External Validation of Clinical Prediction Models in Unilateral Primary Aldosteronism

BACKGROUND

Targeted treatment of primary aldosteronism (PA) is informed by adrenal vein sampling (AVS), which remains limited to specialized centers. Clinical prediction models have been developed to help select patients who would most likely benefit from AVS. Our aim was to assess the performance of these models for PA subtyping.

METHODS

This external validation study evaluated consecutive patients referred for PA who underwent AVS at a tertiary care referral center in Alberta, Canada during 2006–2018. In alignment with the original study designs and intended uses of the clinical prediction models, the primary outcome was the presence of lateralization on AVS. Model discrimination was evaluated using the C-statistic. Model calibration was assessed by comparing the observed vs. predicted probability of lateralization in the external validation cohort.

RESULTS

The validation cohort included 342 PA patients who underwent AVS (mean age, 52.1 years [SD, 11.5]; 201 [58.8%] male; 186 [54.4%] with lateralization). Six published models were assessed. All models demonstrated low-to-moderate discrimination in the validation set (C-statistics; range, 0.60–0.72), representing a marked decrease compared with the derivation sets (range, 0.80–0.87). Comparison of observed and predicted probabilities of unilateral PA revealed significant miscalibration. Calibration-in-the-large for every model was >0 (range, 0.35–1.67), signifying systematic underprediction of lateralizing disease. Calibration slopes were consistently <1 (range, 0.35–0.87), indicating poor performance at the extremes of risk.

CONCLUSIONS

Overall, clinical prediction models did not accurately predict AVS lateralization in this large cohort. These models cannot be reliably used to inform the decision to pursue AVS for most patients.

Apparent failed and discordant adrenal vein sampling: A potential confounding role of cortisol cosecretion?

OBJECTIVE

Adrenal vein sampling (AVS) and computed tomography (CT) often show confusingly discordant lateralisation results in primary aldosteronism (PA). We tested a biochemical algorithm using AVS data to detect cortisol cosecretion as a potential explanation for discordant cases.

DESIGN

Retrospective analysis from a large PA + AVS database.

PATIENTS

All patients with PA and AVS, 2005-2020.

MEASUREMENTS

An algorithm using biochemical data from paired AVS + CT images was devised from physiological first principles and informed by data from unilateral, AVS-CT concordant patients. The algorithm involved calculations based upon the expectation that low cortisol levels exist in adrenal vein effluent opposite an aldosterone-and-cortisol-producing adrenal mass and may reverse lateralisation due to inflated aldosterone/cortisol ratios.

MAIN OUTCOMES

The algorithm was applied to cases with discordant CT-AVS lateralisation to determine whether this might be a common or explanatory finding. Clinical and biochemical characteristics of identified cases were collected via chart review and compared to CT-AVS concordant cases to detect evidence of biological plausibility for cortisol cosecretion.

RESULTS

From a total of 588 AVS cases, 141 AVS + CT pairs were clear unilateral PA cases, used to develop the three-step algorithm for AVS interpretation. Applied to 88 AVS + CT discordant pairs, the algorithm suggested possible cortisol cosecretion in 40%. Case review showed that the proposed cortisol cosecretors, as identified by the algorithm, had low/suppressed adrenocorticotropic hormone levels, larger average nodule size and lower plasma aldosterone.

CONCLUSIONS

Pending external validation and outcome verification by surgery and tissue immunohistochemistry, cortisol cosecretion from aldosteronomas may be a common explanation for discordant CT-AVS results in PA.

