What is the prevalence of resistant hypertension in the United States? Curr Opin Cardiol. 2012;27:386-391. [PMID: 22596184 DOI: 10.1097/hco.0b013e328353ad6e]

The Impact of Socioeconomic Inequalities on the Risk of Hypertension in Bangladesh: A Systematic Review and Meta-Analysis

Hypertension is a prevalent health issue in Bangladesh, impacting a significant portion of the population. This meta-analysis explored how social status inequalities impact hypertension risk in Bangladesh. We systematically searched various electronic databases and rigorously selected 12 studies for inclusion in the analyses. The I2 statistic measured between study heterogeneity, and pooled effect estimates were obtained using the DerSimonian and Laird random effects model to address this variability. Publication bias was assessed through a funnel plot and Egger's test. Sensitivity analysis was conducted to evaluate the robustness of the findings. All analyses were performed using STATA 17. The analyses indicated that females had a significantly higher risk of developing hypertension compared to males, with a pooled odds ratio (OR) of 1.15 (95% confidence interval [CI]: 1.02-1.27). Urban residents showed a pooled OR of 1.11 (95% CI: 1.03-1.19) compared to rural residents. The pooled ORs for hypertension were 1.02 (95% CI: 0.89-1.14) for primary education, 1.07 (95% CI: 0.94-1.21) for secondary education, and 1.25 (95% CI: 1.03-1.47) for higher secondary education, suggesting an increasing risk with higher education levels. Wealth status showed a pooled OR of 1.08 (95% CI: 0.87-1.29) for the poorer class, 1.13 (95% CI: 1.04-1.22) for the middle class, 1.38 (95% CI: 0.68-2.07) for the richer class, and 1.49 (95% CI: 0.97-2.00) for the richest class, indicating a greater risk of hypertension among wealthier individuals. Working individuals had a 39% lower risk of hypertension (OR = 0.61, 95% CI: 0.43-0.80) compared to nonworking individuals.

Kalanchoe crenata Andrews (Haw.) Improves Losartan's Antihypertensive Activity

BACKGROUND

Cardiovascular diseases constitute one of the leading causes of morbidity and mortality worldwide. Herbal medicines represent viable alternatives to the synthetic drugs currently employed in the control of hypertension. This study aimed to isolate and identify the chemical markers of Kalanchoe crenata and to investigate the antihypertensive and anti-matrix metalloproteinase (MMP2) activities of an aqueous extract of the leaves.

METHODS

The main constituents of the aqueous extract of K. crenata were separated by ultra-performance liquid chromatography-mass spectrometry, and their presence was identified by NMR spectroscopy. Renovascular hypertension was induced in male Wistar rats using the two-kidney one-clip method (HTN groups), while control animals (Sham groups) were submitted to Sham surgery. Six groups of 10 animals each were treated daily for eight weeks as follows: Sham 1 (carrier), Sham 2 (K. crenata extract), HTN.1 (carrier), HTN.2 (K. crenata extract), HTN 3 (losartan), and HTN 4 (K. crenata extract with losartan).

RESULTS

The main compounds of the extract were patuletin 3-O-(4″-O-acetyl-α-L-rhamnopyranosyl)-7-O-(3‴-O-acetyl-α-L-rhamnopyranoside) (1), patuletin 3-O-α-L-rhamnopyranosyl-7-O-L-rhamnopyranoside (2), and trans-caffeoyl-malic acid (3), with compounds 1 and 2 being chemical markers of the species. Significant reductions (p < 0.05) in systolic blood pressure and MMP2 (72kDa isoform) activity were observed in the HTN 4 group.

CONCLUSIONS

The association of K. crenata extract and losartan presented in vivo effects against hypertension.

COVID-19 pandemic impact on hypertension management in North East London: an observational cohort study using electronic health records

OBJECTIVE

There are established inequities in the monitoring and management of hypertension in England. The COVID-19 pandemic had a major impact on primary care management of long-term conditions such as hypertension. This study investigated the possible disproportionate impact of the pandemic across patient groups.

