Primary hyperaldosteronism without suppressed renin due to secondary hypertensive kidney damage

Rare Coexistence of Aldosterone-producing Adrenocortical Adenoma Confirmed by an Immunohistochemical Analysis of Steroidogenic Enzymes with Adrenal Ectopic Thyroid Tissue: A Case Report and Literature Review

A 56-year-old man presented with a history of hypertension; clinically, the patient had primary aldosteronism (PA) and a 4-cm left adrenal tumor. The left adrenal glands, resected by adrenalectomy, also contained ectopic thyroid tissue (ETT). An immunohistochemical analysis of steroid-converting enzymes revealed an aldosterone-producing adenoma (APA). Among 19 previously reported cases of adrenal ETT, 4 had adrenal hormonal abnormalities, all of which were PA. This is the first case of adrenal ETT coexisting with APA, confirmed by steroid-converting enzyme expression. Further analyses using cumulative case data are required to clarify the correlation between adrenal ETT and APA.

A case of malignant nephrosclerosis occurring with serum renin in the normal range

A 37-year-old Japanese man was admitted to our hospital for evaluation of severe hypertension and visual impairment. His serum creatinine was 4.16 mg/dL. Plasma renin activity was normal (2.7 ng/mL/h), but plasma aldosterone concentration was elevated (27.2 ng/dL). A kidney biopsy showed concentric subendothelial edematous thickening of the arterioles (onion skin pattern) with luminal narrowing or obstruction, and malignant nephrosclerosis was diagnosed. Antihypertensive therapies, including an angiotensin II receptor blocker and spironolactone, were administered and effectively preserved kidney function and normalized blood pressure. This case indicates that hyperaldosteronemia in the presence of normal renin levels might also cause malignant hypertension.

Aldosterone, Renin, and Aldosterone-to-Renin Ratio Variability in Screening for Primary Aldosteronism

CONTEXT

The plasma aldosterone concentration (PAC), renin, and aldosterone-to-renin ratio (ARR) are used to screen for primary aldosteronism (PA). Substantial intra-individual variability of PAC and ARR using plasma renin activity in the context of usual antihypertensive therapy has been described, but there is no data on ARR variability calculated using direct renin concentration (DRC).

OBJECTIVE

To describe the intra-individual variability of PAC, DRC, and ARR in the absence of interfering medications in patients with and without PA.

DESIGN

Retrospective cohort study.

PATIENTS

Hypertensive patients referred for investigation of PA, with at least 2 ARR measurements while off interfering medications.

SETTING

Endocrine hypertension service of a tertiary center, from May 2017 to July 2021.

MAIN OUTCOME MEASURES

PAC, DRC, and ARR variability was calculated as coefficient of variation (CV) and percent difference (PD).

RESULTS

Analysis of 223 patients (55% female, median age 52 years), including 162 with confirmed PA, demonstrated high variability with a sample CV of 22-25% in the PAC and sample CV of 41% to 42% in the DRC and ARR in both the PA and non-PA groups. The degree of variability was substantially higher than the assays' analytical CV. Sixty-two patients (38%) with PA had at least one ARR below 70 pmol/L:mU/L (2.4 ng/dL:mU/L), a cut-off for first-line screening of PA.

CONCLUSIONS

Significant intra-individual variability in PAC, DRC, and hence ARR occurs in a large proportion of patients being investigated for PA. These findings support the need for at least 2 ARR before PA is excluded or further investigated.

Primary aldosteronism - a multidimensional syndrome

Primary aldosteronism is a common cause of hypertension and is a risk factor for cardiovascular and renal morbidity and mortality, via mechanisms mediated by both hypertension and direct insults to target organs. Despite its high prevalence and associated complications, primary aldosteronism remains largely under-recognized, with less than 2% of people in at-risk populations ever tested. Fundamental progress made over the past decade has transformed our understanding of the pathogenesis of primary aldosteronism and of its clinical phenotypes. The dichotomous paradigm of primary aldosteronism diagnosis and subtyping is being redefined into a multidimensional spectrum of disease, which spans subclinical stages to florid primary aldosteronism, and from single-focal or multifocal to diffuse aldosterone-producing areas, which can affect one or both adrenal glands. This Review discusses how redefining the primary aldosteronism syndrome as a multidimensional spectrum will affect the approach to the diagnosis and subtyping of primary aldosteronism.

