MANAGEMENT OF ENDOCRINE DISEASE: The role of surgical adrenalectomy in primary aldosteronism

Treating Primary Aldosteronism-Induced Hypertension: Novel Approaches and Future Outlooks

Primary aldosteronism (PA) is the most common cause of secondary hypertension and is associated with increased morbidity and mortality when compared with blood pressure-matched cases of primary hypertension. Current limitations in patient care stem from delayed recognition of the condition, limited access to key diagnostic procedures, and lack of a definitive therapy option for nonsurgical candidates. However, several recent advances have the potential to address these barriers to optimal care. From a diagnostic perspective, machine-learning algorithms have shown promise in the prediction of PA subtypes, while the development of noninvasive alternatives to adrenal vein sampling (including molecular positron emission tomography imaging) has made accurate localization of functioning adrenal nodules possible. In parallel, more selective approaches to targeting the causative aldosterone-producing adrenal adenoma/nodule (APA/APN) have emerged with the advent of partial adrenalectomy or precision ablation. Additionally, the development of novel pharmacological agents may help to mitigate off-target effects of aldosterone and improve clinical efficacy and outcomes. Here, we consider how each of these innovations might change our approach to the patient with PA, to allow more tailored investigation and treatment plans, with corresponding improvement in clinical outcomes and resource utilization, for this highly prevalent disorder.

Biomarkers to Guide Medical Therapy in Primary Aldosteronism

Primary aldosteronism (PA) is an endocrinopathy characterized by dysregulated aldosterone production that occurs despite suppression of renin and angiotensin II, and that is non-suppressible by volume and sodium loading. The effectiveness of surgical adrenalectomy for patients with lateralizing PA is characterized by the attenuation of excess aldosterone production leading to blood pressure reduction, correction of hypokalemia, and increases in renin-biomarkers that collectively indicate a reversal of PA pathophysiology and restoration of normal physiology. Even though the vast majority of patients with PA will ultimately be treated medically rather than surgically, there is a lack of guidance on how to optimize medical therapy and on key metrics of success. Herein, we review the evidence justifying approaches to medical management of PA and biomarkers that reflect endocrine principles of restoring normal physiology. We review the current arsenal of medical therapies, including dietary sodium restriction, steroidal and nonsteroidal mineralocorticoid receptor antagonists, epithelial sodium channel inhibitors, and aldosterone synthase inhibitors. It is crucial that clinicians recognize that multimodal medical treatment for PA can be highly effective at reducing the risk for adverse cardiovascular and kidney outcomes when titrated with intention. The key biomarkers reflective of optimized medical therapy are unsurprisingly similar to the physiologic expectations following surgical adrenalectomy: control of blood pressure with the fewest number of antihypertensive agents, normalization of serum potassium without supplementation, and a rise in renin. Pragmatic approaches to achieve these objectives while mitigating adverse effects are reviewed.

Identifying primary aldosteronism patients who require adrenal venous sampling: a multi-center study

Adrenal venous sampling (AVS) is crucial for subtyping primary aldosteronism (PA) to explore the possibility of curing hypertension. Because AVS availability is limited, efforts have been made to develop strategies to bypass it. However, it has so far proven unsuccessful in applying clinical practice, partly due to heterogeneity and missing values of the cohorts. For this purpose, we retrospectively assessed 210 PA cases from three institutions where segment-selective AVS, which is more accurate and sensitive for detecting PA cases with surgical indications, was available. A machine learning-based classification model featuring a new cross-center domain adaptation capability was developed. The model identified 102 patients with PA who benefited from surgery in the present cohort. A new data imputation technique was used to address cross-center heterogeneity, making a common prediction model applicable across multiple cohorts. Logistic regression demonstrated higher accuracy than Random Forest and Deep Learning [(0.89, 0.86) vs. (0.84, 0.84), (0.82, 0.84) for surgical or medical indications in terms of f-score]. A derived integrated flowchart revealed that 35.2% of PA cases required AVS with 94.1% accuracy. The present model enabled us to reduce the burden of AVS on patients who would benefit the most.

