Saline Infusion Test highly associated with the incidence of cardio- and cerebrovascular events in primary aldosteronism

Oral Salt Loading Test is Associated With 24-Hour Blood Pressure and Organ Damage in Primary Aldosteronism Patients

Objective

In the present study, we investigated the most useful confirmatory test for reflecting the severity of primary aldosteronism (PA), by evaluating 24-hour blood pressure (BP), urine albumin, left ventricular mass (LVM), and intima media thickness (IMT).

Methods

This study included 113 patients (80 PA and 33 non-PA hypertensive patients) who were admitted to Oita University Hospital and evaluated using ambulatory blood pressure monitoring (ABPM). First, casual blood pressure (BP) and ABPM parameters were compared between PA and non-PA patients. Second, patients were divided into PA-positive and PA-negative groups based on confirmatory tests, including the saline infusion test (SIT), captopril challenge test (CCT), and oral salt loading test (OSLT), and casual BP and ABPM parameters were compared between the 2 groups. In addition, urine albumin excretion, LVM, and maximum IMT as markers of organ damage were compared between the 2 groups.

Results

The ABPM parameters but not casual BP, were higher in PA patients than in non-PA patients. Nocturnal and 24-hour systolic BP (SBP) in OSLT-positive patients were significantly higher than in OSLT-negative patients. ABPM parameters in other confirmatory tests were not different between the PA-positive and PA-negative groups. Urine albumin excretion in OSLT-positive patients was significantly higher than in the OSLT-negative patients. However, in other confirmatory tests, organ damage markers were not different between the 2 groups.

Conclusion

The OSLT is potentially useful not only for the diagnosis of PA but also for assessment of 24-hour SBP and organ damage, as indicated by urine albumin excretion.

Prevalence, diagnosis and outcomes of treatment for primary aldosteronism

Primary aldosteronism (PA) is the most common potentially curable form of hypertension. The overproduction of aldosterone leads to an increased risk of cardiovascular and cerebrovascular events as well as adverse effects to the heart and kidney and psychological disorders. PA is mainly caused by unilateral aldosterone excess due to an aldosterone-producing adenoma or bilateral excess due to bilateral adrenocortical hyperplasia. The diagnostic work-up of PA comprises three steps: screening, confirmatory testing and differentiation of unilateral surgically-correctable forms from medically treated bilateral PA. These specific treatments can mitigate or reverse the increased risks associated with PA. Herein we summarise the prevalence, outcomes and current and future clinical approaches for the diagnosis of primary aldosteronism.

Basal Plasma Aldosterone Concentration Predicts Therapeutic Outcomes in Primary Aldosteronism

Purpose

Normal basal plasma aldosterone concentration (PAC) reflects mild aldosterone excess compared to high basal PAC. We previously reported lower risk for cardiovascular and cerebrovascular events in patients with primary aldosteronism (PA) and normal basal PAC (nPA) than in those with high basal PAC (hPA). However, the differences in therapeutic outcomes between nPA and hPA are unclear. The aim of this multi-institutional, retrospective cohort study was to determine the clinical significance of nPA to therapeutic outcomes, including adrenalectomy (ADX) and treatment with mineralocorticoid receptor antagonists (MRAs).

Methods

A total of 1146 patients with PA who were diagnosed and underwent adrenal venous sampling (AVS) between January 2006 and October 2016 were enrolled. The clinical parameters at baseline and after ADX or treatment with MRA were compared between the nPA and hPA groups.

Results

Significantly higher rates of absent clinical success (36.6 vs. 21.9%, P = 0.01) and absent biochemical success (26.4 vs. 5.2%, P < 0.01) were found for the nPA group than for the hPA group, respectively. Logistic regression analysis identified baseline PAC as a significant independent predictor of absent clinical success of ADX and MRAs.

Conclusions

Plasma aldosterone concentration at baseline was a significant and independent predictor of absent clinical success of ADX and MRA. Mineralocorticoid receptor antagonist treatment appeared to be a better therapeutic choice than ADX in the nPA group.

Mild primary aldosteronism (PA) followed by overt PA are possibly the most common forms of low renin hypertension: a single-center retrospective study

Low renin hypertension (LRH) is a common condition in hypertensive patients, and mainly includes primary aldosteronism (PA) and low renin essential hypertension. To investigate the distributions and clinical manifestations of the main LRH forms, we reviewed 1267 hypertensive patients who underwent assessment for plasma renin activity (PRA) and plasma aldosterone concentration (PAC) by standardized protocols in our specialized center. LRH was defined as PRA < 1.0 ng/mL/h. A saline infusion test (SIT) was performed when LRH patients showed positive screening results for PA. The main LRH forms were defined as follows: post-SIT PAC > 10 ng/dL as 'overt PA', post-SIT PAC 5-10 ng/dL as 'mild PA', and post-SIT PAC < 5 ng/dL or negative screening results as 'non-PA'. Overall, 760 patients were defined as LRH, with 160 classified as overt PA, 268 as mild PA, and 332 as non-PA. The total proportion of PA amounted to 56.3% with 21.0% overt PA and 35.3% mild PA. Compared with the mild PA, patients with overt PA had higher systolic and diastolic blood pressures, lower serum potassium, higher urine potassium excretion, more frequent incidence of stage 3 hypertension, hypokalemia, diabetes mellitus, and classical unilateral adenoma on computerized tomography (P < 0.05). PA including overt and mild forms is indeed a major form of LRH. Clinical manifestations in mild PA are less severe than those in overt PA. Nevertheless, mild PA is more prevalent than overt PA in LRH and should be recognized.

Primary Aldosteronism and Cerebrovascular Diseases

As diagnostic techniques have advanced, primary aldosteronism (PA) has emerged as the most common cause of secondary hypertension. The excess of aldosterone caused by PA resulted in not only cardiovascular complications, including coronary artery disease, myocardial infarction, arrhythmia, and heart failure, but also cerebrovascular complications, such as stroke and transient ischemic attack. Moreover, PA is associated more closely with these conditions than is essential hypertension. In this review, we present up-to-date findings on the association between PA and cerebrovascular diseases.