Characteristics of aldosterone-producing adenomas in patients without plasma renin activity suppression

Primary aldosteronism (PA) usually accompanies suppressed plasma renin activity (PRA) through a negative feedback mechanism. While some cases of PA with unsuppressed PRA were reported, there have been no studies about the characteristics of PA with unsuppressed PRA; thus, these characteristics were examined herein. Nine patients with unsuppressed PRA and 86 patients with suppressed PRA were examined. All patients underwent segmental adrenal venous sampling (sAVS) and adrenalectomy, and were pathologically confirmed to have cytochrome P450 11B2 (CYP11B2)-positive aldosterone-producing adenoma according to international histopathology consensus criteria. Unsuppressed and suppressed PRA were defined as PRA levels of > 1.0 and ≤ 1.0 ng/mL/hr, respectively, in multiple blood samples obtained in the resting position. The unsuppressed PRA group had higher morning cortisol levels (12.6 [8.5, 13.5] vs. 8.5 [7.1, 11.0] μg/dL, P = 0.03) and higher cortisol levels after a 1 mg dexamethasone suppression test (DST) (2.2 [1.6, 2.5] vs. 1.3 [1.0, 1.9] μ g/dL, P = 0.004) than the suppressed PRA group. The unsuppressed PRA group also showed higher aldosterone levels on the non-surgical side during sAVS (P = 0.02 before adrenocorticotropic hormone (ACTH) stimulation, P = 0.002 after ACTH stimulation), a higher intensity of CYP17 expression in the resected adrenal gland (P = 0.02), and a lower clinical complete success rate 1 year after surgery (P = 0.04) compared with those in the suppressed PRA group. These findings suggest that PA should not be ruled out by unsuppressed PRA among patients with hypertension, particularly when their cortisol levels remain unsuppressed in the 1 mg DST. Meanwhile, it should be acknowledged that patients with unsuppressed PRA have higher aldosterone levels on the non-surgical side, and a lower likelihood of postoperative complete clinical success is to be expected.

Higher risk of chronic kidney disease and progressive kidney function impairment in primary aldosteronism than in essential hypertension. Case-control study

PURPOSE

To study the differences in the prevalence, risk, and grade of control of different cardiometabolic comorbidities in patients with primary aldosteronism (PA) and essential hypertension (EH) matched by age, sex, and blood pressure levels at diagnosis.

METHODS

Case-control study of a secondary base (PA patients in follow-up in a tertiary hospital between 2018 and 2020). Controls were patients with non-functioning adrenal incidentalomas and EH, matched by age, sex, and baseline diastolic blood pressure (DBP) and systolic blood pressure (SBP).

RESULTS

Fifty patients with PA and 50 controls were enrolled in the study. At diagnosis, PA patients had a higher prevalence of chronic kidney disease (CKD) than controls (18.4% vs. 2.1%, P = 0.008). No differences were detected in the prevalence of other cardiometabolic comorbidities nor in their degree of control (P > 0.05). All patients received antihypertensive medical treatment and 10 PA patients underwent unilateral laparoscopic adrenalectomy. After a median follow-up of 31.9 [IQR = 1.0-254.8] months, PA patients presented a greater degree of declination of kidney function than controls (average decrease in glomerular filtration rate (MDRD-4) -17.6 ± 3.1 vs. -2.8 ± 1.8 ml/min/1.73 m², P < 0.001). There were no differences in the grade of SBP (P = 0.840) and DBP control (P = 0.191), nor in the risk of developing other comorbidities or in their degree of control.

