Potentially high prevalence of primary aldosteronism in a primary-care population

Diagnosis and management of primary hyperaldosteronism in patients with hypertension: a practical approach endorsed by the British and Irish Hypertension Society

Alongside the lack of homogeneity among international guidelines and consensus documents on primary hyperaldosteronism, the National UK guidelines on hypertension do not provide extensive recommendations regarding the diagnosis and management of this condition. Local guidelines vary from area to area, and this is reflected in the current clinical practice in the UK. In an attempt to provide support to the clinicians involved in the screening of subjects with hypertension and clinical management of suspected cases of primary hyperaldosteronism the following document has been prepared on the behalf of the BIHS Guidelines and Information Service Standing Committee. Through remote video conferences, the authors of this document reviewed an initial draft which was then circulated among the BIHS Executive members for feedback. A survey among members of the BIHS was carried out in 2022 to assess screening strategies and clinical management of primary hyperaldosteronism in the different regions of the UK. Feedback and results of the survey were then discussed and incorporated in the final document which was approved by the panel after consensus was achieved considering critical review of existing literature and expert opinions. Grading of recommendations was not performed in light of the limited available data from properly designed randomized controlled trials.

Minimally Invasive Partial vs. Total Adrenalectomy for the Treatment of Unilateral Primary Aldosteronism: A Systematic Review and Meta-Analysis

BACKGROUND

This systematic review and metanalysis was conducted to assess differences between perioperative and functional outcomes in patients undergoing minimally-invasive partial (mi-PA) and total adrenalectomy (mi-TA) for unilateral primary aldosteronism (uPHA).

MATERIAL AND METHODS

Multiple scientific databases (PUBMED, Web of Science, and Cochrane Library) were searched up to November 2021 for surgical series comparing mi-PA vs. mi-TA for uPHA according to the PRISMA statement. Primary outcomes of interest were perioperative and functional outcomes.

RESULTS

Overall, a total of 802 patients from six eligible studies were identified, with mi-PA and mi-TA performed in 40.4% (n = 324) and 59.6% (n = 478) of cases, respectively. No differences were recorded between the two groups according to number of transfusions, EBL and Clavien-Dindo complications ≥2. Similarly, no differences in clinical success, persistence of postoperative hypokalemia and improvement in HTN were reported between mi-PA and mi-TA.

CONCLUSIONS

In a uPHA setting, mi-PA and mi-TA provide comparable perioperative and functional outcomes despite the use of mi-PA remains limited to patients with small adenoma size, or hereditary/bilateral disease. Due to limited use of standardized reporting criteria in most of current series, the quest for a superiority of mi-PA over mi-TA in the treatment of uPHA still remains open.

Time-Dependent Risk of Atrial Fibrillation in Patients With Primary Aldosteronism After Medical or Surgical Treatment Initiation

[Figure: see text].

Increased risk of atrial fibrillation was reported in patients with primary aldosteronism. However, data are limited regarding the time-dependent risk of atrial fibrillation in surgically or medically treated primary aldosteronism. From the National Health Insurance Claim database in Korea (2003–2017), a total of 1418 patients with primary aldosteronism (adrenalectomy [ADX], n=755, mineralocorticoid receptor antagonist n=663) were age- and sex-matched at a 1:5 ratios to patients with essential hypertension (n=7090). Crude incidence of new onset atrial fibrillation was 2.96% in primary aldosteronism and 1.97% in essential hypertension. Because of nonproportional hazard observed in new onset atrial fibrillation, analysis time was split at 3 years. Compared with essential hypertension, risk of new onset atrial fibrillation peaked at 1 year gradually declined but remained elevated up to 3 years in overall treated primary aldosteronism (adjusted hazard ratio [aHR] 3.02; P<0.001) as well as in both ADX (aHR, 3.54; P<0.001) and mineralocorticoid receptor antagonist groups (aHR 2.27; P=0.031), which became comparable to essential hypertension afterward in both groups (ADX aHR, 0.38; P=0.102; mineralocorticoid receptor antagonist aHR, 0.60; P=0.214). Nonetheless, mineralocorticoid receptor antagonist group was associated with increased risk of nonfatal stroke (aHR, 1.21; P=0.031) compared with essential hypertension, whereas ADX was not (aHR, 1.26; P=0.288). Our results suggest the risk of new-onset atrial fibrillation remained elevated up to 3 years in treated primary aldosteronism compared with essential hypertension, which declined to comparable risk in essential hypertension thereafter. Monitoring for atrial fibrillation up to 3 years after treatment, particularly ADX, might be warranted.

The Value of Different Single or Combined Indexes of the Captopril Challenge Test in the Diagnosis of Primary Aldosteronism

OBJECTIVE

The result interpretation of the captopril challenge test (CCT) for the diagnosis of primary aldosteronism (PA) is not standardized. Superiorities of different indexes in the CCT have not been fully investigated. We aimed to comprehensively evaluate the value and influence factors of different CCT-associated indexes in the diagnosis of PA.

METHODS

We enrolled 312, 85, 179 and 97 patients in the groups of PA, essential hypertension (EH), unilateral PA (UPA) and bilateral PA (BPA), respectively. For each single index investigated, we computed diagnostic estimates including the area under the receiver operating characteristic curve (AUC). We performed pre-specified subgroup analyses to explore influence factors. We assessed the diagnostic value of combined indexes in binary logistic regression models.

RESULTS

Post-CCT aldosterone to renin ratio (ARR) (AUC = 0.8771) and plasma aldosterone concentration (PAC) (AUC = 0.8769) showed high value in distinguishing PA from EH, and their combination (AUC = 0.937) was even superior to either alone. The diagnostic efficacy was moderately high for post-CCT aldosterone to angiotensin II ratio (AA2R) (AUC = 0.834) or plasma renin activity (PRA) (AUC = 0.795) but low for the suppression percentage of PAC (AUC = 0.679). Post-CCT PAC had a significantly higher AUC in the UPA than BPA subgroup (AUC = 0.914 vs 0.827, P<0.05).

CONCLUSION

We can take post-CCT ARR and PAC altogether into account to distinguish PA from EH, while caution should be taken to interpret CCT results with the suppression percentage of PAC. Post-CCT PAC may perform better to identify the unilateral than bilateral form of PA.

