Resistant Hypertension: Mechanisms and Treatment. Curr Hypertens Rep. 2017;19:56. [PMID: 28597403 DOI: 10.1007/s11906-017-0754-x]

Screening of serum markers in patients with resistant hypertension

Background

This study delves into the intricacies of resistant hypertension (RH), a prevalent yet enigmatic chronic cardiovascular ailment that is linked to a myriad of complications. Although its full pathogenesis is still shrouded in mystery, the field of proteomics offers a beacon of hope, with its potential to shed light on the proteins that orchestrate the tapestry of life. Harnessing the power of proteomics is essential for demystifying the pathogenesis of RH, enabling more precise diagnostics and treatments, and ultimately improving prognostic outcomes.

Methods

Our approach was to employ rigorous statistical analyses to home in on proteins with significant expression variances between our two cohorts. We complemented this with bioinformatics tools to unravel the intricate functions and pathways of these proteins. By synthesizing these insights with the clinical profiles of our patients, we were able to distill a set of definitive biomarkers with diagnostic potential. In our quest for clarity, we also embarked on a retrospective journey, amassing and scrutinizing clinical data from both RH and hypertension (HTN) patients. We crafted and rigorously assessed risk factor models to evaluate their diagnostic prowess.

Results

Our exploration spanned across 30 blood samples from RH patients and 20 from those grappling with HTN. Our inquiry yielded some compelling revelations: (1) RH patients showcased 29 unique proteins, in contrast to the 59 unique proteins found in HTN patients. A deeper dive into the proteomic data unveiled molecular functions predominantly tied to lipid metabolism, protein networking, and oxidative stress, with a spotlight on pathways such as cholesterol metabolism, coagulation, and the complement cascade. (2) By charting receiver operating characteristic curves and rigorously analyzing the proteomic data, we surfaced 11 proteins with notable diagnostic potential, tightly interwoven with clinical metrics.

Conclusion

Our research has pinpointed 11 proteins that stand as promising serum biomarkers, endowed with significant diagnostic value. This discovery marks a stride towards a more nuanced understanding and management of resistant hypertension.

Recent developments in the management of resistant hypertension: focus on endothelin receptor antagonists

Resistant hypertension is characterized by the inability of guideline-recommended triple combination therapy to control blood pressure (BP) to target. It is associated with a significantly increased risk of adverse outcomes. Despite abundant preclinical evidence supporting the critical role of the endothelin pathway in resistant hypertension (RH), clinical implementation of endothelin antagonists for the treatment of hypertension was hindered by various factors. Recently, the novel dual endothelin-receptor antagonist aprocitentan was tested in individuals with resistant hypertension in the PRECISION trial and provided compelling evidence supporting both short and longer-term safety and clinically meaningful and sustained BP lowering efficacy. These findings resulted in the recent regulatory approval of aprocitentan by the FDA. Aprocitentan may be a particularly useful antihypertensive option for individuals with advanced age, chronic kidney disease, and albuminuria.

Impact of Intermittent Hypoxia Related to Obstructive Sleep Apnoea Syndrome on Low-Grade Inflammation in Hypertensive Patients: Potential Implications for Cardiovascular Risk

There is evidence for a particular relationship between low-grade inflammation (LGI) and intermittent hypoxia (IH) related to obstructive sleep apnoea syndrome (OSAS). However, despite the potential deleterious cardiovascular consequences associated with this LGI in hypertensive patients, few studies have investigated the impact of IH related to OSAS on CRP levels in this subpopulation. In total, 1404 hypertensive patients were selected retrospectively from the Sleep Laboratory database. CRP levels ≥3 mg/L but <10 mg/L were used as cut-offs to identify hypertensive patients with LGI. Logistic regressions were conducted to examine the risk of LGI associated with IH related to OSAS in hypertensive patients. LGI was frequent (33.8%) in hypertensive patients. After adjustment for confounders, multivariate logistic regressions revealed that only moderate to severe OSAS (apnoea-hypopnoea index ≥ 15/h) with high IH (oxygen desaturation index ≥ 15/h) [OR 1.51 (95% CI 1.06-2.14)] was significantly associated with LGI in hypertensive patients (p-value = 0.045). Consistent with our hypothesis, our results demonstrated the existence of a particular subtype of hypertensive patients at high cardiovascular risk characterised by the presence of LGI induced by IH hypoxia related to moderate to severe OSAS, which justifies the establishment of adequate management of this pathology to allow better cardiovascular prevention in this subpopulation.

