Evidence for a subgroup of essential hypertensives with non-suppressible excretion of aldosterone during sodium loading

ACE Inhibition to Distinguish Low-Renin Hypertension From Primary Aldosteronism

BACKGROUND

Primary aldosteronism (PA) is a distinct cause of low-renin hypertension (LRH), characterized by inappropriate aldosterone production. We investigated the distinction between LRH and PA by leveraging the physiological effects of angiotensin-converting enzyme inhibition.

METHODS

We conducted a retrospective cohort study including 756 patients with LRH who underwent a captopril challenge test (CCT) for evaluation of PA. The distinction between PA and LRH was assessed using 4 CCT criteria: (1) Post-CCT plasma renin activity <1 ng/mL per hour and plasma aldosterone concentration decrease <30%; (2) Post-CCT aldosterone-to-renin ratio (ARR) >30 ng/dL per ng/mL per hour; (3) Post-CCT plasma renin activity <1 ng/mL per hour; and (4) Post-CCT plasma aldosterone concentration >11 ng/dL. Longitudinal outcomes following aldosterone-targeted therapy were assessed using the Primary Aldosteronism Surgery Outcome and Primary Aldosteronism Medical Outcome criteria.

RESULTS

There was a continuous spectrum of nonsuppressible aldosterone production post-CCT. When interpreting CCT results based on both renin and aldosterone responses (criteria 1 or 2), 57.8% to 66.3% of patients were classified as having PA. In contrast, when based on aldosterone or renin responses alone (criteria 3 or 4), 82.5% to 95.1% of patients were classified as having PA. Complete or partial treatment response rates following aldosterone-targeted therapy were high, ranging from 86.5% to 91.7%, regardless of CCT interpretation.

CONCLUSIONS

These findings highlight the blurred distinction between LRH and PA. Although persistently suppressed renin, or elevated aldosterone, following captopril facilitated the maximum capture of PA cases, the implementation of aldosterone-targeted therapy provided similar benefits to all patints, regardless of CCT interpretation. Empirical aldosterone-directed therapy for patients with LRH suspected of having PA may be an appropriate alternative to laborious diagnostics to confirm PA.

LC-MS/MS-Based Assay for Steroid Profiling in Peripheral and Adrenal Venous Samples for the Subtyping of Primary Aldosteronism

Given the largely unexplored application of liquid chromatography-tandem mass spectrometry (LC-MS/MS) steroid analysis in primary aldosteronism (PA), we aimed to investigate its diagnostic utility in PA classification and to characterize steroid secretion patterns across PA subtypes. We retrospectively enrolled 67 patients with PA and collected samples from both peripheral and adrenal veins. We performed a steroid analysis to compare the steroid panel differences between aldosterone-producing adenoma (APA), bilateral adrenal hyperplasia (BAH), and unilateral adrenal hyperplasia (UAH). Analyses included steroid concentrations and secretion ratios, with the latter calculated as individual steroid concentrations divided by total steroid content. The concentrations of 18-hydroxycortisol (18-OHF) were higher in the peripheral veins of patients with APA than in those with BAH and UAH (p < 0.01). A threshold of 4.83 ng/mL for peripheral 18-OHF specifically identified APA cases. In APA cases, adrenal vein secretion ratios of aldosterone, 18-hydroxycorticosterone (18-OHB), and 18-OHF were significantly higher in dominant versus non-dominant adrenal veins (p < 0.001). A secretion ratio of 18-OHF ≥ 14.6‰ and 18-OHB ≥ 4.03‰ from the adrenal vein achieved 100% specificity for identifying the dominant secretory side in cases of APA. Collectively, our findings demonstrate that LC-MS/MS steroid profiling effectively differentiates APA from other PA subtypes. The biochemical criteria for the secretion ratios of 18-OHF and 18-OHB from the adrenal vein provide objective criteria for lateralization diagnosis in APA. These findings could refine diagnostic strategies for PA subtyping.

Comparing ARR Versus Suppressed PRA as Screening Tests for Primary Aldosteronism

BACKGROUND

In many practices, the screening for primary aldosteronism relies on a single-blood draw for plasma aldosterone concentration (PAC) and plasma renin activity (PRA) to establish an aldosterone-to-renin ratio (ARR). ARR levels vary between expert centers and repeated assays in the same individual, emphasizing the potential variability of this screening approach. A suppressed PRA to <1 ng/mL per h has been proposed as an alternative test to the ARR.