The value of the post-captopril aldosterone/renin ratio for the diagnosis of primary aldosteronism and the influential factors: A meta-analysis

OBJECTIVE

The procedure for the captopril challenge test (CCT) in diagnosing primary aldosteronism (PA) is not standardized. We performed a meta-analysis to evaluate the controversial diagnostic value and influential factors of the post-captopril aldosterone/renin ratio (ARR).

METHODS

We searched literature in databases for eligible studies (until October 1, 2020). We extracted information regarding study and patient characteristics, CCT methods, outcome data. We pooled studies using the random-effect model. We performed meta-regression and six pre-specified subgroup analyses to explore heterogeneity.

RESULTS

Nineteen studies involving 4568 subjects were included. The pooled sensitivity and specificity were 0.825 (95% CI 0.804-0.844) and 0.919 (95% CI 0.908-0.928). The area under the summary receiver operating characteristic curve was 0.9487 (95% CI 0.9207-0.9767). Meta-regression revealed that heterogeneity might derive from time interval (p = 0.0117) and study population (p = 0.0033). Subgroup analyses showed significant differences between the subgroups stratified by the dose, posture, study region, time interval, cut-off value and study population for sensitivity and/or specificity (p < 0.05).

CONCLUSION

Post-captopril ARR is comparably valuable for diagnosing PA at cut-offs from 12.0 to 50.0. Conducting the CCT in the supine position with 25 mg of captopril may attain greater sensitivity. Conducting the CCT in the seated position with 50 mg of captopril may attain greater specificity. A 90-min time interval may perform best in both the sensitivity and specificity.

Factors Associated with Resolution of Hypertension after Adrenalectomy in Patients with Primary Aldosteronism

BACKGROUND

The aim of this study was to investigate the factors associated with resolution of hypertension after adrenalectomy in patients with primary aldosteronism. A secondary aim was to describe our use of the contralateral ratio in adrenal venous sampling (AVS) in the setting of suboptimal successful cannulation rates.

METHODS

A retrospective review of patients who underwent AVS followed by unilateral adrenalectomy for primary aldosteronism was performed.

RESULTS

Complete resolution of hypertension and hypokalemia was seen in 17 of 40 patients (42.5%), while a clinical improvement in hypertension was seen in 38 of 40 (95%). Shorter duration of hypertension, mean aldosteronoma resolution score (ARS), and a high ARS of 3 to 5 were associated with resolution of hypertension after adrenalectomy (P=0.02, P=0.02, and P=0.004, respectively). Of the individual components of ARS, only a duration of hypertension of ≤6 years was associated with resolution of hypertension after adrenalectomy (P=0.03).

CONCLUSION

A shorter duration of hypertension was significantly associated with resolution of hypertension after adrenalectomy in patients with primary aldosteronism.

The Potential Role of Primary Care in Case Detection/Screening of Primary Aldosteronism

Endocrine hypertension, particularly primary aldosteronism (PA), was previously considered to account for less than 1% of all hypertension and was suspected only when patients presented with spontaneous hypokalemia. However, the last 20 years of PA research has now clearly shown that PA is not a rarity, but rather, may account for up to 13% of unselected hypertensive individuals and between 10% and 20% of those with resistant hypertension. Most of these patients do not have spontaneous hypokalemia. The population prevalence of PA likely far exceeds actual detection rates in routine clinical care. As PA represents one of the most common, potentially reversible causes of hypertension, and is associated with significant cardiovascular complications over the long term, it is clear that a pragmatic strategy for targeted case detection in primary care is needed.

CONN SYNDROME PRESENTING AS CENTRAL RETINAL VEIN OCCLUSION

PURPOSE

To describe a case of central retinal vein occlusion in a young patient presenting with symptomatic malignant hypertension because of Conn syndrome.

METHODS

Single interventional case report.

RESULTS

A 44-year-old man presented with a 1-day history of headache and vision loss in his right eye on a background of malignant hypertension. He was diagnosed with right central retinal vein occlusion. Further investigation of his malignant hypertension revealed Conn syndrome because of an aldosterone-secreting adenoma in the left adrenal gland.

CONCLUSION

This is the first reported case of Conn syndrome presenting as central retinal vein occlusion. Conn syndrome should be suspected in young patients with central retinal vein occlusion because it is a common cause of hypertension and carries significant cardiovascular risk if left untreated.

Salt-dependent Blood Pressure in Human Aldosterone Synthase-Transgenic Mice

Hypertension is one of the most important, preventable causes of premature morbidity and mortality in the developed world. Aldosterone is a major mineralocorticoid hormone that plays a key role in the regulation of blood pressure and is implicated in the pathogenesis of hypertension and heart failure. Aldosterone synthase (AS, cytochrome P450 11B2, cyp11B2) is the sole enzyme responsible for the production of aldosterone in humans. To determine the effects of increased expression of human aldosterone synthase (hAS) on blood pressure (BP), we established transgenic mice carrying the hAS gene (cyp11B2). We showed that hAS overexpression increased levels of aldosterone in hAS^+/- mice. On high salt diet (HS), BPs of hAS^+/- mice were significantly increased compared with WT mice. Fadrozole (an inhibitor of aldosterone synthase) treatment significantly reduced BPs of hAS^+/- mice on HS. This is the first time overexpression of AS in a transgenic mouse line has shown an ability to induce HP. Specifically inhibiting AS activity in these mice is a promising therapy for reducing hypertension. This hAS transgenic mouse model is therefore an ideal animal model for hypertension therapy studies.

[Long-term blood pressure outcome after unilateral adrenalectomy for primary hyperaldosteronism]

OBJECTIVES

To evaluate long-term results of adrenalectomy for primary aldosteronism (PA) and to identify prognostic factors associated.

METHODS

Exhaustive retrospective review of all consecutive patients undergoing adrenalectomy for PA between 2002 and 2013 in our department. All patients underwent preoperative: clinical evaluation (age, sex, height, weight, systolic and diastolic BP under treatment, identification of anti-hypertension treatment), biological evaluation (potassium, renin, aldosterone) and radiological evaluation (CT and/or MRI). Blood pressure was assessed postoperatively at 1 month, 1 year, then at the date of the latest news. The patients were classified into three categories: cured (no antihypertensive therapy in postoperative associated with strictly lower blood pressures of 140/90mmHg), improved (decreased number of drugs or number unchanged but with better blood pressure control), and refractory (no change in the number of drug and blood pressure, or deterioration of one or other of these two parameters).

