusion, coaxial guidewire technique, fast intraprocedural cortisol testing (CCF) technique to improve AVS success rate, which combines CT image fusion, coaxial guidewire technique, and fast intraprocedural cortisol testing.

OBJECTIVE

To evaluate the effectiveness and safety of the AVS--CCF technique.

METHODS

We retrospectively evaluated 105 patients who undervent AVS from June 2016 to October 2020. There were 51 patients in the AVS--CCF group and 54 patients in the AVS group. We compared two groups with technical success rate, procedure time, radiation exposure, volume of contrast medium, and complications (adrenal vein rupture, dissection, infarction, or thrombosis; intraglandular or periadrenal hematoma; and contrast-induced nephropathy).

RESULTS

The technical success rate was higher for AVS--CCF than for AVS without CCF (98 vs. 83.3% for bilateral adrenal veins, P = 0.016). AVS--CCF was associated with a shorter procedure time (63.6 ± 24.6 vs. 94.8 ± 40.8 min, P < 0.001), shorter fluoroscopy time (15.6 ± 12.6 vs. 20.4 ± 15.0 min, P = 0.043), and lower contrast medium volume (25.10 ± 21.82 vs. 44.1 ± 31.0 ml, P < 0.001). There were no significant differences between groups with respect to the time for cannulating the left or right adrenal vein or the peak skin radiation dose. Adrenal vein rupture occurred in 14 patients and intraglandular hematoma in 1 patient.

CONCLUSION

The CCF technique during AVS not only contributed to improved technical success rates but also associated with decreased procedure time, radiation exposure, and contrast medium volume.

"Double-Down" Adrenal Vein Sampling Results in Patients with Apparent Bilateral Aldosterone Suppression: Utility of Repeat Sampling including Super-Selective Sampling

PURPOSE

To report outcomes of patients undergoing adrenal vein sampling (AVS) for primary aldosteronism with results indicating apparent bilateral adrenal suppression (ABAS), in which the adrenal aldosterone-to-cortisol ratios are decreased bilaterally ("double-down") compared to the non-adrenal sample, and evaluate repeat AVS results.

MATERIALS AND METHODS

Between 2003 and 2020, 762 patients underwent AVS. Twenty patients (2.6%; male, 12; female, 8; age 50.3 ± 9.7 years) with ABAS on initial AVS were identified. Ten underwent repeat AVS. Super-selective AVS (SS-AVS) was employed in 6 of 10 repeat AVS (60%). Outcomes after AVS were analyzed. A lateralization index (LI) >4 was considered an indication for adrenalectomy.

RESULTS

Repeat AVS was diagnostic in 70% of patients (n = 7), with 6 of 7 lateralizing with LI >4 (median LI = 32.3; range 4.6-54.8) and 1 of 7 nearly lateralizing (LI = 3.5). All 7 patients underwent adrenalectomy. ABAS was redemonstrated in 3 patients (30%): 2 with unilateral adenomas on cross-sectional imaging underwent adrenalectomy despite ABAS results and 1 was lost to follow-up. Four of 6 patients (66%) who underwent SS-AVS were diagnosed with unilateral disease (median LI = 43.3; range 23.9-54.8), with one patient's diagnosis reliant upon a single super-selective sample. In total, 9 patients underwent adrenalectomy after repeat AVS, all of whom had improved blood pressure control postoperatively. Ten patients did not undergo repeat AVS: 6 were lost to follow-up, 3 underwent medical management, and 1 underwent adrenalectomy.

CONCLUSIONS

AVS should be repeated when "double-down" ABAS results are encountered. Super-selective sampling may provide worthwhile diagnostic data when employed during repeat AVS.

Subtype diagnosis, treatment, complications and outcomes of primary aldosteronism and future direction of research: a position statement and consensus of the Working Group on Endocrine Hypertension of the European Society of Hypertension

: Primary aldosteronism is a frequent cause of secondary hypertension requiring a specific pharmacological treatment with mineralocorticoid receptor antagonist or with unilateral adrenalectomy. These treatments have shown to reduce the excess of cardiovascular risk characteristically associated with this disease. In part I of this consensus, we discussed the procedures for the diagnosis of primary aldosteronism. In the present part II, we address the strategies for the differential diagnosis of primary aldosteronism subtypes and therapy. We also discuss the evaluation of outcomes and provide suggestions for follow-up as well as cardiovascular and metabolic complications specifically associated with primary aldosteronism. Finally, we analyse the principal gaps of knowledge and future challenges for research in this field.