External Validation of Prediction Models for Unilateral Primary Aldosteronism

Primary aldosteronism (PA) is the most common cause of remediable hypertension. Treatment is informed by establishing whether disease is unilateral (localized to one adrenal gland) or bilateral. Adrenalectomy is the guideline-recommended treatment of choice for unilateral PA. However, the currently recommended subtyping test, adrenal vein sampling (AVS), is often limited in accessibility. Thus, prediction models have been developed to diagnose unilateral PA and therefore bypass AVS. However, their generalizability remains unknown. In this retrospective study, we aimed to externally validate the performance of prediction models for unilateral PA in a large population of PA patients at a Canadian referral center who underwent AVS during 2006–2018. The presence of unilateral disease was indicated by a lateralization index of &gt;3 on AVS. We identified 6 clinical prediction models from the literature. The discrimination and calibration of each model were systematically evaluated. For the original models, the derivation cohorts were based out of Japan, France, Italy, and England, with mean age between 46–54 years and 43–56% being male. The derivation cohorts were generally small, with 4 of the 6 studies reporting less than 50 people with unilateral PA. Common variables reported to be predictive of unilateral PA included male sex, hypokalemia, elevated aldosterone-renin ratio, and the presence of a unilateral adrenal nodule on imaging. The validation cohort included 342 PA patients who underwent successful AVS (average age, 52.1 years; 58.8% male). Among them, 186 (54.4%) demonstrated unilateral disease, and the remaining 156 (45.6%) were considered to have bilateral disease. The baseline characteristics of the validation cohort were broadly similar to those of the derivation cohorts, except for potential differences in ethnicity. When applying the models to the validation cohort, subjects were excluded if any candidate variables were missing. All 6 models demonstrated poor discrimination in the validation set (C-statistics; range, 0.59–0.72), representing a marked decrease compared to the derivation sets where they were reported (range, 0.80–0.87). Assessment of calibration by comparing observed and predicted probabilities of the unilateral subtype revealed significant miscalibration. Calibration-in-the-large for every model was &gt;0 (range, 0.36–2.23), signifying systematic underprediction of unilateral PA. Calibration slopes were all &lt;1 (range, 0.35–0.85), indicating poor performance at the extremes of risk. These results suggest that the original models were optimistic due to overfitting in the derivation cohorts and therefore lack generalizability. This is primarily because these models were developed in small data sets. In conclusion, clinical assessment with prediction models for unilateral PA cannot be readily used to bypass AVS in the general PA population.

Outcomes of a Specialized Clinic on Rates of Investigation and Treatment of Primary Aldosteronism

Importance

Primary aldosteronism (PA) is one of the most common causes of secondary hypertension but remains largely unrecognized and untreated.

Objective

To understand the outcomes of a specialized clinic on rates of evaluation and treatment of PA in the context of secondary factors.

Design, Setting, and Participants

This population-based cohort study was conducted in Alberta, Canada, using linked administrative data between April 1, 2012, and July 31, 2019, on adults identified as having hypertension.

Main Outcomes and Measures

We evaluated each step of the diagnostic and care pathway for PA to determine the proportion of people with hypertension who received screening, subtyping, and targeted treatment for PA. Variations in diagnosis and treatment were examined according to individual-level, clinician-level, and system-level characteristics.

Results

Of the 1.1 million adults with hypertension, 7941 people (0.7%) were screened for PA. Among those who were screened, 1703 (21.4%) had positive test results consistent with possible PA, and 1005 (59.0%) of these were further investigated to distinguish between unilateral and bilateral forms of PA. Only 731 individuals (42.9%) with a positive screen result received disease-targeted treatment. Geographic zones and clinician specialty were the strongest determinants of screening, subtyping, and treatment of PA, with the highest rates corresponding to the location of the provincial endocrine hypertension program.

Conclusions and Relevance

In this cohort, less than 1% of patients expected to have PA were ever formally diagnosed and treated. These findings suggest that a system-level approach to assist with investigation and treatment of PA may be highly effective in closing care gaps and improving clinical outcomes.

Repeat Adrenal Vein Sampling in Aldosteronism: Reproducibility and Interpretation of Persistently Discordant Results

CONTEXT

The reproducibility of adrenal vein sampling (AVS) is unknown.

OBJECTIVE

This work aimed to determine reproducibility of biochemical results and diagnostic lateralization in patients undergoing repeat AVS.

METHODS

A retrospective chart review was conducted of single-center, single-operator AVS procedures at a tertiary care center. Included were patients with confirmed primary aldosteronism (PA) undergoing repeat AVS because of concerns about technical success or discordant diagnostic results. Simultaneous AVS was performed by an experienced operator using a consistent protocol of precosyntropin and postcosyntropin infusion. Among successfully catheterized adrenal veins (selectivity index ≥ 2), the correlation of the adrenalaldosterone/cortisol (A/C) ratio was measured between the first and second AVS. The secondary outcome measure was diagnostic agreement on repeat AVS lateralization (lateralization index ≥ 3).

