Plasma and urine aldosterone to plasma renin activity ratio in the diagnosis of primary aldosteronism.

OBJECTIVE: To establish the best cut-off value of the aldosterone (ALD)/plasma renin activity (PRA) ratio when screening patients for primary aldosteronism. One hundred and six patients with primary aldosteronism and 100 essential hypertensive patients were investigated in rigorous standardized conditions. METHODS: The ALD/PRA cut-off values were calculated from both the plasma and urine ALD/PRA ratio and analyzed by receiver operating characteristic (ROC) curve. In patients with PRA below 0.2 ng/ml/h [our radioimmunoassay detection limit], values were calculated both with PRA levels set at 0.2 ng/ml/h ('adjusted') and with PRA levels detected ('unadjusted') in the assay. RESULTS: ROC analysis on the ALD/PRA ratio indicated that the best performance was obtained when the plasma ALD (ng/dl)/PRA ratio was used in comparison with that observed in the urine ALD (microg/day)/PRA ratio. In patients with primary aldosteronism, as a whole group, the cut-off value of 69 corresponded to the best compromise value between sensitivity (96%) and specificity (85%), with and without PRA adjustment. In patients with aldosterone-producing adenoma, the cut-off to obtain 100% sensitivity with high specificity (85%) proved to be 69, with and without PRA adjustment. In patients with bilateral adrenal hyperplasia, both with and without PRA adjustment, the best compromise between sensitivity (94%) and specificity (86%) was a cut-off value of 71. CONCLUSION: The best cut-off to identify patients with primary aldosteronism, corresponding to 69, was obtained by using the plasma ALD/PRA ratio. Adjustment of PRA to 0.2 ng/ml/h does not interfere with calculation of the plasma ALD/PRA ratio cut-off.

Carotid vascular remodeling in patients with pheochromocytoma.

CONTEXT: The influence of catecholamines on vascular remodeling in humans was investigated. OBJECTIVE: The objective was to study the carotid vascular wall in patients with pheochromocytoma (PHEO). DESIGN AND SETTING: An observational study was conducted in a university referral center for blood pressure diseases. PATIENTS: Fourteen patients with PHEO, 15 matched high-normal essential hypertensives, 15 mild essential hypertensives, and 15 controls underwent two-dimensional conventional ultrasonography and ultrasonic tissue characterization of the carotid wall. MAIN OUTCOME MEASURES: Intimal media thickness (IMT), diameter, and corrected ultrasonic integrated backscatter signal (C-IBS) of carotid arteries were evaluated. RESULTS: IMT in PHEOs (0.844 +/- 0.18 mm, mean +/- sd) was greater than not only controls (0.596 +/- 0.09 mm, P < 0.0002) but also high-normal (0.710 +/- 0.17 mm, P < 0.03), and even mild (0.727 +/- 0.20 mm, P = 0.06) hypertensives. IMT in the latter was higher than in controls (P < 0.03), without difference in comparison with high-normal hypertensives. C-IBS values in PHEOs (-21.71 +/- 2.0 dB, mean +/- sd) were greater than in controls (-26.20 +/- 1.73 dB, P < 0.0001) but also than in high-normal (-23.84 +/- 1.16 dB, P < 0.002) and mild (-23.37 +/- 1.99 dB, P < 0.01) hypertensives. C-IBS values in controls were lower than in high-normal (P < 0.0005) and mild (P < 0.0001) hypertensives. Carotid diameter was not significantly different in the four groups. In PHEOs, C-IBS was associated with urinary noradrenaline (r = 0.640, P < 0.01) and normethanephrine (r = 0.737, P < 0.009). CONCLUSIONS: Carotid IMT of PHEOs is higher than in controls and matched groups of hypertensives with comparable or even higher blood pressure. This vascular rearrangement is characterized by increased IBS values due to collagen deposition and vascular fibrosis. Therefore, our data show that abnormal catecholamine levels take part per se in carotid wall remodeling of patients with PHEO.

Vascular reactivity in congenital hypogonadal men before and after testosterone replacement therapy.

