原发性醛固酮症的发现及对此综合征的筛查

1954年4月，面对一位呈高血压、低血钾，伴神经肌肉症状，被诊断为“失钾性肾炎”的女性患者，Jerome W．Conn根据他对肾上腺皮质激素的病理生理研究，以及不久前天然的肾上腺盐皮质激素醛固酮被分离鉴定，提出此患者的病因为肾上腺盐皮质激素过多。详细的内分泌代谢研究支持Conn的判断。肾上腺手术探查发现一侧肾上腺肿瘤，肿瘤切除后患者被治愈。1964年Conn提出了在高血压患者中根据醛固酮过多及低血浆肾素活性对此综合征进行筛查的创意。     

The ovarian cycle as a factor of variability in the laboratory screening for primary aldosteronism in women

Primary aldosteronism is increasingly investigated in hypertension being associated with an elevated cardiovascular risk. Aldosterone has been reported to increase in the luteal phase in normal women but to our knowledge the influence of the ovarian cycle on the first screening for primary aldosteronism (that is, on the levels of plasma aldosterone and its relationship to PRA levels) was never investigated. We measured hormonal levels during one cycle in 26 low-renin mild hypertensive outpatients. LH, FSH, 17 beta-estradiol, progesterone, aldosterone and PRA were assayed at the seventh, fourteenth, twenty-first and twenty-eighth days of the cycle after 30 min of recumbency. Aldosterone and PRA increased from the seventh (follicular phase) to twenty-first day (luteal phase) from 11.2 to 17.8 ng 100 ml(-1) and from 0.23 to 0.35 ng ml(-1) h(-1), respectively (both P=0.004) The proportion of patients with aldosterone >15 ng 100 ml(-1) significantly increased from the follicular to the luteal phase, (8/26 vs 19/25, P=0.018); a similar increase was found for Aldosterone-PRA Ratio >30 combined with either a minimum PRA value of 0.5 ng ml(-1) h(-1) or aldosterone >15 ng 100 ml(-1) (7/26 vs 16/25 and 7/26 vs 17/25 respectively, P<0.05). Aldosterone was positively related to PRA and progesterone. Higher aldosterone levels may be frequently encountered in the second part of the ovarian cycle in low-renin hypertensive women. This variability appears to be an important factor to be taken into account in the first-step laboratory screening for primary aldosteronism and should be considered in the process of standardization of the diagnostic work-up for this disease.     

Single dose captopril as a diagnostic test for primary aldosteronism

Most diagnostic tests for primary aldosteronism use maneuvers to expand the extracellular fluid volume, thereby suppressing the renin-angiotensin system. This results in a decline in plasma aldosterone concentrations in normal subjects and essential hypertension (EH) patients, but not in patients with primary aldosteronism. Captopril blocks angiotensin II synthesis and might be used as a diagnostic test for primary aldosteronism. We have measured plasma aldosterone concentrations 2 h after the administration of 25 mg captopril in 9 normotensive subjects, 10 patients with EH, and 12 patients with primary aldosteronism while they were ingesting an unrestricted diet. The plasma aldosterone concentration decreased to less than 15 ng/dl in all normotensive subjects and in 9 of 10 patients with EH, but remained greater than 15 ng/dl in 4 of 5 patients with idiopathic hyperaldosteronism and in all patients with an aldosterone-producing adenoma. The aldosterone to renin ratio was greater than 50 in 4 of 5 patients with idiopathic hyperaldosteronism and in all adenoma patients, but less than 50 in all normotensive subjects and EH patients. A nomogram comparing the plasma aldosterone concentration with the aldosterone to renin ratio clearly separated primary aldosteronism patients from EH patients.     

Clinical evaluation of the captopril screening test for primary aldosteronism

In order to investigate the validity of angiotensin converting enzyme inhibition with captopril as a screening test for primary aldosteronism (PA), 50 mg of captopril were administered orally to 7 patients with PA, 17 with essential hypertension (EH), 5 with renovascular hypertension (RVH), 2 with renoparenchymal hypertension (RH) and 8 normal volunteers. The plasma aldosterone concentration (PAC) was suppressed to less than 15 ng/dl in all of the EH, RVH and RH patients and normal subjects 90 min after administration of captopril, but not suppressed in 6 of 7 patients with PA. In addition, the plasma renin activity (PRA) was increased to greater than 1 ng/ml/h in 10 of 17 patients with EH and in all with RVH, RH and the normal controls, but to less than that in 6 of 7 PA and the remaining EH patients. The PAC to PRA ratio after captopril was greater than 20 in all patients with PA, while it remained below 20 in EH, RVH and RH patients and normal controls. From these results, we conclude that the PAC to PRA ratio in the captopril administration test is a simple and useful tool to detect PA in hypertensive patients. In addition, the test has a great advantage in that it can be safely applied to outpatients with relatively severe hypertension.     