RESULTS

There were 46 sets of AVS from 23 patients at a median of 3 months apart. There was moderate correlation in A/C ratios in the adrenal veins and inferior vena cava (Spearman r = 0.49-0.59, P < .05) pre cosyntropin. Post cosyntropin, the correlation was better (Spearman r = 0.67-0.76, P < .05). In technically successful AVS, there was moderate correlation between the repeated lateralization indices (Spearman r = 0.53, P < .05). In 15 patients in whom repeat AVS was performed because of apparent lateralization discordance with computed tomography imaging, the final diagnosis was the same in the second AVS procedure. Initial failed AVS was successful 75% of the time on repeat attempt.

CONCLUSION

Repeat AVS was feasible and usually successful when an initial attempt failed. There was modest correlation between individual repeat adrenal A/C ratios and lateralization indices when AVS was performed twice. The final lateralization diagnosis was identical in all cases. This demonstrates that AVS is a reliable and reproducible localizing test in PA.

Surgical Outcomes Among Primary Aldosteronism Patients Without Visible Adrenal Lesions

CONTEXT

Many patients with unilateral primary aldosteronism (PA) have normal adrenal imaging, but little is known about their outcome following adrenalectomy.

OBJECTIVE

To evaluate biochemical and clinical outcomes after adrenalectomy in patients with unilateral PA and normal-appearing adrenal imaging.

DESIGN

Retrospective cohort study of patients seen between January 2006 and May 2018.

SETTING

A Canadian tertiary care PA referral center.

PATIENTS

Consecutive individuals with PA, normal cross-sectional adrenal imaging, and lateralizing adrenal vein sampling (AVS) who underwent adrenalectomy during the study period.

PRIMARY OUTCOME

Biochemical response to adrenalectomy graded according to the Primary Aldosteronism Surgical Outcome criteria.

RESULTS

A total of 40 patients were included. Biochemical outcomes were available for 33 people (mean age, 54.7 years; 91% male; median follow-up, 2.7 months), with 28 (85%) showing a complete or partial response and 5 (15%) with no response. Clinical outcomes were available for 36 people (mean age, 54.6 years; 86% male; median follow-up, 9.8 months), with 31 (86%) demonstrating a complete or partial response and 5 (14%) with no response.

CONCLUSIONS

The prognosis after adrenalectomy is highly favorable for patients with unilateral PA and normal-appearing adrenal imaging. Patients with lateralizing disease should be considered for surgery despite apparently normal adrenal imaging.

Adrenal vein sampling: External validation of multinomial regression modelling and left adrenal vein-to-peripheral vein ratio to predict lateralization index without right adrenal vein sampling

BACKGROUND

Adrenal vein sampling (AVS) failure is mainly due to right adrenal vein unavailability. Multinomial regression modelling (MRM) and left adrenal vein-to-peripheral vein ratio (LAV/PV) were proposed to predict the lateralization index without the right AVS.

OBJECTIVE

To assess external validity of MRM and LAV/PV to predict lateralization index when right adrenal vein sampling is missing.

DESIGN

Diagnostic retrospective study.

PATIENTS

Development and validation cohorts included AVS of 174 and 122 patients, respectively, from 2 different centres.

MEASUREMENTS

Development and validation cohort data were used, respectively, for calibration and for validation of MRM and LAV/PV to predict the lateralization index without the right adrenal vein sampling. Sensitivity and specificity of MRM and LAV/PV were compared between both centres at different pre-established specificity thresholds based on receiver operating characteristic curves generated from the development cohort data.

RESULTS

At a specificity threshold of 95% set in the development cohort, specificity values exceeded 90% (range, 90.6%-98.8%) for all verified MRM and LAV/PV models in the validation cohort. Corresponding sensitivities for MRM and LAV/PV, respectively, range from 54.1% to 83.7% and 32.8% to 88.4% for the development cohort compared to 33.3%-87.5% and 2.8%-79.2% for the validation cohort. Overall, diagnostic accuracy of both methods was higher to detect right (82.8%-93.5%) than left (70.2%-80.6%) lateralization index status in both centres.

CONCLUSIONS

Minimal changes in specificity from development to validation cohorts validate the use of MRM and LAV/PV to predict the lateralization index when the right AVS is missing. Both methods had better accuracy for right than left lateralization detection.

Basal contralateral aldosterone suppression is rare in lateralized primary aldosteronism

CONTEXT

Unilateral aldosteronomas should suppress renin and contralateral aldosterone secretion. Complete aldosterone suppression in contralateral adrenal vein sample (AVS) could predict surgical outcomes.

