Prevalence of resistant hypertension in the United States, 2003-2008

Oh, the places you'll go! My many colored serotonin (apologies to Dr. Seuss)

Serotonin [5-hydroxytryptamine (5-HT)] has a truly fascinating history in the cardiovascular world. Discovered in the blood, 5-HT has long been appropriately regarded as a vasoconstrictor. A multitude of in vitro studies of isolated vessels support that addition of 5-HT causes vascular contraction. In only a few cases was 5-HT a vasodilator. Moreover, the potency and threshold of 5-HT causing contraction is increased in arteries from hypertensive vs. normotensive subjects, both animal and human. As such, we and others have hypothesized that 5-HT would contribute to hypertension by elevating arterial tone. In stark contrast to these decades of findings, we observed that a chronic infusion of 5-HT into conscious rats caused a reduction in blood pressure and nearly normalized blood pressure of experimentally hypertensive rats. Going back to the early work of Irvine Page, one of the scientists who discovered 5-HT, reveals an early recognized but never understood ability of 5-HT to reduce systemic blood pressure. Our laboratory, in collaboration with colleagues around the world, has dedicated itself to understanding the mechanisms of 5-HT-induced reduction in blood pressure. This manuscript takes you through a brief history of the discovery of 5-HT, in vitro serotonergic pharmacology of blood vessels, in vivo work with 5-HT and our studies that suggests the venous vasculature, potentially in combination with small arterioles, may be important to the actions of 5-HT in reducing blood pressure. 5-HT has certainly ended up in a place I never expected it to go.

Minoxidil for Treatment of Resistant Hypertension in Chronic Kidney Disease--A Retrospective Cohort Analysis

Resistant hypertension is still a challenge and reserve antihypertensive agents are often necessary to achieve blood pressure control. One reserve antihypertensive is minoxidil, a direct vasodilator that is known for its strong blood pressure-lowering effect, but contemporary studies are sparse. The authors retrospectively analyzed 54 inpatients with uncontrolled hypertension despite the combined use of current antihypertensive agents. To investigate the effect of minoxidil when added to other antihypertensive agents, blood pressure was evaluated at the time minoxidil treatment was initiated and at discharge. Minoxidil treatment was associated with a significant reduction in blood pressure from 162.4±15.1/83.2±12.7 mm Hg to 135.8±12.2/72.8±6.9 mm Hg (P<.0001). This effect was sustained across all analyzed subgroups. Although the well-known adverse events of minoxidil limit its widespread use, these data show that minoxidil as a reserve antihypertensive agent still has a niche indication in the particular subgroup of patients with treatment-resistant or uncontrolled hypertension.

Untreated, Uncontrolled, and Apparent Resistant Hypertension: Results of the German Health Examination Survey 2008-2011

The prevalence and associated factors of untreated, uncontrolled, and apparent-resistant hypertension (RH) in Germany are unknown. Based on European Society of Hypertension criteria, apparent RH was defined as blood pressure (BP) ≥140/90 mm Hg (≥140/85 mm Hg in diabetics) under treatment with three different classes of antihypertensive agents including a diuretic. Data from the German Health Examination Survey (2008-2011; n=7115, age 18-79 years) including standardized BP measurements and Anatomical Therapeutic Chemical-coded taken medications were analyzed. Among patients aware of their hypertensive status (n=2205), 37.9% were uncontrolled and, among those, 33.4% were untreated. Being aware and having untreated and uncontrolled BP was associated with male sex, young age, not having cardiovascular disease, not performing BP self-measurement, not being obese, and not smoking. Apparent RH occurred in 6.8% of treated aware hypertensive patients and was positively associated with having diabetes. The proportion of uncontrolled BP is still high. Not having "obvious risk factors" has become a risk itself for having untreated and uncontrolled hypertension.

Lactobacillus casei strain C1 attenuates vascular changes in spontaneously hypertensive rats

Hypertension can be caused by various factors while the predominant causes include increase in body fluid volume and resistance in the circulatory system that elevate the blood pressure. Consumption of probiotics has been proven to attenuate hypertension; however, the effect is much strain-dependent. In this study, a newly isolated Lactobacillus casei (Lb. casei) strain C1 was investigated for its antihypertensive properties in spontaneously hypertensive rats (SHR). Lactic acid bacteria (LAB) suspension of 11 log colony-forming unit (CFU) was given to SHR (SHR+LAB, n=8), and phosphate buffer saline (PBS) was given as a control in SHR (SHR, n=8) and in Wistar rats as sham (WIS, n=8). The treatment was given via oral gavage for 8 weeks. The results showed that the weekly systolic blood pressure (SBP), mean arterial pressure (MAP), diastolic blood pressure (DBP) and aortic reactivity function were remarkably improved after 8 weeks of bacterial administration in SHR+LAB. These effects were mostly attributed by restoration of wall tension and tensile stress following the bacterial treatment. Although not statistically significant, the level of malondialdehye (MDA) in SHR+LAB serum was found declining. Increased levels of glutathione (GSH) and nitric oxide (NO) in SHR+LAB serum suggested that the bacterium exerted vascular protection through antioxidative functions and relatively high NO level that induced vasodilation. Collectively, Lb. casei strain C1 is a promising alternative for hypertension improvement.

[Medical expert consensus in AH on the clinical use of triple fixed-dose antihypertensive therapy in Spain]

INTRODUCTION

The opinion of experts (different specialties) on the triple fixed-dose antihypertensive therapy in clinical practice may differ.

MATERIALS AND METHODS

Online questionnaire with controversial aspects of the triple therapy answered by panel of experts in hypertension (HT) using two-round modified Delphi method.

RESULTS

The questionnaire was completed by 158 experts: Internal Medicine (49), Nephrology (26), Cardiology (83). Consensus was reached (agreement) on 27/45 items (60%); 7 items showed differences statistically significant. Consensus was reached regarding: Predictive factors in the need for combination therapy and its efficacy vs. increasing the dose of a pretreatment, and advantage of triple therapy (prescription/adherence/cost/pressure control) vs. free combination.