CONCLUSIONS

PA patients have a higher prevalence of CKD at the time of diagnosis when compared to EH matched by age, sex, and blood pressure levels. Furthermore, the risk of kidney function impairment throughout the follow-up is significantly greater in PA patients and is independent of the degree of blood pressure control.

A case of primary aldosteronism with a negative aldosterone-to-renin ratio

Background

Primary aldosteronism (PA), as a cause of secondary hypertension, can cause more serious cardiovascular damage than essential hypertension. The aldosterone-to-renin ratio (ARR) is recommended as the most reliable screening method for PA, but ARR screening is often influenced by many factors. PA cannot be easily excluded when negative ARR.

Case presentation

We report the case of a 45-year-old Chinese man with resistant hypertension. Three years ago, he underwent a comprehensive screening for secondary hypertension, including the ARR, and the result was negative. After that, the patient's blood pressure was still poorly controlled with four kinds of antihypertensive drugs, the target organ damage of hypertension progressed, and hypokalaemia was difficult to correct. When the patient was hospitalized again for comprehensive examination, we found that aldosterone levels had significantly increased, although the ARR was negative. An inhibitory test with saline was further carried out, and the results suggested that aldosterone was not inhibited; therefore, PA was diagnosed. We performed a unilateral adenoma resection for this patient, and spironolactone was continued to control blood pressure. After the operation, blood pressure is well controlled, and hypokalaemia is corrected.

Conclusion

When the ARR is negative, PA cannot be easily excluded. Comprehensive analysis and diagnosis should be based on the medication and clinical conditions of patients.

Aldosterone-producing adenoma associated with non-suppressed renin: a case series

Although the aldosterone/renin ratio (ARR) is the preferred screening test for primary aldosteronism (PA), patients with non-suppressed renin and a falsely negative ARR on non-interfering medications have occasionally been reported. This report describes the clinical characteristics and outcomes of seven patients with proven aldosterone-producing adenoma (APA) and non-suppressed renin.Chart review of seven PA patients with an APA and a non-suppressed plasma renin concentration (PRC > 8.4 mU/L) was undertaken to collect data on anthropometric and biochemical characteristics, diagnostic evaluation and postsurgical outcomes.Seven patients (two women and five men) with a proven APA had median (range) PRC, plasma aldosterone and ARR of 20 (9-43) mU/L, 750 (270-1940) pmol/L and 45 (8-62, normal <70), respectively, on non-interfering medications. Six patients had two consecutive ARR measurements and in five of them both were normal. Renal artery stenosis was carefully excluded in all patients. Further evaluation for PA was pursued because of high clinical suspicion (either hypokalaemia and/or a known adrenal mass lesion on imaging). All underwent adrenal vein sampling confirming unilateral PA which was managed by unilateral adrenalectomy. Postsurgical follow-up data either confirmed or were highly suggestive of cure of PA.Strict control of factors known to influence the ARR is crucial to avoid false-negative results. Other causes that could explain a non-suppressed renin should be excluded. In patients with a consistently non-suppressed renin further diagnostic workup for PA should be considered if clinical suspicion remains high.

Baseline Plasma Aldosterone Level and Renin Activity Allowing Omission of Confirmatory Testing in Primary Aldosteronism

CONTEXT

Previous studies have proposed cutoff value of baseline plasma aldosterone concentration (bPAC) under renin suppression that could diagnose primary aldosteronism (PA) without confirmatory testing. However, those studies are limited by selection bias due to a small number of patients and a single-center study design.

OBJECTIVE

This study aimed to determine cutoff value of bPAC and baseline plasma renin activity (bPRA) for predicting positive results in confirmatory tests for PA.

DESIGN

The multi-institutional, retrospective, cohort study was conducted using the PA registry in Japan (JPAS/JRAS). We compared bPAC in patients with PA who showed positive and negative captopril challenge test (CCT) or saline infusion test (SIT) results.

PATIENTS

Patients with PA who underwent CCT (n = 2256) and/or SIT (n = 1184) were studied.