OBJECTIVES

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Unilateral Disease Is Common in Patients With Primary Aldosteronism Without Adrenal Nodules

BACKGROUND

Patients with primary aldosteronism (PA) without apparent adrenal nodularity have not been well characterised in the literature. The aim of this study was to assess for unilateral aldosterone hypersecretion among patients with primary aldosteronism with normal-appearing adrenals using adrenal vein sampling (AVS).

METHODS

In this cross-sectional study performed at a Canadian tertiary care centre, we reviewed all consecutive PA patients lacking a definitive adrenal nodule who were referred for AVS in the work-up of PA between January 2006 and May 2018. AVS indications included an elevated aldosterone-to-renin ratio and high-probability features of PA.

RESULTS

In total, 174 patients were included (mean age, 52.0 years; 62.6% male), and 70 (40.2%) had unilateral aldosterone hypersecretion. There was a positive linear association between higher age categories (by decade) and lateralisation (P = 0.03). For every decade of age, there was a 30% higher odds of lateralisation (odds ratio, 1.03 per year; 95% confidence interval, 1.00-1.05). The frequency of lateralisation was higher in males compared with females (47.7% vs 27.7%), with a 2-fold greater odds of unilateral disease (odds ratio, 2.38; 95% confidence interval, 1.23-4.61). Traditional biomarkers of lateralisation among patients with adrenal nodules (eg, serum potassium and aldosterone-to-renin ratio levels) were not predictive of lateralisation in this population.

CONCLUSIONS

Many patients with PA who lack definitive adrenal nodules have lateralising disease. Efforts to optimise referrals for AVS may be prioritised by focusing on patients most likely to have unilateral disease, especially males and older adults.

SUN-LB96 Basal Contralateral Aldosterone Suppression Is Rare in Lateralized Primary Aldosteronism and Can Be Useful in Predicting Surgical Outcome

Background: Adrenal venous sampling (AVS) is performed to distinguish between unilateral or bilateral source of aldosterone in primary aldosteronism (PA). Unilateral aldosteronomas should lead to suppression of renin and contralateral (CL) aldosterone secretion, assessed by the CL suppression ratio. We recently found that CL aldosterone suppression was relatively rare using the ratio of basal aldosterone concentration of the opposite adrenal vein/periphery (A_OPP/A_P) in contrast to the traditional cortisol-corrected aldosterone ratio ((A/C)_OPP(A/C)_P). Pathology studies showed frequent zona glomerulosa (ZG) hyperplasia adjacent to a dominant aldosteronoma, which could also indicate probable ZG hyperplasia in the CL adrenal. The ratio of basal CL suppression could be a usefull parameter to predict cure following unilateral adrenalectomy (UA), but controversy remains in the literature.

Objectives:

1. To evaluate the prevalence of basal CL suppression using the A_OPP/A_P ratio as compared to the (A/C)_OPP/(A/C)_P ratio at previously established cut-offs.

2. To determine the best cut-off to predict clinical and biochemical surgical cure in two Canadian referral centers.

3. To compare the accuracy of the A_OPP/A_P ratio to the basal lateralization ratio (LR) and the post-ACTH LR in predicting the surgical outcome.

Methods: 330 patients with PA and successful bilateral simultaneous basal and post-ACTH stimulated AVS (selectivity index >2 basally and >5 post-ACTH) were included; 124 patients found to be lateralized underwent UA. The follow-up data were evaluated for clinical and biochemical cure at 3 and 12 months using the PASO criteria.

Results: Using A_OPP/A_P and (A/C)_OPP/(A/C)_P at the cut-off of 1, the prevalence of CL suppression is 6% and 45%, respectively. The median CL suppression ratio is 2.3 (1.3-5.1) in lateralized cases of PA using A_OPP/A_P. Using ROC curves, the A_OPP/A_P ratio is associated with clinical cure at 3 and 12 months and biochemical cure at 12 months. (A/C)_OPP/(A/C)_P is associated with biochemical cure only. The cut-offs for A_OPP/A_P offering the best sensitivity and specificity 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 LR and post-ACTH LR are associated with clinical cure but only the post-ACTH LR is associated with biochemical cure.

Conclusions: Basal CL suppression defined by the A_OPP/A_P ratio is rare and incomplete compared to the traditional (A/C)_OPP/(A/C)_P ratio in lateralized cases of PA. This may reflect the frequent micronodular hyperplasia adjacent to dominant aldosteronomas and possibly in the CL adrenal. Basal CL aldosterone suppression may predict clinical postoperative outcome, but with modest accuracy.