CONCLUSIONS

This consensus provides an overview of the clinical use of triple therapy in moderate-severe and resistant/difficult to control HT.

Coronary flow reserve in patients with resistant hypertension

Resistant hypertension is associated with increased risk for cardiovascular events. Coronary flow reserve (CFR) is impaired in patients with hypertension and an independent predictor of cardiac mortality. However, there are no published data on CFR in the subset of treatment-resistant hypertension. The aim of this study was to assess CFR in patients with resistant hypertension. Twenty-five consecutive patients with primary resistant hypertension, scheduled for renal denervation, 25 matched patients with controlled hypertension, and 25 healthy controls underwent transthoracic colour Doppler echocardiography at rest and during adenosine infusion. Patients with hypertension were pair-matched with regard to age, sex, ischemic heart disease, diabetes mellitus, smoking status, and body-mass index. Healthy controls were selected according to age and sex. Mean flow velocity was measured in the left coronary anterior descending artery. Baseline mean flow velocities were similar in patients with controlled and resistant hypertension. CFR was significantly lower in patients with resistant hypertension as compared to individuals with non-resistant hypertension (2.7 ± 0.6 vs. 3.1 ± 0.8; p = 0.03). Systolic office blood pressure was significantly higher in patients with resistant hypertension (169 ± 20 vs. 144 ± 21 mm Hg; p < 0.01). Heart rate, ventricular mass, and ejection fraction were similar in the two groups. Healthy controls showed significantly lower baseline velocity, higher CFR, and lower blood pressure as compared to hypertensives. Resistant hypertension was associated with impaired CFR as compared to individuals with non-resistant hypertension indicating impaired cardiac microvascular function which may contribute to the increased risk of adverse outcome in patients with resistant hypertension.

Impact of Sleep-Disordered Breathing Treatment on Patient Reported Outcomes in a Clinic-Based Cohort of Hypertensive Patients

STUDY OBJECTIVES

We hypothesized that patient reported outcomes (PROs) improve with positive airway pressure (PAP) in patients with sleep-disordered breathing (SDB) and hypertension (HTN).

METHODS

Questionnaire-based PROs (sleepiness [Epworth Sleepiness Scale, (ESS)], depression [Patient Health Questionnaire-9 (PHQ-9)], and fatigue [Fatigue Severity Scale (FSS)]) were retrospectively examined in patients with SDB and HTN at baseline and within a year following PAP initiation. PRO changes were estimated using multivariable linear mixed-effect models adjusted for baseline age, sex, race, body mass index, resistant hypertension (RHTN) status, cardiac and diabetes history, and correlation between repeated measurements. Age and race by PAP interaction terms (mean change, 95% CI) were examined.

RESULTS

894 patients with HTN and SDB were examined. 130 (15%) had baseline RHTN (age 58 ± 12 y, 52.9 % male, BMI 36.2 ± 9.1 kg/m²). In multivariable models, a significant improvement in sleepiness ESS (-2.09, 95% CI: -2.37, -1.82), PHQ-9 (-1.91, 95% CI: -2.25, -1.56), and FSS scores (-4.06 95% CI: -4.89, -3.22) was observed. A significant race by PAP effect interaction was observed (p < 0.0001 for all PROs); Caucasians had greater improvements than non-Caucasians. The interaction term of effect of PAP and age was significant for ESS (p = 0.04) and PHQ-9 (p = 0.0003), indicating greater improvement in younger patients.

CONCLUSIONS

Consistent improvement of broad PRO domains in response to PAP in SDB was observed in this clinic-based hypertensive cohort; Caucasians and younger patients derived greater benefit.

Refractory and Resistant Hypertension: Antihypertensive Treatment Failure versus Treatment Resistance

Resistant hypertension has for many decades been defined as difficult-to-treat hypertension in order to identify patients who may benefit from special diagnostic and/or therapeutic considerations. Recently, the term "refractory hypertension" has been proposed as a novel phenotype of antihypertensive failure, that is, patients whose blood pressure cannot be controlled with maximal treatment. Early studies of this phenotype indicate that it is uncommon, affecting less than 5% of patients with resistant hypertension. Risk factors for refractory hypertension include obesity, diabetes, chronic kidney disease, and especially, being of African origin. Patients with refractory are at high cardiovascular risk based on increased rates of known heart disease, prior stroke, and prior episodes of congestive heart failure. Mechanisms of refractory hypertension need exploration, but early studies suggest a possible role of heightened sympathetic tone as evidenced by increased office and ambulatory heart rates and higher urinary excretion of norepinephrine compared to patients with controlled resistant hypertension. Important negative findings argue against refractory hypertension being fluid dependent as is typical of resistant hypertension, including aldosterone levels, dietary sodium intake, and brain natriuretic peptide levels being similar or even less than patients with resistant hypertension and the failure to control blood pressure with use of intensive diuretic therapy, including both a long-acting thiazide diuretic and a mineralocorticoid receptor antagonist. Further studies, especially longitudinal assessments, are needed to better characterize this extreme phenotype in terms of risk factors and outcomes and hopefully to identify effective treatment strategies.

Current Status of Renal Denervation in Hypertension

Over the past 7 years, prospective cohorts and small randomized controlled studies showed that renal denervation therapy (RDN) in patients with resistant hypertension is safe but associated with variable effects on BP which are not substantially better than medical therapy alone. The failure of the most rigorously designed randomized sham-control study, SYMPLICITY HTN-3, to meet the efficacy endpoints has raised several methodological concerns. However, recently reported studies and ongoing trials with improved procedural characteristics, identification of patients with true treatment-resistant hypertension on appropriate antihypertensive regimens further explore potential benefits of RDN. The scope of this review is to summarize evidence from currently completed studies on RDN and discuss future perspectives of RDN therapy in patients with resistant hypertension.