RESULTS

We evaluated 43 patients, 23 men and 20 women, with a median follow-up of 74.4 months [16.8 to 141]. Pathological analysis described 34 adenomas (79%), 7 hyperplasias (16%) (5 micro-nodular and 2 macro-nodular) and 2 adrenocortical carcinoma (5%). The postoperative long-term assessment found 20% of cured patients (n=8), 65% of improved (n=26) and 15% of refractory (n=6). Prognostic factors associated with favorable long-term blood pressure outcome were those typically associated with ARS score [preoperative number of anti-hypertension drugs (P=0.005), BMI<25kg/m² (P=0.009), and duration of hypertension (P=0.007)].

CONCLUSION

Adrenalectomy for PA is a long-term effective treatment for blood pressure control. Prognostic factors associated with long-term success are those conventionally described in ARS score.

LEVEL OF EVIDENCE

4.

Effect of postural changes on aldosterone to plasma renin ratio in patients with suspected secondary hypertension

AIMS

To study the influence of postural changes on aldosterone to renin ratio (ARR) in patients with suspected secondary hypertension and to evaluate the sensitivity and specificity of the recommended seated ARR compared to supine and upright ARR for primary aldosteronism screening.

METHODS

Fifty-three hypertensive patients were prospectively hospitalized for secondary hypertension exploration (age: 51 ± 12, 66% males). After withdrawal of drugs interfering with renin angiotensin system, plasma aldosterone and direct renin concentration were measured in the morning, at bed after an overnight supine position, then out of bed after 1 hour of upright position and finally 2 hours later after 15 minutes of seating. Minimal renin value was set at 5 μUI/mL.

RESULTS

Referring to ARR cut-off of 23 pg/μUI, the sensitivity of seated ARR was 57.1% and specificity was 92.3%. The negative and positive predictive values were 95.1% and 45.2% respectively. Compared to these results, a cut-off of 19 improved sensitivity to 85.7% with a specificity of 89.7%. Negative and positive predictive values were 98.3% and 41.1% respectively. Seated ARR mean value was lower than supine and upright ARR mean values, due to an overall increase in renin at seating compared to the supine position by factor 1.9 while aldosterone just slightly increased by factor 1.2. Seated ARR correlated to supine and upright ARR: correlation coefficients (r) 0.90 and 0.93 respectively (P<0.001).

CONCLUSIONS

Current recommended measurement of ARR in the seating position is fairly correlated to supine and upright ARR. A suggested cut-off value of 19 instead of 23 pg/μUI increased the discriminating power of this test.

Interfering with mineralocorticoid receptor activation: the past, present, and future

Aldosterone is a potent mineralocorticoid produced by the adrenal gland. Aldosterone binds to and activates the mineralocorticoid receptor (MR) in a plethora of tissues, but the cardiovascular actions of aldosterone are of primary interest clinically. Although MR antagonists were developed as antihypertensive agents, they are now considered to be important therapeutic options for patients with heart failure. Specifically, blocking only the MR has proven to be a difficult task because of its similarity to other steroid receptors, including the androgen and progesterone receptors. This lack of specificity caused the use of the first-generation mineralocorticoid receptor antagonists to be fraught with difficulty because of the side effects produced by drug administration. However, in recent years, several advances have been made that could potentially increase the clinical use of agents that inhibit the actions of aldosterone. These will be discussed here along with some examples of the beneficial effects of these new therapeutic agents.

Endocrine and hypertensive disorders of potassium regulation: primary aldosteronism

The identification of primary aldosteronism as a common cause of resistant hypertension is a significant advance in our ability to care for patients with hypertension. Primary aldosteronism is common, and when unrecognized is associated with an increased incidence of adverse cardiovascular outcomes. Identification of primary aldosteronism is based on use of the plasma aldosterone level, plasma renin activity, and the aldosterone:renin ratio. Differentiation between unilateral and bilateral autonomous adrenal aldosterone production then guides further therapy, with use of mineralocorticoid-receptor blockers for patients with bilateral autonomous adrenal aldosterone production and laparoscopic adrenalectomy for patients with unilateral autonomous aldosterone production. In this review, we discuss in detail the pathogenesis of primary aldosteronism-induced hypertension and potassium disorders, the evaluation of the patient with suspected primary aldosteronism, and the management of primary aldosteronism, both through medications and surgery.

Predictors of successful outcome after adrenalectomy for primary aldosteronism

The underlying cause of resistant hypertension after adrenalectomy for primary hyperaldosteronism remains controversial. The objective of this study was to identify preoperative factors predictive of resistant hypertension in patients after undergoing retroperitoneoscopic adrenalectomy. Between 2003 and 2009, 124 patients with unilateral aldosterone-producing adenoma or unilateral adrenal hyperplasia underwent retroperitoneoscopic adrenalectomy at our institution. Clinical and biochemical data were reviewed retrospectively at baseline and after a median follow-up time of 59.2 ± 37.2 months. Adrenalectomy cured hypertension in 68 patients (54.8%) and 43 (34.8%) had persistent hypertension that was much easier to control after surgery, whereas 13 patients (10.4%) had continued hypertension and poor blood pressure control. Multivariate regression analysis revealed that the main determinants of postoperative cure were duration of hypertension less than 5 years [odds ratio (OR): 6.515, 95% confidence interval (CI) 2.278-10.293), number of antihypertensive medications ≤2 (OR: 2.939, 95% CI 1.254-5.235), preoperative response to spironolactone (OR: 3.405, 95% CI 1.681-6.985), the TT genotype of the CYP11B2 gene (344 C/T) (OR: 2.765, 95% CI 1.221-4.986), and the presence of adenoma rather than hyperplasia (OR: 5.274, 95% CI 2.150-8.141). The main determinants of surgical cure or control of hypertension in patients with primary hyperaldosteronism were duration of hypertension, number of antihypertensive medications, preoperative response to spironolactone, the presence of adenoma, and CYP11B2 (344 C/T) genotype. Consideration of these factors may help in the evaluation of patients for surgery and for the identification of patients with continued postoperative hypertension that may require more long-term monitoring and treatment.

Adrenal venous sampling for stratifying patients for surgery of adrenal nodules detected using dynamic contrast enhanced CT

PURPOSE

We aimed to assess the value of adrenal venous sampling (AVS) for diagnosing primary aldosteronism (PA) subtypes in patients with a unilateral nodule detected on adrenal computed tomography (CT) and scheduled for adrenalectomy.