Controversies and advances in adrenal venous sampling in the diagnostic workup of primary aldosteronism

Adrenal venous sampling (AVS) is a key part of the diagnostic workup of primary aldosteronism, distinguishing unilateral from bilateral disease and determining treatment options. Although AVS is a well-established procedure, many aspects remain controversial, including optimal patient selection for the procedure and exactly how AVS is performed and interpreted. Despite the controversies, a growing body of evidence supports the use of AVS in most patients with primary aldosteronism, though some specific patient groups may be able to forego AVS and proceed directly to treatment. Although AVS remains a difficult procedure, success rates may be improved with the use of advanced CT imaging techniques and/or rapid cortisol assays. New advances in nuclear imaging and steroid profiling may also offer alternatives or adjuncts to AVS in the future.

Adrenal Venous Sampling: Where Do We Stand?

Adrenal venous sampling is the gold standard test to identify surgically curable primary aldosteronism, but it is markedly underused in clinical practice being perceived as a technically challenging and invasive procedure and, moreover, as difficult to interpret. This review provides updated information on current indications to adrenal venous sampling and how to perform and interpret adrenal venous sampling.

A short review of primary aldosteronism in a question and answer fashion

OBJECTIVES

The aim of this study was to present up to date information concerning the diagnosis and treatment of primary aldosteronism (PA). PA is the most common cause of endocrine hypertension. It has been reported up to 24% of selective referred hypertensive patients.

METHODS

We did a search in Pub-Med and Google Scholar using the terms: PA, hyperaldosteronism, idiopathic adrenal hyperplasia, diagnosis of PA, mineralocorticoid receptor antagonists, adrenalectomy, and surgery. We also did cross-referencing search with the above terms. We had divided our study into five sections: Introduction, Diagnosis, Genetics, Treatment, and Conclusions. We present our results in a question and answer fashion in order to make reading more interesting.

RESULTS

PA should be searched in all high-risk populations. The gold standard for diagnosis PA is the plasma aldosterone/plasma renin ratio (ARR). If this test is positive, then we proceed with one of the four confirmatory tests. If positive, then we proceed with a localizing technique like adrenal vein sampling (AVS) and CT scan. If the lesion is unilateral, after proper preoperative preparation, we proceed, in adrenalectomy. If the lesion is bilateral or the patient refuses or is not fit for surgery, we treat them with mineralocorticoid receptor antagonists, usually spironolactone.

CONCLUSIONS

Primary aldosteronism is the most common and a treatable case of secondary hypertension. Only patients with unilateral adrenal diseases are eligible for surgery, while patients with bilateral and non-surgically correctable PA are usually treated by mineralocorticoid receptor antagonist (MRA). Thus, the distinction between unilateral and bilateral aldosterone hypersecretion is crucial.

MANAGEMENT OF ENDOCRINE DISEASE: Diagnosis and management of primary aldosteronism: the Endocrine Society guideline 2016 revisited

The syndrome of primary aldosteronism (PA) is characterized by hypertension with excessive, autonomous aldosterone production and is usually caused by either a unilateral aldosterone-producing adenoma or bilateral adrenal hyperplasia. The diagnostic workup of PA is a sequence of three phases comprising screening tests, confirmatory tests and the differentiation of unilateral from bilateral forms. The latter step is necessary to determine the optimal treatment approach of unilateral laparoscopic adrenalectomy (for patients with unilateral PA) or medical treatment with a mineralocorticoid receptor antagonist (for patients with bilateral PA). Since the publication of the revised Endocrine Society guideline 2016, a number of key studies have been published. They challenge the recommendations of the guideline in some areas and confirm current practice in others. Herein, we present the recent developments and current approaches to the medical management of PA.

Update in adrenal venous sampling for primary aldosteronism

PURPOSE OF REVIEW

Current guidelines recommend adrenal venous sampling (AVS) to identify the surgically curable causes of hyperaldosteronism. In contrast with this recommendation, AVS remains markedly underutilized in clinical practice, which leads to deny curative adrenalectomy, to many patients with primary aldosteronism. The purpose of this review is to challenge the views that AVS is a technically challenging, invasive and risky procedure, which moreover, is difficult to interpret.