Renal Function Alters Antihypertensive Regimens in Type 2 Diabetic Patients

To determine the prevalence of multidrug antihypertensive therapy (MDAT), records were evaluated for patients with both type 2 diabetes and hypertension during a 5-year period at Joslin Diabetes Center. Hypertension control was defined as requiring multiple drugs if three or more antihypertensive drugs were used, one of which must be a diuretic (unless patient is receiving dialysis), or use of four or more antihypertensive drugs, one of which a diuretic (unless patient is receiving dialysis) was established. The objective was to determine the prevalence of multidrug requirement for hypertensive therapy in relationship to four levels of renal function estimated by the Modification of Diet in Renal Disease formula for glomerular filtration rate (GFR). Among 10,151 patients, mean estimated GFR was 80 mL/min. Using standard (ASN) classification for renal function, we noted the following breakdown of MDAT use: Estimated GFR Drugs, Mean No. ≥3 Drugs, No. (%) ≥4 Drugs, No. (%) <30 3.1 379 (67) 214 (38) 30-60 2.7 1233 (55) 538 (24) 60-90 2.0 1279 (33) 458 (12) >90 1.5 600 (17) 185 (5) Prevalence of multidrug antihypertensive therapy is markedly increased in the presence of reduced renal function.

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.

Carotid baroreceptor stimulation blood pressure response mapped in patients undergoing carotid endarterectomy (C-Map study)

OBJECTIVE

Continuous stimulation of the carotid baroreceptors has been shown to evoke a sustained systolic blood pressure (SBP) reduction in hypertensive subjects. This study conducted a detailed mapping of the SBP and heart rate response to electrical stimulus at different locations in the carotid sinus region in patients undergoing a carotid endarterectomy (CEA).

METHODS

The Carotid Sinus Autonomic Response Mapping (C-Map) Study is a multicenter, prospective, non-randomized, acute feasibility study conducted in 10 hypertensive subjects undergoing CEA. Electrode pairs were placed in multiple locations in the region of the carotid sinus for acute stimulation, and the tests were repeated after plaque removal and vessel repair.

RESULTS

The configuration that elicited the largest pressure reduction in 8 of 10 patients was with the electrodes arranged longitudinally along the medial (in relation to the bifurcation) wall of the internal carotid artery (ICA) near the bifurcation (11.2±8.1mmHg, p<0.05). There was no difference in average maximum response pre vs. post plaque removal. Spontaneous baroreflex sensitivity increased from 6.0±3.2ms/mmHg pre-CEA to 8.2±5.4ms/mmHg post-CEA (p=0.040).

CONCLUSIONS

Endarterectomy surgery did not affect maximal acute stimulation response but improved baroreflex sensitivity acutely. Acute extravascular baroreceptor stimulation (BRS) mapping demonstrated that blood pressure reductions are dependent on electrode location and orientation. In most subjects, the largest SBP reductions were elicited in the region of the medial wall of the ICA. This area can be targeted for future BRS lead design and implant.

Effect of a Clinical Pharmacist–Managed Service on Blood Pressure in an Underserved Population With Resistant Hypertension

Background. Evidence indicates pharmacist-managed hypertension clinics are beneficial in reducing blood pressure (BP). There is currently no evidence evaluating the effect of pharmacist-managed resistant hypertension clinics in a medically underserved patient population. Objective. To determine the impact of a pharmacist-managed resistant hypertension service on BP in a medically underserved population. Methods. This was a prospective cohort study evaluating 12 medically underserved patients enrolled in a pharmacist-managed resistant hypertension service at the St Louis County Department of Health. BP was measured in clinic and at home. Follow-up occurred biweekly by phone and in clinic at least monthly while uncontrolled. This study was approved by the St Louis College of Pharmacy Institutional Review Board and St Louis County Department of Health director for clinical and research services. Primary outcome of change in home systolic BP and secondary outcomes of change in home diastolic BP and clinic systolic and diastolic BP were evaluated. Results. Twelve patients were included in the analysis (2 patients did not receive home BP monitors). Home systolic BP was reduced from the first encounter, 140 (12) mm Hg, to last contact, 130 (15) mm Hg ( P = .01). Clinic systolic BP also decreased significantly from the first encounter, 152 (10) mm Hg, to last contact, 136 (17) mm Hg ( P = .004). Clinic BP goal and home BP goal was attained by 30% and 40% of participants, respectively. Conclusions. A pharmacist-managed resistant hypertension service is effective in significantly reducing BP in medically underserved patients.

Mast cell activation disease and the modern epidemic of chronic inflammatory disease

A large and growing portion of the human population, especially in developed countries, suffers 1 or more chronic, often quite burdensome ailments which either are overtly inflammatory in nature or are suspected to be of inflammatory origin, but for which investigations to date have failed to identify specific causes, let alone unifying mechanisms underlying the multiple such ailments that often afflict such patients. Relatively recently described as a non-neoplastic cousin of the rare hematologic disease mastocytosis, mast cell (MC) activation syndrome-suspected to be of greatly heterogeneous, complex acquired clonality in many cases-is a potential underlying/unifying explanation for a diverse assortment of inflammatory ailments. A brief review of MC biology and how aberrant primary MC activation might lead to such a vast range of illness is presented.

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.

Device-Based Therapy for Drug-Resistant Hypertension: An Update

Drug-resistant hypertension (RH) remains a significant and common cardiovascular risk despite the availability of multiple potent antihypertensive medications. Uncontrolled resistant hypertension contributes substantially to excessive cardiovascular and renal morbidity and mortality. Clinical and experimental evidence suggest that sympathetic nervous system over-activity is the main culprit for the development and maintenance of drug-resistant hypertension. Both medical and interventional strategies, targeting the sympathetic over-activation, have been designed in patients with hypertension over the past few decades. Minimally invasive, catheter-based, renal sympathetic denervation (RDN) and carotid baroreceptor activation therapy (BAT) have been extensively evaluated in patients with RH in clinical trials. Current trial outcomes, though at times impressive, have been mostly uncontrolled trials in need of validation. Device-based therapy for drug-resistant hypertension has the potential to provide alternative treatment options to certain groups of patients who are refractory or intolerant to current antihypertensive medications. However, more research is needed to prove its efficacy in both animal models and in humans. In this article, we will review the evidence from recent renal denervation, carotid baroreceptor stimulation therapy, and newly emerged central arteriovenous anastomosis trials to pinpoint the weak links, and speculate on potential alternative approaches.