Prolonged postoperative hypoaldosteronism related to hyperkalemia in patients with aldosterone-producing adenoma

Hyperkalemia is developed in a part of patients with aldosterone-producing adenoma (APA) after adrenalectomy, suspected to be due to the insufficiency of aldosterone secretion. The purpose of this study is to determine the frequency and characteristics of prolonged postoperative hypoaldosteronism (PPHA) using chemiluminescent enzyme immunoassay (CLEIA). We studied 58 patients with APA with long time after adrenalectomy and whose PAC was measured using a CLEIA kit. The PAC value measured using CLEIA was significantly lower than that of using RIA between two consecutive visits before and after the shift of measuring method of PAC (median [interquantile range], 123.0 [99.8-164.0] vs. 39.5 [15.8-64.2] pg/mL, p < 0.01). PAC was below the minimum limit of quantification (4.0 pg/mL) of the CLEIA kit at least once in nine patients (15.5%) who had PPHA. The PPHA group were older (mean ± standard deviation, 61.3 ± 8.5 vs. 50.5 ± 10.1 years, p < 0.01) and had lower eGFR (60.3 ± 14.0 vs. 82.3 ± 22.8 mL/min/1.73 m2, p < 0.01) than the non-PPHA group. The frequency of postoperative hyperkalemia (maximum serum potassium >5.5 mEq/L) was higher in the PPHA group than in the non-PPHA group (55.6% vs. 8.2%, p < 0.01). In conclusion, a few patients with APA long time after adrenalectomy had unmeasurable PAC using CLEIA. PPHA is likely to develop in patients with APA after adrenalectomy who are older and have impaired renal function. Additionally, PPHA is related to the occurrence of postoperative hyperkalemia.

Superselective adrenal arterial embolization for primary aldosteronism without lateralized aldosterone secretion: an efficacy and safety, proof-of-principle study

Superselective adrenal arterial embolization (SAAE) appears to be beneficial in primary aldosteronism (PA) patients with lateralized aldosterone secretion (unilateral PA). As confirmed by adrenal vein sampling (AVS), nearly 40% of PA patients would be PA without lateralized aldosterone secretion (bilateral PA). We aimed to investigate the efficacy and safety of SAAE on bilateral PA. We identified 171 bilateral PA patients from 503 PA patients who completed AVS. Thirty-eight bilateral PA patients received SAAE, and 31 completed a median 12-month clinical follow-up. The blood pressure and biochemical improvements of these patients were carefully analyzed. 34% of patients were identified as bilateral PA. Plasma aldosterone concentration, plasma renin activity, and aldosterone/renin ratio (ARR) were significantly improved 24-h after SAAE. SAAE was associated with 38.7% and 58.6% of complete/partial clinical and biochemical success within a median 12-month follow-up. A significant reduction in left ventricular hypertrophy was shown in patients who obtained complete biochemical success compared with partial/absent biochemical success. SAAE was associated with a more apparent nighttime blood pressure reduction than daytime blood pressure reduction in patients with complete biochemical success. No major adverse safety events related to SAAE were reported during the intraoperative, postoperative, and follow-up periods. SAAE was associated with blood pressure and biochemical improvements in part of bilateral PA and appeared safe. The biochemistry success was accompanied by improved cardiac remodeling and a more prominent decrease in nocturnal blood pressure. This study was part of a trial registered with the Chinese Clinical Trial Registry, number ChiCTR2100047689.

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.

