Treatment of Resistant and Refractory Hypertension.

Resistant hypertension (RHTN) is defined as uncontrolled blood pressure despite the use of ≥3 antihypertensive agents of different classes, including a diuretic, usually thiazide-like, a long-acting calcium channel blocker, and a blocker of the renin- angiotensin system, either an ACE (angiotensin-converting enzyme) inhibitor or an ARB (angiotensin receptor blocker), at maximal or maximally tolerated doses. Antihypertensive medication nonadherence and the white coat effect, defined as elevated blood pressure when measured in clinic but controlled when measured outside of clinic, must be excluded to make the diagnosis. RHTN is a high-risk phenotype, leading to increased all-cause mortality and cardiovascular disease outcomes. Healthy lifestyle habits are associated with reduced cardiovascular risk in patients with RHTN. Aldosterone excess is common in patients with RHTN, and addition of spironolactone or amiloride to the standard 3-drug antihypertensive regimen is effective at getting the blood pressure to goal in most of these patients. Refractory hypertension is defined as uncontrolled blood pressure despite use of ≥5 antihypertensive agents of different classes, including a long-acting thiazide-like diuretic and an MR (mineralocorticoid receptor) antagonist, at maximal or maximally tolerated doses. Fluid retention, mediated largely by aldosterone excess, is the predominant mechanism underlying RHTN, while patients with refractory hypertension typically exhibit increased sympathetic nervous system activity.

The Unrecognized Prevalence of Primary Aldosteronism: A Cross-sectional Study.

BACKGROUND: Primary aldosteronism is a nonsuppressible renin-independent aldosterone production that causes hypertension and cardiovascular disease. OBJECTIVE: To characterize the prevalence of nonsuppressible renin-independent aldosterone production, as well as biochemically overt primary aldosteronism, in relation to blood pressure. DESIGN: Cross-sectional study. SETTING: 4 U.S. academic medical centers. PARTICIPANTS: Participants with normotension (n = 289), stage 1 hypertension (n = 115), stage 2 hypertension (n = 203), and resistant hypertension (n = 408). MEASUREMENTS: Participants completed an oral sodium suppression test, regardless of aldosterone or renin levels, as a confirmatory diagnostic for primary aldosteronism and to quantify the magnitude of renin-independent aldosterone production. Urinary aldosterone was measured in participants in high sodium balance with suppressed renin activity. Biochemically overt primary aldosteronism was diagnosed when urinary aldosterone levels were higher than 12 µg/24 h. RESULTS: Every blood pressure category had a continuum of renin-independent aldosterone production, where greater severity of production was associated with higher blood pressure, kaliuresis, and lower serum potassium levels. Mean adjusted levels of urinary aldosterone were 6.5 µg/24 h (95% CI, 5.2 to 7.7 µg/24 h) in normotension, 7.3 µg/24 h (CI, 5.6 to 8.9 µg/24 h) in stage 1 hypertension, 9.5 µg/24 h (CI, 8.2 to 10.8 µg/24 h) in stage 2 hypertension, and 14.6 µg/24 h (CI, 12.9 to 16.2 µg/24 h) in resistant hypertension; corresponding adjusted prevalence estimates for biochemically overt primary aldosteronism were 11.3% (CI, 5.9% to 16.8%), 15.7% (CI, 8.6% to 22.9%), 21.6% (CI, 16.1% to 27.0%), and 22.0% (CI, 17.2% to 26.8%). The aldosterone-renin ratio had poor sensitivity and negative predictive value for detecting biochemically overt primary aldosteronism. LIMITATION: Prevalence estimates rely on arbitrary and conventional thresholds, and the study population may not represent nationwide demographics. CONCLUSION: The prevalence of primary aldosteronism is high and largely unrecognized. Beyond this categorical definition of primary aldosteronism, there is a prevalent continuum of renin-independent aldosterone production that parallels the severity of hypertension. These findings redefine the primary aldosteronism syndrome and implicate it in the pathogenesis of "essential" hypertension. PRIMARY FUNDING SOURCE: National Institutes of Health.

Association Between Sleep Apnea and Blood Pressure Control Among Blacks.