Detecting and treating primary aldosteronism: primary aldosteronism.

Primary aldosteronism (PA) is the most common cause of mineralocorticoid hypertension. Different studies, using the plasma aldosterone concentration to plasma renin activity ratio (PAC/PRA) for the screening of patients with hypertension, have shown a marked increase in the detection rate of PA. Idiopathic bilateral adrenal hyperplasia (IHA) and aldosterone-producing adrenal adenoma (APA), are the leading causes of primary aldosteronism. Glucocorticoid-remediable aldosteronism (GRA), also called familial hyperaldosteronism type I, familial hyperaldosteronism type II and carcinomas are rare causes of PA. Patients with hypertension and hypokalemia, those with a family history of hypertension and stroke at an early age, or patients with medication-resistant hypertension should be screened for PA using the PAC/PRA ratio. If a high ratio is found, a sodium loading test or a captopril test is warranted to confirm the diagnosis. Adrenal gland imaging is important in subtype differentiation (APA vs IHA). Adrenal venous sampling should be used when other tests prove inconclusive. Genetic testing has facilitated detection of GRA. Surgery is considered the treatment of choice for patients with APA, while bilateral hyperplasia subtypes are treated medically. Normalization of aldosterone levels or aldosterone receptor blockade are necessary to prevent the morbidity and mortality associated with hypertension, hypokalemia, and cardiovascular damage.     

Diagnosis of primary aldosteronism: from screening to subtype differentiation.

Numerous studies conducted in recent years have reported an increase in the prevalence of primary aldosteronism (PA). This increase has arisen because of changes in our screening methods used to detect PA, notably the widespread use of the ratio of plasma aldosterone concentration to plasma renin activity. A positive screening result, however, is not diagnostic and requires a confirmatory test. Strategies for screening and confirmation of PA and the techniques to identify the two main subtypes of PA--aldosterone-producing adenoma (APA) and bilateral adrenal hyperplasia (BAH)--are particularly important because hypertension in APA can be cured by adrenalectomy, whereas individuals affected with BAH can receive targeted medical treatment with mineralocorticoid receptor antagonists.     

在高血压患者中筛选原发性醛固酮增多症国人血浆醛固酮/肾素活性比值标准的探讨

目的血浆醛固酮/血浆肾素活性比值(ARR)测定是目前从高血压患者中检出原发性醛固酮增多症(原醛)患者最常用和有效的筛选方法。ARR 值在不同人种中有很大差别,测定条件对其结果影响较大。本研究在严格控制药物、体位等条件下,建立中国人筛选原醛 ARR 值。方法根据肾上腺增强 CT 检查结果,将110例高血压患者分为原发性高血压组(65例)和肾上腺腺瘤/增生组(45例)。停用对肾素和醛固酮分泌有影响的降压药物至少2周,利尿剂包括螺内酯停用4周。对于不宜停服降压药物的患者,改服非双氢吡啶类钙拮抗剂维拉帕米缓释片(varapamil-SR)和(或)α受体阻滞剂特拉唑嗪(terazosin)。低血钾患者补钾至正常水平。采血日晨起保持立位2 h 后,于上午9～10点立位取肘静脉血测定血浆肾素活性、血浆醛固酮浓度,计算 ARR。结果 ARR 值以醛固酮 pg/ml/肾素活性 ng·ml~(-1)·h~(-1)为单位。立位 ARR 值在原发性高血压组为100.00±48.65,肾上腺腺瘤/增生组为699.33±213.33。由 ROC 曲线所得切割值为240,立位 ARR 较卧位 ARR 更有筛查价值。在肾上腺腺瘤/增生组93.3%(42/45)患者的 ARR 值高于240,原发性高血压组90.7%(59/65)患者ARR 值低于该值。取 ARR 值240为切割点,我们从近178例高血压患者中检出15例原醛患者(手术病理证实),所有15例患者 ARR 均大于240,显示极高的敏感性和特异性。结论采用本研究试验条件,中国人立位 ARR 值为240。ARR 测定是一项简便、有效的原醛筛查方法,测定时须注意体位、药物、血钾的影响。     

Reliability of screening methods for the diagnosis of primary aldosteronism.