Etiology and Management of Treatment-Resistant Hypertension in African American Adults ≥18 Years: A Literature Review

Treatment-resistant hypertension (TRH) is defined as blood pressure levels that remain above the therapeutic goal despite concurrent use of three or more antihypertensive medications taken at maximally tolerated doses, one of which should be a diuretic. Additionally, individuals on four or more antihypertensive agents regardless of blood pressure are also considered to have TRH. Amongst people diagnosed with TRH, African American adults face a huge management gap, resulting in increased cardiovascular disease risk. The primary objective of this review was to identify the commonly encountered etiologies and extensively discuss the current management strategies of TRH with a particular focus on African Americans. Relevant studies were identified by analyzing scientific databases and journals such as PubMed, Cochrane, MEDLINE, Cureus, and American Heart Association (AHA). The studies identified and examined common causes of TRH, describing their pathophysiology and highlighting different treatment options for the respective etiologies. The most prevalent etiologies of TRH amongst African Americans were chronic kidney disease (CKD), renal artery stenosis (RAS), fibromuscular dysplasia, obstructive sleep apnea (OSA), endocrine causes (Conn syndrome, Cushing syndrome, etc.), sympathetic nervous system overactivity, lifestyle factors, inaccurate blood pressure measurement, and inappropriate treatment. Of the etiologies reviewed, OSA, lifestyle factors, and CKD exhibited a striking prevalence among the subpopulation studied. Unfortunately, there was a paucity of articles addressing this topic amongst African Americans, and therefore there was not a substantial appreciation of the prevalence of some of the identified etiologies in the population of interest. Thorough diagnostic testing for associated or underlying conditions provides a basis for successful management. This review brought to the fore the need for doctors and patients to collaborate in order to improve TRH management and help patients lead healthier lives.

Primary Aldosteronism Screening Rates Differ with Sex, Race, and Comorbidities

Background

Primary aldosteronism (PA) is a common but under‐recognized cause of secondary hypertension. Data directly comparing screening rates across single and overlapping indications are lacking.

Methods and Results

We conducted a retrospective review of adults with hypertension seen in outpatient clinics at a tertiary referral academic center between January 1, 2017, and June 30, 2020. We included patients with hypertension plus at least one of the following: resistant hypertension; age<35 years; obstructive sleep apnea; hypokalemia; or an adrenal mass. We excluded patients with adrenal insufficiency, severe renal disease, or heart failure, and renovascular hypertension. Of 203 535 patients with hypertension, 86044 (42.3%) met at least 1 PA screening criterion, and of these, 2898 (3.4%) were screened for PA. Screening occurred in 2.7% of patients with resistant hypertension; 4.2% of those with obstructive sleep apnea; 5.1% of those <35 years; 10.0% of those with hypokalemia; and 47.3% of patients with an adrenal mass. Screening rates were higher in patients with multiple risk factors: 16.8% for ≥3, 5.7% for 2, and 2.5% for 1 criterion. Multiple logistic regression showed that the odds of PA screening were higher in patients with hypokalemia: odds ratio (95% CI): 3.0 (2.7–3.3); women: 1.3 (1.2–1.4); Black versus White: 1.5 (1.4–1.7); those with obstructive sleep apnea, chronic renal disease, stroke, and dyslipidemia.

Conclusions

Consideration for PA is given in a small subset of at‐risk patients, and typically after comorbidities have developed.

Validation of three novel clinical prediction tools for primary aldosteronism subtyping

The 20-point clinical prediction SPACE score, the aldosterone-to-lowest potassium ratio (APR), aldosterone concentration (AC) and the AC relative reduction rate after saline infusion test (SIT) have recently been proposed for primary aldosteronism (PA) subtyping prior to adrenal vein sampling (AVS). To validate those claims, we performed a retrospective cross-sectional study that included all patients at our center who had positive SIT to confirm PA and were diagnosed with either bilateral disease (BPA) according to AVS or with lateralized disease (LPA) if biochemically cured after adrenalectomy from November 2004 to the end of 2019. Final diagnoses were used to evaluate the diagnostic performance of proposed clinical prediction tools. Our cohort included 144 patients (40 females), aged 32-72 years (mean 54 years); 59 with LPA and 85 with BPA. The originally suggested SPACE score ≤8 and SPACE score >16 rules yielded about 80% positive predictive value (PPV) for BPA and LPA, respectively. Multivariate analyses with the predictors constituting the SPACE score highlighted post-SIT AC as the most important predictor of PA subtype for our cohort. APR-based tool of <5 for BPA and >15 for LPA yielded about 75% PPV for LPA and BPA. The proposed post-SIT AC <8.79 ng/dL criterion yielded 41% sensitivity and 90% specificity, while the relative post-SIT AC reduction rate of >33.8% criterion yielded 80% sensitivity and 51% specificity for BPA prediction. The application of any of the validated clinical prediction tools to our cohort did not predict the PA subtype with the high diagnostic performance originally reported.