METHODS

We compared 2 potential screening approaches to identify probable primary aldosteronism (ARR≥30 or ARR≥20 versus PRA suppressed below 1 ng/mL per h) in a cohort of 94 829 paired PRA and PAC samples submitted by clinicians to evaluate the presence of primary aldosteronism.

RESULTS

Of 94 829 patients, 20.3% tested positive based on ARR≥20 (95% CI, 20.0%-20.5%), 13.9% based on ARR≥30 (95% CI, 13.6%-14.1%), versus 45.9% based on suppressed PRA (<1 ng/mL per minute [95% CI, 45.5%-46.2%]). In the PRA group, a range of aldosterone levels was observed: 5.5% had PAC >15 ng/dL, 25.2% had PAC 5 to 15 ng/dL, and 15.2% had PAC <5 ng/dL, compared with 6%, 12.7%, and 1.6% in the ARR≥20 group and 4.7%, 8.5%, and 0.7% in the ARR≥30 group.

CONCLUSIONS

In this cohort of individuals being screened for primary aldosteronism, substantially more individuals were identified using criteria focused on suppression of renin activity compared with using the aldosterone renin ratio as a screening tool.

The Spectrum of Dysregulated Aldosterone Production: An International Human Physiology Study

CONTEXT

Primary aldosteronism is a form of low-renin hypertension characterized by dysregulated aldosterone production.

OBJECTIVE

To investigate the contributions of renin-independent aldosteronism and ACTH-mediated aldosteronism in individuals with a low-renin phenotype representing the entire continuum of blood pressure.

DESIGN/PARTICIPANTS

Human physiology study of 348 participants with a low-renin phenotype with severe and/or resistant hypertension, hypertension with hypokalemia, elevated blood pressure and stage I/II hypertension, and normal blood pressure.

SETTING

4 international centers.

INTERVENTIONS/MAIN OUTCOME MEASURES

The saline suppression test (SST) to quantify the magnitude of renin-independent aldosteronism; dexamethasone suppression and ACTH-stimulation tests to quantify the magnitude of ACTH-mediated aldosteronism; adrenal venous sampling to determine lateralization.

RESULTS

There was a continuum of nonsuppressible and renin-independent aldosterone production following SST that paralleled the magnitude of the blood pressure continuum and transcended conventional diagnostic thresholds. In parallel, there was a full continuum of ACTH-mediated aldosteronism wherein post-SST aldosterone levels were strongly correlated with ACTH-stimulated aldosterone production (r = 0.75, P < .0001) and nonsuppressible aldosterone production postdexamethasone (r = 0.40, P < .0001). Beyond participants who met the criteria for primary aldosteronism (post-SST aldosterone of ≥10 ng/dL or ≥277 pmol/L), the continuum of nonsuppressible and renin-independent aldosterone production persisted below this diagnostic threshold, wherein 15% still had lateralizing aldosteronism amenable to surgical adrenalectomy and the remainder were treated with mineralocorticoid receptor antagonists.

CONCLUSION

In the context of a low-renin phenotype, there is a continuum of primary aldosteronism and dysregulated aldosterone production that is prominently influenced by ACTH. A large proportion of individuals with low renin may benefit from aldosterone-directed therapy.

Who and How Should We Screen for Primary Aldosteronism?

There are mounting data that at least 30% of hypertensives who are appropriately screened have primary aldosteronism (PA), rather than the commonly reported figure of 5% to 10%. Second, there are similar data that undertreated patients with PA have a 3-fold higher risk profile than essential hypertensives with the same blood pressure levels. Third, clinicians managing hypertension measure success as sustainable lowering of blood pressure; untreated hypertensive patients with PA are thus in double jeopardy. Finally, and crucially, fewer than 1% of patients with hypertension are ever screened-let alone investigated-for PA. Accordingly, for "Who should we screen?" the answer is simple-all patients with hypertension. For "How they should be screened?" the answer is also simple-add spironolactone 25 mg/day for 4 weeks and measure the blood pressure response. In established hypertension, a fall of <10 mm Hg means PA is unlikely; above 12 mm Hg PA, it is probable. Newly presenting hypertension is much the same-hold off on first-order antihypertensive(s) and prescribe spironolactone 25 mg/day for 4 weeks. If blood pressure falls into the normal range, continue; if it does not, prescribe a standard antihypertensive. It is likely that the above protocols-a first start, amenable to refinement-will find additional hypertensives with unilateral PA; it is probable that the overwhelming majority will have bilateral disease. What this means is that we have a major public health issue on our hands: how can this be the case?