An attempt has been made in studies on 1,036 consecutive, referred, hypertensive patients to determine the reliability of four measurements, as screening tests for primary aldosteronism: serum sodium, serum potassium, stimulated plasma renin activity (PRA) (after furosemide administration, 40 mg intravenously, and ambulation for 2 hours) and the plasma aldosterone concentration after a 2 liter infusion of 0.9 per cent saline solution, all performed during an 8 hour outpatient study. Based on the results of subsequent tests in selected patients, which showed failure of deoxycorticosterone (DOC) and fludrocortisone to produce normal suppression of plasma levels and excretion of aldosterone, 22 of the 1,036 patients were considered to have primary aldosteronism. Adrenal scans and adrenal vein aldosterone measurements revealed that primary aldosteronism was caused by a unilateral adrenal adenoma in five patients, probably by an adrenal adenoma in three other patients and by excessive aldosterone release from both adrenals in 14 patients.Serum sodium and serum potassium measurements were inadequate screening procedures because of unacceptably high rates of false-positive and false-negative results. A low PRA alone failed to differentiate patients with primary aldosteronism from 14 times the number of patients with “low-renin hypertension.” The saline suppression test yielded an encouragingly high sensitivity (0.77) when a plasma aldosterone concentration of 8.5 ng/dl after the saline infusion was used as the criterion of hyperaldosteronism. This diagnostic yield was improved to give a sensitivity of 0.95 by combining this saline suppression criterion with the alternative requirement that the patients have a low stimulated PRA, a fasting serum potassium concentration below 3.5 meq/liter and no depressor response to the administration of saralasin. It is concluded that this combination of laboratory procedures provides a safe, efficient and highly reliable means of discovering patients with primary aldosteronism among unselected hypertensive patients.     

Insulin sensitivity in patients with primary aldosteronism: a follow-up study

CONTEXT: The relationship between aldosterone and glucose metabolism is poorly understood, and there is substantial disparity among findings of studies that have examined glucose tolerance and insulin sensitivity in patients with primary aldosteronism. OBJECTIVE: The objective of the study was to determine the outcome of glucose tolerance and insulin sensitivity in patients with primary aldosteronism after treatment. DESIGN: This was a prospective study of patients who received a diagnosis of primary aldosteronism and were followed up for an average period of 5.7 yr (range, 3-9 yr). SETTING: The study was conducted at a university referral center. PATIENTS: A consecutive sample of 47 patients with tumoral or idiopathic aldosteronism was followed up after either surgical or medical treatment. Patients with primary aldosteronism were compared with 247 patients with essential hypertension with the same severity and duration of disease and 102 normotensive subjects. MAIN OUTCOME MEASURES: Short- and long-term changes in glucose tolerance and insulin sensitivity were measured. RESULTS: After adjustment for age, gender, and body mass index, patients with primary aldosteronism had greater homeostasis model assessment index (P < 0.05) and plasma insulin response to an oral glucose load (P < 0.05) and lower quantitative insulin sensitivity check index (P < 0.01) than normotensive controls. Changes in insulin sensitivity were significantly greater in essential hypertension than primary aldosteronism, and this difference was confirmed by assessment with the hyperinsulinemic-euglycemic clamp (P < 0.01). Treatment of primary aldosteronism decreased blood pressure significantly, and during the initial 6 months of follow-up, parameters of insulin sensitivity were restored to normal. Analysis of subsequent follow-up showed nonsignificant changes in glucose metabolism parameters in both adrenalectomized and spironolactone-treated patients. CONCLUSIONS: Insulin resistance is present in patients with tumoral and idiopathic aldosteronism, but the defect appears less severe than in patients with essential hypertension. Treatment with surgery or aldosterone antagonists restores rapidly and persistently normal sensitivity to insulin.     