Discordance Between Imaging and Adrenal Vein Sampling in Primary Aldosteronism Irrespective of Interpretation Criteria

BACKGROUND

Subtyping of primary aldosteronism (PA) using imaging and adrenal vein sampling (AVS) may yield discordant results, causing confusion in management. Interpretation criteria for AVS lateralization may affect discordance rates.

METHODS

We identified consecutive patients with PA who underwent AVS at a quaternary care center between January 2006 and May 2018. Patient demographics, laboratory results, diagnostic imaging, and AVS results were retrieved. Adrenal cross-sectional imaging was compared with AVS findings. The presence of lateralization was defined using varying thresholds for the lateralization index (LI) from >2:1 to >5:1. Discordance was defined by a unilateral lesion on imaging with contralateral or nonlateralization on AVS.

RESULTS

A total of 342 patients were included; 68.7% had hypokalemia. With cross-sectional imaging, 191 (55.6%) patients had unilateral lesions, 47 (13.7%) had bilateral lesions, and 104 (30.4%) had normal imaging. Overall discordance rates were high, ranging from 22% to 28% for LI thresholds of >2:1 and >5:1, respectively. Discordance between imaging and AVS was positively correlated with LI threshold stringency (P < 0.001). Patients with normal or bilateral lesions on imaging frequently lateralized on AVS. Lateralization, when present, was approximately equal between left and right sides, irrespective of the LI threshold.

CONCLUSIONS

Discrepancies between imaging and AVS were common, even among patients with nonspecific imaging. Discordance was greatest with the strictest AVS interpretation criteria. Even under the most lenient thresholds, apparent discordance between imaging and AVS exceeded 20% and may limit the ability to make surgical decisions. Reliance on imaging alone for detecting lateralization may be misleading.

Plasmocytoma presented as pancreatic head mass

Multiple myeloma is a malignant tumour characterized by proliferation of a single clone of plasma cells, this cell line will produce large amount of ineffective immunoglobulins that are ineffective at fighting infection resulting in immunosuppression.

These are medullary tumours most of the time; however, in rare cases they may arise extra medullary.

The incidence of extramedullary plasmocytoma is about 5% and they arise in the chest most of the time; but they can also arise in other body systems like gastrointestinal system, which is involved in 10% of the time. We present a very rare case of primary plasmocytoma involving the pancreas. According to our research, there are only 25 cases of primary pancreatic plasmocytoma reported in english literature.

Defining contralateral adrenal suppression in primary aldosteronism: implications for diagnosis and outcome

OBJECTIVE

Unilateral primary aldosteronism (PA) should have a contralaterally normal and therefore suppressed adrenal zona glomerulosa. However, there is no validated definition of adrenal suppression. We created two biochemical hypotheses of adrenal suppression based upon measurements taken during adrenal vein sampling (AVS) to determine whether either proved useful for interpretation of AVS or prediction of hypertension outcome in operated cases.

DESIGN

Retrospective database analysis.

PATIENTS

Ninety-nine cases of PA from a tertiary hypertension unit.

MEASUREMENTS

Hypothesis 1 was the proportional suppression of the uninvolved/lowest adrenal(aldo/cortisol) to IVC(aldo/cortisol) ratio pre- and post cosyntropin. Hypothesis 2 was the absolute decrease in the uninvolved adrenal(aldo/cortisol) ratio after cortrosyn injection. ROC analysis performed using lateralization and hypertension resolution as the outcomes of interest.

RESULTS

Hypothesis 1 proved highly predictive of lateralization with a ROC AUC of 0.958, P < 0.0001, giving adrenal(aldo/cortisol):IVC(aldo/cortisol) <1.4 as the optimized criterion (sensitivity 90%, specificity 94%). For blood pressure outcomes in the surgical subgroup (n = 52), hypertension resolution was most commonly seen among subjects with adrenal suppression by both definitions although there was significant overlap with subjects requiring ongoing medication.

CONCLUSIONS

Post cosyntropin suppression of the uninvolved adrenal-to-IVC ratio is a highly useful definition of adrenal suppression that accurately predicts unilateral PA. This may be particularly useful in a case where AVS fails to catheterize one of the adrenal veins but suppression is seen on the other side. Adrenal suppression may also predict blood pressure outcome, however, a much larger PA database is likely necessary to determine the relative contribution of this predictor.