CONTEXT: The contribution of endogenous testosterone (TS) in the functional integrity of peripheral circulation in men was studied. OBJECTIVE: The objective of this study was to observe vascular reactivity in male congenital hypogonadal patients before and after prolonged exposure to normal TS levels. DESIGN: This was a longitudinal study in which, basically and after 6-month (range, 6-8 months) androgen treatment, we investigated forearm blood flow (strain-gauge plethysmography) changes induced by intraarterial acetylcholine (Ach), alone or in the presence of N(G)-monomethyl-l-arginine infusion, and by sodium nitroprusside. We also evaluated, by Doppler ultrasound, flow-mediated dilation of the brachial artery (BA) in response to reactive hyperemia (RH) and glyceryl trinitrate (GTN). SETTING: The studies were conducted at university referral centers for andrologic and blood pressure diseases. PATIENTS: Eight adult male Caucasian hypogonadal patients and nine healthy matched control subjects were studied. INTERVENTION: Intervention was TS enanthate (250 mg in 1 ml oily solution) by im injection every 3 wk. RESULTS: At baseline, BA diameter and RH, flow-mediated dilation, and GTN responses showed no difference between the two groups. TS therapy increased plasma total TS (P < 0.02) and reduced high-density lipoprotein (P < 0.01) and total cholesterol (P < 0.04). It did not affect vasodilation to sodium nitroprusside (355 +/- 47%), but it further reduced the vascular response to Ach (187 +/- 29%, P < 0.01 vs. baseline) and abolished the inhibition by N(G)-monomethyl-l-arginine on Ach (inhibition, 3.2%). Moreover, TS therapy decreased (P < 0.01) flow-mediated dilation, whereas it did not modify BA diameter and responses to RH and GTN. CONCLUSIONS: Hypogonadal patients show impaired vascular reactivity, including endothelial-dependent vasodilation due to reduced nitric oxide availability. TS administration further impairs nitric oxide availability in these patients.

Primary aldosteronism in normokalemic patients with adrenal incidentalomas.

OBJECTIVE: Since primary aldosteronism has been reported in asymptomatic incidental adrenal masses (adrenal incidentalomas, AI), the aim of our study was to detect primary aldosteronism in normokalemic patients with AI and to verify whether a raised plasma aldosterone (ALD)/plasma renin activity (PRA) ratio may be useful for diagnosis. DESIGN: One-hundred and twenty-five normokalemic patients with solid AI (90 hypertensives and 35 normotensives) and 82 essential hypertensives (EH) were studied. Upright ALD and PRA determination was performed in all cases while patients with abnormal ALD/PRA ratios were submitted to confirmatory tests (saline infusion and captopril tests) for diagnosis of primary aldosteronism. METHODS: ALD and PRA were measured by specific radioimmunoassays. RESULTS: PRA values in AI hypertensives (1.05+/-0.13 ng/ml/h) were lower than in AI normotensives (1.14+/-0.14 ng/ml/h, P<0.05) and in EH (1.68+/-0.15 ng/ml/h, P<0.0001). The ALD/PRA ratio in AI hypertensives (46.4+/-5.1) was higher than in AI normotensives (30.7+/-5.8, P<0.03) and in EH (33.2+/-3.5). Four patients with EH and 2 AI normotensive patients had elevated ALD/PRA ratios but normal responses to the suppressive tests, thus excluding diagnosis of primary aldosteronism. Eight patients with AI and hypertension had a high ALD/PRA ratio, and 7 of these were further studied: in 5 patients diagnosis of primary aldosteronism was well-established by dynamic tests, adrenal vein sampling or by surgery. CONCLUSIONS: Primary aldosteronism in normokalemic patients with incidentally discovered adrenal masses was detected in 4 of all cases and in at least 5.5% of those with hypertension. Consequently, these patients, particularly if hypertensive, need to be routinely studied to exclude this hormonal disease. Evaluation of the ALD/PRA ratio seems to be a simple and reliable test for diagnosis.

Anthropometric, haemodynamic, humoral and hormonal evaluation in patients with incidental adrenocortical adenomas before and after surgery.