Effect of Cardiac-Cycle-Synchronized Selective Vagal Stimulation on Heart Rate and Blood Pressure in Rats

INTRODUCTION

Activation of the baroreflex system through the selective vagal nerve stimulation (sVNS) may become a treatment option for therapy-resistant hypertension, which is a frequently observed problem in the antihypertensive therapy. In previous studies, we used continuous sVNS to lower blood pressure (BP) without major side effects in a rat model. As continuous stimulation is energy consuming and sVNS could be implemented in an antihypertensive stimulator, it was the aim of this study to investigate the efficacy of pulsatile, cardiac-cycle-synchronized sVNS (cssVNS) on the reduction of BP.

METHODS

A multichannel cuff electrode was wrapped around the left vagal nerve in six male Wistar rats under Isoflurane anesthesia. BP was recorded in the left carotid artery. An electrocardiogram (ECG) was obtained via subcutaneous needle electrodes. The aortic depressor nerve fibers in the vagal nerve bundle were selectively stimulated with 18 parameter settings within a window of 15-30 ms after the R-peak in the ECG. The stimulation paradigm included every heartbeat, every second heart beat, and every third heart beat. BP and heart rate were initially recorded over 10 min.

RESULTS

Using cssVNS, BP could be significantly reduced over 30 min and maintained at this level. While the highest BP reduction was seen during cssVNS at every heartbeat with minimal bradycardia, less-yet significant-BP reduction was seen during cssVNS at every second or third heartbeat without causing detectable bradycardia.

CONCLUSION

cssVNS can chronically reduce BP in rats avoiding measurable bradycardic side effects. This energy-efficient technique might allow the implementation of sVNS using an implantable device to permanently lower BP in patients.

FUNDING

The study was funded by Bundesministerium fur Bildung und Forschung/German Federal Ministry of Education and Research among the call "Individualisierte Medizintechnik" under the grant number FKZ 13GW0120B.

Interventional therapy for hypertension: Back on track again?

Treatment-resistant hypertension, or resistant hypertension, is defined as blood pressure that remains above target despite concurrent use of at least three antihypertensive agents from different classes at optimal doses, one of which should be a diuretic. Important considerations in the diagnosis of treatment-resistant hypertension include the exclusion of pseudoresistance and the evaluation of potential secondary causes of hypertension and of concomitant conditions that maintain high blood pressure. The ability to diagnose true treatment-resistant hypertension is important for selection of patients who may be appropriately treated with an invasive therapy. Currently, there are three interventional approaches to treat resistant hypertension, namely: (1) reduction of the activity of the sympathetic nervous system by renal nerve ablation, (2) stimulation of baroreceptors and (3) creation of a peripheral arterial venous anastomosis. This review focuses on the rationale behind these invasive approaches and the clinical results.

Renal Sympathetic Denervation: Hibernation or Resurrection?

The most current versions of renal sympathetic denervation have been invented as minimally invasive approaches for the management of drug-resistant hypertension. The anatomy, physiology and pathophysiology of renal sympathetic innervation provide a strong background supporting an important role of the renal nerves in the regulation of blood pressure (BP) and volume. In addition, historical data with surgical sympathectomy and experimental data with surgical renal denervation indicate a beneficial effect on BP levels. Early clinical studies with transcatheter radiofrequency ablation demonstrated impressive BP reduction, accompanied by beneficial effects in target organ damage and other disease conditions characterized by sympathetic overactivity. However, the failure of the SYMPLICITY 3 trial to meet its primary efficacy end point raised a lot of concerns and put the field of renal denervation into hibernation. This review aims to translate basic research into clinical practice by presenting the anatomical and physiological basis for renal sympathetic denervation, critically discussing the past and present knowledge in this field, where we stand now, and also speculating about the future of the intervention and potential directions for research.

[Prevalence of true resistant hypertension among uncontrolled hypertensive patients referred to a tertiary health care center]

OBJECTIVES

Estimate the prevalence of resistant hypertension (rHTN) in uncontrolled hypertensive treated patients referred to a tertiary care center specialized for hypertension management.

METHODS

The study was prospective observational. Between January 2013 and April 2015, we recruited hypertensive treated patients, 18years age or older, under antihypertensive drugs since at least 12months, and referred to the hypertension unit of Tizi-ouzou university hospital for uncontrolled hypertension. rHTn was defined as an office blood pressure≥140mmHg despite a triple therapy including renin angiotensin system blockers, calcium antagonists and diuretics at optimal doses, since at least 4weeks.

RESULTS

We screened 2367 patients with a mean age of 61.1±11.2years and 64.2% of men. Eight hundred forty-three (35.6%) patients had suboptimal treatment, 364 (15.4%) a poor adherence to treatment and 202 (8.5%) a white-coat effect. An excessive salt intake and a drug-related hypertension were identified in 281 (11.9%) and 36 (1.5%) patients, respectively. A secondary cause of hypertension was diagnosed in 468 (19.8%) subjects. Finally, only 173 patients showed a true rHTN requiring four drugs or more and its prevalence was 7.3% (CI 95%: 6.3-8.3).

CONCLUSION

Less than one patient from ten referred in our center for uncontrolled hypertension had a true rHTN, and more than fifty percent of patients had pseudo-resistance. Most of patients with seemingly rHTN can reach blood pressure target provided they undergo thorough work up and care by a specialized team.

Resistant Hypertension: An Incurable Disease or Just a Challenge For Our Medical Skill?

Resistant hypertension is classically defined as a clinical condition in which target blood pressure values of 140/90 mmHg are not achieved despite an optimal pharmacological therapy of at least three antihypertensive drugs, including a diuretic. The aim of this review is to give an outline of the nosography of this disorder, highlighting the differences between true and apparent resistant hypertension. Since the proportions of patients who can be defined as resistant to antihypertensive treatment is elevated, this distinction is mandatory in order to identify only those who need special clinical attention and, possibly, newer non-traditional techniques. While at first glance resistant hypertension may appear as an insuperable problem, an accurate clinical work-up of these patients, aimed at excluding reversible causes and optimizing pharmacological treatment, represents an effective solution in most cases.