MATERIALS AND METHODS

This retrospective study included 80 consecutive patients with PA undergoing CT and AVS. Different lateralization indices were assessed, and a cutoff established using receiver operating characteristic curve analysis. The value of CT alone versus CT with AVS for differentiating PA subtypes was compared. The adrenalectomy outcome was assessed, and predictors of cure were determined using univariate analysis.

RESULTS

AVS was successful in 68 patients. A cortisol-corrected aldosterone affected-to-unaffected ratio cutoff of 2.0 and affected-to-inferior vena cava ratio cutoff of 1.4 were the best lateralization indices, with accuracies of 82.5% and 80.4%, respectively. CT and AVS diagnosed 38 patients with aldosterone-producing adenomas, five patients with unilateral adrenal hyperplasia, and 25 patients with bilateral adrenal hyperplasia. Of the 52 patients with a nodule detected on CT, subsequent AVS diagnosed bilateral adrenal hyperplasia in 14 patients (27%). Compared to the results of combining CT with AVS, the accuracy of CT alone for diagnosing aldosterone-producing adenomas was 71.1% (P < 0.001). The cure rate for hypertension after adrenalectomy was 39.2%, with improvement in 53.5% of patients. On univariate analysis, predictors of persistent hypertension were male gender and preoperative systolic blood pressure.

CONCLUSION

To avoid inappropriate surgery, AVS is necessary for diagnosing unilateral nodules with aldosterone hypersecretion detected by CT.

Primary aldosteronism associated with subclinical Cushing syndrome

BACKGROUND

Recently, it has been reported that the incidence of primary aldosteronism (PA) among patients with hypertension is much more frequent than previously reported.

AIM

In the present study, we investigated the frequency and features of PA associated with subclinical Cushing syndrome (SCS).

MATERIAL AND METHODS

Subjects included consecutive patients (no.=39) who were diagnosed as PA and performed adrenal venous sampling between 2003 and 2011 in our institute.

RESULTS

In 39 subjects who were diagnosed as PA, 29 patients were operated and 5 cases (12.8%) showed no suppression in low-dose dexamethasone suppression test. Four cases of them were demonstrated to be associated with SCS, and one was associated with overt Cushing syndrome (CS). Post-operatively, 3 cases received replacement therapy of hydrocortisone, while others did not. Pathological findings indicated the diagnosis of aldosterone-producing adenoma in 4 cases associated with SCS, and of idiopathic hyperaldosteronismin in one case associated with overt CS. In all 5 cases, immunohistochemical analysis demonstrated the immunoreactivities of both 3βHSD and P450c17 in the adrenocortical tumors, the marked cortical atrophy in the zona fasciculata and reticularis, the decreased dehydroepiandrosterone sulfotransferase expression, and suppression of hypothalamo- pituitary-adrenal axis indicating the autonomous secretion of cortisol from the tumor.

CONCLUSIONS

The present study suggests that PA is frequently associated with SCS with prevalence of more than 10%, justifying the routine examinations for SCS in PA cases.

Interaction between nitric oxide and superoxide in the macula densa in aldosterone-induced alterations of tubuloglomerular feedback

Tubuloglomerular feedback (TGF)-mediated constriction of the afferent arteriole is modulated by a balance between release of superoxide (O(2)(-)) and nitric oxide (NO) in macula densa (MD) cells. Aldosterone activates mineralocorticoid receptors that are expressed in the MD and induces both NO and O(2)(-) generation. We hypothesize that aldosterone enhances O(2)(-) production in the MD mediated by protein kinase C (PKC), which buffers the effect of NO in control of TGF response. Studies were performed in microdissected and perfused MD and in a MD cell line, MMDD1 cells. Aldosterone significantly enhanced O(2)(-) generation both in perfused MD and in MMDD1 cells. When aldosterone (10(-7) mol/l) was added in the tubular perfusate, TGF response was reduced from 2.4 ± 0.3 μm to 1.4 ± 0.2 μm in isolated perfused MD. In the presence of tempol, a O(2)(-) scavenger, TGF response was 1.5 ± 0.2 μm. In the presence of both tempol and aldosterone in the tubular perfusate, TGF response was further reduced to 0.4 ± 0.2 μm. To determine if PKC is involved in aldosterone-induced O(2)(-) production, we exposed the O(2)(-) cells to a nonselective PKC inhibitor chelerythrine chloride, a specific PKCα inhibitor Go6976, or a PKCα siRNA, and the aldosterone-induced increase in O(2)(-) production was blocked. These data indicate that aldosterone-stimulated O(2)(-) production in the MD buffers the effect of NO in control of TGF response, an effect that was mediated by PKCα.

Aldosterone-to-renin ratio for diagnosing aldosterone-producing adenoma: a multicentre study

BACKGROUND

Biological diagnostic criteria for diagnosing aldosterone-producing adenoma (APA) are not well-established.

AIM

The aim of the study was to establish the best biological predictors of APA.

METHODS

A prospective register was implemented in 17 secondary or tertiary hypertension centres. The inclusion criterion was one of the following: onset of hypertension before 40 years of age; history of hypokalaemia; drug-resistant hypertension (resistant to three drugs); or spironolactone efficiency on BP.

RESULTS

Among the 338 collected cases, 192 patients had two aldosterone-to-renin ratio (ARR) determinations (after 1 hour supine and at least 1 hour upright) on the same occasion. Twenty-five patients (8.2%) had biological hyperaldosteronism and an adrenal adenoma identified by computed tomography. APA was histologically confirmed in all 12 patients who underwent surgery. Histologically proven APAs were used as the 'gold standard' in receiver operating characteristic (ROC) curve analysis. ARRs were computed with a minimum renin value set at 5 ng/L to avoid misclassification of so-called 'low-renin hypertension'. To predict an APA, the ARR area under the ROC curve was 0.93. A supine ARR cut-off value of 32ng/ng provided the highest sum of sensitivity (92%) plus specificity (92%). On the basis of an ARR≥32 ng/ng in the supine and/or upright position, sensitivity reached 100%.

CONCLUSION

The proposed cut-off value of 32 ng/ng for ARR (minimum renin value set at 5 ng/L) in one of two determinations had 100% sensitivity and 72% specificity with 20% positive and 100% negative predictive values for diagnosing APA.