BACKGROUND: Blacks have a high prevalence of hypertension and uncontrolled blood pressure (BP), each of which may be partially explained by untreated sleep apnea. We investigated the association of sleep apnea with uncontrolled BP and resistant hypertension in blacks. METHODS: Between 2012 and 2016, Jackson Heart Sleep Study participants (N=913) underwent an in-home Type 3 sleep apnea study, clinic BP measurements, and anthropometry. Moderate or severe obstructive sleep apnea (OSA) was defined as a respiratory event index ≥15, and nocturnal hypoxemia was quantified as percent sleep time with <90% oxyhemoglobin saturation. Prevalent hypertension was defined as either a systolic BP ≥130 mm Hg or diastolic BP >80mm Hg, use of antihypertensive medication, or self-report of a diagnosis of hypertension. Controlled BP was defined as systolic BP <130 mm Hg and diastolic BP <80 mm Hg; uncontrolled BP as systolic BP ≥130 mm Hg or diastolic BP ≥80 mm Hg with use of 1 to 2 classes of antihypertensive medication; and resistant BP as systolic BP ≥130 mm Hg or diastolic BP ≥80 mm Hg with the use of ≥3 classes of antihypertensive medication (including a diuretic) or use of ≥4 classes of antihypertensive medication regardless of BP level. Multinomial logistic regression models were fit to determine the association between OSA severity and uncontrolled BP or resistant hypertension (versus controlled BP) after multivariable adjustment. RESULTS: The analytic sample with hypertension (N=664) had a mean age of 64.0 (SD,10.6) years, and were predominately female (69.1%), obese (58.6%), and college educated (51.3%). Among the sample, 25.7% had OSA, which was untreated in 94% of participants. Overall, 48% of participants had uncontrolled hypertension and 14% had resistant hypertension. After adjustment for confounders, participants with moderate or severe OSA had a 2.0 times higher odds of resistant hypertension (95% confidence interval [CI], 1.14-3.67). Each standard deviation higher than <90% oxyhemoglobin saturation was associated with an adjusted odds ratio for resistant hypertension of 1.25 (95% CI 1.01-1.55). OSA and <90% oxyhemoglobin saturation were not associated with uncontrolled BP. CONCLUSION: Untreated moderate or severe OSA is associated with increased odds of resistant hypertension. These results suggest that untreated OSA may contribute to inadequate BP control in blacks.

Resistant Hypertension Management: Comparison of the 2017 American and 2018 European High Blood Pressure Guidelines.

PURPOSE OF REVIEW: To compare European and American guidelines for the diagnosis, evaluation, and management of resistant hypertension. RECENT FINDINGS: Resistant hypertension is defined as high blood pressure that remains above goal with the use of 3 or more antihypertensive agents, commonly a renin-angiotensin blocker (either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker), a long-acting calcium channel blocker, and thiazide or thiazide-like diuretic. Resistant hypertension is common, with a recent analysis indicating that it affects approximately 17-19% of adult Americans with hypertension. Pseudocauses of apparent resistant hypertension, including inaccurate blood pressure measurement, white coat effect, undertreatment, and poor medication adherence, must be excluded in order to confirm true resistant hypertension. Evaluation of resistant hypertension requires identifying and treating secondary causes of hypertension, including obstructive sleep apnea, primary aldosteronism, and renal artery stenosis. Treatment of resistant hypertension includes a combined use of lifestyle modification and prescription of effective multiple-drug combinations. Preferential use of a long-acting thiazide-like diuretic, either chlorthalidone or indapamide, and a mineralocorticoid receptor blocker, most commonly spironolactone, is recommended if needed to achieve blood pressure control. Aside for small exceptions, European and American guidelines agree in terms of recommendations for diagnosing, evaluating, and treating resistant hypertension.

Role of Mineralocorticoid Receptors in Obstructive Sleep Apnea and Metabolic Syndrome.

PURPOSE OF REVIEW: This review will summarize recent developments in the research on the mineralocorticoid receptor and its impact on obstructive sleep apnea and metabolic syndrome. RECENT FINDINGS: Aldosterone excess plays an important role in the association between resistant hypertension and obstructive sleep apnea. The prevalence of obesity is increasing rapidly worldwide and is especially common among patients with obstructive sleep apnea, resistant hypertension, and metabolic syndrome, suggesting probable mechanistic links between these three conditions. Mineralocorticoid receptor expression is increased in obese individuals, which may contribute to the common association between obesity and hyperaldosteronism. Mineralocorticoid receptor blockers reduce the severity of obstructive sleep apnea among resistant hypertension patients. A large body of literature demonstrates a strong association between obesity, hyperaldosteronism, resistant hypertension, and sleep apnea, including specific benefit of treatment with mineralocorticoid receptor blockers for these separate disorders.

