Masked Uncontrolled Hypertension Is Accompanied by Increased Out-of-Clinic Aldosterone Secretion.

Masked uncontrolled hypertension (MUCH) in treated patients is defined as controlled office blood pressure (BP) but uncontrolled out-of-clinic ambulatory BP. Previously, we have shown that patients with MUCH have evidence of heightened out-of-clinic sympathetic nervous system activity. The aim is to test the hypothesis that MUCH patients have higher aldosterone secretion compared with patients with true controlled hypertension. Two hundred twenty-two patients were recruited after having controlled office BP readings at ≥3 clinic visits. Patients taking MR (mineralocorticoid receptor) antagonists and epithelial sodium channel blockers were excluded. All patients were evaluated by clinic automated office BP and morning serum aldosterone and plasma renin activity. Out-of-clinic ambulatory BP monitoring and 24-hour urinary aldosterone, catecholamines, and metanephrines were also measured. Sixty-four patients had MUCH, and the remaining 48 patients had true controlled hypertension. MUCH patients had significantly higher out-of-clinic levels of 24-hour urinary aldosterone, catecholamines, and metanephrines compared with true controlled hypertension. The 2 groups did not differ in serum aldosterone, plasma renin activity, or aldosterone-renin ratio collected in clinic. In addition, 32.8% of MUCH patients had high out-of-clinic 24-hour urinary aldosterone (≥12 µg) but normal clinic serum aldosterone (<15 ng/dL) and aldosterone-renin ratio (<20). Further, in correlation matrix analysis, higher 24-hour urinary catecholamines and metanephrines were associated with higher 24-hour urinary aldosterone and plasma renin activity levels in MUCH patients. Patients with MUCH have higher out-of-clinic urinary aldosterone levels compared with patients with true controlled hypertension. This study suggests that patients with MUCH likely have higher out-of-clinic sympathetic nervous system tone increases aldosterone secretion mediated by increased renin release that may contribute to their higher out-of-clinic BP.

Urinary catecholamines during stress and ambulatory blood pressure in children born full term but small for gestational age: a pilot study.

OBJECTIVES: Increased sympathetic activity is proposed to be a mechanism of high blood pressure in children born small for gestational age. Ambulatory blood pressure monitoring is a form of blood pressure measurement that can detect high blood pressure outside the hospital in patients with normal office blood pressure. This condition is called masked hypertension. There are limited data on association between ambulatory blood pressure and urinary catecholamines during exposure to stress in children born small for gestational age. METHODS: Nineteen children born small for gestational age and 17 healthy controls ages 6-14 years old were included. Demographic data and office blood pressure were collected. Urinary catecholamines were collected before and after exposure to stress including mathematical test and venipuncture. Afterwards, ambulatory blood pressure monitoring was performed to obtain 24-hour blood pressure profiles. RESULTS: All children had normal office blood pressure but ambulatory blood pressure monitoring revealed masked hypertension in six children born small for gestational age (32%) and two controls (11.7%). After stress, median percentage of increase in urine norepinephrine levels was greater in children born small for gestational age with masked hypertension than that of children born small for gestational age without masked hypertension (9.2 vs. -13.2 µg/g creatinine, P = 0.05). There was no increase in urine norepinephrine levels in controls with masked hypertension. Among children born small for gestational age, awake SBP z-scores had significant positive correlations with pre- and post-stress urinary dopamine levels (r = 0.530, P = 0.02 and r = 0.597, P = 0.007, respectively). CONCLUSION: Masked hypertension is not uncommon in children born small for gestational age. After stress, urinary norepinephrine levels were increased in children born small for gestational age with masked hypertension.

Left ventricular mass independently associates with 24-hour sodium excretion in young masked hypertensive adults: The African-PREDICT study.

BACKGROUND: Due to the known contribution of excess sodium intake on elevations in blood pressure, salt reduction regulations are being introduced in countries all over the world. To study the contribution of sodium intake on cardiovascular disease development, we determined whether left ventricular mass associates with sodium excretion in young adults free from overt cardiovascular disease and those with masked hypertension. METHODS: We included 681 participants (41% men and 50% black) in a cross-sectional analysis from the African-PREDICT study with complete 24-hour urine collections and successful ambulatory blood pressure monitoring (>70% valid readings). The participants were categorized as normotensive (n = 534) or masked hypertensive (n = 147). In addition, we determined left ventricular mass index (LVMI) along with traditional risk factors. RESULTS: Masked hypertensive individuals had higher sodium excretion (149 vs. 128 mmol/L/day) and LVMI (78.1 vs. 69.6 g/m2) than normotensives. In single, partial and multiple regression analyses, LVMI independently associated with higher sodium excretion in the total group of young adults (ß = 0.089; p = 0.011). This result was also evident among masked hypertensives (ß = 0.215; p = 0.008), but not in normotensives (ß = 0.054; p = 0.134). CONCLUSION: Our results indicated that higher sodium excretion (reflecting a higher salt intake) may contribute to increased left ventricular mass, potentially driven by the early development of masked or undetected hypertension.

Urinary angiotensinogen level is correlated with blood pressure level and proteinuria in patients with masked hypertension.

Urinary angiotensinogen (UAGT) level is an index of the intrarenal-renin angiotensin system status and is significantly correlated with blood pressure (BP) and proteinuria in patients with hypertension (HT). We aimed to investigate the possible relationship between UAGT levels and albuminuria in masked hypertensives. A total of 96 nondiabetic treated hypertensive patients were included in this study. The patients were divided into two groups: masked hypertensives (office BP <140/90 mmHg and ambulatory BP ≥130/80 mmHg) and controlled hypertensives (office BP <140/90 mmHg and ambulatory BP <130/80). The mean UAGT/UCre level and urinary albumin-creatinine ratio (UACR) of masked hypertensives were higher than those of controlled hypertensives (7.76 µg/g vs 4.02 µg/g, p < 0.001 and 174.21 mg/g vs 77.74 mg/g, p < 0.001, respectively). A significant positive correlation was found between UAGT/UCre levels and ambulatory systolic BP and diastolic BP levels in patients with masked HT, but this was not found with office SBP or DBP levels. Importantly, UAGT/UCre levels showed a significant positive correlation with UACR in both groups, but correlation of the UAGT levels with UACR was more pronounced in masked hypertensives (r = 0.854, p < 0.001 vsr = 0.512, p < 0.01). As a result, UAGT level was increased in patients with masked HT, which was associated with an elevation in albuminuria. Overproduction of the UAGT may play a pivotal role in development of proteinuria.

Urinary sodium excretion and ambulatory blood pressure findings in patients with hypertension.

Use of ambulatory blood pressure (BP) monitoring (ABPM) allows for identification of dipping, nondipping, extreme dipping, and reverse dipping of BP. Using office BP and ABPM, hypertension subtypes can be identified: sustained normotension (SNT), white-coat hypertension, masked hypertension, and sustained hypertension. The comparison of hemodynamic parameters and salt intake has not been investigated among these patient groups. Office BP, ABPM, augmentation index (AIx), pulse wave velocity (PWV), cardiac output (CO), and total peripheral resistance (TPR) were automatically measured. Estimation of salt intake was assessed by 24-hour urinary sodium excretion. Urinary sodium excretion was not different among groups. AIx, PWV, CO, and TPR were lowest in patients with SNT. CO was lowest while AIx adjusted for a heart rate of 75 beats per minute, PWV, and TPR were highest in the extreme dipper group. No relationship was detected between hypertension subtypes and urinary sodium excretion.