Primary Aldosteronism: State-of-the-Art Review

We are witnessing a revolution in our understanding of primary aldosteronism (PA). In the past 2 decades, we have learned that PA is a highly prevalent syndrome that is largely attributable to pathogenic somatic mutations, that contributes to cardiovascular, metabolic, and kidney disease, and that when recognized, can be adequately treated with widely available mineralocorticoid receptor antagonists and/or surgical adrenalectomy. Unfortunately, PA is rarely diagnosed, or adequately treated, mainly because of a lack of awareness and education. Most clinicians still possess an outdated understanding of PA; from primary care physicians to hypertension specialists, there is an urgent need to redefine and reintroduce PA to clinicians with a modern and practical approach. In this state-of-the-art review, we provide readers with the most updated knowledge on the pathogenesis, prevalence, diagnosis, and treatment of PA. In particular, we underscore the public health importance of promptly recognizing and treating PA and provide pragmatic solutions to modify clinical practices to achieve this.

Primary Aldosteronism: Where Are We Now? Where to From Here?

Primary aldosteronism, the most common secondary form of hypertension, is thought to be present in ≈5% to 10% of hypertensive adults. However, recent studies indicate that its prevalence may be at least 3-fold higher based on the identification of renin-independent (autonomous) aldosterone production that is not suppressible with dietary sodium loading in a large fraction of adults with primary hypertension. Currently, the screening rate for primary aldosteronism in adults with primary hypertension is <1%. This review summarizes current thinking about primary aldosteronism from the standpoint of 3 key questions: Where are we now? Where to from here? So how do we get there?

Primary aldosteronism

In 1955 Dr Jerome Conn first documented primary aldosteronism (PA). Since then, screening, diagnosis and treatment have developed, in the process both refining and complicating management. Currently, screening requires 4-6 weeks of lead-up, including major changes in antihypertensive therapy, followed by a blood draw for plasma aldosterone concentration (PAC) and plasma renin activity (PRA) or concentration (PRC). Screening is considered indicative of PA on the basis of the PAC and the aldosterone to renin ratio (ARR). This is then followed by one or more of 6 confirmatory/exclusion tests. Three things have changed. First is now incontrovertible evidence that a single spot PAC is a deeply flawed index of true aldosterone status, so that many referred patients with PA fall at the first hurdle. A valid index of aldosterone status is an integrated value, measured as urinary aldosterone excretion (UEA) over 24 h. On the basis of the UEA, the prevalence of PA appears to be 3-5 times higher than the currently accepted figure of 5-10% of hypertensives. The second is the recognition that inadequately treated PA has a cardiovascular risk profile ~threefold that of matched essential hypertensives. Third is the realization that <1% of hypertensives are ever screened for PA, who are thus in double jeopardy for the risks of untreated PA on top of those for hypertension per se. Taken together, this a major if occult public health issue; if it is to be addressed, radical changes in management are needed. Some are in screening, which needs to be simply done on all newly-presenting hypertensives; others are major simplifications of screening in established hypertension. The front-line actors need to be Internists/Primary Care Providers; the costs will be significant, but much less than those of increased morbidity/premature mortality in unrecognized PA. Possible suggestions as to how best to address this constitute the final chapter of this article.

Primary Aldosteronism: Where Are We Now? Where to from Here?

The past nine years have seen major advances in establishing the etiology of unilateral primary aldosteronism, and very possibly that of bilateral hyperaldosteronism, in response to somatic mutations in aldosterone synthase expressing cells. Though there have been important advances in the management of primary aldosteronism, in small but convincing studies, they represent minor changes to current guidelines. What has been totally absent is consideration of the public health issue that primary aldosterone represents, and the public policy issues that would be involved in addressing the disorder. In his introduction to PiPA 6, Martin Reincke calculated that only one in a thousand patients in Germany with primary aldosteronism were treated appropriately, an astounding figure for any disease in the 21st century. Towards remedying this totally unacceptable public health issue, the author proposes a radical simplification and streamlining of screening for primary aldosteronism, and the management of most patients by general practitioners. The second bottle-neck in current management is that of mandatory adrenal venous sampling for all but 1-2% of patients, a costly procedure requiring rare expertise. Ideally, it should be reserved - on the basis of likelihood, enhanced imaging, or peripheral steroid profiles - for a small minority of patients with clear evidence for unilateral disease. Only when costs are minimized and roadblocks removed will primary aldosteronism be properly treated as the public health issue that it is.