DESIGN

Open cohort of people with diagnosed hypertension.

SETTINGS

North East London primary care practices from January 2019 to October 2022.

PARTICIPANTS

All 224 329 adults with hypertension registered in 193 primary care practices.

OUTCOMES

Monitoring and management of hypertension were assessed using two indicators: (i) blood pressure recorded within 1 year of the index date and (ii) blood pressure control to national clinical practice guidelines.

RESULTS

The proportion of patients with a contemporaneous blood pressure recording fell from a 91% pre-pandemic peak to 62% at the end of the pandemic lockdown and improved to 77% by the end of the study. This was paralleled by the proportion of individuals with controlled hypertension which fell from a 73% pre-pandemic peak to 50% at the end of the pandemic lockdown and improved to 60% by the end of the study. However, when excluding patients without a recent blood pressure recording, the proportions of patients with controlled hypertension increased to 81%, 80% and 78% respectively.Throughout the study, in comparison to the White ethnic group, the Black ethnic group was less likely to achieve adequate blood pressure control (ORs 0.81 (95% CI 0.78 to 0.85, p<0.001) to 0.87 (95% CI 0.84 to 0.91, p<0.001)). Conversely, the Asian ethnic group was more likely to have controlled blood pressure (ORs 1.09 (95% CI 1.05 to 1.14, p<0.001) to 1.28 (95% CI 1.23 to 1.32, p<0.001)). Men, younger individuals, more affluent individuals, individuals with unknown or unrecorded ethnicity or those untreated were also less likely to have blood pressure control to target throughout the study.

CONCLUSION

The COVID-19 pandemic had a greater impact on blood pressure recording than on blood pressure control. Inequities in blood pressure control persisted during the pandemic and remain outstanding.

Effect of Continuous Positive Airway Pressure on Blood Pressure in Patients with Resistant Hypertension and Obstructive Sleep Apnea: An Updated Meta-analysis

PURPOSE OF REVIEW

The effect of continuous positive airway pressure (CPAP) on resistant hypertension in patients at high risk with obstructive sleep apnea (OSA) needs further investigation. We aimed to determine the effect of CPAP on blood pressure in patients with resistant hypertension and OSA. Databases including PubMed, EMBASE, MEDLINE, the Cochrane Library, and CMB were searched. Data were pooled using a random-effects or fixed-effects model to derive weighted mean differences (WMDs) and 95% confidence intervals (CIs).

RECENT FINDINGS

A total of 12 trials and 718 participants were included. Compared with control, CPAP significantly reduced 24-h systolic blood pressure (SBP) (WMD: - 5.92 mmHg [ - 8.72, - 3.11]; P＜0.001), 24-h diastolic blood pressure (DBP) (WMD: - 4.44 mmHg [- 6.26 , - 2.62]; P  ＜0.001),   daytime SBP (WMD: - 5.76 mmHg [ - 9.16,  - 2.36]; P ＜0.001),  daytime DBP (WMD: - 3.92 mmHg [- 5.55,  - 2.30];  nighttime SBP (WMD: - 4.87 mmHg [ - 7.96 ,  - 1.78]; P = 0.002), and nighttime DBP (WMD: - 2.05 mmHg [- 2.99,  - 1.11]; P＜0.001) in patients with resistant hypertension and OSA. CPAP improved the blood pressure both in the short (＜3 months) and long term (≥ 3  months). No significant impact on mean heart rate was noted (WMD: -2.76 beats per min [- 7.50, 1.97]; P = 0.25). CPAP treatment was associated with BP reduction in patients with resistant hypertension and OSA.