Prevalence, Predictors, and Outcomes of Resistant Hypertension in Egyptian Population

Background

Hypertension is a leading problem; it affects around thirty million adult Egyptians, according to the last national registry. The exact prevalence of resistant hypertension (RH) in Egypt wasn't spotted before. The purpose of this study was to determine the prevalence, predictors, and impact on adverse cardiovascular outcomes among adult Egyptians with RH.

Methods

The present study examined a cohort of 990 hypertensive patients who were divided into two groups based on their blood pressure control; group I (n = 842) patients who achieved blood pressure control and group II (n = 148) patients who met the RH definition criteria. All patients underwent a close follow-up for one year to evaluate the major cardiovascular events.

Results

The prevalence of RH was 14.9%. The main predictors impacting the cardiovascular outcomes of RH were advanced age (≥65 years), the presence of chronic kidney diseases, a BMI ≥ 30 kg/m², and NSAID use. After one year of follow-up, the RH group displayed noticeably higher rates of major cardiovascular events, including new-onset atrial fibrillation (6.8% vs. 2.5%, P = 0.006), cerebral stroke (4.1% vs. 1.2%, P = 0.011), myocardial infarction (4.7% vs. 1.3%, P = 0.004), and acute heart failure (4.7% vs. 1.8%, P = 0.025).

Conclusion

The prevalence of RH in Egypt is moderately high. Patients with RH have a far higher risk of cardiovascular events than those whose blood pressure is within control.

Associated factors and hemodynamic characteristics of resistant hypertension in the elderly

The purpose of this study was to explore the associated factors and hemodynamic characteristics of resistant hypertension (RHTN) in the elderly. A total of 283 patients aged ≥60 years with hypertension were evaluated by the CNAP™ monitor. Among them, 240 patients were non-RHTN (controlled hypertension with use of three or fewer antihypertensive medications) and 43 patients were RHTN (uncontrolled hypertension despite the concurrent use of ≥3 antihypertensive drugs at optimized doses, including a diuretic, or achieving target blood pressure with the use of ≥4 antihypertensive medications). RHTN was associated with higher body mass index (BMI), longer hypertension duration, and coronary heart disease (p = .004, p < .001, and p = .042, respectively). The mean number of antihypertensive medications was greater in patients with RHTN (p < .001). Hemodynamic analysis revealed higher cardiac output in the RHTN group than in the non-RHTN group, while no difference was observed in systemic vascular resistance. Screening for secondary etiology showed that, among the 43 patients with RHTN, 8 (18.6%) had chronic kidney disease, 8 (18.6%) had obstructive sleep apnea, 4 (9.3%) had primary aldosteronism, 2 (4.7%) had renovascular disease. No significant differences were observed in the cardiac output and systemic vascular resistance values between different causes of RHTN. These findings suggest that higher body mass index, longer hypertension duration, and coronary heart disease emerged as the associated factors of RHTN in the elderly. RHTN is characterized by higher cardiac output. Screening for the possible secondary etiology of RHTN in the elderly patients is necessary and important.

Emerging mechanisms involving brain Kv7 channel in the pathogenesis of hypertension

Hypertension is a prevalent health problem inducing many organ damages. The pathogenesis of hypertension involves a complex integration of different organ systems including the brain. The elevated sympathetic nerve activity is closely related to the etiology of hypertension. Ion channels are critical regulators of neuronal excitability. Several mechanisms have been proposed to contribute to hypothalamic-driven elevated sympathetic activity, including altered ion channel function. Recent findings indicate one of the voltage-gated potassium channels, Kv7 channels (M channels), plays a vital role in regulating cardiovascular-related neurons activity, and the expression of Kv7 channels is downregulated in hypertension. This review highlights recent findings that the Kv7 channels in the brain, blood vessels, and kidneys are emerging targets involved in the pathogenesis of hypertension, suggesting new therapeutic targets for treating drug-resistant, neurogenic hypertension.