RECENT FINDINGS

Several studies, including a large international survey on how AVS is being performed and used at major referral centres worldwide the AVIS-1 Study - and a randomized clinical trial comparing and AVS and a computed tomography based strategy, will be examined.

SUMMARY

The results of these studies have sound implications for clinical practice in that they allow to define what to do and what not to do for proper performance and interpretation of AVS and avoidance of the main concern, for example the risk of adrenal vein rupture.

Improved technical success and radiation safety of adrenal vein sampling using rapid, semi-quantitative point-of-care cortisol measurement

Objective

Primary aldosteronism is a curable cause of hypertension which can be treated surgically or medically depending on the findings of adrenal vein sampling studies. Adrenal vein sampling studies are technically demanding with a high failure rate in many centres. The use of intraprocedural cortisol measurement could improve the success rates of adrenal vein sampling but may be impracticable due to cost and effects on procedural duration.

Design

Retrospective review of the results of adrenal vein sampling procedures since commencement of point-of-care cortisol measurement using a novel single-use semi-quantitative measuring device for cortisol, the adrenal vein sampling Accuracy Kit. Measurements: Success rate and complications of adrenal vein sampling procedures before and after use of the adrenal vein sampling Accuracy Kit. Routine use of the adrenal vein sampling Accuracy Kit device for intraprocedural measurement of cortisol commenced in 2016.

Results

Technical success rate of adrenal vein sampling increased from 63% of 99 procedures to 90% of 48 procedures ( P = 0.0007) after implementation of the adrenal vein sampling Accuracy Kit. Failure of right adrenal vein cannulation was the main reason for an unsuccessful study. Radiation dose decreased from 34.2 Gy.cm2 (interquartile range, 15.8–85.9) to 15.7 Gy.cm2 (6.9–47.3) ( P = 0.009). No complications were noted, and implementation costs were minimal.

Conclusions

Point-of-care cortisol measurement during adrenal vein sampling improved cannulation success rates and reduced radiation exposure. The use of the adrenal vein sampling Accuracy Kit is now standard practice at our centre.

Niche point-of-care endocrine testing - Reviews of intraoperative parathyroid hormone and cortisol monitoring

Point-of-care (POC) testing, which provides quick test results in near-patient settings with easy-to-use devices, has grown continually in recent decades. Among near-patient and on-site tests, rapid intraoperative and intra-procedural assays are used to quickly deliver critical information and thereby improve patient outcomes. Rapid intraoperative parathyroid hormone (ioPTH) monitoring measures postoperative reduction of parathyroid hormone (PTH) to predict surgical outcome in patients with primary hyperparathyroidism, and therefore contributes to the change of parathyroidectomy to a minimally invasive procedure. In this review, recent progress in applying ioPTH monitoring to patients with secondary and tertiary hyperparathyroidism and other testing areas is discussed. In-suite cortisol monitoring facilitates the use of adrenal vein sampling (AVS) for the differential diagnosis of primary aldosteronism and adrenocorticotropic hormone (ACTH)-independent Cushing syndrome. In clinical and psychological research settings, POC testing is also useful for rapidly assessing cortisol in plasma and saliva samples as a biomarker of stress. Careful resource utilization and coordination among stakeholders help to determine the best approach for implementing cost-effective POC testing. Technical advances in integrating appropriate biosensors with microfluidics-based devices hold promise for future real-time POC cortisol monitoring.

Radiology of the adrenal incidentalomas. Review of the literature

The term "adrenal incidentaloma" is a radiological term. Adrenal incidentalomas are adrenal tumors discovered in an imaging study that has been obtained for indications exclusive to adrenal conditions (Udelsman 2001; Linos 2003; Bulow et al. 2006; Anagnostis et al. 2009). This definition excludes patients undergoing imaging testing as part of staging and work-up for cancer (Grumbach et al. 2003; Anagnostis et al. 2009). Papierska et al. (2013) have added the prerequisite that the size of a tumor must be "greater than 1cm in diameter", in order to be called incidentaloma. Although in the most cases these masses are non-hypersecreting and benign, they still represent an important clinical concern because of the risk of malignancy or hormone hyperfunction (Barzon et al. 2003). Th e adrenal tumors belong to the commonest incidental findings having been discovered (Kanagarajah et al. 2012).