Bilateral Adrenalectomy in a Patient With Refractory Primary Aldosteronism Due to Adrenal Hyperplasia

Primary aldosteronism (PA) is a frequent cause of secondary hypertension. The main cause of PA is bilateral adrenal hyperplasia, and treatment is usually medical with mineralocorticoid receptor antagonists (MRAs) such as spironolactone or eplerenone. In this paper, we present a rare clinical case of a middle-aged female with refractory arterial hypertension and hypokalemia that complementary medical tests confirmed PA due to bilateral hyperplasia, and despite a maximum dose of spironolactone and oral potassium supplements, there was no clinical response. Because of this, finally, the patient needed surgical treatment based on bilateral adrenalectomy, which was effective. This is unusual and poorly described in the medical literature.

Surgical Quality, Antihypertensive Therapy, and Electrolyte Balance: A Novel Trifecta to Assess Long-Term Outcomes of Adrenal Surgery for Unilateral Primary Aldosteronism

Background: To propose a trifecta that summarizes endpoints and predicts their maintenance after adrenalectomy (n = 90) for unilateral primary aldosteronism (UPA). Methods: Trifecta was defined as coexistence of: ≥50% antihypertensive therapeutic intensity score reduction (∆TIS), no hypokalemia at 3 months, and no Clavien grade 2–5. Logistic regression was used to identify predictors of trifecta. Probability of clinical, biochemical, and simultaneous success according to trifecta were assessed by Kaplan–Meier. Cox regression was used to identify predictors of long-term clinical, biochemical, and simultaneous success. For all analyses, a two-sided p < 0.05 was considered significant. Results: Simultaneous success rate was 50%. On multivariable analysis, TIS was an independent predictor of trifecta achievement (HR 3.28; 95% CI 1.07–10.9; p = 0.03). At Kaplan–Meier, trifecta predicted higher success for all endpoints (each p < 0.03). On multivariable Cox analysis, adenoma size (AS) ≥6 cm and trifecta were independent predictors of biochemical (AS: HR 2.87; 95% CI 1.53–5.36; trifecta: HR 2.1; 95% CI 1.13–3.90; each p < 0.02) and simultaneous success (AS: HR 3.81; 95% CI 1.68–8.65; trifecta: HR 4.29; 95% CI 2.08–8.86; each p < 0.01), while trifecta was an independent predictor of complete clinical success (HR 2.84; 95% CI 1.45–5.58; p < 0.01). Conclusions: Trifecta and AS are independent predictors of either long-term complete clinical, biochemical, or combined success after adrenalectomy for UPA.

Morphologically Normal-Appearing Adrenal Glands as a Prevalent Source of Aldosterone Production in Primary Aldosteronism

BACKGROUND

Normal-appearing adrenal glands on cross-sectional imaging may still be the source of aldosterone production in primary aldosteronism (PA).

METHODS

We evaluated the prevalence of aldosterone production among morphologically normal-appearing adrenal glands and the impact of this phenomenon on interpretations of localization studies and treatment decisions. We performed a retrospective cohort study of PA patients with at least 1 normal adrenal gland and reanalyzed contemporary studies to assess interpretations of imaging and adrenal venous sampling (AVS) at the individual patient and adrenal levels.