Primary aldosteronism: Treatment of the disease, and new therapeutic approaches

Primary aldosteronism is currently considered to represent 5-13% of hypertension, yet fewer than 1% of patients with the disorder are ever diagnosed and treated. Current management of patients screened and confirmed positive for primary aldosteronism involves imaging, and with very few exceptions adrenal venous sampling to lateralize (or not) hyperaldosteronism. Unilateral disease is treated by adrenalectomy: bilateral disease by mineralocorticoid receptor antagonists and conventional antihypertensives as/if required. New therapeutic approaches include (i) routine screening on first presentation for hypertension; (ii) harmonisation of cut-offs for renin and aldosterone, plus use of 24-h urinary rather than spot plasma values for the latter; (iii) adoption of a dexamethasone enhanced seated saline suppression test for confirmation exclusion; (iv) enhanced imaging and steroid profiles as partial replacement for adrenal venous sampling; and finally (v), inclusion of low dose spironolactone in first-line therapy for hypertension.

Primary Aldosteronism: Present and Future

Primary aldosteronism (PA), currently recognized to be 5-10% of hypertension, has a cardiovascular risk profile double that in age-, sex-, and blood pressure-matched essential hypertensives. Screening for PA is by determining the plasma aldosterone to renin ratio (ARR), followed by one of half a dozen confirmatory/exclusion tests. Unilateral hyperaldosteronism normally reflects an aldosterone producing adenoma; bilateral disease is the more common form, and termed idiopathic hyperaldosteronism (IHA). Subjects confirmed undergo imaging, followed by adrenal venous sampling (AVS) for lateralization. Unilateral lesions undergo laparoscopic adrenalectomy, to normalize aldosterone levels, and in approximately half reduction of BP/antihypertensive use. Bilateral hyperaldosteronism is treated by low dose mineralocorticoid receptor antagonists MRAs, plus amiloride/conventional antihypertensives, if/as indicated.In the future, what is needed is recognition that inappropriate aldosterone levels for sodium status (i.e., PA) represents up to 50% of "essential" hypertensives; all hypertensive should thus be screened by a modified ARR, using 24-h urinary aldosterone rather than a single plasma aldosterone. The current reluctance to do so reflects the costs of AVS if PA is confirmed-optimally by a standard seated saline suppression test-followed by surgery or life-long MRAs. Increasingly AVS will be replaced by plasma steroid assays capable of discriminating APA from the far more common IAH. Third generation MRAs (as selective as eplerenone, as potent as spironolactone, non-steroidal) are in development; in the interim, to minimize side effects and maximize compliance, spironolactone dosage should be set at 12.5-25 mg/day.

Aldosterone Research: 65 Years, and Counting

Aldosterone was characterized as the major mineralocorticoid hormone 65 years ago, and since then its physiologic role in epidural electrolyte homeostasis the province of nephrologists. In epithelia it acts via the mineralocorticoid receptor (MR) to retain Na⁺ and excrete K⁺; MRs, however, are widely expressed in organs not known to be aldosterone target tissues. MRs are not merely "aldosterone receptors," as they have equivalently high affinity for the physiologic glucocorticoids, and for progesterone. In epithelia (plus in the blood vessel wall and in the nucleus tractus solitarius of the brain) MRs are "protected" by coexpression of the enzyme 11β-hydroxysteroid dehydrogenase. This enzyme converts cortisol-which circulates at much higher concentrations than aldosterone-to receptor-inactive cortisone, thus allowing aldosterone selectively to activate "protected" MR. In tissues which do not express 11β-hydroxysteroid dehydrogenase, the default MR ligand is cortisol, which circulates at ≥100-fold higher plasma free concentrations than aldosterone. In such tissues there is as yet scant evidence for the physiologic role of cortisol-occupied MR: over the past decade, however, it has become clear that in damaged tissues cortisol can act as an MR-agonist, mimicking the effects seen with aldosterone under experimental conditions, in vitro and in vivo. Many pathophysiologic roles have been attributed to aldosterone: on the current evidence there are none outside its long established epithelial actions, those on the blood vessel wall and on the nucleus tractus solitarius.

Spironolactone in cardiovascular disease: an expanding universe?

Spironolactone has been marketed for over half a century as a ‘potassium-sparing diuretic’, used primarily in patients with ascites. With the realization that primary aldosteronism is the most common (5-13%) form of secondary hypertension, it has become widely used as a mineralocorticoid receptor antagonist. More recently, in the wake of the RALES trial, spironolactone in addition to standard therapy has been shown to be very beneficial in heart failure with a reduced ejection fraction. Despite the failure of the TOPCAT trial, spironolactone is being increasingly used in diastolic heart failure (i.e. with a preserved ejection fraction). The third currently accepted role for spironolactone is in hypertension resistant to three conventional antihypertensives including a diuretic, where it has been proven to be effective, in contra-distinction to renal artery denervation. Finally, brief consideration will be given to ‘areas in waiting’ – pulmonary hypertension/fibrosis, cancer – where spironolactone may play very useful roles.