Adrenal venous sampling for primary aldosteronism: laboratory medicine best practice

Primary aldosteronism (PA) is the most common form of secondary hypertension and is critical to identify because when caused by an aldosterone-producing adenoma (APA) or another unilateral form, it is potentially curable, and even when caused by bilateral disease, antihypertensives more specific to PA treatment can be employed (ie, aldosterone antagonists). Identification of unilateral forms is not generally accomplished with imaging because APAs may be small and elude detection, and coincidental identification of a non-functioning incidentaloma contralateral to an APA may lead to removal of an incorrect gland. For this reason, the method of choice for identifying unilateral forms of PA is selective adrenal venous sampling (AVS) followed by aldosterone and cortisol analysis on collected samples. This procedure is technically difficult from a radiological standpoint and, from the laboratory perspective, is fraught with opportunities for preanalytical, analytical and postanalytical error. We review the process of AVS collection, analysis and reporting. Suggestions are made for patient preparation, specimen labelling practices and nomenclature, analytical dilution protocols, which numerical results to report, and the necessary subsequent calculations. We also identify and explain frequent sources of confusion in the aldosterone and cortisol results and provide an example of tabular reporting to facilitate interpretation and communication between laboratorian, radiologist and clinician.

Subtype Diagnosis of Primary Aldosteronism: Is Adrenal Vein Sampling Always Necessary?

Aldosterone producing adenoma and bilateral adrenal hyperplasia are the two most common subtypes of primary aldosteronism (PA) that require targeted and distinct therapeutic approaches: unilateral adrenalectomy or lifelong medical therapy with mineralocorticoid receptor antagonists. According to the 2016 Endocrine Society Guideline, adrenal venous sampling (AVS) is the gold standard test to distinguish between unilateral and bilateral aldosterone overproduction and therefore, to safely refer patients with PA to surgery. Despite significant advances in the optimization of the AVS procedure and the interpretation of hormonal data, a standardized protocol across centers is still lacking. Alternative methods are sought to either localize an aldosterone producing adenoma or to predict the presence of unilateral disease and thereby substantially reduce the number of patients with PA who proceed to AVS. In this review, we summarize the recent advances in subtyping PA for the diagnosis of unilateral and bilateral disease. We focus on the developments in the AVS procedure, the interpretation criteria, and comparisons of the performance of AVS with the alternative methods that are currently available.

Abnormal gel flotation caused by contrast media during adrenal vein sampling

INTRODUCTION

During adrenal venous sampling (AVS) procedure, radiologists administer a contrast agent via the catheter to visualize the proper catheter position.

MATERIALS AND METHODS

A patient with primary aldosteronism diagnostic-hypothesis was admitted for AVS. A venogram was performed to
confirm the catheter's position with 2mL of Iopamidol 300 mg/mL. Samples were collected with syringe connected to a hydrophilic coated catheter by low-pressure aspiration from each of the four collection sites: inferior vena cava in the suprarenal portion, inferior vena cava in the infrarenal portion, left adrenal vein, and right adrenal vein; then immediately transferred from syringe to tubes with gel separator. All tubes were centrifuged at 1200 x g for 10 minutes.

RESULTS

At the end of centrifugation process, primary blood tubes containing blood from inferior vena cava and left adrenal vein exhibited the standard gel separator barrier, while tubes from right adrenal vein showed abnormal flotation of gel separator. The radiologist confirmed the usage of 2.6 mL instead of 2.0 mL of Iopamidol 300 mg/mL. This iodinated contrast media, with 1.33 g/cm3 of density, was used close to the right adrenal vein due to some difficulty to access it.

CONCLUSION

The abnormal flotation of gel separator in samples taken from right adrenal vein can be explained by the usage of the iodinated
contrast media. We suggest using plain-tubes (without gel separator) for AVS in order to avoid preanalytical nonconformities. Moreover, a blood volume equivalent to twice the catheter extension should be discarded to eliminate residual contrast media before collection of samples for laboratory assays.