Lack of control of hypertension in primary cardiovascular disease prevention in Europe: Results from the EURIKA study

BACKGROUND

The prevalence of and factors associated with uncontrolled hypertension and apparent resistant hypertension were assessed in the European Study on Cardiovascular Risk Prevention and Management in Usual Daily Practice (EURIKA; NCT00882336).

METHODS

EURIKA was a cross-sectional observational study including patients being treated for the primary prevention of cardiovascular disease in 12 European countries. Patients were assessed if they were being treated for hypertension (N=5220). Blood pressure control was defined according to European guidelines, with sensitivity analysis taking account of patients' age and diabetes status. Associated factors were assessed using multivariate analysis.

RESULTS

In the primary analysis, a total of 2691 patients (51.6%) had uncontrolled hypertension. Factors significantly associated with an increased risk of having uncontrolled hypertension included female sex (odds ratio [OR]: 2.29; 95% confidence interval [CI]: 1.93-2.73), body mass index (BMI; OR per kg/m(2): 1.03; 95% CI: 1.01-1.04), and geographic location. A total of 749 patients (14.3%) had apparent resistant hypertension. Factors significantly associated with an increased risk of having apparent resistant hypertension included BMI (OR per kg/m(2): 1.06; 95% CI: 1.04-1.08), diabetes (OR: 1.28; 95% CI: 1.06-1.53), use of statins (OR: 1.36; 95% CI: 1.15-1.62), serum uric acid levels (OR: 1.16; 95% CI: 1.09-1.23), and geographic location. Similar results were seen in sensitivity analyses.

CONCLUSIONS

Over 50% of patients treated for hypertension continued to have uncontrolled blood pressure and 14.3% had apparent resistant hypertension. Positive associations were seen with other cardiovascular risk factors.

Catheter-based Renal Artery Denervation for Resistant Hypertension: Promise Unfulfilled or Unsettled?

Resistant hypertension affects approximately 10-15 % of the hypertensive population and is associated with an increased occurrence of adverse cardiovascular outcomes. Recently, renal denervation (RDN) has emerged as a novel, non-pharmacologic therapy for resistant hypertension that is designed to ablate the sympathetic nerves distributed around the renal arteries, thus diminishing sympathetic nervous system activity and its influence on hypertension. RDN appeared to have a powerful BP-lowering effect in early clinical trials. However, a pivotal follow-up trial, SYMPLICITY HTN-3, showed no additional benefit of the therapy when compared with a sham procedure. Various aspects of the trial have been examined to explain this inconsistency, including a potent placebo effect and uncertainty about whether RDN actually occurred. Further research is needed to clarify the role of RDN in the management of resistant hypertension.

Resistant hypertension in patients with type 2 diabetes: clinical correlates and association with complications

OBJECTIVE

The phenotype of resistant hypertension in patients with type 2 diabetes has been poorly characterized. This cross-sectional analysis of the large cohort from the Renal Insufficiency and Cardiovascular Events (RIACE) study was aimed at assessing the clinical correlates and association with complications of resistant hypertension in patients with type 2 diabetes.

METHODS

The RIACE study enrolled 15,773 patients consecutively visiting 19 diabetes clinics during the years 2007-2008. Resistant hypertension, defined as BP values not on target (i.e. >130/80 mmHg, respectively) with three antihypertensive agents, was detected in 2363 individuals (15% of the whole RIACE cohort, 17.4% of hypertensive individuals, and 21.2% of treated hypertensive patients). Patients without resistant hypertension [nonresistant hypertension (NRH)], that is on target with one (n = 1569), two (n = 1369), and three (n = 803) drugs, and individuals with uncontrolled hypertension, that is untreated or not on target with less than three drugs (n = 7440), served as controls.

RESULTS

As compared with NRH and uncontrolled hypertension patients, patients with resistant hypertension were older and more frequently women and had significantly higher waist circumference, albuminuria, and serum creatinine, and lower glomerular filtration rate. Prevalence values of chronic kidney disease and advanced retinopathy were significantly higher in resistant hypertension than in both nonresistant hypertension and uncontrolled hypertension individuals, whereas cardiovascular disease was more frequent in resistant hypertension versus uncontrolled hypertension, but not nonresistant hypertension patients, especially those on 2-3 drugs.

CONCLUSIONS

Resistant hypertension is relatively common in patients with type 2 diabetes. In these individuals, age, female sex and waist circumference are independent correlates of resistant hypertension, which is strongly associated with microvascular (especially renal) disease, whereas relation with macrovascular complications is unclear.

Effects of continuous positive airway pressure on blood pressure in patients with resistant hypertension and obstructive sleep apnea: a meta-analysis

OBJECTIVE

To systematically analyze the studies that have examined the effect of continuous positive airway pressure (CPAP) on blood pressure (BP) in patients with resistant hypertension and obstructive sleep apnea (OSA).

METHODS

Design - meta-analysis of observational studies and randomized controlled trials (RCTs) indexed in PubMed and Ovid (All Journals@Ovid). participants: individuals with resistant hypertension and OSA; interventions - CPAP treatment.

RESULTS

A total of six studies met the inclusion criteria for preintervention to postintervention analyses. The pooled estimates of mean changes after CPAP treatment for the ambulatory (24-h) SBP and DBP from six studies were -7.21 mmHg [95% confidence interval (CI): -9.04 to -5.38; P < 0.001; I² 58%) and -4.99 mmHg (95% CI: -6.01 to -3.96; P < 0.001; I² 31%), respectively. The pooled estimate of the ambulatory SBP and DBP from the four RCTs showed a mean net change of -6.74 mmHg [95% CI: -9.98 to -3.49; P < 0.001; I² 61%] and -5.94 mmHg (95% CI: -9.40 to -2.47; P = 0.001; I² 76%), respectively, in favor of the CPAP group.

CONCLUSION

The pooled estimate shows a favorable reduction of BP with CPAP treatment in patients with resistant hypertension and OSA. The effects sizes are larger than those previously reported in patients with OSA without resistant hypertension.