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.

The Potential of ACTH in the Genesis of Primary Aldosteronism

Aldosterone is a homeostatic hormone, rising in volume depletion, sodium deficiency, and potassium loading, in response to angiotensin11 and elevation of plasma potassium. Pathophysiologically, in primary aldosteronism (PA) aldosterone levels are inappropriate for the patient's sodium and potassium status, and thus outside the normal feedback loop. ACTH is equivalent with A11 and [K(+)] in elevating aldosterone: its effects differ from those of the other secretagogues in four ways. First, it is not sustained; second, it raises aldosterone and cortisol secretion with equal potency; third, it is outside the normal feedback loops, reflecting the epithelial action of aldosterone; and finally its possible role in driving inappropriate aldosterone secretion (aka PA) is not widely recognized. Thirty years ago, it was shown that on a fixed sodium intake of 175 meq/day 36 of 100 unselected hypertensives, in whom PA has been excluded on contemporary criteria, had 24 h urinary aldosterone levels above the upper limit of normotensive controls. More recently, the dexamethasone enhanced fludrocortisone suppression test (FDST) showed 29% of unselected hypertensives to have plasma aldosterone concentrations above the upper limit of normotensive controls. In subjects negative for PA on the FDST, 27% were extremely hyper-responsive to ultra-low dose ACTH infusion; the remaining 73% showed minimal aldosterone elevation, as did normotensive controls: all three groups had negligible cortisol responses. On treadmill testing, no differences were found between groups in (minimally altered) ACTH and cortisol levels: hyper-responders to ultra-low ACTH, however, showed a major elevation in PAC. The implications of these studies, when validated, are substantial for PA, in that approximately half of hypertensive patients appear to show inappropriate aldosterone levels for their sodium status. The physiological role(s) of ACTH as an acute aldosterone secretagogue, and the mechanisms whereby its continuous secretion is curtailed, remain to be established.

Primary Aldosteronism: New Answers, New Questions

There have been 2, and possibly 3, major questions for primary aldosteronism (PA) answered at least in principle over the past 5 years. The first is that of somatic mutations underlying the majority of aldosterone producing adenomas. The second is the extension of our knowledge of the genetics of familial hypertension, and the third the role of renal intercalated cells in sodium homeostasis. New questions for the next 5 years include a single accepted confirmatory/exclusion test; standardisation of assays and cut-offs; alternatives to universal adrenal venous sampling; reclassification of 'low renin hypertension'; recognition of the extent of 'occult' PA; inclusion of low-dose mineralocorticoid receptor antagonist in first-line therapy for hypertension; and finally, possible resolution of the aldosterone/inappropriate sodium status enigma at the heart of the cardiovascular damage in PA.

Treatment of primary aldosteronism

The prevalence of primary hyperaldosteronism approaches 10% of all hypertensive patients, and besides efficient diagnostic procedures, effective treatment is of increasing importance to reverse increased morbidity and mortality. Aldosterone-producing adenoma and unilateral adrenal hyperplasia are amenable to cure by endoscopic adrenalectomy. Bilateral adrenal hyperplasia (micro- or macronodular), which comprises two-thirds of primary hyperaldosteronism, is treated primarily by mineralocorticoid receptor antagonists (starting dose 12.5-25mg/day spironolactone with titration up to 100mg/day, alternatively 50-100mg/day eplerenone). If blood pressure is not normalised by this first-line treatment, additional treatment with potassium-sparing diuretics (amiloride or triamterene) or calcium channel antagonists is necessary. The start of medication should be closely monitored by serum electrolyte and creatinine controls.

Progress in primary aldosteronism: present challenges and perspectives

Primary Aldosteronism (PA) is a disorder of the adrenal zona glomerulosa (ZG) in which aldosterone secretion is increased and is relatively autonomous of normal regulatory mechanisms. A recent conference in Munich organized by Prof. Reincke addressed advances and challenges related to the screening, diagnosis, and identification of uni- and bilateral involvement of the diseased adrenal of PA. Some infrequently addressed issues are described herein. We postulate that most cases of PA are due to the activation by unknown mechanisms of subset of cells resulting in the formation of a multiple foci or nodules of hyperactive zona glomerulosa cells. This implies that one or several yet unidentified stimuli can drive aldosterone overproduction, as well as the proliferation of aldosterone-producing cells. Current diagnostic procedures allow to determine whether inappropriate aldosterone production is driven by one or both adrenal glands and thus to establish optimal treatment.