Primary Aldosteronism: Changing Definitions and New Concepts of Physiology and Pathophysiology Both Inside and Outside the Kidney

In the 60 years that have passed since the discovery of the mineralocorticoid hormone aldosterone, much has been learned about its synthesis (both adrenal and extra-adrenal), regulation (by renin-angiotensin II, potassium, adrenocorticotrophin, and other factors), and effects (on both epithelial and nonepithelial tissues). Once thought to be rare, primary aldosteronism (PA, in which aldosterone secretion by the adrenal is excessive and autonomous of its principal regulator, angiotensin II) is now known to be the most common specifically treatable and potentially curable form of hypertension, with most patients lacking the clinical feature of hypokalemia, the presence of which was previously considered to be necessary to warrant further efforts towards confirming a diagnosis of PA. This, and the appreciation that aldosterone excess leads to adverse cardiovascular, renal, central nervous, and psychological effects, that are at least partly independent of its effects on blood pressure, have had a profound influence on raising clinical and research interest in PA. Such research on patients with PA has, in turn, furthered knowledge regarding aldosterone synthesis, regulation, and effects. This review summarizes current progress in our understanding of the physiology of aldosterone, and towards defining the causes (including genetic bases), epidemiology, outcomes, and clinical approaches to diagnostic workup (including screening, diagnostic confirmation, and subtype differentiation) and treatment of PA.

Diagnostic criteria for adrenal venous sampling

PURPOSE OF REVIEW

Primary aldosteronism accounts for 3 to 5% of all hypertension cases. Unilateral aldosterone hypersecretion can be treated with adrenalectomy. Guidelines for primary aldosteronism management recommend adrenal vein sampling (AVS) to ascertain unilateral primary aldosteronism before surgery. Many different protocols are used to perform AVS and for the interpretation of its results, but without hard evidence of why one should be given preference. Experts have proposed recommendations to guide clinical practice and the grounds for future research to address this situation.

RECENT FINDINGS

Proper patient preparation is a prerequisite for interpretable results. New trends are emerging to improve adequate cannulation of adrenal veins including: training of a limited number of dedicated radiologists, contrast computed tomography of adrenal veins before or during AVS, and rapid assays to measure cortisol concentrations during AVS. Cosyntropin stimulation is performed in several centers to avoid the variability of cortisol secretion during AVS, but whether this improves diagnostic performance is unknown.

SUMMARY

Better markers of adequate catheter placement are currently under investigation, including other adrenal steroids and metanephrines. Innovative strategies for interpreting partially failed AVS are also being developed. Other approaches to ascertain primary aldosteronism subtype will be necessary because of limited patient access to AVS.

The Management of Primary Aldosteronism: Case Detection, Diagnosis, and Treatment: An Endocrine Society Clinical Practice Guideline

OBJECTIVE

To develop clinical practice guidelines for the management of patients with primary aldosteronism.

PARTICIPANTS

The Task Force included a chair, selected by the Clinical Guidelines Subcommittee of the Endocrine Society, six additional experts, a methodologist, and a medical writer. The guideline was cosponsored by American Heart Association, American Association of Endocrine Surgeons, European Society of Endocrinology, European Society of Hypertension, International Association of Endocrine Surgeons, International Society of Endocrinology, International Society of Hypertension, Japan Endocrine Society, and The Japanese Society of Hypertension. The Task Force received no corporate funding or remuneration.

EVIDENCE

We searched for systematic reviews and primary studies to formulate the key treatment and prevention recommendations. We used the Grading of Recommendations, Assessment, Development, and Evaluation group criteria to describe both the quality of evidence and the strength of recommendations. We used "recommend" for strong recommendations and "suggest" for weak recommendations.

CONSENSUS PROCESS

We achieved consensus by collecting the best available evidence and conducting one group meeting, several conference calls, and multiple e-mail communications. With the help of a medical writer, the Endocrine Society's Clinical Guidelines Subcommittee, Clinical Affairs Core Committee, and Council successfully reviewed the drafts prepared by the Task Force. We placed the version approved by the Clinical Guidelines Subcommittee and Clinical Affairs Core Committee on the Endocrine Society's website for comments by members. At each stage of review, the Task Force received written comments and incorporated necessary changes.

CONCLUSIONS

For high-risk groups of hypertensive patients and those with hypokalemia, we recommend case detection of primary aldosteronism by determining the aldosterone-renin ratio under standard conditions and recommend that a commonly used confirmatory test should confirm/exclude the condition. We recommend that all patients with primary aldosteronism undergo adrenal computed tomography as the initial study in subtype testing and to exclude adrenocortical carcinoma. We recommend that an experienced radiologist should establish/exclude unilateral primary aldosteronism using bilateral adrenal venous sampling, and if confirmed, this should optimally be treated by laparoscopic adrenalectomy. We recommend that patients with bilateral adrenal hyperplasia or those unsuitable for surgery should be treated primarily with a mineralocorticoid receptor antagonist.