OBJECTIVE: To compare clinical and humoral parameters before and after surgery in patients with incidental adrenocortical adenomas. DESIGN: Six patients with subclinical Cushing's syndrome and nine with non-functioning adenomas were investigated before and 12 Months after removal of the mass. METHODS: Anthropometric (body weight, body mass index and waist to hip ratio), haemodynamic (blood pressure and heart rate), metabolic (lipids and oral glucose tolerance test (OGTT)), hormonal (cortisol, plasma renin activity, aldosterone, androgens and catecholamines) and bone metabolism (hydroxyproline, parathyroid hormone, osteocalcin and ostase) parameters were evaluated. RESULTS: In the whole group, a significant decrease in body weight (69.7+/-3.5 vs 70.8+/-3.5 kg, P<0.03), in systolic (135.3+/-5.1 vs 145.6+/-4.9 mmHg, P<0.009) and diastolic (83.7+/-1.9 vs 91.0+/-3.5 mmHg, P<0.03) blood pressure and in glucose levels in response to OGTT (106.4+/-9.6 vs 127.5+/-6.5 mg/dl, P<0.05) was observed after surgery. All other parameters examined did not change significantly. This trend was also found in both groups separately. Analytical data showed a high frequency of overweight/obesity (66.6%), hypertension (66.6%) and impaired glucose profile (26.6%) in our patients, with a greater prevalence of these cardiovascular risk factors in the subclinical Cushing's syndrome group. After surgery, values normalized or improved in eight out of ten hypertensive patients and in three out of four patients with impaired glucose profile. CONCLUSIONS: Solid adrenocortical incidentalomas are associated with some cardiovascular risk factors which may be corrected after removal of the mass. Therefore, surgery may be an appropriate choice in patients with subclinical Cushing's syndrome but also in those with solid non-functioning adenomas and coexistent cardiovascular risk factors.

Plasma chromogranin A in incidental non-functioning, benign, solid adrenocortical tumors.

OBJECTIVE: To evaluate whether adenomas arising from the adrenal cortex, a tissue of epithelial origin, are associated with high chromogranin A (CgA) levels and whether such tumors may express and release this protein. In addition, to investigate whether high CgA levels imply a neuroendocrine differentiation of the adrenocortical adenomas and, therefore, represent a humoral marker of malignant transformation of these tumors. DESIGN: Plasma CgA of 80 patients with non-functioning, benign adrenocortical adenomas was compared with that of 137 tumor-free subjects. In 15 patients, the masses were surgically removed and CgA was measured 2 months later. The other 65 patients with adrenocortical adenomas underwent clinical and radiological follow-up (range 24-36 months). METHODS: CgA was evaluated by immunoradiometric assay in peripheral blood and by immunohistochemistry in adrenal tissue specimens. RESULTS: An increase in plasma CgA (P<0.001) was observed in patients with adrenocortical adenomas (83.4+/-7.5 ng/ml) in comparison with tumor-free subjects (43.1+/-1.5 ng/ml). The prevalence of high CgA levels was 25% in the former and 0.7% in the latter. By multiple regression analysis, an increase (49%) in the expected median CgA value was estimated for adrenocortical adenomas (P<0.001). Receiver operating characteristic analysis showed a good diagnostic performance of CgA in identifying patients with adrenocortical adenomas (pure accuracy=0.78, 95% CI=0.71-0.84). In the operated patients, CgA levels did not change before (80.6+/-16.5 ng/ml) and after (74.3+/-16.3 ng/ml) surgery and in no case was CgA immunoreactivity found in adenoma tissues. The non-operated patients did not develop signs or symptoms of disease and showed no features of malignant transformation of the masses. CONCLUSIONS: Our data showed a strong association between adrenocortical adenomas and high CgA levels. CgA hypersecretion was not due to adenoma tissue, which did not show immunoreactivity for CgA. Finally, elevated CgA levels did not represent a humoral marker of malignant transformation of cortical adenomas.

Normalization of catecholamine production following resection of phaeochromocytoma positively influences carotid vascular remodelling.

OBJECTIVE: To evaluate the influence of plasma catecholamines on the vascular structure in humans, the effects of catecholamine normalization on the carotid wall of patients with phaeochromocytoma (PHEO) were investigated. A prospective study in patients with PHEO before and after (first follow-up: 20.5+/-1.8 months, second follow-up: 31.5+/-2.2 months) successful surgery was conducted in the University Referral Center for Blood Pressure Diseases. Ten consecutive patients with PHEOs and ten age- and blood pressure-matched controls were investigated. Intima-media thickness (IMT) by two-dimensional conventional ultrasonography and corrected ultrasonic integrated backscatter signal (C-IBS) analysis of carotid arteries were investigated in basal conditions and after mass removal. RESULTS: In PHEOs, at variance with the expected reduction in metanephrines and catecholamines, no variation in body weight, blood pressure and lipid profile was observed after operation. IMT and C-IBS values in patients with PHEO were greater (at least P<0.01) than in controls. At long-term follow-up after surgery, a significant reduction in mean carotid IMT (P<0.0009) and C-IBS (P<0.009) values was observed. A significant correlation (r=0.54, P<0.03) was found between absolute reduction in C-IBS values and absolute decrement in urinary normetanephrine levels. CONCLUSIONS: Our study shows that normalization of catecholamine levels after the removal of PHEO improves carotid IMT and reduces carotid wall fibrosis even without influencing blood pressure and lipid profile. These findings confirm that high catecholamine tone in humans directly influences vascular remodelling of carotid arteries.