Comparative Safety and Effectiveness of Aldosterone Antagonists Versus Beta-Blockers as Fourth Agents in Patients With Apparent Resistant Hypertension

BACKGROUND

Limited evidence exists regarding long-term effectiveness and safety of aldosterone antagonists (AAs) versus beta blockers (BBs) as fourth-line antihypertensive agents in patients with resistant hypertension (RH). We evaluated the comparative effectiveness and safety of aldosterone AA versus BB.

METHODS

We conducted a real-world retrospective cohort study using IBM MarketScan commercial claims and Medicare Supplemental claims (2007-2019). Patients with RH entered the cohort (ie, index date) when they newly initiated either AA or BB. The effectiveness outcome was major adverse cardiovascular events. Safety outcomes were hyperkalemia, gynecomastia, and kidney function deterioration. Potential confounding was addressed by adjustment for baseline characteristics via stabilized inverse probability of treatment weighting (SIPTW) based on propensity scores. Cox proportional hazards regression with SIPTWs were used to estimate adjusted hazard ratio (aHR) and 95% CI comparing risk for outcomes between AA and BB groups.

RESULTS

We identified 80 598 patients with RH (mean age: 61 years, 51% males), of which 6626 initiated AA and 73 972 initiated BB as the fourth antihypertensive agent. Among patients with RH, initiation of AA as a fourth-line antihypertensive agent did not significantly reduce major adverse cardiovascular event risk relative to BB initiation (aHR, 0.77 [95% CI, 0.50-1.19]) but did substantially increase the risk of hyperkalemia (aHR, 3.86 [95% CI, 2.78-5.34]), gynecomastia (aHR, 9.51 [95% CI, 5.69-15.89]), and kidney function deterioration (aHR, 1.63 [95% CI, 1.34-1.99]).

CONCLUSIONS

Long-term clinical trials powered to assess major adverse cardiovascular events are necessary to understand the risk-benefit trade-off of AA as fourth-line therapy for RH.

Application of omics in hypertension and resistant hypertension

Hypertension is a major modifiable risk factor that affects the global health burden. Despite the availability of multiple antihypertensive drugs, blood pressure is often not optimally controlled. The prevalence of true resistant hypertension in treated hypertensive patients is ~2-20%, and these patients are at higher risk for adverse events and poor clinical outcomes. Therefore, an in-depth dissection of the pathophysiological mechanisms of hypertension and resistant hypertension is needed to identify more effective targets for regulating blood pressure. Omics technologies, such as genomics, transcriptomics, proteomics, metabolomics, and microbiomics, can accurately present the characteristics of organisms at varying molecular levels. Integrative omics can further reveal the network of interactions between molecular levels and provide a complete dynamic view of the organism. In this review, we describe the applications, progress, and challenges of omics technologies in hypertension. Specifically, we discuss the application of omics in resistant hypertension. We believe that omics approaches will produce a better understanding of the pathogenesis of hypertension and resistant hypertension and improve diagnostic and therapeutic strategies, thus increasing rates of blood pressure control and reducing the public health burden of hypertension.

Renal NOXA1/NOX1 Signaling Regulates Epithelial Sodium Channel and Sodium Retention in Angiotensin II-induced Hypertension