Case detection, diagnosis, and treatment of patients with primary aldosteronism: an endocrine society clinical practice guideline

OBJECTIVE

Our objective was to develop clinical practice guidelines for the diagnosis and treatment of patients with primary aldosteronism.

PARTICIPANTS

The Task Force comprised a chair, selected by the Clinical Guidelines Subcommittee (CGS) of The Endocrine Society, six additional experts, one methodologist, and a medical writer. The Task Force received no corporate funding or remuneration.

EVIDENCE

Systematic reviews of available evidence were used to formulate the key treatment and prevention recommendations. We used the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) 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

Consensus was guided by systematic reviews of evidence and discussions during one group meeting, several conference calls, and multiple e-mail communications. The drafts prepared by the task force with the help of a medical writer were reviewed successively by The Endocrine Society's CGS, Clinical Affairs Core Committee (CACC), and Council. The version approved by the CGS and CACC was placed on The Endocrine Society's Web site for comments by members. At each stage of review, the Task Force received written comments and incorporated needed changes.

CONCLUSIONS

We recommend case detection of primary aldosteronism be sought in higher risk groups of hypertensive patients and those with hypokalemia by determining the aldosterone-renin ratio under standard conditions and that the condition be confirmed/excluded by one of four commonly used confirmatory tests. 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 the presence of a unilateral form of primary aldosteronism should be established/excluded by bilateral adrenal venous sampling by an experienced radiologist and, where present, optimally treated by laparoscopic adrenalectomy. We recommend that patients with bilateral adrenal hyperplasia, or those unsuitable for surgery, optimally be treated medically by mineralocorticoid receptor antagonists.

Is aldosterone the missing link in refractory hypertension?: aldosterone-to-renin ratio as a marker of inappropriate aldosterone activity

Use of the random aldosterone-to-renin ratio (ARR) as a reliable marker of inappropriate aldosterone activity has led to primary aldosteronism (PA) being increasingly diagnosed in hypertensive patients. At least 10% of hypertensives have been found to have PA, the majority of whom presumably have bilateral adrenal hyperplasia or idiopathic hyperaldosteronism as an aetiology for PA. Whilst these patients clearly have excess aldosterone activity, they have in common many features that are found in hypertensive patients in general, amongst which include heightened angiotensin II adrenal sensitivity. Whether these individuals belong within the spectrum of 'essential hypertension' is being debated, but is probably irrelevant clinically since they appear to respond favourably to spironolactone treatment. In addition, there is recent evidence suggesting that these patients overexpress a key enzyme involved in aldosterone production, the aldosterone synthase, the activity of which appears to relate to its genotypic variation.

A review of the medical treatment of primary aldosteronism

PURPOSE

Use of the aldosterone-to-renin ratio (ARR) has suggested that at least one in 10 hypertensive subjects have primary aldosteronism (PA). There is thus a timely need to review the literature for effective drug therapies and to speculate on other therapeutic options by taking into account recent advances in understanding of the PA disease pathophysiological process.

DATA SOURCE

A MEDLINE and EMBASE search of all articles published from the start of the databases until July 1999 and reviews of the bibliographies of textbooks.

STUDY SELECTION

Primary research articles on the medical treatment of PA with emphasis on diagnosis, treatment option, drug dosage, therapeutic response and adverse drug effect.

DATA EXTRACTION

Study design and quality were assessed. Relevant data on diagnostic methodology, drug usage and response were analysed and compared.

DATA SYNTHESIS

A select number of subjects with aldosterone-producing adenoma (APA) can be expected to respond well to surgical treatment For the majority of PA cases especially subjects with idiopathic hyperaldosteronism (IHA), long-term medical treatment is now safe and feasible although no randomized controlled trials have been carried out to date. The best therapeutic response is obtained by directly antagonizing aldosterone at the receptor level using medium to low dose spironolactone and this response can be predicted by a raised ARR. The response to other potassium-sparing diuretics and calcium channel blockers are modest. IHA responds better than angiotensin II-unresponsive APA to angiotensin converting enzyme inhibitors and this may also be true with angiotensin II receptor blockers. The discovery of the aldosterone synthase gene opens up the possibility for gene therapy.

CONCLUSION

The diagnosis of PA allows appropriate management with resultant blood pressure control in many hypertensive subjects who otherwise have resistant hypertension despite multiple drug therapy.