Subtype Diagnosis of Primary Aldosteronism: Approach to Different Clinical Scenarios

Identification and management of patients with primary aldosteronism are of utmost importance because it is a frequent cause of endocrine hypertension, and affected patients display an increase of cardio- and cerebro-vascular events, compared to essential hypertensives. Distinction of primary aldosteronism subtypes is of particular relevance to allocate the patients to the appropriate treatment, represented by mineralocorticoid receptor antagonists for bilateral forms and unilateral adrenalectomy for patients with unilateral aldosterone secretion. Subtype differentiation of confirmed hyperaldosteronism comprises adrenal CT scanning and adrenal venous sampling. In this review, we will discuss different clinical scenarios where execution, interpretation of adrenal vein sampling and subsequent patient management might be challenging, providing the clinician with useful information to help the interpretation of controversial procedures.

Issues in the Diagnosis and Treatment of Primary Aldosteronism

Primary aldosteronism (PA) is associated with a high rate of cardio- and cerebrovascular complications and metabolic alterations. PA is also recognized as the most frequent, although often unrecognized, secondary form of hypertension. Guidelines have been released to assist clinicians in the diagnostic work-up and subtype differentiation of PA. In this review we discuss and compare the available guidelines in the context of our professional experience and evaluate diagnostic and therapeutic aspects that are still a matter of debate.

Adrenal vein sampling in primary aldosteronism: towards a standardised protocol

Primary aldosteronism comprises subtypes that need different therapeutic strategies. Adrenal vein sampling is recognised by Endocrine Society guidelines as the only reliable way to correctly diagnose the subtype of primary aldosteronism. Unfortunately, despite being the gold-standard procedure, no standardised procedure exists either in terms of performance or interpretation criteria. In this Personal View, we address several questions that clinicians are presented with when considering adrenal vein sampling. For each of these questions we provide responses based on the available evidence, and opinions based on our experience. In particular, we discuss the most appropriate way to prepare the patient, whether adrenal vein sampling can be avoided for some subgroups of patients, the use of ACTH (1-24) during the procedure, the most appropriate criteria for interpretation of adrenal vein cannulation and lateralisation, the use of contralateral suppression, and strategies to improve success rates of adrenal vein sampling in centres with little experience.

Pathophysiology, diagnosis, and treatment of mineralocorticoid disorders

The renin-angiotensin-aldosterone system (RAAS) is a major regulator of blood pressure control, fluid, and electrolyte balance in humans. Chronic activation of mineralocorticoid production leads to dysregulation of the cardiovascular system and to hypertension. The key mineralocorticoid is aldosterone. Hyperaldosteronism causes sodium and fluid retention in the kidney. Combined with the actions of angiotensin II, chronic elevation in aldosterone leads to detrimental effects in the vasculature, heart, and brain. The adverse effects of excess aldosterone are heavily dependent on increased dietary salt intake as has been demonstrated in animal models and in humans. Hypertension develops due to complex genetic influences combined with environmental factors. In the last two decades, primary aldosteronism has been found to occur in 5% to 13% of subjects with hypertension. In addition, patients with hyperaldosteronism have more end organ manifestations such as left ventricular hypertrophy and have significant cardiovascular complications including higher rates of heart failure and atrial fibrillation compared to similarly matched patients with essential hypertension. The pathophysiology, diagnosis, and treatment of primary aldosteronism will be extensively reviewed. There are many pitfalls in the diagnosis and confirmation of the disorder that will be discussed. Other rare forms of hyper- and hypo-aldosteronism and unusual disorders of hypertension will also be reviewed in this article.

Measurement of thyroxine and cortisol in canine and feline blood samples using two immunoassay analysers

OBJECTIVES

The AIA-360 (Tosoh Corporation) is an automated immunoassay analyser. The aims of this study were to estimate the precision of thyroxine and cortisol AIA-360 immunoassays in canine and feline samples and to compare the results produced with those obtained by a chemiluminescence analyser (Immulite® 1000, Siemens).

METHODS

Blood samples from 240 clinical cases (60 dogs and 60 cats for both thyroxine and cortisol) were analysed using both instruments.