Unadjusted Plasma Renin Activity as a "First-Look" Test to Decide Upon Further Investigations for Primary Aldosteronism

The authors sought to define the 95th percentile of plasma renin activity (PRA) in a sample of patients with confirmed primary aldosteronism (PA) prior to adjustment of medications as a practical "first-look" test to identify those with very low ultimate likelihood of having PA. The aldosterone to renin ratio (ARR) was measured without adjustment of antihypertensive medications, with further workup as appropriate. Two groups were defined: patients with surgically "confirmed PA" (n=58) and patients with "high-probability PA" (n=59), defined as having any of the following: computed tomography-confirmed adrenal adenoma plus lateralizing adrenal vein sampling (AVS) without surgery, high ARR and hypokalemia but nonlateralizing AVS, or ARR more than four times the upper limit of normal. The PRA 95th percentile was 1.0 ng/mL/h. All outliers had hypokalemia and two had adrenal adenomas. There was no difference between the confirmed and high probability groups. In the absence of highly suspicious clinical features, patients with unadjusted PRA >1.0 ng/mL/h do not warrant further investigation for PA.

A clinical prediction score for diagnosing unilateral primary aldosteronism may not be generalizable

BACKGROUND

A published clinical prediction score indicated that a unilateral adrenal adenoma and either hypokalemia or an estimated glomerular filtration rate of 100 ml/min/1.73 m2 was 100% specific for unilateral primary aldosteronism. This study aimed to validate this score in a separate cohort of patients with primary aldosteronism.

METHODS

A review of patients with primary aldosteronism from June 2005 to July 2013 at a single center's hypertension clinic. One hundred twelve patients with primary aldosteronism underwent successful adrenal vein sampling and the 110 patients with full data available were included in the final analysis. Adrenal vein sampling was performed all patients desiring surgery by the simultaneous collection of sample prior to and 15 minutes after a cosyntropin infusion with a 3:1 aldosterone/cortisol ratio diagnosing unilateral primary aldosteronism. The derived score was applied to the cohort. Sensitivity and specificity were calculated for clinical prediction score of ≥5 points.

RESULTS

There were 64 patients found to have unilateral primary aldosteronism and 48 had bilateral disease. A score ≥5 points had 64% sensitivity (95% confidence interval, 51-76) and 85% specificity (95% confidence interval, 71-94) for unilateral disease. Four patients had lateralization of primary aldosteronism to the side contralateral to the adenoma.

CONCLUSIONS

The 100% specificity of the score for the unilateral origin of primary aldosteronism was not validated in this cohort with a score of ≥5 points. At best, a high score in this prediction rule may be an additional tool for helping to confirm a decision to offer patients adrenal vein sampling.

High-probability features of primary aldosteronism may obviate the need for confirmatory testing without increasing false-positive diagnoses

This retrospective review examined all primary aldosteronism (PA) adrenal vein sampling (AVS), diagnoses, and outcomes from an endocrine hypertension unit where confirmatory testing was abandoned in 2005 to determine the potential rate of false-positive diagnoses. Patients with outcome-verified PA (surgical patients) were compared with patients with high-probability PA (nonsurgical but high aldosterone-renin ratio, imaging abnormalities, and/or hypokalemia) or possible PA (nonsurgical, no features besides mild elevation of aldosterone-renin ratio, a potential false diagnosis of PA). Of 83 patients, 58% had unilateral PA and 42% had bilateral aldosteronism. Less than 3% of the cohort showed bilateral aldosteronism without hypokalemia or computed tomographic findings, potentially representing the false-positive PA diagnosis rate with omission of confirmatory tests in this population. In a hypertension referral unit enriched in high-probability PA cases and where high AVS success is achieved, omission of a PA confirmatory test yields a high rate of surgical diagnosis with few potential false-positive diagnoses.