MAIN OUTCOME MEASURES

The main outcomes were cutoff value of bPAC (ng/dL) and bPRA (ng/mL/h) for predicting positive CCT and/or SIT results.

RESULTS

In patients with renin suppression (bPRA ≤ 0.3), the cutoff value of bPAC that would give 100% specificity for predicting a positive SIT result was lower than that for predicting a positive CCT result (30.85 vs 56.35, respectively). Specificities of bPAC cutoff values ≥ 30.85 for predicting positive SIT and CCT results remained high (100.0% and 97.0%, respectively) in patients with bPRA ≤ 0.6. However, the specificities of bPAC cutoff values ≥ 30.85 for predicting positive SIT and CCT results decreased when patients with bPRA > 0.6 were included.

CONCLUSION

Confirmatory testing could be omitted in patients with bPAC ≥ 30.85 in the presence of bPRA ≤ 0.6.

The Association between eGFR and the Aldosterone-to-Renin Ratio and Its Effect on Screening for Primary Aldosteronism

OBJECTIVES

Long-term exposure to excessive aldosterone secretion from the adrenal gland may cause renal damage in patients with primary aldosteronism (PA). The aldosterone-to-renin ratio (ARR) may be significantly affected by renal function, especially in patients with renal damage related to long-term PA. The objective of this study was to investigate the association between the estimated glomerular filtration rate (eGFR) and ARR as well as its effect on screening for PA.

METHODS

This study was performed in Zhongshan Hospital, Fudan University, China. 803 patients with hypertension were consecutively recruited from 2012 to 2015. All participants underwent routine biochemical measurements, including plasma renin activity (PRA) and plasma aldosterone concentration (PAC). In all patients with a PAC higher than 10 ng/dl, a saline perfusion test was conducted, and a CT scan or adrenal venous sampling was also performed if needed. Receiver operating characteristic (ROC) analysis was conducted in all eGFR < 90 and eGFR ≥ 90 groups separately to determine the optimal cut-off values of ARR.

RESULTS

The optimal cut-off point for PA was an ARR of 40 ng/dl per ng/ml.h in the whole population, 52 ng/dl per ng/ml.h in subjects with an eGFR higher than 90 ml/min/1.73 m², and 18 ng/dl per ng/ml.h in subjects with an eGFR lower than 90 ml/min/1.73 m². Patients with an eGFR higher than 90 ml/min/1.73 m² had significantly lower PRA and higher ARR levels than patients with an eGFR lower than 90 ml/min/1.73 m² (P < 0.05).

CONCLUSIONS

Unsuppressed renin and lower ARR levels were associated with decreased eGFR in patients with primary aldosteronism. Diagnostic criteria of ARR by stratified eGFR may be an optimal strategy for the screening of primary aldosteronism.

Elevated Plasma Renin Activity Caused by Accelerated-malignant Hypertension in a Patient with Aldosterone-producing Adenoma Complicated with Renal Insufficiency

During the malignant phase of hypertension in patients with primary aldosteronism complicated with severe renal failure, the plasma renin activity may markedly increase with a false negative screening result for primary aldosteronism, thus potentially leading to a missed diagnosis of primary aldosteronism. We herein report the case of 37-year-old man who presented with accelerated-malignant hypertension complicated with severe renal insufficiency. The plasma renin activity was markedly increased in the malignant phase of hypertension, which were atypical results for primary aldosteronism. However, a plain abdominal computed tomography scan revealed a left adrenal nodule, which was diagnosed as aldosterone-producing adenoma by adrenal venous sampling.