Hypertension in Women: Evaluation and Management

Hypertension is the most commonly encountered chronic medical condition in primary care and one of the most significant modifiable cardiovascular risk factors for women and men. Timely diagnosis and evidence-based management offer an important opportunity to reduce the risk of hypertension-related morbidity and mortality, including cardiovascular events, end-stage renal disease, and heart failure. Clinical trials have shown significant improvements in patient-oriented outcomes when hypertension is well-controlled, yet many hypertensive patients remain undiagnosed, uncontrolled, or managed with inappropriate pharmacotherapy. This article discusses the initial diagnosis, evaluation, and management of hypertension in nonpregnant women, with topics for obstetrician-gynecologists and women's health providers.

Controversies Surrounding Renal Denervation: Lessons Learned From Real-World Experience in Two United Kingdom Centers

Renal denervation (RDN) is a therapy that targets treatment-resistant hypertension (TRH). The Renal Denervation in Patients With Uncontrolled Hypertension (Symplicity) HTN-1 and Symplicity HTN-2 trials reported response rates of >80%; however, sham-controlled Symplicity HTN-3 failed to reach its primary blood pressure (BP) outcome. The authors address the current controversies surrounding RDN, illustrated with real-world data from two centers in the United Kingdom. In this cohort, 52% of patients responded to RDN, with a 13±32 mm Hg reduction in office systolic BP (SBP) at 6 months (n=29, P=.03). Baseline office SBP and number of ablations correlated with office SBP reduction (R=-0.47, P=.01; R=-0.56, P=.002). RDN appears to be an effective treatment for some patients with TRH; however, individual responses are highly variable. Selecting patients for RDN is challenging, with only 10% (33 of 321) of the screened patients eligible for the study. Medication alterations and nonadherence confound outcomes. Adequate ablation is critical and should impact future catheter design/training. Markers of procedural success and improved patient selection parameters remain key research aims.

The rise, fall, and possible resurrection of renal denervation

Renal denervation has a chequered history. Dramatic reductions in blood pressure after denervation of the renal arteries were observed in early trials, but later trials in which denervation was tested against a sham procedure produced neutral results. Although a sound pathophysiological basis exists for interruption of the renal sympathetic nervous system as a treatment for hypertension, trial data to date are insufficient to support renal denervation as an established clinical therapy. In this Perspectives article, we summarize the currently available trial data, device development, and trials in progress, and provide recommendations for future trial design.

Reductions of left ventricular mass and atrial size following renal denervation: a meta-analysis

BACKGROUND

Renal denervation (RDN), a novel therapy for resistant hypertension, has been shown to have an effect on cardiac remodeling in several small studies. We aimed to pool currently available data to assess the effects of RDN on left ventricular hypertrophy (LVH) and left atrial (LA) enlargement.

METHODS AND RESULTS

Two investigators independently searched PubMed, EMBASE and Cochrane Library Central Register of Controlled Trials database for studies reporting change in left ventricular mass index (LVMI) or LA size before and after RDN. Twelve publications met our pre-defined inclusion criteria. Echocardiographic data showed that RDN markedly reduced both LVMI [weighted mean difference (WMD) = -15.77 g/m(2); 95 % confidence interval (CI) -22.51 to -9.02 g/m(2)] and LA diameter [WMD = -2.48 mm; 95 % CI -4.12 to -0.83 mm] after 6 months. Data from cardiac magnetic resonance also showed a significant reduction in LVMI [WMD = -5.43 g/m(2), 95 % CI -10.01 to -0.35 g/m(2)) at 6 months. Changes in LVH and LA size at 12 months were more pronounced than those at 6 months. Meta-regression analysis failed to demonstrate a significant relationship between RDN-induced LVMI reduction and BP lowering at 6 months.

CONCLUSIONS

RDN led to significant regressions of both LVH and LA enlargement at 6 months, which were sustained at least up to 12 months.

Continuous Positive Airway Pressure in Patients With Obstructive Sleep Apnea and Resistant Hypertension: A Meta-Analysis of Randomized Controlled Trials

This study aimed to analyze the effect of continuous positive airway pressure (CPAP) on blood pressure (BP) in patients with obstructive sleep apnea (OSA) and resistant hypertension. Randomized controlled trials (RCTs) that evaluated the effect of CPAP on BP in patients with OSA and resistant hypertension, indexed in MEDLINE, Embase, and the Cochrane Library from inception until March 20, 2015, were included in the meta-analysis. A total of five RCTs were identified to meet the inclusion criteria. The pooled changes after CPAP treatment for 24-hour ambulatory systolic BP and diastolic BP (DBP) were -4.78 mm Hg (95% confidence interval [CI], -7.95 to -1.61) and -2.95 mm Hg (95% CI, -5.37 to -0.53) in favor of the CPAP group. CPAP was also associated with reduction in nocturnal DBP (mean difference, -1.53 mm Hg, 95% CI, -3.07 to 0). The results indicated a favorable reduction in BP with CPAP treatment in patients with OSA and resistant hypertension.

Kidney Function Decline and Apparent Treatment-Resistant Hypertension in the Elderly

BACKGROUND

Cross-sectional studies show a strong association between chronic kidney disease and apparent treatment-resistant hypertension, but the longitudinal association of the rate of kidney function decline with the risk of resistant hypertension is unknown.

METHODS

The population-based Three-City included 8,695 participants older than 65 years, 4265 of them treated for hypertension. We estimated the odds ratios (OR) of new-onset apparent treatment-resistant hypertension, defined as blood pressure ≥ 140/90 mmHg despite use of 3 antihypertensive drug classes or ≥ 4 classes regardless of blood pressure, associated with the mean estimated glomerular filtration rate (eGFR) level and its rate of decline over 4 years, compared with both controlled hypertension and uncontrolled nonresistant hypertension with ≤ 2 drugs. GFR was estimated with three different equations.