A marked proportional rise in IVC aldosterone following cosyntropin administration during AVS is a signal to the presence of adrenal hyperplasia in primary aldosteronism

We hypothesized aldosteronoma responsiveness to cosyntropin may be a characterizing feature that could be determined in addition to standard adrenal vein sampling (AVS) data. We reviewed an AVS database from June 2005 to October 2011 including 65 patients with confirmed primary aldosteronism (PA) who underwent AVS and, if applicable, unilateral adrenalectomy. Patients were divided into confirmed lateralized and non-lateralized groups and subgrouped by histology. Plasma aldosterone in inferior vena cava (IVC) pre- and post-cosyntropin infusion during AVS was measured. Peak aldosterone and proportional change was compared between groups. Baseline and peak IVC aldosterone was higher in lateralized patients but incremental aldosterone rise was much greater in subjects with bilateral hyperplasia. From receiver operator characteristics (ROC) analysis, the optimized diagnostic cut point of peak IVC aldosterone of >649 pmol l(-1) would have a sensitivity of 94% for surgical disease although specificity of just 59%. A 250% increase in IVC aldosterone following cosyntropin would be specific enough to exclude 87% of surgical/lateralized disease. These diagnostic capabilities are similar to other results with non-AVS tests performed for diagnosis of lateralization. Although not specific enough to replace standard AVS interpretation, a marked IVC aldosterone increase after cosyntropin during AVS is a useful additional test to diagnose non-lateralizing forms of PA. Such a calculation requires no additional expense or tests.

Radiologic placement of central venous catheters: rates of success and immediate complications in 3412 cases

OBJECTIVE

To determine the success and immediate complication rates associated with 3412 central venous catheter placements performed in an interventional radiology suite.

METHODS

Success and immediate complication rates were prospectively recorded for 3412 consecutive patients who had central venous catheters radiologically placed at a tertiary care centre between July 1993 and October 2000. The indication for placement and the insertion site were also recorded.

RESULTS

The most common indication for both short- and long-term venous access was hemodialysis, and the right internal jugular vein was the most common site for catheter insertion. Placement was successful for 98.8% of tunnelled lines and 99.3% of temporary catheters. The rate for immediate complications (including pneumothorax, air emboli, bleeding and arterial puncture) for tunnelled catheter placements was 3.8% and for temporary catheter placements was 1.6%; no major complications were documented.

CONCLUSION

Our results lend further evidence to the claim that the success and immediate complication rates of radiologically placed central venous catheters compare favourably with blind placement and surgical placement of central venous catheters.

Extraprostatic biopsy improves the staging of localized prostate cancer

OBJECTIVE

To evaluate the role and safety of biopsy of the seminal vesicles and neurovascular bundles in determining the pathologic stage of prostatic carcinoma.

METHODS

Eighty-one consecutive patients were enrolled in a comprehensive cryosurgical biopsy protocol that included sextant intraprostatic plus extraprostatic biopsy. The pathologic stage, determined after biopsy, was compared with the clinical stage, determined by digital rectal examination (DRE) and transrectal ultrasonographic (TRUS) evaluation. As well, complication rates for these patients were compared with rates for a separate group that underwent sextant intraprostatic biopsy alone.

RESULTS

Of the 81 patients, 61 (75%) were confirmed to have cancer by biopsy. None of these patients was considered to have extraprostatic extension by clinical evaluation (DRE and TRUS), but 16 of 61 (26%) were identified to have extraprostatic cancer in the seminal vesicles (8 of 61, 13%) or in the neurovascular bundles (8 of 61, 13%) by extraprostatic biopsy. There was no significant difference in the complication rates between sextant intraprostatic biopsy and sextant intraprostatic plus extraprostatic biopsy (p>0.97).

CONCLUSIONS

Extraprostatic biopsy identifies extension of carcinoma in a large proportion of patients in whom clinical evaluation by DRE and TRUS indicates organ-confined disease. Extraprostatic biopsy is therefore warranted as routine evaluation before surgery in order to correctly stage prostatic carcinoma and select appropriate therapy.

Fluoroscopically guided percutaneous gastrostomy: current status

The authors review the current status of fluoroscopically guided percutaneous gastrostomy (FGPG). The indications for this procedure have been expanded since the technique was first described over a decade ago. Ther are few contraindications to FGPG, although modifications are required in some situations. The procedure involves placing a feeding tube into the stomach by a modified Seldinger technique. According to the literature, most interventionalists do not routinely employ gastropexy. The insertion of gastrojejunostomy feeding tubes rather than gastrostomy feeding tubes to reduce gastroesophageal reflux remains controversial. Complications after FGPG are rare. Feeding tubes inserted in this manner allow satisfactory establishment and maintenance of enteral feeding. The technique compares favourably with other methods of inserting gastrostomy tubes.