RESULTS

Deming regression calculations showed excellent correlation (thyroxine, canine rs  = 0 · 94, feline rs  = 0 · 97; cortisol, canine rs  = 0 · 97, feline rs  = 0 · 97). Agreement between the two instruments was examined by Bland-Altman difference plots, which identified wide confidence intervals and outliers for thyroxine (canine n = 6, feline n = 4) and cortisol (canine n = 3, feline n = 4) results. Inter/intra-run precision of the AIA-360 was excellent for both cortisol and thyroxine (coefficients of variation <7%).

CLINICAL SIGNIFICANCE

The instrument showed excellent correlation for cortisol and thyroxine in canine and feline samples demonstrating that the AIA-360 can be used in clinical practice. The agreement studies suggest that the results from the AIA-360 cannot be used interchangeably with those generated by the Immulite 1000 and should be interpreted using reference intervals that have been established specific to the AIA-360.

An expert consensus statement on use of adrenal vein sampling for the subtyping of primary aldosteronism

Adrenal venous sampling is recommended by current guidelines to identify surgically curable causes of hyperaldosteronism but remains markedly underused. Key factors contributing to the poor use of adrenal venous sampling include the prevailing perceptions that it is a technically challenging procedure, difficult to interpret, and can be complicated by adrenal vein rupture. In addition, the lack of uniformly accepted standards for the performance of adrenal venous sampling contributes to its limited use. Hence, an international panel of experts working at major referral centers was assembled to provide updated advice on how to perform and interpret adrenal venous sampling. To this end, they were asked to use the PICO (Patient or Problem, Intervention, Control or comparison, Outcome) strategy to gather relevant information from the literature and to rely on their own experience. The level of evidence/recommendation was provided according to American Heart Association gradings whenever possible. A consensus was reached on several key issues, including the selection and preparation of the patients for adrenal venous sampling, the procedure for its optimal performance, and the interpretation of its results for diagnostic purposes even in the most challenging cases.

Fast intraoperative testosterone assay confirms the location of an ovarian virilizing tumor in a young girl

The detection of testosterone-producing ovarian tumors in childhood and adolescence by imaging techniques only can be difficult because of the tumors' radiological structure and sometimes diminutive size. We describe an 11.5-year-old girl with a 9-month history of voice deepening, mild hirsutism, minor acne, increased growth velocity, weight gain, and clitoromegaly. Laboratory investigation revealed an extremely elevated serum testosterone level without any additional endocrine abnormalities. Abdominal ultrasound and MRI showed a sparsely noticeable solid mass in the center of the right ovary. At laparotomy, blood was selectively drawn from the right and the left ovarian veins. Rapid testosterone measurement revealed a 70-fold higher testosterone concentration in the right ovarian vein within 45 min. Based on this finding, a right salpingo-oophorectomy was performed. The patient's postoperative testosterone level declined within 24 h. The histopathological diagnosis was Leydig cell tumor. In conclusion, the implementation of a fast intraoperative testosterone assay enabled the localization and curative therapy of a Leydig cell tumor. This technique seems to be a good alternative to preoperative selective venous blood sampling when body imaging does not unveil the tumor's site.

Efficacy of adrenal venous sampling is increased by point of care cortisol analysis

Primary aldosteronism (PA) is a common cause of secondary hypertension and is caused by unilateral or bilateral adrenal disease. Treatment options depend on whether the disease is lateralized or not, which is preferably evaluated with selective adrenal venous sampling (AVS). This procedure is technically challenging, and obtaining representative samples from the adrenal veins can prove difficult. Unsuccessful AVS procedures often require reexamination. Analysis of cortisol during the procedure may enhance the success rate. We invited 21 consecutive patients to participate in a study with intra-procedural point of care cortisol analysis. When this assay showed nonrepresentative sampling, new samples were drawn after redirection of the catheter. The study patients were compared using the 21 previous procedures. The intra-procedural cortisol assay increased the success rate from 10/21 patients in the historical cohort to 17/21 patients in the study group. In four of the 17 successful procedures, repeated samples needed to be drawn. Successful sampling at first attempt improved from the first seven to the last seven study patients. Point of care cortisol analysis during AVS improves success rate and reduces the need for reexaminations, in accordance with previous studies. Successful AVS is crucial when deciding which patients with PA will benefit from surgical treatment.