RESULTS

Baseline prevalence of apparent treatment-resistant hypertension and of controlled and uncontrolled nonresistant hypertension, were 6.5%, 62.3% and 31.2%, respectively. During follow-up, 162 participants developed apparent treatment-resistant hypertension. Mean eGFR decline with the MDRD equation was 1.5±2.9 mL/min/1.73 m² per year: 27.7% of the participants had an eGFR ≥3 and 10.1% ≥ 5 mL/min/1.73 m² per year. After adjusting for age, sex, obesity, diabetes, and cardiovascular history, the ORs for new-onset apparent treatment-resistant hypertension associated with a mean eGFR level, per 15 mL/min/1.73 m² drop, were 1.23 [95% confidence interval 0.91-1.64] compared to controlled hypertension and 1.10 [0.83-1.45] compared to uncontrolled nonresistant hypertension; ORs associated with a decline rate ≥ 3 mL/min/1.73 m² per year were 1.89 [1.09-3.29] and 1.99 [1.19-3.35], respectively. Similar results were obtained when we estimated GFR with the CKDEPI and the BIS1 equations. ORs tended to be higher for an eGFR decline rate ≥ 5 mL/min/1.73 m² per year.

CONCLUSION

The speed of kidney function decline is associated more strongly than kidney function itself with the risk of apparent treatment-resistant hypertension in the elderly.

Efficacy and safety of a novel multi-electrode radiofrequency ablation catheter for renal sympathetic denervation in pigs

Objective

To investigate the safety and efficacy of a self-developed novel multi-electrode radiofrequency ablation catheter (Spark) for catheter-based renal denervation (RDN).

Methods

A total of 14 experimental miniature pigs were randomly divided into four groups (55°& 5-watt, 55°& 8-watt, 65°& 5-watt, and 65° & 8-watt groups). Spark was used for left and right renal artery radiofrequency ablation. Blood samples collected from renal arteries and veins as well as renal arteriography were performed on all animals before, immediately after, and three months after procedure to evaluate the effects of Spark on the levels of plasma renin, aldosterone, angiotensin I, and angiotensin II as well as the pathological changes of renal arteries.

Results

One pig died of an anesthetic accident, 13 pigs successfully underwent the bilateral renal artery ablation. Compared with basic measurements, pigs in all the four groups had significantly decreased mean arterial pressure after procedure. Histopathological analysis showed that this procedure could result in intimal hyperplasia, significant peripheral sympathetic nerve damage in the renal arteries such as inflammatory cell infiltration and fibrosis in perineurium, uneven distribution of nerve fibers, tissue necrosis, severe vacuolization, fragmented and unclear nucleoli myelin degeneration, sparse axons, and interruption of continuity. In addition, the renal artery radiofrequency ablation could significantly reduce the levels of plasma renin, aldosterone, angiotensin I, and angiotensin II in pigs.

Conclusions

The results suggest that this type of multi-electrode catheter-based radiofrequency ablation could effectively remove peripheral renal sympathetic nerves and reduce the activity of systemic renin-angiotensin system in pigs, thus facilitating the control of systemic blood pressure in pigs.

Angiotensin II (de)sensitization: Fluid intake studies with implications for cardiovascular control

Cardiovascular disease is the leading cause of death worldwide and hypertension is the most common risk factor for death. Although many anti-hypertensive pharmacotherapies are approved for use in the United States, rates of hypertension have increased over the past decade. This review article summarizes a presentation given at the 2015 meeting of the Society for the Study of Ingestive Behavior. The presentation described work performed in our laboratory that uses angiotensin II-induced drinking as a model system to study behavioral and cardiovascular effects of the renin-angiotensin system, a key component of blood pressure regulation, and a common target of anti-hypertensives. Angiotensin II (AngII) is a potent dipsogen, but the drinking response shows a rapid desensitization after repeated injections of AngII. This desensitization appears to be dependent upon the timing of the injections, requires activation of the AngII type 1 (AT1) receptor, requires activation of mitogen-activated protein (MAP) kinase family members, and involves the anteroventral third ventricle (AV3V) region as a critical site of action. Moreover, the response does not appear to be the result of a more general suppression of behavior, a sensitized pressor response to AngII, or an aversive state generated by the treatment. More recent studies suggest that the treatment regimen used to produce desensitization in our laboratory also prevents the sensitization that occurs after daily bolus injections of AngII. Our hope is that these findings can be used to support future basic research on the topic that could lead to new developments in treatments for hypertension.

Drug resistant hypertension – no simple way out

Hypertension poses growing challenge for health policy-makers and doctors worldwide. Recently published results of Symplicity-III trial (HTN-3), the first blinded, randomized, multicenter study on the efficacy of renal denervation for the treatment of resistant hypertension did not show a significant reduction of BP in patients with resistant hypertension 6 months after renal-artery denervation, as compared with controls. In this paper we review clinical and experimental studies on renal denervation. In order to identify causes of inconsistent results in renal denervation studies we look at basic science support for renal denervation and at designs of clinical trials.

Longitudinal Effect of CPAP on BP in Resistant and Nonresistant Hypertension in a Large Clinic-Based Cohort

BACKGROUND

Clinic-based effectiveness studies of sleep-disordered breathing (SDB) treatment in reducing BP in resistant hypertension (RHTN) vs non-RHTN are sparse. We hypothesize that CPAP use in SDB reduces BP significantly in RHTN and non-RHTN in a large clinic-based cohort.

METHODS

Electronic medical records were reviewed in patients with SDB and comorbid RHTN and non-RHTN for CPAP therapy initiation (baseline) and subsequent visits. We estimated generalizable BP changes from multivariable mixed-effects linear models for systolic BP (SBP), diastolic BP, and mean arterial pressure, adjusting for RHTN status, age, sex, race, BMI, cardiac history, and diabetes and repeated measure correlation.

RESULTS

Of 894 patients, 130 (15%) had RHTN at baseline (age, 58 ± 12 years; 52% men; BMI, 36 ± 9 kg/m(2)). Patients with RHTN had significantly higher BP overall (P < .001), most notably for SBP (6.9 mm Hg; 95% CI, 3.84, 9.94). In the year following CPAP initiation, improvements in BP indexes did not generally differ based on RHTN status in which RHTN status was a fixed effect. However, there was a significant decrease in SBP (3.08 mm Hg; 95% CI, 1.79, 4.37), diastolic BP (2.28; 95% CI, 1.56, 3.00), and mean arterial pressure (2.54 mm Hg; 95% CI, 1.73, 3.36) in both groups.

