Primary aldosteronism: evidence against a second epidemic

Comparison between screening for primary aldosteronism with and without drug adjustment

OBJECTIVE

Few studies have evaluated the performance of non-drug-adjusted primary aldosteronism (PA) screening. Therefore, we aimed to examine the consistency between PA screening results with and without drug adjustment and to explore the effectiveness of screening without drug adjustment.

METHODS

This prospective study included 650 consecutive patients with a high risk of incidence PA. Patients who initially screened positive underwent rescreening with drug adjustments and confirmatory tests. Regarding the remaining patients, one of every three consecutive patients underwent rescreening with drug adjustments and confirmatory tests. The changes in aldosterone and renin concentrations were compared between patients with essential hypertension (EH) and those with PA before and after drug adjustment. Sensitivity and specificity were used to assess the diagnostic performance of screening without drug adjustment, using the confirmatory test results as the reference.

RESULTS

We screened 650 patients with hypertension for PA. Forty-nine patients were diagnosed with PA and 195 with EH. Regarding drugs, 519 patients were taking angiotensin-converting enzyme inhibitors (ACEIs), angiotensin II receptor blockers (ARBs), calcium channel blockers (CCBs), or diuretics alone or in combination. Forty-one patients were taking beta-blockers. Ninety patients were taking beta-blockers in combination with other drugs. In patients treated with ACEIs, ARBs, CCBs, or diuretics alone, or in combination, or beta-blockers alone, PA positivity was determined using the criteria, aldosterone-to-renin ratio (ARR) >38 pg/mL/pg/mL and plasma aldosterone concentration (PAC) >100 pg/mL, and negativity, using the criteria, ARR <9 pg/mL/pg/mL; the sensitivity and specificity were 94.7% and 94.5%, respectively. After drug adjustment, the sensitivity and specificity of screening were 92.1% and 89%, respectively.

CONCLUSIONS

In patients not treated with beta-blockers combined with others, when ARR >38 pg/mL/pg/mL and plasma aldosterone concentration (PAC) >100 pg/mL, or, ARR <9 pg/mL/pg/mL, non-drug-adjusted screening results were identical to with drug adjustment. Non-drug-adjusted screening could reduce the chance of medication adjustment, enable patients to continue their treatments and avoiding adverse effects, is of clinical importance.

Japan Endocrine Society clinical practice guideline for the diagnosis and management of primary aldosteronism 2021

Primary aldosteronism (PA) is associated with higher cardiovascular morbidity and mortality rates than essential hypertension. The Japan Endocrine Society (JES) has developed an updated guideline for PA, based on the evidence, especially from Japan. We should preferentially screen hypertensive patients with a high prevalence of PA with aldosterone to renin ratio ≥200 and plasma aldosterone concentrations (PAC) ≥60 pg/mL as a cut-off of positive results. While we should confirm excess aldosterone secretion by one positive confirmatory test, we could bypass patients with typical PA findings. Since PAC became lower due to a change in assay methods from radioimmunoassay to chemiluminescent enzyme immunoassay, borderline ranges were set for screening and confirmatory tests and provisionally designated as positive. We recommend individualized medicine for those in the borderline range for the next step. We recommend evaluating cortisol co-secretion in patients with adrenal macroadenomas. Although we recommend adrenal venous sampling for lateralization before adrenalectomy, we should carefully select patients rather than all patients, and we suggest bypassing in young patients with typical PA findings. A selectivity index ≥5 and a lateralization index >4 after adrenocorticotropic hormone stimulation defines successful catheterization and unilateral subtype diagnosis. We recommend adrenalectomy for unilateral PA and mineralocorticoid receptor antagonists for bilateral PA. Systematic as well as individualized clinical practice is always warranted. This JES guideline 2021 provides updated rational evidence and recommendations for the clinical practice of PA, leading to improved quality of the clinical practice of hypertension.

Increased myocardial sodium signal intensity in Conn's syndrome detected by 23Na magnetic resonance imaging

AIMS

Sodium intake has been linked to left ventricular hypertrophy independently of blood pressure, but the underlying mechanisms remain unclear. Primary hyperaldosteronism (PHA), a condition characterized by tissue sodium overload due to aldosterone excess, causes accelerated left ventricular hypertrophy compared to blood pressure matched patients with essential hypertension. We therefore hypothesized that the myocardium constitutes a novel site capable of sodium storage explaining the missing link between sodium and left ventricular hypertrophy.

METHODS AND RESULTS

Using 23Na magnetic resonance imaging, we investigated relative sodium signal intensities (rSSI) in the heart, calf muscle, and skin in 8 PHA patients (6 male, median age 55 years) and 12 normotensive healthy controls (HC) (8 male, median age 61 years). PHA patients had a higher mean systolic 24 h ambulatory blood pressure [152 (140; 163) vs. 125 (122; 130) mmHg, P < 0.001] and higher left ventricular mass index [71.0 (63.5; 106.8) vs. 55.0 (50.3; 66.8) g/m2, P = 0.037] than HC. Compared to HC, PHA patients exhibited significantly higher rSSI in the myocardium [0.31 (0.26; 0.34) vs. 0.24 (0.20; 0.27); P = 0.007], calf muscle [0.19 (0.16; 0.22) vs. 0.14 (0.13; 0.15); P = 0.001] and skin [0.28 (0.25; 0.33) vs. 0.19 (0.17; 0.26); P = 0.014], reflecting a difference of +27%, +38%, and +39%, respectively. Treatment of PHA resulted in significant reductions of the rSSI in the myocardium, calf muscle and skin by -13%, -27%, and -29%, respectively.