Relations between white coat effect of blood pressure and arterial stiffness

The aim of this study was to analyze the relationship between brachial-ankle pulse wave velocity (b-a PWV) and white coat effect (WCE), that is the difference between the elevated office blood pressure (BP) and the lower mean daytime pressure of ambulatory BP, in a mixed population of normotention, untreated sustained hypertension, sustained controlled hypertension, sustained uncontrolled hypertension, white coat hypertension, white coat uncontrolled hypertension. A total of 444 patients with WCE for systolic BP (54.1% female, age 61.86 ± 13.3 years) were enrolled in the study. Patients were separated into low WCE (<9.5 mm Hg) and high WCE (≥9.5 mm Hg) according to the median of WCE. The subjects with a high WCE showed a greater degree of arterial stiffness than those with a low WCE for systolic BP values (P < .05). The b-a PWV were 17.2 ± 3.3 m/s and 18.4 ± 3.4 m/s in low WCE and high WCE, respectively. The b-a PWV increased with the increase of WCE, showing a positive correlation between them (P > .05 for non-linearity). The significant association between the high WCE and the b-a PWV was confirmed by the results of multiple regression analysis after adjusting for confounding factors (β = .78, 95% Cl .25-1.31, P = . 004). Similar results were observed in subgroups. In conclusion, WCE is significantly associated with arterial stiffness. More research is needed to determine the WCE and target organ damage.

Aprocitentan and the endothelin system in resistant hypertension

Endothelin has emerged as a target for therapeutic intervention in systemic hypertension. As a vasoconstrictor, co-mitogenic agent, linking pulse pressure and vascular remodeling, and mediator of aldosterone and catecholamine release, endothelin is a key player in hypertension and end-organ damage. In 10-20% of the hypertensive population, the high blood pressure is resistant to administration of antihypertensive drugs of different classes in combination. Because endothelin is not targeted by the current antihypertensive drugs this may suggest that this resistance is due, in part at least, to a dependence on endothelin. This hypothesis is supported by the observation that this form of hypertension is often salt-sensitive, and that the endothelin system is stimulated by salt. In addition, the endothelin system is activated in subjects at risk of developing resistant hypertension, such as African-Americans or patients with obesity or obstructive sleep apnea. Aprocitentan is a novel, potent, dual endothelin receptor antagonist (ERA) currently in phase 3 development for the treatment of difficult-to-treat hypertension. This article discusses the research which underpinned the discovery of this ERA and the choice of its first clinical indication for patients with forms of hypertension which cannot be well controlled with classical antihypertensive drugs.

Eligibility for Baroreflex Activation Therapy and medication adherence in patients with apparently resistant hypertension

Uncontrolled hypertension is a main risk factor for cardiovascular morbidity. Baroreflex activation therapy (BAT) is an effective therapy option addressing true resistant hypertension. We evaluated patients’ eligibility for BAT in a staged assessment as well as adherence to antihypertensive drug therapy. Therefore, we analyzed files of 345 patients, attending the hypertension clinic at University Medicine Göttingen. Additionally, gas chromatographic‐mass spectrometric urine analyses of selected individuals were performed evaluating their adherence. Most common cause for a revoked BAT recommendation was blood pressure (BP) control by drug adjustment (54.2%). Second leading cause was presence of secondary hypertension (31.6%). Patients to whom BAT was recommended (59 (17.1%)) were significantly more often male (67.8% vs. 43.3%, P = .0063), had a higher body mass index (31.8 ± 5.8 vs. 30.0 ± 5.7 kg/m², P = .0436), a higher systolic office (168.7 ± 24.7 vs. 147.7 ± 24.1 mmHg, P < .0001), and 24h ambulatory BP (155.0 ± 14.6 vs. 144.4 ± 16.8 mmHg, P = .0031), took more antihypertensive drugs (5.8 ± 1.3 vs. 4.4 ± 1.4, P < .0001), and suffered more often from numerous concomitant diseases. Eventually, 27 (7.8%) received a BAT system. In the toxicological analysis of 75 patients, mean adherence was 75.1%. 16 patients (21.3%) showed non‐adherence. Thus, only a small number of patients eventually received a BAT system, as treatable reasons for apparently resistant hypertension could be identified frequently. This study is—to our knowledge—the first report of a staged assessment of patients’ suitability for BAT and underlines the need for a careful examination and indication. Non‐adherence was proven to be a relevant issue concerning apparently resistant hypertension and therefore non‐eligibility for interventional antihypertensive therapy.