Extraordinarily high aldosterone, 901.0 ng/dL, in a patient with primary aldosteronism: an insight into the underlying mechanism

A 43-yr-old hypertensive male was admitted due to hypokalemia (1.8 mEq/L) and renal dysfunction (eGFR, 20.0 mL/min/1.73 m2). His plasma aldosterone was 901.0 ng/dL, plasma renin activity 5.7 ng/mL/hr, and aldosterone/renin activity ratio 158. Angiotensin II (AII) was 0.7 pg/mL, ACTH <1.0 pg/mL, and cortisol 21.6 μg/dL. Liquid chromatography-tandem mass spectrometry analysis showed that aldosterone (104 times the control) as well as its precursors were significantly elevated in the patient's plasma. A left adrenal (4-cm-diameter) tumor with 131I-Adosterol uptake was found and removed. Four days later, plasma aldosterone and renin activity had dropped to 7.73 ng/dL and 1.6 ng/mL/hr, respectively. However, they rose to 24.0 ng/dL and 10.9 ng/mL/hr, respectively, by Day 102. Nevertheless, magnetic resonance angiography found no evidence of a renovascular lesion. The tumor was a benign adrenocortical adenoma composed predominantly of clear cells positive for 17α-hydroxylase, [hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerases], and aldosterone synthase. A quantitative real-time polymerase chain reaction analysis of the tumor cells revealed that expression of the gene encoding aldosterone synthase was 85 times the control level. In addition, the tumor cells harbored G151R mutation of the inward rectifying potassium channel subfamily j, member 5 gene. The striking overexpression of aldosterone synthase by the tumor cells was considered the primary mechanism for the extravagant overproduction of aldosterone in this case. This overexpression may have resulted from integration of signals from AII and forced membrane depolarization due to the potassium channel mutation.

Urinary Aldosterone/Creatinine Ratio After Fludrocortisone Suppression Consistent with PHA in a Cat

A 9 yr old cat was presented with clinical signs and laboratory abnormalities attributed to arterial hypertension (mean systolic arterial pressure, 290 mm Hg). Plasma aldosterone concentration was increased at the time of admission (651 pmol/L), but serum creatinine and potassium concentrations were within the reference range. A second increased aldosterone (879 pmol/L) and normal plasma renin activity (1.85 ng/mL/hr) resulted in an increased aldosterone/renin ratio, which was suggestive of primary hyperaldosteronism (PHA). To further support the diagnosis of PHA, the urinary aldosterone/creatinine ratio was calculated both before and after oral administration of fludrocortisone acetate (0.05 mg/kg q 12 hr for 4 consecutive days). The urinary aldosterone/creatinine ratio was 92.6 × 10(-9) before fludrocortisone administration and 155.8 × 10(-9) 4 days later. Absence of suppression was typical of PHA. The cat had a limited response to antihypertensive medication and died before treatment for PHA could be instituted. A necropsy was not permitted by the owner.

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 case of primary aldosteronism with end stage renal disease

A 52-year-old woman was referred to our hospital due to chronic renal failure with a 10-year history of hypertension. We found polycystic kidney disease, pulmonary tuberculosis and an aldosterone-producing adrenocortical mass. At this time, her serum potassium level and blood pressure were within the normal range. She refused hemodialysis and then was hospitalized because of uremic encephalopathy. On admission, her serum potassium level was normal without treatment and plasma aldosterone concentration highly elevated. She received hemodialysis, and thereafter hypokalemia developed. We then administered spironolactone, whereupon serum potassium level returned to the normal range. In this case, we thought that normokalemia was balanced hypokalemia of primary aldosteronism with hyperkalemia of chronic renal failure, and that hypokalemia developed after hemodialysis was due to an imbalanced primary aldosteronism with end stage renal disease.

Kidney impairment in primary aldosteronism

BACKGROUND

Kidney impairment is noted in primary aldosteronism (PA), and probably initiated by glomerular hyperfiltration.

METHODS

A prospectively defined survey was conducted on 602 patients who were suspected of PA in the multiple-center Taiwan Primary Aldosteronism Investigation (TAIPAI) database. Estimated glomerular filtration rate (eGFR) was calculated and followed up at 1 yr after treatment.