National patterns in intensity and frequency of outpatient care for apparent treatment-resistant hypertension.

BACKGROUND: Apparent treatment-resistant hypertension (aTRH) is associated with an increased risk of adverse cardiovascular outcomes. We studied the frequency and intensity of care for aTRH among participants aged 65 years and older in the US-based REGARDS study linked with Medicare claims. METHODS: Blood pressure (BP) was measured twice and averaged. aTRH was defined by the use of ≥3 classes of antihypertensive medication and uncontrolled BP (UaTRH, systolic/diastolic BP ≥140/90 mmHg), or ≥4 classes with controlled BP (CaTRH). Participants were categorized as not having aTRH (no aTRH), CaTRH or UaTRH. RESULTS: Among 4650 participants with hypertension, 468 (10.1%) had UaTRH, 247 (5.3%) had CaTRH, and 3935 (84.6%) had hypertension but did not have aTRH. For hypertension-related visits, those with UaTRH saw primary care physicians and cardiologists more frequently than those without aTRH (mean primary care visits per year: 2.77 vs 2.27, P<.001; cardiologists: 0.50 vs 0.35, P=.014). Among those with UaTRH, CaTRH, and no aTRH, respectively 73.5%, 68.0%, and 67.5% had >1 hypertension-related visit per year. Among those with UaTRH, males vs females (prevalence ratio=0.78; 95% CI 0.69-0.89), whites vs blacks (0.88; 95% CI 0.78-0.99), and current smokers vs non-smokers (0.66; 95% CI 0.48-0.89) were less likely to receive >1 hypertension-related visit per year. Diagnostic intensity, measured by testing for end organ damage and secondary hypertension, was similar between groups. CONCLUSIONS: Many people with UaTRH are not seen more than once per year for hypertension and may benefit from increased care.

Refractory versus resistant hypertension.

PURPOSE OF REVIEW: Refractory hypertension is a recently proposed phenotype of antihypertensive treatment failure. As such it represents an extreme subtype of resistant or difficult-to-treat hypertension. Resistant hypertension is relatively common with an estimated prevalence of 10-20% of treated hypertensive patients. It is typically defined as having an uncontrolled blood pressure on three or more antihypertensive medications, including a diuretic. Refractory hypertension is rare with a prevalence of approximately 5% of patients with uncontrolled resistant hypertension. It is defined as an uncontrolled blood pressure with the use of five or more antihypertensive medications, including a long-acting thiazide diuretic, such as chlorthalidone, and a mineralocorticoid receptor antagonist such as spironolactone. RECENT FINDINGS: Persistent excess fluid retention is thought to commonly underlie development of resistant hypertension, recent studies suggest that refractory may be more likely attributable to heightened sympathetic output as opposed to inappropriate fluid retention. SUMMARY: Treatment recommendations for resistant hypertension are generally based on intensification of diuretic therapy, especially with combined use of chlorthalidone and spironolactone. Although fuller elucidation is needed, such an approach may not be appropriate for refractory hypertension, which instead, may require effective sympathetic inhibition, either with medications or device-based approaches.

Drug Development for Hypertension: Do We Need Another Antihypertensive Agent for Resistant Hypertension?

The prevalence of resistant hypertension is seemingly much lower than had been reported in early studies. Recent analyses suggest that <5 % of treated hypertensive patients remain uncontrolled if fully adherent to an optimized antihypertensive treatment. However, these patients do have increased cardiovascular risk and need effective therapeutic approaches. Drug development is a high-risk, complex, lengthy, and very expensive process. In this article, we discuss the factors that should be considered in the process of developing a new agent for treatment of resistant hypertension.

Comparisons of sleep apnoea rate and outcomes among patients with resistant and non-resistant hypertension.