We evaluated the eligibility for baroreflex activation therapy (BAT) of 345 patients, attending the hypertension clinic at University Medicine Göttingen. Patients’ drug adherence was investigated by 75 toxicological analyses. Most common cause for a revoked BAT recommendation was blood pressure control by drug adjustment. Eventually, only less patients (7.8%) received a BAT system. Patients receiving a BAT recommendation showed specific characteristics and suffered numerous comorbidities, leading to a high cardiovascular risk, and therefore seem to greatly benefit from BAT implantation. 21.3% of patients showed non‐adherence, proving non‐adherence to be a relevant issue.

Renovascular Hypertension

Renovascular hypertension (RVH) is relatively common but underrecognized cause of resistant hypertension in clinical practice. Most patients with RVH have suboptimal control of hypertension in spite of being on multiple anti hypertensive medications. Prompt diagnosis and management is crucial to prevent long term morbidity and mortality. Initial evaluation by primary care physicians can expedite this to improve patient outcomes by co-managing hypertension specialists. In addition to pharmacologic and nonpharmacologic measures, some patients may benefit from angioplasty. This article discusses various definitions of hypertension, approach to diagnosis of RVH, and management. Data from clinical trials are discussed with evidence-based medicine practice recommendations.

Aortic blood pressure and arterial stiffness in patients with controlled resistant and non-resistant hypertension

The purpose of the current study was to determine whether aortic blood pressure (BP) and arterial stiffness are greater in patients with controlled resistant hypertension (RHTN) than controlled non-resistant hypertension (non-RHTN) despite similar clinic BP level. Participants were recruited from University of Alabama at Birmingham (UAB) Hypertension Clinic. Controlled hypertension was defined as automated office BP measurement with BP < 135/85 mm Hg. A total of 141 participants were evaluated by pulse wave analysis (PWA) and carotid-femoral pulse wave velocity (cf-PWV). Among them, 75 patients had controlled RHTN with use of 4 or more antihypertensive medications and 56 patients had controlled non-RHTN with use of 3 or less antihypertensive medications. Compared to patients with controlled non-RHTN, those with controlled RHTN were more likely to be African American and had a higher prevalence of diabetes mellitus and congestive heart failure. The mean number of antihypertensive medications was greater in patients with controlled RHTN (4.4 ± 0.8 vs 2.3 ± 0.7, P < .001). Clinic brachial BP, aortic BP, augmentation pressure (AP), augmentation index normalized for heart rate of 75 beats per minute (AIx@75) and cf-PWV were similar in both groups. In summary, there was no significant difference in central BP or arterial stiffness between patients with controlled RHTN and controlled non-RHTN. These findings suggest that the higher residual cardiovascular risk observed in patients with RHTN after achieving BP control compared to patients with more easily controlled hypertension is not likely attributable to persistent differences in central BP and arterial stiffness.

Leptin Induces Hypertension Acting on Transient Receptor Potential Melastatin 7 Channel in the Carotid Body

RATIONALE

Obesity leads to resistant hypertension and mechanisms are poorly understood, but high plasma levels of leptin have been implicated. Leptin increases blood pressure acting both centrally in the dorsomedial hypothalamus and peripherally. Sites of the peripheral hypertensive effect of leptin have not been identified. We previously reported that leptin enhanced activity of the carotid sinus nerve, which transmits chemosensory input from the carotid bodies (CBs) to the medullary centers, and this effect was abolished by nonselective blockers of Trp (transient receptor potential) channels. We searched our mouse CB transcriptome database and found that the Trpm7 (transient receptor potential melastatin 7) channel was the most abundant Trp channel.