Persistent hypertension after adrenalectomy for an aldosterone-producing adenoma: weight as a critical prognostic factor for aldosterone's lasting effect on the cardiac and vascular systems

BACKGROUND

Primary aldosteronism caused by an aldosterone producing adrenal tumor/aldosteronoma (APA), is a potentially curable form of hypertension, via unilateral adrenalectomy. Resolution of hypertension (HTN) is not as prevalent after tumor resection, as are the normalization of aldosterone secretion, hypokalemia, and other metabolic abnormalities. Here, we review the immediate and long-term medical outcomes of laparoscopic adrenalectomy in patients with an APA, and attempt to identify any distinctive sex differences in the management of resistant HTN.

METHODS

We performed a retrospective review of the prospective adrenal database at the University of Wisconsin between January 2001 and October 2010. Of the 165 adrenalectomies performed, 32 were for the resection of an APA. Patients were grouped according to their postoperative HTN status. Those patients with normal blood pressure (≤120/80 mm Hg) and on no antihypertensive medication (CURE) were compared with those who continued to require medication for blood pressure control (HTN). We evaluated sex, age, body mass index, tumor size, duration of time with high blood pressure, and the differences in systolic and diastolic blood pressure following adrenalectomy. Statistical analysis was performed using Student's t-test. Statistical significance was defined as a P value of <0.05.

RESULTS

We identified 32 patients with an APA based on biochemical and radiographic studies, two patients were excluded, due to missing data. There were 19 males (63%) and 11 (37%) females, with a mean age was 48.3 ± 2.1 y, and mean tumor size was 24 ± 3 mm. Postoperatively, patients required significantly fewer antihypertensive medications (1.5 ± 0.2 versus 3.3 ± 0.3, P < 0.001). Nine patients (31%) had complete resolution of their HTN, requiring no postoperative antihypertensive medication. The only significant difference between the sexes, was a lower body mass index in women (27.6 ± 1.7 versus 33.4 ± 2.1 kg/m(2), P = 0.04). Ninety percent of the cohort had at least a 20 mm Hg decline in their systolic blood pressure postoperatively, placing them in the prehypertensive or normal blood pressure categories. Sixty-six percent of the CURE patients required at least 6 mo for resolution of their HTN. All 20 patients who presented with hypokalemia, had immediate resolution postoperatively and did not require continuance of the preoperative spironolactone or potassium supplementation.

CONCLUSIONS

Laparoscopic adrenalectomy for aldosterone producing adenoma results in the normalization of, or more readily manageable blood pressure in 90% of patients, within 6 mo. Metabolic disturbances are immediately corrected with tumor resection. Weight is an important contributing factor in resolving HTN.

Common secondary causes of resistant hypertension and rational for treatment

Resistant hypertension is defined as uncontrolled blood pressure despite the use of three antihypertensive drugs, including a diuretic, in optimal doses. Treatment resistance can be attributed to poor adherence to antihypertensive drugs, excessive salt intake, physician inertia, inappropriate or inadequate medication, and secondary hypertension. Drug-induced hypertension, obstructive sleep apnoea, primary aldosteronism, and chronic kidney disease represent the most common secondary causes of resistant hypertension. Several drugs can induce or exacerbate pre-existing hypertension, with non-steroidal anti-inflammatory drugs being the most common due to their wide use. Obstructive sleep apnoea and primary aldosteronism are frequently encountered in patients with resistant hypertension and require expert management. Hypertension is commonly found in patients with chronic kidney disease and is frequently resistant to treatment, while the management of renovascular hypertension remains controversial. A step-by-step approach of patients with resistant hypertension is proposed at the end of this review paper.

Primary aldosteronism among newly diagnosed and untreated hypertensive patients in a Swedish primary care area

OBJECTIVE

To evaluate the prevalence of primary aldosteronism (PA) in newly diagnosed and untreated hypertensive patients in primary care using the aldosterone/renin ratio (ARR), and to assess clinical and biochemical characteristics in patients with high and normal ARR.

DESIGN

Patient survey study.

SETTING AND SUBJECTS

A total of 200 consecutive patients with newly diagnosed and untreated hypertension from six primary health care centres in Sweden were included.

MAIN OUTCOME MEASURES

ARR was calculated from serum aldosterone and plasma renin concentrations. The cut-off level for ARR was 65. Patients with an increased ARR were considered for confirmatory testing with the fludrocortisone suppression test (FST), followed by adrenal computed tomographic radiology (CT) and adrenal venous sampling (AVS).

RESULTS

Of 200 patients, 36 patients had an ARR > 65. Of these 36 patients, 11 patients had an incomplete aldosterone inhibition during FST. Three patients were diagnosed with an aldosterone producing adenoma (APA) and eight with bilateral adrenal hyperplasia (BHA). Except for moderately lower level of P-K in patients with an ARR > 65 and in patients with PA, there were no biochemical or clinical differences found among hypertensive patients with PA compared with patients without PA.

CONCLUSION

Eleven of 200 evaluated patients (5.5%) were considered to have PA. The diagnosis of PA should therefore be considered in newly diagnosed hypertensive subjects and screening for the diagnosis is warranted.

Management of resistant arterial hypertension: role of spironolactone versus double blockade of the renin-angiotensin-aldosterone system

BACKGROUND

Currently there is no consensus regarding which add-on therapy to use in resistant hypertension. This study was designed to compare two treatment options, spironolactone (SPR) versus dual blockade of the renin-angiotensin-aldosterone system (RAAS).

METHODS

Forty-two patients with true resistant hypertension were included in the study. An open-label prospective crossover design was used to add a second RAAS blocker to previous treatment and then SPR following 1 month of wash-out. BP was measured in the office and by ambulatory blood pressure monitoring (ABPM). Changes in laboratory tests were also studied for both treatments. The predictive values of aldosterone-renin ratio (ARR) and serum potassium of determining the antihypertensive response were analyzed for both arms.

RESULTS

Following the first stage of dual blockade, SBP dropped significantly both in office (reduction of 12.9 ± 19.2 mmHg)) and by ABPM (reduction of 7.1 ± 13.4 mmHg). Office DBP was unchanged but was significantly reduced as measured by ABPM (3.4 ± 6.2 mmHg). On SPR treatment, office BP was reduced 32.2 ± 20.6/10.9 ± 11.6 mmHg. By ABPM the reduction was 20.8 ± 14.6/8.8 ± 7.3 mmHg (P < 0.001). The BP control was achieved by 25.6% of patients in dual blockade and 53.8% in SPR with office blood pressure. By ABPM, 20.5% were controlled on dual blockade and up to 56.4% with SPR. Serum potassium was a weak inverse predictor of the blood pressure-lowering effect of SPR.