BACKGROUND AND OBJECTIVE: We directly compared sleep apnoea (SA) rates and risk of cardiovascular and mortality outcomes among SA patients with resistant hypertension (RH) and non-RH within a large diverse hypertension population. METHODS: A retrospective cohort study between 1 January 2006 and 31 December 2010 among hypertensive adults (age ≥ 18 years) was performed within an integrated health system. Rates of SA in RH and non-RH were determined. Multivariable logistic regression analyses were used to calculate OR for SA. Cox proportional hazard modelling was used to estimate hazard ratios (HRs) for cardiovascular and mortality outcomes between SA in RH versus SA in non-RH adjusting for age, gender, race, BMI, chronic kidney disease and other comorbidities. RESULTS: SA was identified in 33 682 (7.2%) from 470 386 hypertensive individuals. SA in RH accounted for 5806 (9.6%) compared to SA in non-RH 27 876 individuals (6.8%). Multivariable OR (95% CI) for SA was 1.16 (1.12, 1.19), 3.57 (3.47, 3.66) and 2.20 (2.15, 2.25) for RH versus non-RH, BMI ≥ 30, and males, respectively. Compared to SA in non-RH individuals, SA in RH had a multivariable adjusted HR (95% CI) of 1.24 (1.13, 1.36), 1.43 (1.28, 1.61), 0.98 (0.85, 1.12) and 1.04 (0.95, 1.14) for ischaemic heart event (IHE), congestive heart failure (CHF), stroke and mortality, respectively. CONCLUSION: We observed a modest increase in likelihood for SA among RH compared to non-RH patients. Risks for IHE and CHF were higher for SA in RH compared to SA in non-RH patients; however, there were no differences in risk for stroke and mortality.

Comparative risk of renal, cardiovascular, and mortality outcomes in controlled, uncontrolled resistant, and nonresistant hypertension.

We sought to compare the risk of end-stage renal disease (ESRD), ischemic heart event (IHE), congestive heart failure (CHF), cerebrovascular accident (CVA), and all-cause mortality among 470,386 individuals with resistant and nonresistant hypertension (non-RH). Resistant hypertension (60,327 individuals) was subcategorized into two groups: 23,104 patients with cRH (controlled on four or more medicines) and 37,223 patients with uRH (uncontrolled on three or more medicines) in a 5-year retrospective cohort study. Cox proportional hazard modeling was used to estimate hazard ratios adjusting for age, gender, race, body mass index, chronic kidney disease (CKD), and comorbidities. Resistant hypertension (cRH and uRH), compared with non-RH, had multivariable adjusted hazard ratios (95% confidence intervals) of 1.32 (1.27-1.37), 1.24 (1.20-1.28), 1.46 (1.40-1.52), 1.14 (1.10-1.19), and 1.06 (1.03-1.08) for ESRD, IHE, CHF, CVA, and mortality, respectively. Comparison of uRH with cRH had hazard ratios of 1.25 (1.18-1.33), 1.04 (0.99-1.10), 0.94 (0.89-1.01), 1.23 (1.14-1.31), and 1.01 (0.97-1.05) for ESRD, IHE, CHF, CVA, and mortality, respectively. Men and Hispanics had a greater risk for ESRD within all three cohorts. Individuals with resistant hypertension had a greater risk for ESRD, IHE, CHF, CVA, and mortality. The risk of ESRD and CVA were 25% and 23% greater, respectively, in uRH compared with cRH, supporting the linkage between blood pressure and both outcomes.

Hyperaldosteronism as a common cause of resistant hypertension.

Resistant hypertension affects an estimated 10-15 million American adults and is increasing in prevalence. The etiology of resistant hypertension is almost always multifactorial, including obesity, older age, high dietary salt, chronic kidney disease, and aldosterone excess. Classical primary aldosteronism and lesser degrees of aldosterone excess, possibly originating from visceral adipocytes, contribute broadly to antihypertensive treatment resistance. Treatment of resistant hypertension is predicated on appropriate lifestyle changes and use of effective combinations of antihypertensive agents from different classes. Blockade of aldosterone with spironolactone has been shown to be particularly effective for treatment of resistant hypertension. The antihypertensive benefit of spironolactone is not limited to patients with demonstrable hyperaldosteronism but instead can be effective in resistant hypertensive patients regardless of aldosterone levels. Chlorthalidone is a potent, long-acting thiazide-like diuretic and should be used preferentially to treat resistant hypertension as it is superior to normally used doses of hydrochlorothiazide.

Incident ESRD and treatment-resistant hypertension: the reasons for geographic and racial differences in stroke (REGARDS) study.