CONCLUSION

Myocardial tissue rSSI is increased in PHA patients and treatment of aldosterone excess effectively reduces rSSI, thus establishing the myocardium as a novel site of sodium storage in addition to skeletal muscle and skin.

Progress in the Management of Primary Aldosteronism

Primary aldosteronism (PA) is now considered as one of leading causes of secondary hypertension, accounting for 5-10% of all hypertensive patients and more strikingly 20% of those with resistant hypertension. Importantly, those with the unilateral disease could be surgically cured when diagnosed appropriately. On the other hand, only a very limited portion of those suspected to have PA has been screened, diagnosed, or treated to date. With current advancement in medical technologies and genetic research, expanding knowledge of PA has been accumulated and recent achievements have also been documented in the care of those with PA. This review is aimed to have focused description on updated topics of the following; importance of PA screening both in the general and specialized settings and careful interpretation of screening data, recent achievements in hormone assays and sampling methods and their clinical relevance, and expanding knowledge on PA genetics. Improvement in workup processes and novel treatment options, as well as better understanding of the PA pathogenesis based on genetic research, might be expected to result in increased cure and better care of the patients.

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

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

Mineralocorticoid receptor antagonists: emerging roles in cardiovascular medicine

Spironolactone was first developed over 50 years ago as a potent mineralocorticoid receptor (MR) antagonist with undesirable side effects; it was followed a decade ago by eplerenone, which is less potent but much more MR-specific. From a marginal role as a potassium-sparing diuretic, spironolactone was shown to be an extraordinarily effective adjunctive agent in the treatment of progressive heart failure, as was eplerenone in subsequent heart failure trials. Neither acts as an aldosterone antagonist in the heart as the cardiac MR are occupied by cortisol, which becomes an aldosterone mimic in conditions of tissue damage. The accepted term "MR antagonist", (as opposed to "aldosterone antagonist" or, worse, "aldosterone blocker"), should be retained, despite the demonstration that they act not to deny agonist access but as inverse agonists. The prevalence of primary aldosteronism is now recognized as accounting for about 10% of hypertension, with recent evidence suggesting that this figure may be considerably higher: in over two thirds of cases of primary aldosteronism therapy including MR antagonists is standard of care. MR antagonists are safe and vasoprotective in uncomplicated essential hypertension, even in diabetics, and at low doses they also specifically lower blood pressure in patients with so-called resistant hypertension. Nowhere are more than 1% of patients with primary aldosteronism ever diagnosed and specifically treated. Given the higher risk profile in patients with primary aldosteronism than that of age, sex, and blood pressure matched essential hypertension, on public health grounds alone the guidelines for first-line treatment of all hypertension should mandate inclusion of a low-dose MR antagonist.

Aldosterone and the risk of hypertension

Aldosterone, the key hormone in the mineralocorticoid pathway, plays a fundamental role in salt and water homeostasis, blood pressure regulation, and cardiovascular remodeling. Both genomic and nongenomic mechanisms influence aldosterone-induced renal sodium reabsorption. Furthermore, the mineralocorticoid receptors in nonepithelial tissues, including the heart and vascular smooth muscle cells, have recently been discovered. Thus, aldosterone likely has pleiotropic effects that contribute to the modulation of blood pressure. Among patients with hypertension in general, and among those with more severe or resistant hypertension in particular, a higher-than-expected prevalence of primary hyperaldosteronism is noted. Among individuals with resistant hypertension, aldosterone antagonists have also been shown to be effective in lowering blood pressure. Most significantly, recent community-based studies among non-hypertensive individuals in the general population have demonstrated that both higher serum aldosterone concentrations and a higher aldosterone to renin ratio portend a greater risk of developing hypertension. The combination of the aforementioned observations underscores the importance of the mineralocorticoid pathway in the pathogenesis of hypertension.

Mineralocorticoid receptor antagonists and renal involvement in primary aldosteronism: opening of a new era

Primary aldosteronism (PA) is one of the commonest forms of curable hypertension, and use of the plasma aldosterone-to-renin ratio as a screening test has led to a more efficient identification of this condition. Both animal and human studies have indicated that PA is associated with a variety of cardiovascular and renal complications that reflect the capability of elevated aldosterone to induce tissue damage exceeding that induced by hypertension itself. Involvement of the kidney in PA is highly relevant because structural renal damage is associated with less favorable outcome, both in terms of blood pressure response to treatment and possibility to develop progressive renal failure. However, early involvement of the kidney in PA is characterized by functional changes that are largely reversible with treatment. Unilateral adrenalectomy or administration of mineralocorticoid receptor antagonists are the current options for treating an aldosterone-producing adenoma or idiopathic adrenal hyperplasia. Both treatments are effective in correcting hypertension and hypokalemia, and currently available information on their capability to prevent deterioration of renal function indicates that both surgery and medical treatment are of considerable value.