CONCLUSION

SPR has a greater antihypertensive effect than dual blockade of the RAAS in resistant hypertension. SPR at daily doses of 25-50 mg shows a potent antihypertensive effect when added to prior regimes of single RAAS axis blockade in patients with resistant arterial hypertension.

Captopril suppression: limitations for confirmation of primary aldosteronism

Introduction: The aldosterone/renin ratio (ARR) is the first line screening test for primary aldosteronism (PA). However, in hypertensive patients with an increased ARR, PA needs to be confirmed by other means.

Methods: A 25 mg oral captopril test was performed in 16 healthy subjects to obtain reference values for aldosterone and ARR at 120 minutes after the test. Subsequently these data were applied to 46 hypertensive patients screened for PA with an increased ARR.

Results: At 120 minutes after the captopril test ARR decreased in healthy subjects within a narrow range, but remained high in patients with PA and in patients with primary hypertension, especially for those with low renin characteristics. At 120 minutes after captopril, the range of ARR in primary hypertensive patients overlapped in 88% of the cases with the range of the ARR in the PA patients. Sensitivity and specificity of basal ARR and ARR after the captopril test to diagnose PA, calculated as receiver operator characteristics, showed an area under the curve of 0.595 for basal ARR and 0.664 for ARR at 120 minutes after the test.

Conclusion: The ARR at 120 minutes after the captopril test is only marginally better than basal ARR in diagnosing PA in hypertensive patients screened with an increased ARR. Owing to an overall limited capacity to clearly discriminate PA from primary hypertension, the test could not therefore be recommended for the confirmatory diagnosis of PA.

A case of primary aldosteronism caused by multiple adrenocortical macronodules

A 60-year-old man presented with drug-resistant hypertension with hypokalemia, a high plasma aldosterone concentration (PAC) and suppressed plasma rennin activity (PRA). Imaging examinations showed multiple macronodules in the left adrenal gland. Endocrinological findings demonstrated autonomous aldosterone secretion and (131)I-adosterol scintigraphy demonstrated a left sided uptake. Laparoscopic left adrenalectomy normalized serum potassium levels and PAC, and substantially improved hypertension. Pathological and immunohistochemical analysis demonstrated that these nodules were positive for 3β-hydroxysteroid dehydrogenase (HSD3B) but not for CYP17. In addition, zona glomerulosa demonstrated "paradoxical hyperplasia", in which these cells were negative for HSD3B. All of these data indicated that the nodules in the left adrenal gland were mainly responsible for the autonomous aldosterone secretion. We conclude that the primary aldosteronism in this case was caused by multiple macronodules. This is a very rare case of primary aldosteronism caused by multiple adrenocortical macronodules.

Primary aldosteronism: an update

Primary aldosteronism (PA) is common with an estimated prevalence rate of 10% in subjects with essential hypertension and higher in those with resistant hypertension. As well as contributing to hypertension, aldosterone has detrimental effects on the heart, vasculature and kidneys as well as adverse metabolic effects leading to an excess of cardiovascular morbidity. Therefore, recognition and appropriate treatment of PA is of increasing importance. However, the diagnosis of PA and determination of subtype can be problematic. The purpose of this review is to provide an overview of the evidence supporting this increased prevalence of PA, explore the metabolic and cardiovascular consequences of aldosterone excess and discuss optimal diagnostic and therapeutic strategies of PA.

Current options for the treatment of resistant hypertension

Patients with resistant hypertension are those who have uncontrolled blood pressure despite use of three or more antihypertensive medications, or those who require four or more medications to achieve control. When evaluating resistant hypertension it is important to rule out pseudoresistant hypertension that may result from factors including poor blood pressure measurement technique and the white coat effect. Potential contributing factors should be identified and reversed if possible, including obesity, excess alcohol intake and use of interfering medications such as NSAIDS, sympathomimetics and oral contraceptives. Modification of lifestyle factors such as weight loss, sodium restriction and physical activity is paramount for treatment success. Secondary causes of hypertension are common in this patient group and, therefore, appropriate screening tests should be carried out as necessary. Pharmacologic therapy is centered on combination therapy of medications from different mechanisms of action, especially diuretics, which are essential in maximizing antihypertensive effects. The role of mineralocorticoid antagonists is expanding, especially in patients with obstructive sleep apnea and obesity where aldosterone excess may be implicated. Finally, when appropriate, specialist referral may facilitate blood pressure reduction and the ability to meet target blood pressure goals.

Type 2 diabetic patients with resistant hypertension should be screened for primary aldosteronism

BP control in diabetic patients is often poor. The contribution of secondary hypertension due to undiagnosed PA in hypertensive type 2 diabetic patients is not well studied. We prospectively screened 100 consecutive Asian type 2 diabetic patients with difficult-to-control or resistant hypertension for PA. PAC (pmol/L) to PRA (ng/mL/h) ratio was measured; those with PAC-to-PRA ratio >550 (corresponding PAC >415) underwent intravenous 0.9% SLT. Patients with PAC >/=140 following SLT had CT adrenals and bilateral AVS. Thirteen patients (13%) were confirmed to have PA, and all had resistant hypertension. Eight had a surgically correctable form of PA. Patients with PA had higher mean (SD) systolic [159.0 (10.6) vs. 146.0 (10.7) mmHg, p=0.001] and diastolic BP [94.6 (6.0) vs. 87.6 (5.9) mmHg, p=0.001], lower serum potassium [3.5 (0.6) vs. 4.3 (0.5) mmol/L, p=0.001], and higher PAC [679.3 (291.0) vs. 239.5 (169.4) pmol/L, p=0.001]. Identification and institution of definitive treatment for PA resulted in better BP control and in a reduction in the use of antihypertensive medications. Our findings demonstrate a high prevalence of PA in type 2 diabetic patients with resistant hypertension. Systematic screening for PA in this select group is recommended, as targeted treatment improves BP control.

Familial and phenotypic associations of the aldosterone Renin ratio

CONTEXT

The aldosterone to renin ratio (ARR) is a marker of aldosterone excess, widely used to screen for primary aldosteronism (PA). The significance of a raised ARR in normotensive and hypertensive subjects and the phenotypic and familial factors affecting it are unclear.