Raised aldosterone to renin ratio predicts antihypertensive efficacy of spironolactone: a prospective cohort follow-up study

AIMS

Aldosterone/renin ratio is an index for inappropriate aldosterone activity, and it is increasingly being used to screen for primary aldosteronism within the hypertensive population. It may also be a good index to help predict the response to spironolactone. To assess the blood pressure response to oral spironolactone in hypertensive patients with primary aldosteronism identified with raised aldosterone to renin ratio.

METHODS

We conducted a prospective cohort study of hypertensive patients with raised aldosterone/renin ratio, who failed to suppress plasma aldosterone with salt loading and fludrocortisone suppression test. These patients were treated with spironolactone and were followed-up for a period of up to 3 years.

RESULTS

We studied 28 (12 male) subjects with a mean age of 55 (s.d. 10) years who were followed up for a mean period of 12.9 (7) months. At baseline, the patients were taking a mean of 2.1 (1.2) antihypertensive drugs, but despite this 16/28 (57%) had diastolic BP >90 mmHg, 39% with systolic BP >160 mmHg. After commencing spironolactone, three patients complained of breast tenderness but continued treatment and one patient was intolerant of spironolactone and had to stop treatment. Of the remaining 27 patients, the mean number of antihypertensive drugs used dropped to spironolactone plus 0.7 (s.d. 0.9). All but one patient (96%) achieved a diastolic BP</=90 mmHg and 78% achieved a systolic BP</=160 mmHg. In total 48% had BP</=140/90 mmHg and 13/27 (48%) were treated with spironolactone monotherapy. Assessing only patients on drug treatment at baseline (n=24), spironolactone significantly reduced the need for antihypertensive drugs by -0.5 (CI 0.1-1.0), P=0.02, as well as reducing blood pressure [systolic BP -15 mmHg (CI 5-25), P=0.007 and diastolic BP (mmHg) by -8 mmHg (CI 4-13), P=0.001].

CONCLUSIONS

Spironolactone was a highly effective antihypertensive agent in hypertensive patients who had a raised aldosterone/renin ratio. As a raised ratio was highly predictive of nonsuppression of plasma aldosterone suggesting primary aldosteronism, it might be worthwhile using spironolactone in this subgroup of hypertensive patients with raised aldosterone/renin ratios, provided that adrenal adenomas are excluded with imaging techniques.

Stress reduction and preventing hypertension: preliminary support for a psychoneuroendocrine mechanism

Our objective was to identify endocrine-related mechanisms capable of mediating preventive effects of stress reduction in hypertensive heart disease. Since beneficial effects of stress reduction accrue over time, this cross-sectional, descriptive study sought differences between healthy students not practicing a systematic technique for reducing stress (the average stress, or AS, group, n = 33) and a similar group who for 8.5 years had practiced the Transcendental Meditation (TM) technique, used widely to reduce stress (the low stress, or LS, group, n = 22). The two groups of students, matched for age and area of study, performed timed collections of urine that included (separately) the entire waking and sleeping portions of 1 day. They also completed the Profile of Mood States and the State-Trait Anxiety Inventory, self-report instruments sensitive to subjective level of stress. Urine samples were analyzed for adrenocortical steroids by radioimmunoassay, for Na+, K+, Mg2+, Ca2+, and Zn2+ by atomic absorption spectrometry, and for neurotransmitter metabolites by reverse-phase, high-performance, liquid chromatography, and spectrophotometry. The two groups differed significantly on most measures. Specifically, the LS group was lower in cortisol and aldosterone and higher in dehydroepiandrosterone sulfate (DS) and the serotonin metabolite, 5-hydroxyindoleacetic acid (5-HIAA). Excretion of sodium, calcium, zinc, and the norepinephrine metabolite, vanillylmandelic acid (VMA), was also lower in this group, as were Na+/K+ ratio, mood disturbance, and anxiety. In women practicing TM, cortisol correlated inversely and DS directly with number of months of TM practice. The results identify improvements in mood state, adrenocortical activity, and kidney function as probable factors in the preventive and treatment effects of stress reduction. Because suboptimal levels of these parameters result from chronic, subjective stress, the findings add mechanistic support to the contention that hypertensive heart disease is avoidable, even in modern industrialized societies.