Aims: NADPH oxidase (NOX)-derived reactive oxygen species (ROS) are implicated in the pathophysiology of hypertension in chronic kidney disease patients. Genetic deletion of NOX activator 1 (Noxa1) subunit of NOX1 decreases ROS under pathophysiological conditions. Here, we investigated the role of NOXA1-dependent NOX1 activity in the pathogenesis of angiotensin II (Ang II)-induced hypertension (AIH) and possible involvement of abnormal renal function. Results: NOXA1 is present in epithelial cells of Henle's thick ascending limb and distal nephron. Telemetry showed lower basal systolic blood pressure (BP) in Noxa1^-/-versus wild-type mice. Ang II infusion for 1 and 14 days increased NOXA1/NOX1 expression and ROS in kidney of male but not female wild-type mice. Mean BP increased 30 mmHg in wild-type males, with smaller increases in Noxa1-deficient males and wild-type or Noxa1^-/- females. In response to an acute salt load, Na⁺ excretion was similar in wild-type and Noxa1^-/- mice before and 14 days after Ang II infusion. However, Na⁺ excretion was delayed after 1-2 days of Ang II in male wild-type versus Noxa1^-/- mice. Ang II increased epithelial Na⁺ channel (ENaC) levels and activation in the collecting duct principal epithelial cells of wild-type but not Noxa1^-/- mice. Aldosterone induced ROS levels and Noxa1 and Scnn1a expression and ENaC activity in a mouse renal epithelial cell line, responses abolished by Noxa1 small-interfering RNA. Innovation and Conclusion: Ang II activation of renal NOXA1/NOX1-dependent ROS enhances tubular ENaC expression and Na⁺ reabsorption, leading to increased BP. Attenuation of AIH in females is attributed to weaker NOXA1/NOX1-dependent ROS signaling and efficient natriuresis. Antioxid. Redox Signal. 36, 550-566.

Treatment-resistant hypertension

Treatment-resistant hypertension is one of the most significant causes of poor blood pressure regulation. Patients with resistant hypertension are at a higher risk of developing comorbidities compared to the general hypertensive population. As a result, these patients have an increased incidence of disability and premature death, as well as increased treatment costs. Due to the above-mentioned, in the last decade, there has been an increase in researchers' interest in elucidating the pathogenesis, diagnosis, and treatment of resistant hypertension. However, recent data indicate that 20% of female and 24% of male patients with arterial hypertension still have uncontrolled blood pressure, despite maximum doses of three antihypertensive drugs (including a diuretic) and appropriate lifestyle measures. New treatment modalities (i.e. devicebased interventions - catheter-based renal denervation and baroreceptor stimulation) offer hope for achieving adequate blood pressure regulation in these patients. In this paper, we have summarized previous knowledge about the mechanisms underlying the pathogenesis of resistant hypertension, as well as optimal diagnostic methods to differentiate true from pseudo-resistant hypertension. We have also given an overview of the current therapeutic approach, including optimal medical therapy and new treatment modalities (i.e. device-based interventions) and their role in the treatment of resistant hypertension.

Resistance to antihypertensive treatment and long-term risk: The Atherosclerosis Risk in Communities study

More stringent blood pressure (BP) goals have led to greater prevalence of apparent resistant hypertension (ARH), yet the long‐term prognostic impact of ARH diagnosed according to these goals in the general population remains unknown. We assessed the prognostic impact of ARH according to contemporary BP goals in 9612 participants of the Atherosclerosis Risk in Communities (ARIC) study without previous cardiovascular disease. ARH, defined as BP above goal (traditional goal <140/90 mmHg, more stringent goal <130/80 mmHg) despite the use of ≥3 antihypertensive drug classes or any BP with ≥4 antihypertensive drug classes (one of which was required to be a diuretic) was compared with controlled hypertension (BP at goal with 1‐3 antihypertensive drug classes). Cox regression models were adjusted for age, sex, race, study center, BMI, heart rate, smoking, eGFR, LDL, HDL, triglycerides, and diabetes. Using the traditional BP goal, 133 participants (3.8% of the treated) had ARH. If the more stringent BP goal was instead applied, 785 participants (22.6% of the treated) were reclassified from controlled hypertension to uncontrolled hypertension (n = 725) or to ARH (n = 60). Over a median follow‐up time of 19 years, ARH was associated with increased risk for a composite end point (all‐cause mortality, hospitalization for myocardial infarction, stroke, or heart failure) regardless of whether traditional (adjusted HR 1.50, 95% CI: 1.23‐1.82) or more stringent (adjusted HR 1.43, 95% CI: 1.20‐1.70) blood pressure goals were applied. We conclude that in patients free from cardiovascular disease, ARH predicted long‐term risk regardless of whether traditional or more stringent BP criteria were applied.