RESULTS

The diagnosis of PA was confirmed in 330 patients. Among them 17% of these patients had kidney impairment (eGFR<60 ml/min/1.73 m²). Patients with PA had a higher prevalence of estimated hyperfiltration than those with essential hypertension (EH) (14.5% vs. 7.0%, p=0.005). The eGFR independently predicted PA (OR, 1.017) in the propensity-adjusted multivariate logistic model. In PA, plasma renin activity and lower serum potassium (p=0.018) was correlated with kidney impairment (p=0.001), while this relationship was not significant in patients with EH. Either unilateral adrenalectomy or treatment of spironolactone for PA patients caused a decrease of eGFR (p<0.001). Pre-operative hypokalemia (p=0.013) and the long latency of hypertension (p=0.016) could enhance the significant decrease of eGFR after adrenalectomy.

CONCLUSIONS

Patients with aldosteronism had relative estimated hyperfiltration than patients with EH. Calculation of eGFR may increase the specificity in identifying patients with PA. Our findings demonstrate the correlation of serum potassium and renin with estimated hyperfiltration in PA and their relationship to kidney damage. These results provide a high priority for future renal protective strategies and methods for the early diagnosis and prompt treatment of PA.

Disparate effects of eplerenone, amlodipine and telmisartan on podocyte injury in aldosterone-infused rats

BACKGROUND

Several studies in patients with primary aldosteronism (PA) have suggested that aldosterone (ALD) is directly contributing to albuminuria. However, there are limited data pertaining to the direct role of ALD in in vivo models in regard to the induction of renal injury and the involved mechanisms. In the present study, we established a high-dose ALD-infused rat model to evaluate urinary albumin excretion rate (UAER) and podocyte damage. Moreover, we studied the effect of eplerenone (EPL), telmisartan (TEL) and amlodipine (AML) on ALD-induced renal structural and functional changes.

METHODS

Immunohistochemical and real-time PCR analyses, and TUNEL assays were performed to evaluate nephrin expression and podocyte injury.

RESULTS

ALD-receiving rats (ARR) showed a progressive increase in BP, UAER and proteinuria when compared with control rats (CR). Conversely, BP was significantly reduced in ALD + EPL (A/ERR)-, ALD + AML (A/ARR)- and ALD + TEL (A/TRR)-treated rats. However, UAER and proteinuria were decreased only in A/ERR and A/TRR, but not in A/ARR. Only EPL administration provided protection against ALD-induced podocyte apoptosis. Renal tissue of ARR revealed enhanced expression of nephrin protein and mRNA. This effect of ALD was inhibited by EPL, but not by TEL or AML. Conclusions. ALD induces direct glomerular injury independent of its haemodynamic effects; this effect of ALD is, at least in part, mediated through activation of the mineralocorticoid receptor.

A patient with concurrent primary aldosteronism and Page kidney

The ratio of aldosterone-to-renin activity is currently recommended as a screening test for primary aldosteronism (PA). There are many factors interfering the interpretation of aldosterone-renin ratio (ARR) and could hamper in-time diagnosis of PA. Here, we first report a patient with underlying Page phenomenon and an accidentally disclosed adrenal incidentaloma. High renin secretion from Page phenomenon had masked higher ARR into normal ARR obscuring the diagnosis of PA. However, adrenal venous sampling (AVS) confirmed the autonomous aldosterone secretion with left adrenal vein plasma aldosterone concentration (PAC) 124.1 ng/dl and a lateralization ratio 3.3. AVS may discriminate masked PA due to high renin secretion from Page kidney. It is suggested that clinicians should cautiously interpret aldosterone-renin ratio and consider diagnostic AVS if hyperaldosteronism is highly suspected especially in the background of other secondary hypertension.

Intrarenal hemodynamics in primary aldosteronism before and after treatment

CONTEXT

Elevated urinary albumin excretion has been reported in primary aldosteronism and might partially reflect reversible abnormalities initiated by glomerular hyperfiltration.

OBJECTIVE

The aim of the study was to examine the outcome of renal function and intrarenal Doppler velocimetric indices in primary aldosteronism.