BACKGROUND: Studies suggest that treatment-resistant hypertension is common and increasing in prevalence among US adults. Although hypertension is a risk factor for end-stage renal disease (ESRD), few data are available for the association between treatment-resistant hypertension and ESRD risk. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: We analyzed data from 9,974 REGARDS (Reasons for Geographic and Racial Differences in Stroke) Study participants treated for hypertension without ESRD at baseline. PREDICTOR: Treatment-resistant hypertension was defined as uncontrolled blood pressure (BP) with concurrent use of 3 antihypertensive medication classes including a diuretic or use of 4 or more antihypertensive medication classes including a diuretic regardless of BP. OUTCOME: Incident ESRD was identified by linkage of REGARDS Study participants with the US Renal Data System. MEASUREMENTS: During a baseline in-home study visit, BP was measured twice and classes of antihypertensive medication being taken were determined by pill bottle inspection. RESULTS: During a median follow-up of 6.4 years, there were 152 incident cases of ESRD (110 ESRD cases among 2,147 with treatment-resistant hypertension and 42 ESRD cases among 7,827 without treatment-resistant hypertension). The incidence of ESRD per 1,000 person-years for hypertensive participants with and without treatment-resistant hypertension was 8.86 (95% CI, 7.35-10.68) and 0.88 (95% CI, 0.65-1.19), respectively. After multivariable adjustment, the HR for ESRD comparing hypertensive participants with versus without treatment-resistant hypertension was 6.32 (95% CI, 4.30-9.30). Of participants who developed incident ESRD during follow-up, 72% had treatment-resistant hypertension at baseline. LIMITATIONS: BP, estimated glomerular filtration rate, and albuminuria assessed at a single time. CONCLUSIONS: Individuals with treatment-resistant hypertension are at increased risk for ESRD. Appropriate clinical management strategies are needed to treat treatment-resistant hypertension in order to preserve kidney function in this high-risk group.

Left ventricular torsion shear angle volume analysis in patients with hypertension: a global approach for LV diastolic function.

BACKGROUND: Torsion shear angle φ is an important measure of left ventricular (LV) systolic and diastolic functions. Here we provide a novel index utilizing LV normalized torsion shear angle φ ^ volume V ^ loop to assess LV diastolic functional properties. We defined the area within φ ^ V ^ loop as torsion hysteresis area, and hypothesized that it may be an important global parameter of diastolic function. We evaluated the φ ^ changes to increased V ^ during early diastole - d φ ^ / d V ^ as a potential measure of LV suction. METHODS: Sixty resistant hypertension patients (HTN), forty control volunteers were studied using cardiovascular magnetic resonance with tissue tagging. Volumetric and torsional parameters were evaluated. RESULTS: HTN demonstrated concentric remodeling with preserved ejection fraction. HTN had significantly decreased normalized early filling rate, early diastolic mitral annulus velocity and E/A (1.33 ± 1.13 vs. 2.19 ± 1.07, P < 0.0001) vs. control. Torsion hysteresis area was greater (0.11 ± 0.07 vs. 0.079 ± 0.045, P < 0.001) and peak - d φ ^ / d V ^ at early diastole was higher (10.46 ± 8.51 vs. 6.29 ± 3.85, P = 0.002) than control. Torsion hysteresis area was significantly correlated with E/A (r = -0.23, P = 0.025). Thirteen HTN patients had both E/A ratio < 1.12 (Control mean E/A-1SD) and torsion hysteresis area > 0.12 (Control mean torsion hysteresis area + 1SD). CONCLUSIONS: Torsion hysteresis area and peak early diastolic - d φ ^ / d V ^ were significantly increased in hypertensive concentric remodeling. The φ ^ V ^ loop takes into account the active and passive recoil processes of LV diastolic and systolic phases, therefore provides a new global description of LV diastolic function.

Spironolactone improves left atrial function and atrioventricular coupling in patients with resistant hypertension.