Aprocitentan (a Dual Endothelin-Receptor Antagonist) for Treatment-Resistant Hypertension

ABSTRACT

Treatment-resistant hypertension (TRH) is associated with increased cardiovascular risks and progression of chronic kidney disease. The pathophysiology of TRH is multifactorial, including overactivity of the renin-angiotensin-aldosterone system and sympathetic nervous system, endothelial dysfunction, and volume overload. Endothelin-1 is a vasoconstrictive peptide that causes neurohormonal and sympathetic activation, increased aldosterone synthesis and secretion, endothelial dysfunction, vascular hypertrophy and remodeling, and fibrosis. Endothelin-1 acts through 2 receptors, ETA and ETB. Activation of ETA receptors in vascular smooth muscle cells results in vasoconstriction, whereas ETB receptor activation results in vasoconstriction in the vascular smooth muscle cells and vasodilation through nitric oxide release in endothelial cells. Aprocitentan is novel, oral, dual endothelin-receptor antagonist that has demonstrated a more favorable tolerability and safety profile in early clinical trials compared with other endothelin-receptor antagonists studied. Phase 2 trial data support a significant reduction in blood pressure compared to placebo and similar blood pressure reduction compared to a moderately dosed angiotensin-converting enzyme inhibitor in patients with essential hypertension. An ongoing phase 3 randomized clinical trial is evaluating aprocitentan's efficacy and safety in patients with TRH receiving multiple antihypertensives. Additional research is needed to determine aprocitentan's role in therapy, but this agent may be a suitable treatment option for TRH.

Managing the elderly patient with hypertension: current strategies, challenges, and considerations

Introduction: Hypertension is the leading modifiable risk factor for cardiovascular events and mortality in the world.Areas covered: An extensive literature review of articles and clinical trials on PUBMED on the topic of hypertension in the elderly from 1976 through January 2020 was conducted. This review article discusses clinical trials on treatment of hypertension in the elderly, the 2017 American College of Cardiology (ACC)/American Heart Association (AHA) hypertension guidelines, the 2018 European Society of Cardiology/European Society of Hypertension guidelines, and the treatment of hypertension and of resistant hypertension in the elderly.Expert opinion: The 2017 ACC/AHA hypertension guidelines recommend treatment of noninstitutionalized ambulatory community-dwelling adults aged 65 years and older with an average systolic blood pressure of 130 mm Hg or higher with lifestyle measures plus antihypertensive drug to lower the blood pressure to less than 130/80 mm Hg. For elderly adults with hypertension and a high burden of comorbidities and limited life expectancy, clinical judgment, patient preference, and a team-based approach to assess risk/benefit is reasonable for decisions about the intensity of SBP lowering and the choice of antihypertensive drugs to use for treatment.

Resistant/Refractory Hypertension and Sleep Apnoea: Current Knowledge and Future Challenges

Hypertension is one of the most frequent cardiovascular risk factors. The population of hypertensive patients includes some phenotypes whose blood pressure levels are particularly difficult to control, thus putting them at greater cardiovascular risk. This is especially true of so-called resistant hypertension (RH) and refractory hypertension (RfH). Recent findings suggest that the former may be due to an alteration in the renin-angiotensin-aldosterone axis, while the latter seems to be more closely related to sympathetic hyper-activation. Both these pathophysiological mechanisms are also activated in patients with obstructive sleep apnoea (OSA). It is not surprising, therefore, that the prevalence of OSA in RH and RfH patients is very high (as reflected in several studies) and that treatment with continuous positive airway pressure (CPAP) manages to reduce blood pressure levels in a clinically significant way in both these groups of hypertensive patients. It is therefore necessary to incorporate into the multidimensional treatment of patients with RH and RfH (changes in lifestyle, control of obesity and drug treatment) a study of the possible existence of OSA, as this is a potentially treatable disease. There are many questions that remain to be answered, especially regarding the ideal combination of treatment in patients with RH/RfH and OSA (drugs, renal denervation, CPAP treatment) and patients' varying response to CPAP treatment.