OBJECTIVE

We estimated the distribution and heritability of the ARR and tested for associations between ARR and blood pressure (BP) with 11 polymorphisms at the CYP11B1/CYP11B2 locus.

DESIGN AND SETTING

A total of 1172 individuals from 248 Caucasian families ascertained via a hypertensive proband were evaluated.

MAIN OUTCOME MEASURE

Plasma aldosterone was measured by RIA, and plasma renin concentration was measured by the LIAISON Direct Renin chemiluminescent immunoassay.

RESULTS

Unadjusted and adjusted ARR were continuously distributed in normotensives and hypertensives, with no evidence of a cutoff that would identify a separate population with PA. Median ARR was 4.19 ng/liter per mIU/liter (range, 0.04-253.16). ARR levels were higher in females and associated with age, body mass index, and potassium. Antihypertensive agents had significant predictable effects on the ARR. Renin was negatively associated, and ARR was positively associated with ambulatory BP readings (P < 0.001) in subjects not taking antihypertensives. The heritability of the ARR was 38.1% (P < 10(-8)). Plasma aldosterone, but not ARR, was influenced by the intron 2 conversion variation in the CYP11B2 gene (beta = -0.07; P = 0.04).

CONCLUSIONS

The ARR is continuously distributed, is influenced by genetic and environmental factors, and is not a marker of a distinct pathological abnormality but possibly reflects the long-term influence of aldosterone on cardiovascular homeostasis.

The prevalence of a raised aldosterone–renin ratio (ARR) among new referrals to a hypertension clinic

The wider application of the plasma aldosterone to renin activity ratio (ARR) test has led independent groups to report a 10-fold or higher prevalence in the detection and prevalence of primary aldosteronism than previously suggested, although such figures have been contested. We determined the prevalence of a raised ARR in an unselected group of patients who were referred to the hypertension clinic at Aberdeen Royal Infirmary. Over a 4-month period, all newly referred patients had an ARR, urea and electrolytes, and 24-h ambulatory blood pressure monitoring (ABPM) performed in addition to a detailed clinical examination. One hundred and twenty-two patients (mean age 51 +/- 16 years) were examined over the study period; 57 (47%) were receiving no anti-hypertensive medication, 32(26% of total) had a normal 24-h ABPM of which 15 patients were receiving antihypertensive medication ("controlled" hypertensives) and 17(14%) were receiving no anti-hypertensive medication ("white-coat hypertensives). Twenty patients (mean age 58 +/- 11 years) were found to have a raised ARR (> 750), of which 10 patients were receiving beta-blocker therapy as part of their anti-hypertensive regimen. Patients with a raised ARR were more likely (odds ratio 3.6, 95% confidence interval 1.2-13.2, p < 0.05) to be classified as a "non-dipper" compared with those whose blood pressure fell at night. The proportion of newly referred hypertensive patients with a raised ARR is still significant and confirms that of previous studies The ratio appears to be significantly driven by a suppressed renin value and further investigation is required to clarify the status of those patients receiving anti-hypertensive medications, particularly beta-blockers.

Primary aldosteronism associated with severe rhabdomyolysis due to profound hypokalemia

A 55-year-old Japanese man was admitted to our hospital with severe weakness. Without measurement of serum electrolyte concentrations, diuretic therapy for hypertension was started 2 weeks prior to admission. Laboratory findings showed profound hypokalemia (1.4 mEq/L), and extreme elevation of the serum creatinine phosphokinase levels (15,760 IU/L), suggesting that the patient had hypokalemic paralysis and hypokalemia-induced rhabdomyolysis. Further evaluations, including adrenal venous sampling strongly suggested that he had primary aldosteronism. He was treated successfully by laparoscopic adrenalectomy. This case provides an important lesson that serum electrolyte concentrations should be measured in hypertensive patients before the administration of antihypertensive agents.

Effects of trilostane on the pituitary-adrenocortical and renin-aldosterone axis in dogs with pituitary-dependent hypercortisolism

The medical records of 63 dogs with pituitary-dependent hypercortisolism (PDH) before and during treatment with trilostane were reviewed retrospectively. The correct trilostane dosage in dogs with PDH was based on the resolution of clinical signs and the results of an adrenocorticotropic hormone (ACTH) stimulation test. The mean (+/-SD) dose rate of trilostane to achieve good clinical control was 2.8+/-1.0mg/kg bodyweight. Trilostane treatment resulted in a significant decline in basal plasma cortisol concentrations. The median plasma ACTH concentration (39 pmol/L, range 7-132 pmol/L; n=60) at the optimal trilostane dosage time was significantly higher (P<0.001) than before treatment (13 pmol/L, range 2-102 pmol/L). These values did not overlap with plasma ACTH concentrations (range 212-307 pmol/L) of five PDH dogs with trilostane-induced hypocortisolism. The median cortisol/ACTH ratio in well-controlled dogs (0.23, range 0.03-2.5; n=46) was significantly lower (P<0.001) than before treatment (2.59, range 0.27-13.25). Trilostane treatment resulted in an insignificant decrease in plasma aldosterone concentration (PAC), but the median plasma renin activity (PRA) at the time the trilostane dosage was considered optimal (265 fmol/L/s, range 70-3280 fmol/L/s; n=18) was significantly higher (P<0.001) than prior to treatment (115 fmol/L/s, range 15-1330 fmol/L/s). Similarly, the median PAC/PRA ratio during trilostane treatment (0.16, range 0.003-0.92; n=17) was significantly lower (P<0.001) than before treatment (median 0.44, range 0.04-1.33). Trilostane affected both the hypothalamic-pituitary-adrenocortical and the renin-aldosterone axes. The results also suggested that basal plasma ACTH concentration may be used to detect trilostane overdosage.

Menopause not aldosterone-to-renin ratio predicts blood pressure response to a mineralocorticoid receptor antagonist in primary care hypertensive patients

BACKGROUND

It has been suggested that hypertensive patients with raised aldosterone-to-renin ratio (ARR) are specifically sensitive to mineralocorticoid receptor antagonists (MRAs). We have previously shown that patients with an elevated ARR are relatively frequent in the setting of primary care. We therefore designed an interventional study to ascertain whether primary care hypertensive patients with an elevated ARR presented a superior response to MRA treatment than subjects with normal ratio.