To determine the blood pressure independent effects of spironolactone on left atrial (LA) size and function in patients with resistant hypertension (RHTN). Patients with RHTN (n = 36, mean age 55 ± 7) were prospectively recruited. Spironolactone was initiated at 25 mg/day and increased to 50 mg/day after 4 weeks. Other antihypertensives were withdrawn to maintain constant blood pressure. Cardiac magnetic resonance imaging was performed at baseline and after 6 months of spironolactone treatment and changes in LA functional metrics were assessed. LA size and function parameters were improved (p < 0.05) from baseline to month-6: LA volumes indexed to body surface area (LAVI) were reduced (LAVImaximum 41.4 ± 12 vs. 33.2±9.7 mL/m2; LAVIpre-A 32.6 ± 9.8 vs. 25.6 ± 8.1 mL/m2; median LAVIminimum 18.5 [13.9-24.8] vs. 14.1 [10.9-19.2] mL/m2); left atrioventricular coupling index was reduced (28.2 ± 11.5 vs. 22.7 ± 9.2%); LA emptying fractions (LAEF) were increased (median total LAEF 52.4 [48.7-60.3] vs. 55.9 [50.3-61.1] %; active LAEF 40.2 ± 8.6 vs. 43.1 ± 7.8%). LA global longitudinal strain in the active phase was increased (16.3 ± 4.1 vs. 17.8 ± 4.2%). The effect of spironolactone was similar in patients with high (N = 18) and normal (N = 18) aldosterone status (defined by plasma renin activity and 24-h urine aldosterone). Treatment of RHTN with spironolactone is associated with improvements in LA size and function, and atrioventricular coupling, regardless of whether aldosterone levels were normal or high at baseline. This study suggests the need for larger prospective studies examining effects of mineralocorticoid receptor antagonists on atrial function and atrioventricular coupling.

Adverse cardiac remodeling is absent in patients with true controlled resistant hypertension.

Resistant hypertension (RHTN), defined as blood pressure (BP) that is uncontrolled with ≥3 medications, including a long-acting thiazide diuretic, also includes a subset with BP that is controlled with ≥4 medications, so-called controlled RHTN. This resistance is attributed to intravascular volume excess. Patients with RHTN overall have a higher prevalence of left ventricular hypertrophy (LVH) and diastolic dysfunction compared to patients with non-RHTN. We tested the hypothesis that patients with controlled RHTN due to the intravascular volume excess have higher left ventricular mass index (LVMI), higher prevalence of LVH, larger intracardiac volumes, and more diastolic dysfunction compared to patients with controlled non-resistant hypertension (CHTN), defined as BP controlled with ≤3 anti-hypertensive medications. Patients with controlled RHTN (n = 69) or CHTN (n = 63) who were treated at the University of Alabama at Birmingham were offered enrollment and underwent cardiac magnetic resonance imaging. Diastolic function was assessed by peak filling rate, time needed in diastole to recover 80% of stroke volume, E:A ratios and left atrial volume. LVMI was higher in patients with controlled RHTN (64.4 ± 22.5 vs 56.9 ± 11.5; P = .017). Intracardiac volumes were similar in both groups. Diastolic function parameters were not significantly different between groups. There were no significant differences in age, gender, race, body mass index, dyslipidemia between the two groups. The findings show that patients with controlled RHTN have higher LVMI, but comparable diastolic function to those of patients with CHTN.

Effects of a novel aldosterone synthase inhibitor for treatment of primary hypertension: results of a randomized, double-blind, placebo- and active-controlled phase 2 trial.

BACKGROUND: LCI699, a novel inhibitor of aldosterone synthase, reduces serum aldosterone, and may have benefit in the treatment of hypertension. METHODS AND RESULTS: We performed the first double-blind, randomized trial with LCI699 in patients with primary hypertension. We randomized 524 patients to LCI699 0.25 mg once daily (n=92), 0.5 mg once daily (n=88), 1.0 mg once daily (n=86), and 0.5 mg twice daily (n=97); eplerenone 50 mg twice daily (n=84); or placebo (n=77) for 8 weeks. Adrenocorticotropic hormone (250 µg IV) stimulation testing was performed in a subset of patients to quantify the selectivity of LCI699 for aldosterone synthase compared with 11-ß-hydroxylase. Reductions in clinic diastolic blood pressure were significant for LCI699 1.0 mg (-7.1 mm Hg; P=0.0012) and eplerenone 50 mg twice daily (-7.9 mm Hg; P<0.0001) compared with placebo (-2.6 mm Hg) but not other doses of LCI699. Significant reductions in clinic systolic blood pressure were observed with all doses of LCI699 (P<0.005 or better) and eplerenone (P<0.0001). All doses of LCI699 significantly reduced 24-hour ambulatory blood pressure compared with placebo (P<0.01). Adrenocorticotropic hormone stimulation of cortisol was suppressed in ≈20% of subjects receiving LCI699 at a total daily dose of 1.0 mg. Safety and tolerability were similar among LCI699, placebo, and eplerenone. CONCLUSIONS: Aldosterone synthase inhibition with LCI699 significantly lowered clinic and ambulatory blood pressure. A minority of subjects developed blunted adrenocorticotropic hormone-stimulated release of cortisol. These results support additional research to evaluate use of aldosterone synthase inhibition in primary hypertension and/or patients characterized by aldosterone excess. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00758524.