Aldosterone as a key mediator of the cardiometabolic syndrome in primary aldosteronism: an observational study

OBJECTIVE: Primary aldosteronism (PA) is characterized by the onset of both cardiac and gluco-metabolic alterations. The aim of this study was to evaluate the impact of aldosterone excess on the development of such complications, and the effects of surgical and pharmacological treatment on their long-term outcome. METHODS: We prospectively re-examined 61 patients: 25 with aldosterone-producing adenoma (APA), after surgery, and 36 patients with idiopathic hyperaldosteronism (IHA) on pharmacological treatment. The lipid, fasting and dynamic glucose profiles and the echocardiographic parameters were evaluated at diagnosis and at follow-up. RESULTS: After adrenalectomy all patients had normalization of aldosterone levels and were cured of hypokalaemia, and a resolution of hypertension was achieved in 12 of 25 patients. APA patients showed a significant reduction of both plasma glucose (P=0.017) and insulin levels (P=0.001) after 75 g oral glucose tolerance test. Stabilization of glucose metabolism complications was observed in IHA patients. Multiple regression analysis at diagnosis showed a positive correlation between homeostasis model assessment (HOMA) insulin resistance index and HOMA beta cell and serum aldosterone levels in both APA and IHA. Echocardiographic parameters were improved in both APA and IHA at follow-up and the difference was statistically significant for left ventricular mass index (P=0.017) and interventricular septum thickness (P=0.007) in APA patients. CONCLUSIONS: The removal of aldosterone excess in APA patients induces the regression of both cardiac and gluco-metabolic complications, indicating aldosterone as a main determinant of such alterations. In IHA patients the medical treatment seems to avoid the possible progression of the these alterations that appear to be stable.     

Screening for primary aldosteronism

A serum potassium determination is usually recommended for new hypertensive patients as a screening test for primary aldosteronism and as a baseline for drug therapy. Since hypokalemia is not specific for aldosteronism, the authors assessed its use and limitations as a screening test in nine reported studies of 303 patients with aldosterone-producing adenomas (n=252) or adrenal hyperplasia (n=51). The optimal potassium cutoff level and the predictive ability of hypokalemia to detect aldosteronism were analyzed in a primary care setting with different diseases, test characteristics, and prevalences. Optimal screening for primary aldosteronism occurred at serum potassium <3.2 mEq/l in a primary care, low-prevalence population, and at higher potassium levels in higher-prevalence populations. Other screening tests, such as urinary aldoster-one levels and plasma renin activity, showed lower individual test performance characteristics, but when combined were similar in performance to serum potassium measurement. Received from the General Internal Medicine Division, Department of Medicine, Wright State University School of Medicine, Miami Valley Hospital, and Veteran’s Administration Medical Center, Dayton, Ohio. Dr. Snyder is presently a fellow in the Endocrinology Division, Department of Medicine, University of North Carolina School of Medicine, Chapel Hill, North Carolina. Presented in part at the Seventh Annual Meeting of the Society for Research and Education in Primary Care Internal Medicine, Microcomputer Users Group, Washington, D.C., May 3, 1984.     

Screening for primary aldosteronism

Normokalaemic manifestation of primary aldosteronism is a frequent cause of secondary hypertension. It occurs in approximately 5-12% of all patients with hypertension, primarily patients with severe and uncontrolled blood pressure. Main causes are bilateral adrenal hyperplasia (2/3 of cases) and aldosterone-producing adenoma (1/3 of cases). Screening is performed by measurement of the aldosterone/renin ratio, which is raised in affected patients. Suspicion of primary aldosteronism due to a pathological ratio requires confirmatory testing e.g. by saline infusion test or fludrocortisone suppression test. If the diagnosis is confirmed, the underlying cause of aldosterone excess needs to be identified because therapy differs. First, adrenal imaging (CT/MRI) is performed, which is followed by postural testing in cases with a unilateral lesion. Concordant results confirm the diagnosis of an aldosterone-producing adenoma and allow treatment to proceed to adrenalectomy. In cases of equivocal results or normal/bilaterally enlarged adrenal glands on imaging, adrenal venous sampling must be performed for subtype differentiation.     

血浆醛固酮/肾素活性比值——一个敏感的原发性醛固酮增多症的筛查指标

血浆醛固酮／肾素活性比值（ARR）是一个敏感的原发性醛固酮增多症（PA）的筛查指标，ARR的应用使高血压人群中PA的检出率明显增加。但目前ARR仍是一个非标准化的筛选方法，不同研究所采用的ARR切点差别很大，故应对ARR进行更深入和系统的研究，以提高ARR筛查方法的准确性。