METHODS

According to the previously observed distribution in general population, 1/3 and 2/3 of hypertensive patients with high or normal ARR, respectively, were treated with kanrenoate 50-100 mg/day for 2 months. To avoid uncontrolled blood pressure (BP), 49% of patients continued also "ARR-neutral" drugs such as verapamil and/or alpha-adrenergic blockers. Patients groups were matched for most features but an elevated ARR was more frequent in female than in male gender; moreover, 90% of women with raised ARR were in menopause.

RESULTS

A clear reduction of BP values was recorded after both the first and the second month of treatment with kanrenoate, with the maximal effect obtained when the dosage titration at 100 mg/day was accomplished. However, patients previously identified by a raised ARR did not have a larger response to MRA treatment than patients with normal ratio. In contrast, MRA was twofold more effective in reducing SBP in women than in men (after 2 months of treatment -16.4 mm Hg vs.-8.2 mm Hg).

CONCLUSIONS

These results suggest that postmenopausal hypertension is largely dependent on mineralocorticoid receptor activation and selectively sensitive to MRAs.

Clinical and biochemical characteristics of normotensive patients with primary aldosteronism: a comparison with hypertensive cases

OBJECTIVE

It is unknown why some patients with biochemical evidence of primary aldosteronism (PA) do not develop hypertension. We aimed to compare clinical and biochemical characteristics of normotensive and hypertensive patients with PA.

DESIGN AND PATIENTS

Retrospective comparison of 10 normotensive and 168 hypertensive patients with PA for office or ambulatory blood pressure, serum potassium, plasma aldosterone and renin concentrations; the aldosterone:renin ratio, and tumour size. Comparison of initial hormonal pattern and drop in blood pressure following adrenalectomy in five normotensive and nine hypertensive patients matched for age, sex and body mass index.

RESULTS

The 10 normotensive patients were women and presented with hypokalemia or an adrenal mass. Age, plasma aldosterone and renin concentrations were similar in normotensive and hypertensive cases, but kalemia and body mass index were significantly lower in the normotensive patients. Mean tumour diameter was larger in the normotensive patients than in the hypertensive matched patients with an adenoma (P < 0.01). In normotensive patients, diastolic blood pressure and upright aldosterone correlated negatively with kalemia. Blood pressure was lowered similarly after adrenalectomy in five normotensive PA patients and in their matched hypertensive counterparts. Aldosterone synthase expression was detected in four out of five adrenal tumours.

CONCLUSIONS

Blood pressure may be normal in patients with well-documented PA. The occurrence of hypokalemia, despite a normal blood pressure profile, suggests that protective mechanisms against hypertension are present in normotensive patients.

Prevalence of primary hyperaldosteronism in resistant hypertension: a retrospective observational study

BACKGROUND

Results of several studies published since 1999 suggest that primary hyperaldosteronism (also known as Conn's syndrome) affects more than 10% of people with hypertension; however, such a high prevalence has also been disputed. Experts generally agree that resistant hypertension has the highest prevalence of primary hyperaldosteronism, on the basis of small studies. We aimed to assess the prevalence of primary hyperaldosteronism in a large group of patients with resistant hypertension.

METHODS

Patients with resistant hypertension (blood pressure >140/90 mm Hg despite a three drug regimen, including a diuretic) who attended our outpatient clinic were assessed for primary hyperaldosteronism. Serum aldosterone and plasma renin activity were determined and their ratio was calculated. Patients with a positive test (ratio >65.16 and aldosterone concentrations >416 pmol/L) underwent salt suppression tests with intravenous saline and fludrocortisone. Diagnosis of primary hyperaldosteronism was further confirmed by the response to treatment with spironolactone.

FINDINGS

Over 20 years, we studied 1616 patients with resistant hypertension. 338 patients (20.9%) had a ratio of more than 65.16 and aldosterone concentrations of more than 416 pmol/L. On the basis of salt suppression tests, 182 (11.3%) patients had primary hyperaldosteronism, and response to spironolactone treatment further confirmed this diagnosis. Hypokalaemia was seen only in 83 patients with primary hyperaldosteronism (45.6%).

INTERPRETATION

Although the prevalence of primary hyperaldosteronism in patients with resistant hypertension was high, it was substantially lower than previously reported. On the basis of this finding, we could assume that the prevalence of primary hyperaldosteronism in the general unselected hypertensive population is much lower than currently reported. Thus, the notion of an epidemic of primary hyperaldosteronism is not supported.

Drug Insight: eplerenone, a mineralocorticoid-receptor antagonist

Increasing recognition of the role of aldosterone in cardiovascular disease has been supported by a significant body of evidence from animal models. This evidence has been translated into clinical practice, and large-scale, randomized, placebo-controlled trials have confirmed the beneficial effects of mineralocorticoid blockade in patients with heart failure. As a consequence, there has been a resurgence in the use of mineralocorticoid-receptor antagonists in clinical practice that has prompted the search for a potent and specific antagonist without the sexual side effects of spironolactone. Eplerenone, a mineralocorticoid-receptor antagonist with minimal binding to the progesterone and androgen receptors, is now licensed for treatment of heart failure in Europe and heart failure and hypertension in the US; it has also been proposed as a treatment for a variety of cardiovascular conditions. This article reviews the current concepts of the actions of aldosterone at a cellular level. Recent findings regarding its role as a cardiovascular hormone, both in animal models and human studies, are discussed. We also describe the development of mineralocorticoid-receptor blockers following the isolation of aldosterone and discuss the subsequent search for a specific mineralocorticoid antagonist. In addition we detail the effects of eplerenone in a number of clinical situations and outline its potential future applications.

Adrenal incidentalomas: presentation and clinical work-up

BACKGROUND

Through the widespread use of imaging techniques with great sensitivity, adrenal tumours are often diagnosed as an incidental finding. The majority of these adrenal lesions are benign and without evidence of endocrine activity or malignancy. However, in addition to the classic forms of overt adrenal hypersecretion, it has become evident in recent years that even modest adrenal hormonal autonomy, as exhibited in clinically silent phaeochromocytoma, normokalaemic primary aldosteronism and subclinical Cushing syndrome, is associated with significant morbidity. Thus, hormone hypersecretion and growth kinetics must be ruled out for each patient using specific tests to avoid associated morbidity.

CONCLUSIONS

Detection and differential diagnosis of subtle changes in adrenal hormone secretion can pose a diagnostic challenge to the clinician, and accurate diagnosis is dependent on use of tests with reliable sensitivity and specificity.