OBJECTIVE

To examine if leptin induces hypertension acting on the CB Trpm7.

METHODS AND RESULTS

C57BL/6J (n=79), leptin receptor (LepRb) deficient db/db mice (n=22), and LepRb-EGFP (n=4) mice were used. CB Trpm7 and LepRb gene expression was determined and immunohistochemistry was performed; CB glomus cells were isolated and Trpm7-like current was recorded. Blood pressure was recorded continuously in (1) leptin-treated C57BL/6J mice with intact and denervated CB; (2) leptin-treated C57BL/6J mice, which also received a nonselective Trpm7 blocker FTY720 administered systemically or topically to the CB area; (3) leptin-treated C57BL/6J mice transfected with Trpm7 small hairpin RNA to the CB, and (4) Leprb deficient obese db/db mice before and after Leprb expression in CB. Leptin receptor and Trpm7 colocalized in the CB glomus cells. Leptin induced a nonselective cation current in these cells, which was inhibited by Trpm7 blockers. Leptin induced hypertension in C57BL/6J mice, which was abolished by CB denervation, Trpm 7 blockers, and Trpm7 small hairpin RNA applied to CBs. Leprb overexpression in CB of Leprb-deficient db/db mice demethylated the Trpm7 promoter, increased Trpm7 gene expression, and induced hypertension.

CONCLUSIONS

We conclude that leptin induces hypertension acting on Trmp7 in CB, which opens horizons for new therapy.

Melatonin attenuates renal sympathetic overactivity and reactive oxygen species in the brain in neurogenic hypertension

Sympathetic overactivation contributes to the pathogenesis of both experimental and human hypertension. We have previously reported that oxidative stress in sympathetic premotor neurons leads to arterial baroreflex dysfunction and increased sympathetic drive to the kidneys in an experimental model of neurogenic hypertension. In this study, we hypothesized that melatonin, a potent antioxidant, may be protective in the brainstem regions involved in the tonic and reflex control of blood pressure (BP) in renovascular hypertensive rats. Neurogenic hypertension was induced by placing a silver clip (gap of 0.2 mm) around the left renal artery, and after 5 weeks of renal clip placement, the rats were treated orally with melatonin (30 mg/kg/day) by gavage for 15 days. At the end of melatonin treatment, we evaluated baseline mean arterial pressure (MAP), renal sympathetic nerve activity (rSNA), and the baroreflex control of heart rate (HR) and rSNA. Reactive oxygen species (ROS) were detected within the brainstem regions by dihydroethidium staining. Melatonin treatment effectively reduced baseline MAP and sympathoexcitation to the ischemic kidney in renovascular hypertensive rats. The baroreflex control of HR and rSNA were improved after melatonin treatment in the hypertensive group. Moreover, there was a preferential decrease in ROS within the rostral ventrolateral medulla (RVLM) and the nucleus of the solitary tract (NTS). Therefore, our study indicates that melatonin is effective in reducing renal sympathetic overactivity associated with decreased ROS in brainstem regions that regulate BP in an experimental model of neurogenic hypertension.

Plasma xanthine oxidase activity is related to increased sodium and left ventricular hypertrophy in resistant hypertension

BACKGROUND

The extra-renal effects of aldosterone on left ventricular (LV) structure and function are exacerbated by increased dietary sodium in persons with hypertension. Previous studies demonstrated endothelial dysfunction and increased oxidative stress with high salt diet in normotensive salt-resistant subjects. We hypothesized that increased xanthine oxidase (XO), a product of endothelial cells, is related to 24-h urinary sodium and to LV hypertrophy and function in patients with resistant hypertension (RHTN).