CONCLUSIONS

In this clinic-based effectiveness study involving patients closely followed for BP control, a significant reduction of BP measures (strongest for SBP) was observed in response to CPAP which was similar in RHTN and non-RHTN groups thus informing expected clinical CPAP treatment response.

Improvement in All-Cause Mortality With Blood Pressure Control in a Group of US Veterans With Drug-Resistant Hypertension

The current definition of drug-resistant hypertension includes patients with uncontrolled (URH) (taking ≥3 antihypertensive medications) and controlled hypertension (CRH; blood pressure [BP] ≤140/90 mm Hg) (taking ≥4 medications). The authors hypothesized that all-cause mortality is reduced when URH is controlled. Qualified patients followed at the Washington DC VA Medical Center were included. BPs were averaged for each year of follow-up. In 2006, among 2906 patients who met the criteria for drug-resistant hypertension, 628 had URH. During follow-up, 234 patients were controlled (group 1) and 394 patients remained uncontrolled (group 2). The mortality rate among patients with URH was 28% (110 of 394) and among patients with CRH was 13% (30 of 234), a 54% reduction (P<.01). Multivariate analysis identified independent predictors of mortality as uncontrolled HTN (hazard ratio, 2.5; 95% confidence interval, 1.67-3.75; P<.01), age (hazard ratio, 1.03; 95% confidence interval, 1.01-1.04; P<.01), and diabetes (hazard ratio, 1.46; 95% confidence interval, 1.04-2.05; P<.027). The authors conclude that controlling drug-resistant hypertension markedly reduces all-cause mortality.

Resistant Hypertension

Conservatively, ten million people in the USA alone may suffer from RH and may be similarly prevalent elsewhere. Given the strong linear correlation between hypertension and cardiovascular outcomes, better control is paramount. We favor a multi-pronged approach. It may not suffice to address this by pharmacologic means only. Careful attention to modifiable risk factors, particularly sodium intake, adhering to a proper diet (i.e. DASH), and avoiding agents, i.e. non-steroidals, that can elevate the blood pressure, is key. Frequent follow up to establish the right treatment regimen and home blood pressuring monitoring can have a strong impact on control. Finally, consideration of device therapy may be a more viable option in the future.

The SPYRAL HTN Global Clinical Trial Program: Rationale and design for studies of renal denervation in the absence (SPYRAL HTN OFF-MED) and presence (SPYRAL HTN ON-MED) of antihypertensive medications

Renal sympathetic activation plays a key role in the pathogenesis of hypertension, as demonstrated by high renal norepinephrine spillover into plasma of patients with essential hypertension. Renal denervation has demonstrated a significant reduction in blood pressure in unblinded studies of hypertensive patients. The SYMPLICITY HTN-3 trial, the first prospective, masked, randomized study of renal denervation versus sham control, failed its primary efficacy end point and raised important questions around potentially confounding factors, such as drug changes and adherence, study population, and procedural methods. The SPYRAL HTN Global Clinical Trial Program is designed to address limitations associated with predicate studies and provide insight into the impact of pharmacotherapy on renal denervation efficacy. The 2 initial trials of the program focus on the effect of renal denervation using the Symplicity Spyral multielectrode renal denervation catheter in hypertensive patients in the absence (SPYRAL HTN OFF-MED) and presence (SPYRAL HTN ON-MED) of antihypertensive medications. The SPYRAL HTN ON-MED study requires patients to be treated with a consistent triple therapy antihypertensive regimen, whereas the SPYRAL HTN OFF-MED study includes a 3- to 4-week drug washout period followed by a 3-month efficacy and safety end point in the absence of antihypertensive medications. The studies will randomize patients with combined systolic-diastolic hypertension to renal denervation or sham procedure. Both studies allow renal denervation treatments in renal artery branches and accessories. These studies will inform the design of the second pivotal phase of the program, which will more definitively analyze the antihypertensive effect of renal denervation.

Prevalence and Prognostic Significance of Apparent Treatment Resistant Hypertension in Chronic Kidney Disease: Report From the Chronic Renal Insufficiency Cohort Study

The association between apparent treatment resistant hypertension (ATRH) and clinical outcomes is not well studied in chronic kidney disease. We analyzed data on 3367 hypertensive participants in the Chronic Renal Insufficiency Cohort (CRIC) to determine prevalence, associations, and clinical outcomes of ATRH in nondialysis chronic kidney disease patients. ATRH was defined as blood pressure ≥140/90 mm Hg on ≥3 antihypertensives, or use of ≥4 antihypertensives with blood pressure at goal at baseline visit. Prevalence of ATRH was 40.4%. Older age, male sex, black race, diabetes mellitus, and higher body mass index were independently associated with higher odds of having ATRH. Participants with ATRH had a higher risk of clinical events than participants without ATRH-composite of myocardial infarction, stroke, peripheral arterial disease, congestive heart failure (CHF), and all-cause mortality (hazard ratio [95% confidence interval], 1.38 [1.22-1.56]); renal events (1.28 [1.11-1.46]); CHF (1.66 [1.38-2.00]); and all-cause mortality (1.24 [1.06-1.45]). The subset of participants with ATRH and blood pressure at goal on ≥4 medications also had higher risk for composite of myocardial infarction, stroke, peripheral arterial disease, CHF, and all-cause mortality (hazard ratio [95% confidence interval], (1.30 [1.12-1.51]) and CHF (1.59 [1.28-1.99]) than those without ATRH. ATRH was associated with significantly higher risk for CHF and renal events only among those with estimated glomerular filtration rate ≥30 mL/min per 1.73 m(2). Our findings show that ATRH is common and associated with high risk of adverse outcomes in a cohort of patients with chronic kidney disease. This underscores the need for early identification and management of patients with ATRH and chronic kidney disease.