The Potential Role of Obstructive Sleep Apnoea in Refractory Hypertension

PURPOSE OF REVIEW

This review seeks to present an overview of the recently found association between refractory hypertension (RfH) and obstructive sleep apnoea (OSA).

RECENT FINDINGS

RfH was recently defined as an extreme phenotype of resistant hypertension characterized by the lack of blood pressure control despite using ≥ 5 antihypertensive drugs at optimal doses. Current data support that the pathophysiological pathway of both types of hypertension is different. The main mechanism involved in resistant hypertension is fluid retention whereas in the case of RfH is the sympathetic over-activity. OSA is now recognized as a cause of hypertension (especially in the case of difficult-to-treat hypertension). It seems that the biological mechanism linking OSA and arterial hypertension is the sympathetic over-activity related to the respiratory events (apnoeas and hypopnoeas) during the night. So, it is not surprising that, although the literature is scarce, some studies have found a very high prevalence of OSA and an excess of sympathetic activity in patients with RfH. Finally, a very recent study demonstrated that continuous positive airway pressure (CPAP) treatment, which controls sympathetic activation in OSA patients, achieves very significant reductions in blood pressure levels in RfH patients, even greater than in those with resistant (non-refractory) hypertension. The prevalence of OSA in patients with RfH is very high. CPAP treatment achieves a clinically significant reduction in blood pressure levels in those patients with RfH (especially in night readings). Patients with RfH must be sent to a sleep unit for a study.

Achieving control of resistant hypertension: Not just the number of blood pressure medications

Resistant hypertension (RH) has a prevalence of around 12% and is associated with an increased risk of cardiovascular disease, progression to end-stage renal disease, and even mortality. In 2017, the American College of Cardiology and American Heart Association released updated guidelines that detail steps to ensure proper diagnosis of RH, including the exclusion of pseudoresistance. Lifestyle modifications, such as low salt diet and physical exercise, remain at the forefront of optimizing blood pressure control. Secondary causes of RH also need to be investigated, including screening for obstructive sleep apnea. Notably, the guidelines demonstrate a major change in medication management recommendations to include mineralocorticoid receptor antagonists. In addition to advances in medication optimization, there are several device-based therapies that have been showing efficacy in the treatment of RH. Renal denervation therapy has struggled to show efficacy for blood pressure control, but with a re-designed catheter device, it is once again being tested in clinical trials. Carotid baroreceptor activation therapy (BAT) via an implantable pulse generator has been shown to be effective in lowering blood pressure both acutely and in long-term follow up data, but there is some concern about the safety profile. Both a second-generation pulse generator and an endovascular implant are being tested in new clinical trials with hopes for improved safety profiles while maintaining therapeutic efficacy. Both renal denervation and carotid BAT need continued study before widespread clinical implementation. Central arteriovenous anastomosis has emerged as another possible therapy and is being actively explored. The ongoing pursuit of blood pressure control is a vital part of minimizing adverse patient outcomes. The future landscape appears hopeful for helping patients achieve blood pressure goals not only through the optimization of antihypertensive medications but also through device-based therapies in select individuals.

Apparent Treatment-Resistant Hypertension and Cardiovascular Risk in Hemodialysis Patients: Ten-Year Outcomes of the Q-Cohort Study

There has been limited data discussing the relationship between apparent treatment-resistant hypertension (ATRH) and cardiovascular disease risk in patients receiving maintenance hemodialysis. We analyzed data for 2999 hypertensive patients on maintenance hemodialysis. ATRH was defined as uncontrolled blood pressure despite the use of three or more classes of antihypertensive medications, or four or more classes of antihypertensive medications regardless of blood pressure level. We examined the relationships between ATRH and cardiovascular events using a Cox proportional hazards model. The proportion of participants with ATRH was 18.0% (539/2999). During follow-up (median: 106.6 months, interquartile range: 51.3-121.8 months), 931 patients experienced cardiovascular events including coronary heart disease (n = 424), hemorrhagic stroke (n = 158), ischemic stroke (n = 344), and peripheral arterial disease (n = 242). Compared with the non-ATRH group, the ATRH group showed a significant increased risk of developing cardiovascular disease (hazard ratio [HR]: 1.27; 95% confidence interval [CI]: 1.08-1.49), coronary heart disease (HR: 1.28; 95% CI: 1.01-1.62), ischemic stroke (HR: 1.31; 95% CI: 1.01-1.69), and peripheral arterial disease (HR: 1.42; 95% CI: 1.06-1.91) even after adjusting for potential confounders. This study demonstrated that ATRH was significantly associated with increased cardiovascular risk in hemodialysis patients.