Plasma levels of atrial natriuretic peptide are raised in essential hypertension during low and high sodium intake

Plasma levels of alpha-human atrial natriuretic peptide (hANP) were measured in 17 patients with primary hypertension (11 females, 6 males, aged 22-61; blood pressure systolic 154 +/- 7 mmHg, diastolic 92 +/- 4 mmHg) and in 9 normotensive controls (4 males, 5 females, aged 20-71; blood pressure systolic 117 +/- 4 mmHg, diastolic 76 +/- 2 mmHg) during unrestricted sodium diet, at the 4th day of a low sodium intake (40-60 mEq/day) and at the 6th day of sodium loading (280-320 mEq/day) both after an overnight rest and after 4 h of upright posture. In the controls, plasma levels of hANP at 8:00 a.m. were lowered from 73 +/- 11 to 49 +/- 7 pg/ml during low sodium diet and increased to 128 +/- 37 pg/ml after high salt intake. Plasma ANP levels were significantly lower after 4 h of upright posture during unrestricted, low and high sodium intake. In the hypertensive group, plasma ANP levels were elevated during unrestricted diet (203 +/- 43 pg/ml), during the low sodium period (139 +/- 31 pg/ml), and after high sodium intake (267 +/- 63 pg/ml) compared to the controls. All levels were lowered by upright posture. The absolute decrease was more pronounced compared to the normotensives, the relative decline was similar in both groups. In the hypertensives, plasma ANP levels significantly correlate with systolic and diastolic blood pressure (r = 0.468, r = 0.448, P less than 0.05) and with urinary aldosterone during unrestricted diet (r = 0.536, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular and adrenal sensitivity to angiotensin II in essential hypertension

Regulation of aldosterone secretion by sodium chloride is impaired in a group of essential hypertensives: high-salt diet fails to suppress aldosterone in these patients despite low renin values. The mechanism of this impaired regulation of aldosterone has not been clarified so far. We tested the sensitivity of aldosterone secretion and blood pressure to A II in 20 normotensive controls (aged 20-60, MAP 92 +/- 3 mm Hg), in ten normotensives with one or two parents with hypertension, and in 21 patients with essential hypertension (aged 17-65, MAP 119 +/- 4 mm Hg). After a period of 6 days on high-salt intake (300-320 mEq Na+/day), A II (0.1, 0.5, 1.0 and 2.0 ng/kg/min) was infused, each concentration for 30 min. According to aldosterone excretion during sodium loading, patients were divided into group A with complete suppression (n = 12, aldosterone excretion 3.6 +/- 0.4 microgram/day) and in group B with insufficient suppression (n = 9, aldosterone excretion 15.5 +/- 2.3 micrograms/day). Despite similarly low plasma renins, rise of serum aldosterone levels during A II infusion was significantly higher in group B patients than in group A patients and normotensive controls. Rise in mean arterial blood pressure, however, brought about by graded A II infusion was similar in both groups of hypertensives and in normotensive controls. The results demonstrate an increased adrenal sensitivity to A II in a subgroup of essential hypertensives only. A similar adrenal hypersensitivity to A II found by others in patients with hyperaldosteronism due to adrenal hyperplasia supports the hypothesis that the same mechanism underlies both disorders.

Further evaluation of saline infusion for the diagnosis of primary aldosteronism

Normal subjects, normal-renin hypertensive patients, and low-renin hypertensive patients were evaluated by intravenous saline infusion and with a fludrocortisone acetate (Florinef) protocol to clarify diagnostic criteria for primary aldosteronism that are recommended for the saline infusion protocol. The patients consumed a 200 mEq sodium, 70 mEq potassium diet for 6 days, and on the last 3 days received Florinef 0.5 mg orally twice daily. On Days 3 and 6, urinary aldosterone and tetrahydroaldosterone excretions were determined, and on Days 4 and 7 plasma aldosterone (PA) was determined at 0600 after overnight recumbency and at 0800 after 2 hours of walking. Although the level of normal PA suppression by saline infusion has been commonly defined as 10 ng/dl, a value of 5 ng/dl was originally recommended. In 20 normal subjects and 45 normal-renin hypertensive patients, we found that the PA was almost always suppressed below 5 ng/dl. In 18 of 75 low-renin patients including five with aldosterone-producing adenoma (APA), the PA was never suppressed below 10 ng/dl; thus, these 18 patients had classical primary aldosteronism by generally accepted criteria. The Florinef protocol was performed in eight of these 18 patients and was abnormal in all. An abnormal Florinef protocol was also found in seven of 15 patients studied with PA suppression after saline infusion to between 5 and 10 ng/dl, but in only one of 24 patients studied with PA suppression below 5 ng/dl. Additional studies in the subgroup with abnormal results from the Florinef protocol indicated that none of these patients had evidence of APA, so they had nontumorous primary aldosteronism (NTPA).(ABSTRACT TRUNCATED AT 250 WORDS)