DESIGN

We conducted a prospective study of patients with primary aldosteronism who were reevaluated 1 yr after either adrenalectomy or treatment with spironolactone.

SETTING

The study was conducted at a university referral center.

PATIENTS

Fifty-four patients with tumoral or idiopathic aldosteronism were followed after either surgical (n = 24) or medical (n = 30) treatment. Patients with primary aldosteronism were compared with 100 patients with primary hypertension and comparable severity and duration of disease.

MAIN OUTCOME MEASURES

Changes in renal function and intrarenal echo-Doppler indices were measured.

RESULTS

Patients with primary aldosteronism had greater creatinine clearance and urinary albumin excretion than patients with primary hypertension. Patients with primary aldosteronism and creatinine clearance above the median (105 ml/min per 1.73 m(2)) had significantly lower resistance and pulsatility index than patients with creatinine clearance below the median, independent of disease subtype. After 1 yr, creatinine clearance and albuminuria declined, and resistance and pulsatility index increased to the same extent in patients with primary aldosteronism treated with either adrenalectomy or spironolactone. Changes in glomerular filtration and albuminuria were inversely related with baseline values of the resistance index. In primary hypertension, echo-Doppler velocimetric indices did not change during follow-up.

CONCLUSIONS

In primary aldosteronism, sonographic evidence of decreased intrarenal vascular resistance is associated with glomerular hyperfiltration. Both adrenalectomy and spironolactone revert the intrarenal hemodynamic pattern and decrease urinary protein losses.

Rapid Screening Test for Primary Hyperaldosteronism: Ratio of Plasma Aldosterone to Renin Concentration Determined by Fully Automated Chemiluminescence Immunoassays

Background: The ratio of plasma aldosterone concentration to plasma renin activity (PAC/PRA) is the most common screening test for primary hyperaldosteronism (PHA), but it is not standardized among laboratories. We evaluated new automated assays for the simultaneous measurement of PAC and plasma renin concentration (PRC).

Methods: We studied 76 healthy normotensive volunteers and 28 patients with confirmed PHA. PAC and PRC were measured immunochemically in EDTA plasma on the Nichols Advantage® chemiluminescence analyzer, and PRA was determined by an activity assay.

Results: In volunteers, PAC varied from 33.3 to 1930 pmol/L, PRA from 1.13 to 19.7 ng · mL−1 · h−1 (0.215 ng · mL−1 · h−1 = 1 pmol · L−1 · s−1), and PRC from 5.70 to 116 mU/L. PAC/PRA ratios ranged from 4.35 to 494 (pmol/L)/(ng · mL−1 · h−1) and PAC/PRC ratios from 0.69 to 71.0 pmol/mU. In PHA patients, PAC ranged from 158 to 5012 pmol/L, PRA from 0.40 to 1.70 ng · mL−1 · h−1, and PRC from 0.80 to 11.7 mU/L. PAC/PRA ratios were between 298 and 6756 (pmol/L)/(ng · mL−1 · h−1) and PAC/PRC ratios between 105 and 2328 pmol/mU. Whereas PAC or PRC showed broad overlap between PHA patients and volunteers, the PAC/PRC ratio indicated distinct discrimination of these two groups at a cutoff of 71 pmol/mU.

Conclusion: The PAC/PRC ratio offers several practical advantages compared with the PAC/PRA screening method. The present study offers preliminary evidence that it may be a useful screening test for PHA. Further studies are required to validate these results, especially in hypertensive cohorts.