Resistant and refractory hypertension: two sides of the same disease?

Refractory hypertension (RfH) is an extreme phenotype of resistant hypertension (RH), being considered an uncontrolled blood pressure besides the use of 5 or more antihypertensive medications, including a long-acting thiazide diuretic and a mineralocorticoid antagonist. RH is common, with 10-20% of the general hypertensives, and its associated with renin angiotensin aldosterone system hyperactivity and excess fluid retention. RfH comprises 5-8% of the RH and seems to be influenced by increased sympathetic activity. RH patients are older and more obese than general hypertensives. It is strongly associated with diabetes, obstructive sleep apnea, and hyperaldosteronism status. RfH is more frequent in women, younger patients and Afro-americans compared to RFs. Both are associated with increased albuminuria, left ventricular hypertrophy, chronic kidney diseases, stroke, and cardiovascular diseases. The magnitude of the white-coat effect seems to be higher among RH patients. Intensification of diuretic therapy is indicated in RH, while in RfH, therapy failure imposes new treatment alternatives such as the use of sympatholytic therapies. In conclusion, both RH and RfH constitute challenges in clinical practice and should be addressed as distinct clinical entities by trained professionals who are capable to identify comorbidities and provide specific, diversified, and individualized treatment.

Controlled Versus Uncontrolled Resistant Hypertension: Are They in the Same Bag?

PURPOSE OF REVIEW

Resistant hypertension (RHTN) is a condition in which besides the antihypertensive therapy using at least three different drugs (including a diuretics), brachial blood pressure does not reach the target (e.g., 140/90 mmHg).

RECENT FINDINGS

Despite the diversity of clinical presentations, we divide RHTN in two major groups according to blood pressure and number of drugs taken: controlled (C-RHTN) and uncontrolled (UC-RHTN) resistant hypertension, with refractory hypertension (RfHTN) included in the latter subgroup. Both C-RHTN and UC-RHTN are heterogenic and complex syndromes. To better approach this matter, the some pathophysiological mechanisms (increased volemia, hyperactivity, plasma cortisol, adipocitokines, and other pro-inflammatory factors), have a pivotal clinical role. Some features (African ethnic, obesity, age > 60, LV hypertrophy, and vascular stiffness) increase the risk of refractoriness as well as worst prognosis. Based on increased target organ damage, cardiovascular risk and events will be addressed in this review. Our conclusion is that although both C-RHTN and UC-RHTN are extreme phenotypes of hard-to-control BP, some mechanisms of the disease and clinical expressions are distinct. According to these differences, "UC-RHTN and C-RHTN are not in the same bag."

Hypothalamic Ion Channels in Hypertension

Hypertension is a prevalent and major health problem, involving a complex integration of different organ systems, including the central nervous system (CNS). The CNS and the hypothalamus in particular are intricately involved in the pathogenesis of hypertension. In fact, evidence supports altered hypothalamic neuronal activity as a major factor contributing to increased sympathetic drive and increased blood pressure. Several mechanisms have been proposed to contribute to hypothalamic-driven sympathetic activity, including altered ion channel function. Ion channels are critical regulators of neuronal excitability and synaptic function in the brain and, thus, important for blood pressure homeostasis regulation. These include sodium channels, voltage-gated calcium channels, and potassium channels being some of them already identified in hypothalamic neurons. This brief review summarizes the hypothalamic ion channels that may be involved in hypertension, highlighting recent findings that suggest that hypothalamic ion channel modulation can affect the central control of blood pressure and, therefore, suggesting future development of interventional strategies designed to treat hypertension.