METHODS

The study group included persons with RHTN (n = 91), defined as a blood pressure > 140/90 mmHg on ≥ 3 medications at pharmacologically effective doses. Plasma XO activity and 24-h urine were collected, and cardiac magnetic resonance imaging (MRI) was performed to assess LV function and morphology. Sixty-seven normotensive persons on no cardiovascular medications served as controls. A subset of RHTN (n = 19) received spironolactone without salt restriction for six months with follow-up XO activity measurements and MRI analyses.

RESULTS

XO activity was increased two-fold in RHTN vs. normal and was positively correlated with LV mass, LV diastolic function, and 24-h urinary sodium. In RHTN patients receiving spironolactone without salt restriction, LV mass decreased, but LV diastolic function and XO activity did not improve. Baseline urinary sodium was positively associated with rate of change of LV mass to volume ratio and the LV E/A ratio.

CONCLUSIONS

These results demonstrate a potential role of endothelium-derived oxidative stress and excess dietary salt in the pathophysiology of LV hypertrophy and diastolic dysfunction in persons with RHTN unaffected by the addition of spironolactone.

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.

Perivascular adipose tissue and the dynamic regulation of Kv 7 and Kir channels: Implications for resistant hypertension

Resistant hypertension is defined as high blood pressure that remains uncontrolled despite treatment with at least three antihypertensive drugs at adequate doses. Resistant hypertension is an increasingly common clinical problem in older age, obesity, diabetes, sleep apnea, and chronic kidney disease. Although the direct vasodilator minoxidil was introduced in the early 1970s, only recently has this drug been shown to be particularly effective in a subgroup of patients with treatment-resistant or uncontrolled hypertension. This pharmacological approach is interesting from a mechanistic perspective as minoxidil is the only clinically used K⁺ channel opener today, which targets a subclass of K⁺ channels, namely K_ATP channels in VSMCs. Beside K_ATP channels, two other classes of VSMC K⁺ channels could represent novel effective targets for treatment of resistant hypertension, namely K_v 7 (KCNQ) and inward rectifier potassium (K_ir 2.1) channels. Interestingly, these channels are unique among VSMC potassium channels. First, both have been implicated in the control of microvascular tone by perivascular adipose tissue. Second, they exhibit biophysical properties strongly controlled and regulated by membrane voltage, but not intracellular calcium. This review focuses on K_v 7 (K_v 7.1-5) and K_ir (K_ir 2.1) channels in VSMCs as potential novel drug targets for treatment of resistant hypertension, particularly in comorbid conditions such as obesity and metabolic syndrome.

Effect of the physical activity program on the treatment of resistant hypertension in primary care

BACKGROUND

Regular physical activity is widely recommended for patients with arterial hypertension as an essential component of lifestyle modification. Much less is known about the impact of physical exercise on the management of treatment of resistant hypertension (RH). The aim was to assess the effect of physical activity program intensified by mobile phone text reminders on blood pressure control in subjects with RH managed in the primary care.

METHODS

In total, 53 patients with primary hypertension were qualified, including 27 who met the criteria for RH and 26 with well-controlled hypertension (WCH). Ambulatory 24-h blood pressure was monitored and body composition evaluated with bioimpedance and habitual physical activity profile was determined continuously over 72 h with accelerometer. All measurements were performed at baseline and after three and six months. The patients were asked to modify their lifestyle according to American Heart Association Guidelines that included regular aerobic physical activity tailored to individual needs.FindingsPhysical activity in RH increased significantly after six months compared with control subjects (P=0.001). Office systolic blood pressure (SBP) and diastolic blood pressure (DBP) in the RH group decreased significantly after three months but after six months only office DBP remained significantly lower. After three months 24-h SBP decreased by 3.1±11 mmHg (P=0.08) and DBP by 2.0±6 mmHg (P=0.17) in RH, whereas in WCH respective changes were +1.2±10 and -0.3±6 mmHg. After six months 24-h BP changes were similar.

CONCLUSION

Individualized structured physical activity program increases physical activity in the treatment of resistant hypertensives in primary care but the effect on 24-h blood pressure is only transient.