RESULTS

Among 243 patients, 43 (18%) had bilateral normal-appearing adrenals and 200 (82%) had a unilateral normal-appearing adrenal, for a total of 286 normal-appearing adrenal glands. 38% of these normal-appearing adrenal glands were a source of aldosteronism on AVS, resulting in discordance between imaging and AVS findings in 31% of patients. Most patients with lateralizing PA underwent curative unilateral treatment (80%); however, curative treatment was pursued in 92% of patients who had concordant imaging-AVS results but in only 38% who had discordant results (P < 0.05). In young patients, imaging-AVS discordance was detected in 32% of those under 45 years and 21% of those under 35 years. Among 20 contemporary studies (including 4,904 patients and 6,934 normal-appearing adrenal glands), up to 64% of normal-appearing adrenals were a source of aldosteronism resulting in 31% of patients having discordant results.

CONCLUSIONS

Morphologically normal-appearing adrenal glands are commonly the source of aldosterone production in PA, even among young patients. The lack of awareness of this issue may result in inappropriate treatment recommendations.

Hypoparathyroidism: State of the Art on Cell and Tissue Therapies

Hypoparathyroidism is an endocrine disorder characterized by low serum calcium levels, high serum phosphorus levels, and by inappropriate or absent secretion of the parathyroid hormone (PTH). The most common therapeutic strategy to treat this condition is hormone replacement therapy with calcium and vitamin D but, unfortunately, in the long term this treatment may not be sufficient to compensate for the loss of endocrine function. Glandular autotransplantation is considered the most effective technique in place of replacement therapy. Although it leads to excellent results in most cases, autotransplantation is not always possible. Allograft is a good way to treat patients who have not been able to undergo autograft, but this technique has limited success due to side effects related to tissue rejection. This therapy is supported by systemic immunosuppression, which leads to the onset of serious side effects in patients, with a risk of endocrine toxicity. Today, research on endocrine disorders is focused on discovering alternative graft therapies that can allow optimal results with the fewest possible side effects. In this review, we will make an update on the current state of the art about the cell and tissue therapy as treatment for hypoparathyroidism, to identify which type of therapeutic strategy could be valid for a future clinical use.

Adrenocorticotropic Hormone-Stimulated Adrenal Venous Sampling Underestimates Surgically Curable Primary Aldosteronism: A Retrospective Cohort Study and Review of Contemporary Studies

[Figure: see text].

Contralateral Suppression Index Does Not Predict Clinical Cure in Patients Undergoing Surgery for Primary Aldosteronism

BACKGROUND

Adrenal venous sampling (AVS) is recommended before adrenalectomy for patients with primary aldosteronism (PA) over 35 years old. The literature examining contralateral suppression (CoS) on AVS in predicting surgical outcomes is conflicting. We examined the presence of CoS in patients who underwent adrenalectomy while adjusting for clinical and biochemical factors associated with a clinical cure of hypertension (ccHTN).

METHODS

We performed a retrospective review of patients with successful AVS who underwent unilateral adrenalectomy for PA at a quaternary referral center. Patients were excluded if they had overt cortisol co-secretion, or inadequate follow-up. We first evaluated the aldosterone resolution score (ARS) in predicting ccHTN in our cohort. Next, the receiver-operator characteristic analysis (ROC) was used to determine the optimal contralateral suppression index (CSI) cutoff to define CoS. We performed univariable and multivariable analyses of factors associated with ccHTN. The primary outcome was ccHTN defined as blood pressure less than 140/90 mmHg, and off blood pressure medications.

RESULTS

Of the 102 patients on bivariable analysis, age, sex, duration of HTN, number of medications, preoperative systolic blood pressure, and creatinine level were associated with ccHTN. ROC analysis of ARS had an AUC of 0.850 (p < 0.001). On multivariable analysis, only ARS remained associated with ccHTN (OR 3.40, 95% CI 1.20-9.61, p = 0.021). CSI was not significantly associated with ccHTN on ROC, bivariable, or multivariable analyses.

CONCLUSION

The presence of CoS was not useful in predicting ccHTN following unilateral adrenalectomy for PA in our cohort. After adjusting for clinical and biochemical factors, ARS remains a useful predictor for ccHTN.