A case of normoreninemic aldosterone-producing adenoma associated with chronic renal failure: case report and literature review

The diagnosis of aldosterone-producing adenoma (APA) is challenging for endocrinologists, as APA does not always present with the typical constellation of clinical and laboratory features, such as hypertension, hypokalemia, suppressed plasma renin activity (PRA), and high plasma aldosterone concentration (PAC). Very recently, several studies have indicated that APA can be discovered even in normokalemic subjects with normal PRA more frequently than previously considered. Here we report a case of APA associated with chronic renal failure, which showed normokalemia and normal PRA. The patient was referred to our clinic for evaluation of an incidentally discovered adrenal mass with abnormally high PAC. After 6 yr, it was found that the right adrenal tumor showed a marked increase in size. Endocrinological examinations indicated normal PRA and markedly high PAC. Aldosterone showed a better response to the upright posture test than that to ACTH stimulation test. The diagnosis of APA was made based on the markedly high PAC to PRA ratio and the adrenocortical scintigraphy, which showed unequivocal uptake into the tumor. Right laparoscopic adrenalectomy was performed, revealing a right adrenocortical adenoma with massive hemorrhage. Histopathological examinations revealed the presence of two independent adrenocortical adenomas, one APA with predominant clear tumor cells and few c17 (17alpha-hydroxylase) immunoreactivity and the other, cortisol producing adenoma with compact cytoplasm and abundant C17 immunoreactivity. This case indicates a difficulty of diagnosis of "normoreninemic APA" with renal failure. This case is in line with the recent concept that APA is a continuous condition in which only a minority of patients have the classical clinical picture of primary aldosteronism such as hypokalemia. It is possible that normokalemic APA constitutes the most common presentation of the disease.

Pharmacogenomics of primary hypertension--the lessons from the past to look toward the future

A number of recent reviews have addressed the issue of the pharmacogenomics of primary hypertension and related complications by considering the data on the genotype-drug response relationship. Here we mainly discuss the methodological aspects of this issue, trying to integrate 'traditional' clinical and experimental pathophysiology and therapy-pharmacology with the 'new' genetics. Such integration is indispensable to: a). define the appropriate 'context' (genetic background, environment, age, gender, phase of hypertension, previous therapy etc.) in which a given genotype-drug response relationship should be tested (it is indeed likely that many discrepancies among published data originate from context's interference); b). assign the correct clinical meaning to the results obtained by statistics and functional genetics methodologies; c). define a novel clinical entity caused by a disease favoring allele, alone or in combination with other alleles, with a consistent clinical picture, prognosis and responsiveness to the appropriate drug; d). estimate the size of the population target amenable to benefit from a therapeutic intervention developed according to the pharmacogenomics' principles; e). develop a novel drug that selectively interferes with the sequence of events triggered by the genetic mechanism(s) underlying the clinical entity. Peculiar to this strategy is to look for consistency among findings gathered from different 'contexts' after having properly accounted for the context's dependency of the results.

Hyperaldosteronism among black and white subjects with resistant hypertension

Recent reports suggesting that the prevalence of primary hyperaldosteronism may be higher than historically thought have relied on an elevated plasma aldosterone concentration/plasma renin activity ratio to either diagnose or identify subjects at high risk of having primary hyperaldosteronism and have not included suppression testing of all evaluated subjects. In this prospective study of 88 consecutive patients referred to a university clinic for resistant hypertension, we determined the 24-hour urinary aldosterone excretion during high dietary salt ingestion, baseline plasma renin activity, and plasma aldosterone in all subjects. Primary hyperaldosteronism was confirmed if plasma renin activity was <1.0 ng/mL per hour and urinary aldosterone was >12 microg/24-hour during high urinary sodium excretion (>200 mEq/24-hour). Eighteen subjects (20%) were confirmed to have primary hyperaldosteronism. The prevalence of hyperaldosteronism was similar in black and white subjects. Of the 14 subjects with confirmed hyperaldosteronism who have been treated with spironolactone, all have manifested a significant reduction in blood pressure. In this population, an elevated plasma aldosterone/plasma renin activity ratio (>20) had a sensitivity of 89% and a specificity of 71% with a corresponding positive predictive value of 44% and a negative predictive value of 96%. These data provide strong evidence that hyperaldosteronism is a common cause of resistant hypertension in black and white subjects. The accuracy of these results is strengthened by having done suppression testing of all evaluated subjects.