Preferred Fourth-Line Pharmacotherapy for Resistant Hypertension: Are We There Yet?

Resistant hypertension (RH) is defined as blood pressure (BP) that remains above target levels despite adherence to at least three different antihypertensive medications, typically including a diuretic. Epidemiological studies estimate that RH is increasing in prevalence, and is associated with detrimental health outcomes. The pathophysiology underlying RH is complex, involving multiple, overlapping contributors including activation of the renin-angiotensin aldosterone system and the sympathetic nervous system, volume overload, endothelial dysfunction, behavioural and lifestyle factors. Hypertension guidelines currently recommend specific pharmacotherapy for 1st, 2nd and 3rd-line treatment, however no specific fourth-line pharmacotherapy is provided for those with RH. Rather, five different antihypertensive drug classes are generally suggested as possible alternatives, including: mineralocorticoid receptor antagonists, α1-adrenergic antagonists, α2-adrenergic agonists, β-blockers, and peripheral vasodilators. Each of these drug classes vary in their efficacy, tolerability and safety profile. This review summarises the available data on each of these drug classes as a potential fourth-line drug and reveals a lack of robust clinical evidence for preferred use of most of these classes in the setting of RH. Moreover, there is a lack of direct comparative trials that could assist in identifying a preferred fourth-line pharmacologic approach and in providing evidence for hypertensive guidelines for adequate treatment of RH.

Hypertension Canada's 2018 Guidelines for Diagnosis, Risk Assessment, Prevention, and Treatment of Hypertension in Adults and Children

Hypertension Canada provides annually updated, evidence-based guidelines for the diagnosis, assessment, prevention, and treatment of hypertension in adults and children. This year, the adult and pediatric guidelines are combined in one document. The new 2018 pregnancy-specific hypertension guidelines are published separately. For 2018, 5 new guidelines are introduced, and 1 existing guideline on the blood pressure thresholds and targets in the setting of thrombolysis for acute ischemic stroke is revised. The use of validated wrist devices for the estimation of blood pressure in individuals with large arm circumference is now included. Guidance is provided for the follow-up measurements of blood pressure, with the use of standardized methods and electronic (oscillometric) upper arm devices in individuals with hypertension, and either ambulatory blood pressure monitoring or home blood pressure monitoring in individuals with white coat effect. We specify that all individuals with hypertension should have an assessment of global cardiovascular risk to promote health behaviours that lower blood pressure. Finally, an angiotensin receptor-neprilysin inhibitor combination should be used in place of either an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker in individuals with heart failure (with ejection fraction < 40%) who are symptomatic despite appropriate doses of guideline-directed heart failure therapies. The specific evidence and rationale underlying each of these guidelines are discussed.

White-Coat Effect Is Uncommon in Patients With Refractory Hypertension

Refractory hypertension is a recently described phenotype of antihypertensive treatment failure defined as uncontrolled blood pressure (BP) despite the use of ≥5 different antihypertensive agents, including chlorthalidone and spironolactone. Recent studies indicate that refractory hypertension is uncommon, with a prevalence of ≈5% to 10% of patients referred to a hypertension specialty clinic for uncontrolled hypertension. The prevalence of white-coat effect, that is, uncontrolled automated office BP ≥135/85 mm Hg and controlled out-of-office BP <135/85 mm Hg, by awake ambulatory BP monitor in hypertensive patients overall is ≈30% to 40%. The prevalence of white-coat effect among patients with refractory hypertension has not been previously reported. In this prospective evaluation, consecutive patients referred to the University of Alabama at Birmingham Hypertension Clinic for uncontrolled hypertension were enrolled. Refractory hypertension was defined as uncontrolled automated office BP ≥135/85 mm Hg with the use of ≥5 antihypertensive agents, including chlorthalidone and spironolactone. Automated office BP measurements were based on 6 serial readings, done automatically with the use of a BpTRU device unobserved in the clinic. Out-of-office BP measurements were done by 24-hour ambulatory BP monitor. Thirty-four patients were diagnosed with refractory hypertension, of whom 31 had adequate ambulatory BP monitor readings. White-coat effect was present in only 2 patients, or 6.5% of the 31 patients with refractory hypertension, suggesting that white-coat effect is largely absent in patients with refractory hypertension. These findings suggest that white-coat effect is not a common cause of apparent lack of BP control in patients failing maximal antihypertensive treatment.