A prospective study of the prevalence of primary aldosteronism in 1,125 hypertensive patients.

OBJECTIVES: We prospectively investigated the prevalence of curable forms of primary aldosteronism (PA) in newly diagnosed hypertensive patients. BACKGROUND: The prevalence of curable forms of PA is currently unknown, although retrospective data suggest that it is not as low as commonly perceived. METHODS: Consecutive hypertensive patients referred to 14 hypertension centers underwent a diagnostic protocol composed of measurement of Na+ and K+ in serum and 24-h urine, sitting plasma renin activity, and aldosterone at baseline and after 50 mg captopril. The patients with an aldosterone/renin ratio >40 at baseline, and/or >30 after captopril, and/or a probability of PA (by a logistic discriminant function) > or =50% underwent imaging tests and adrenal vein sampling (AVS) or adrenocortical scintigraphy to identify the underlying adrenal pathology. An aldosterone-producing adenoma (APA) was diagnosed in patients who in addition to excess autonomous aldosterone secretion showed: 1) lateralized aldosterone secretion at AVS or adrenocortical scintigraphy, 2) adenoma at surgery and pathology, and 3) a blood pressure decrease after adrenalectomy. Evidence of excess autonomous aldosterone secretion without such criteria led to a diagnosis of idiopathic hyperaldosteronism (IHA). RESULTS: A total of 1,180 patients (age 46 +/- 12 years) were enrolled; a conclusive diagnosis was attained in 1,125 (95.3%). Of these, 54 (4.8%) had an APA and 72 (6.4%) had an IHA. There were more APA (62.5%) and fewer IHA cases (37.5%) at centers where AVS was available (p = 0.002); the opposite occurred where AVS was unavailable. CONCLUSIONS: In newly diagnosed hypertensive patients referred to hypertension centers, the prevalence of APA is high (4.8%). The availability of AVS is essential for an accurate identification of the adrenocortical pathologies underlying PA.

Myocardial ultrasonic backscatter in hypertension: relation to aldosterone and endothelin.

A disproportionate accumulation of fibrillar collagen is a characteristic feature of hypertensive heart disease, but the extent of myocardial fibrosis may differ in different models of hypertension. In experimental studies, aldosterone and endothelins emerge as important determinants of myocardial fibrosis. Changes in myocardial extracellular matrix and collagen deposition can be estimated noninvasively by analysis of the ultrasonic backscatter signal, which arises from tissue heterogeneity within the myocardium and describes myocardial texture. This study was designed to investigate the relations between myocardial integrated backscatter and circulating aldosterone and immunoreactive endothelin in human hypertension. The study population consisted of 56 subjects: 14 healthy normotensive volunteers and 42 hypertensive patients (14 with primary aldosteronism, 7 with renovascular hypertension, and 21 with essential hypertension). The patients with essential and secondary hypertension were matched for age, gender, body mass index, and blood pressure. Myocardial integrated backscatter at diastole was 19.8+/-2.0 and 20.8+/-2.9 decibels in normotensive control subjects and patients with essential hypertension and significantly higher in patients with primary aldosteronism (27.4+/-3.8 decibels, P<0.01) and renovascular hypertension (26.8+/-4.8 decibels, P<0.01). In the population as a whole, as well as in the hypertensive subpopulation, myocardial integrated backscatter was directly related to plasma aldosterone (r=0.73 and 0.71, P<0.01 for both) and immunoreactive endothelin (r=0.60 and 0.56, P<0.01 for both). The data of this study suggest that in human hypertension, circulating aldosterone and immunoreactive endothelin may induce alterations in left ventricular myocardial texture, possibly related to increased myocardial collagen content.