Association of filtered sodium load with medullary volumes and medullary hypoxia in hypertensive African Americans as compared with whites.

BACKGROUND: African Americans develop hypertension earlier with more target manifestations than whites despite having a higher glomerular filtration rate (GFR) for any level of serum creatinine. STUDY DESIGN & PARTICIPANTS: This study tested the hypothesis that increased GFR and sodium reabsorption in African Americans is associated with increased metabolic work and medullary hypoxia in 49 nondiabetic patients with essential hypertension (29 whites and 20 African Americans) following a constant-sodium diet (150 mEq/d) and renin-angiotensin system blockade. PREDICTORS: Ethnicity, age, measured GFR, sodium excretion, and body mass index. OUTCOMES: We examined cortical and medullary volumes and blood flows using multidetector computed tomography and intrarenal deoxyhemoglobin (R2*) using blood oxygen level-dependent magnetic resonance. RESULTS: Blood pressure and sodium excretion were similar, whereas African Americans were more obese and had higher iothalamate GFRs. Renal cortical volumes did not differ, but medullary volumes adjusted for body size and age were higher in African Americans (32.3 ± 11.2 vs 25.1 ± 7.4 cm(3)/m(2) body surface area; P < 0.001). Sodium reabsorption and blood flows were higher in African Americans. Basal cortical deoxyhemoglobin values were similar between ethnic groups, whereas medullary R2* was higher in African Americans (39.7 ± 5.1 vs 36.3 ± 6.5/s; P = 0.02), but decreased to levels similar to whites after furosemide treatment. Levels of the circulating isoprostane prostaglandin F(2α) were higher in African Americans and daily urinary prostaglandin F(2α) excretion in African Americans correlated directly with renal blood flow (R = 0.71; P < 0.01). LIMITATIONS: Studies were limited to treated volunteers with normal kidney function without knowledge of prior nutrient intake. CONCLUSIONS: These data show for the first time that increased sodium reabsorption in obese African American patients with hypertension was associated with enlarged medullary volumes, functional hypoxia related to solute reabsorption, and a direct relationship between blood flows and urinary isoprostane levels. Our results support a model of increased oxygen consumption and oxidative stress in African Americans that may accelerate hypertension and target-organ injury compared with white patients with essential hypertension.

Racial Differences in XO (Xanthine Oxidase) and Mitochondrial DNA Damage-Associated Molecular Patterns in Resistant Hypertension.

BACKGROUND: We previously reported increased plasma XO (xanthine oxidase) activity in patients with resistant hypertension. Increased XO can cause mitochondrial DNA damage and promote release of fragments called mitochondrial DNA damage-associated molecular patterns (mtDNA DAMPs). Here, we report racial differences in XO activity and mtDNA DAMPs in Black and White adults with resistant hypertension. METHODS: This retrospective study includes 91 resistant hypertension patients (44% Black, 47% female) with blood pressure >140/90 mm Hg on ≥4 medications and 37 normotensive controls (30% Black, 54% female) with plasma XO activity, mtDNA DAMPs, and magnetic resonance imaging of left ventricular morphology and function. RESULTS: Black-resistant hypertension patients were younger (mean age 52±10 versus 59±10 years; P=0.001), with higher XO activity and left ventricular wall thickness, and worse diastolic dysfunction than White resistant hypertension patients. Urinary sodium excretion (mg/24 hour per kg) was positively related to left ventricular end-diastolic volume (r=0.527, P=0.001) and left ventricular mass (r=0.394, P=0.02) among Black but not White resistant hypertension patients. Patients with resistant hypertension had increased mtDNA DAMPs versus controls (P<0.001), with Black mtDNA DAMPS greater than Whites (P<0.001). Transmission electron microscopy of skeletal muscle biopsies in resistant hypertension patients demonstrates mitochondria cristae lysis, myofibrillar loss, large lipid droplets, and glycogen accumulation. CONCLUSIONS: These data warrant a large study to examine the role of XO and mitochondrial mtDNA DAMPs in cardiac remodeling and heart failure in Black adults with resistant hypertension.