Clinical characteristics, target organ damage and associate risk factors of resistant hypertension determined by ambulatory blood pressure monitoring in patients aged ≥ 80 years

OBJECTIVES

To investigate clinical characteristics, target organ damage, and the associated risk factors of the patients aged ≥ 80 years with true resistant hypertension (RH).

METHODS

Patients aged ≥ 80 years with hypertension (n = 1163) were included in this study. The included participants attended a structured clinical examination and an evaluation of RH was carried out. The prevalence, clinical characteristics and target organ damage of patients with RH were assessed. The associated clinical risk factors were analyzed by using logistic regression.

RESULTS

The prevalence of RH diagnosis by 24-h ambulatory blood pressure monitoring assessment was 21.15%. End-diastolic left ventricular internal dimension, left ventricular mass index as well as prevalence of left ventricular hypertrophy were significantly greater in patients with RH than in control group. The common carotid artery intimal media thickness, carotid walls thickness, common carotid artery diameter and relative wall thickness were significant greater in RH group than in control. A relatively higher level of creatinine, estimated glomerular filtration rate, microalbuminuria and retinal changes was found in RH group than in control. A multivariate analysis showed that patients with a history of diabetes, higher body mass index (BMI) and lipid profiles were independent risk factors of RH.

CONCLUSIONS

The prevalence of RH in patients aged ≥ 80 years was within the range of reported rates of the general population. Subjects with RH diagnosis showed a higher occurrence of target organ damage than patients with well controlled blood pressure. Patients with diabetes, higher BMI and serum lipid profiles were independent risk factors for RH in patients aged ≥ 80 years.

Hypertension Canada's 2017 Guidelines for Diagnosis, Risk Assessment, Prevention, and Treatment of Hypertension in Adults

Hypertension Canada provides annually updated, evidence-based guidelines for the diagnosis, assessment, prevention, and treatment of hypertension. This year, we introduce 10 new guidelines. Three previous guidelines have been revised and 5 have been removed. Previous age and frailty distinctions have been removed as considerations for when to initiate antihypertensive therapy. In the presence of macrovascular target organ damage, or in those with independent cardiovascular risk factors, antihypertensive therapy should be considered for all individuals with elevated average systolic nonautomated office blood pressure (non-AOBP) readings ≥ 140 mm Hg. For individuals with diastolic hypertension (with or without systolic hypertension), fixed-dose single-pill combinations are now recommended as an initial treatment option. Preference is given to pills containing an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker in combination with either a calcium channel blocker or diuretic. Whenever a diuretic is selected as monotherapy, longer-acting agents are preferred. In patients with established ischemic heart disease, caution should be exercised in lowering diastolic non-AOBP to ≤ 60 mm Hg, especially in the presence of left ventricular hypertrophy. After a hemorrhagic stroke, in the first 24 hours, systolic non-AOBP lowering to < 140 mm Hg is not recommended. Finally, guidance is now provided for screening, initial diagnosis, assessment, and treatment of renovascular hypertension arising from fibromuscular dysplasia. The specific evidence and rationale underlying each of these guidelines are discussed.

Characterization and history of arterial hypertension leading to inpatient treatment

Background and aims

Methods

Results

Conclusion

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.

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.

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.

Nonadherence to antihypertensive medications and associated factors in general medicine clinics

OBJECTIVES

Nonadherence to antihypertensive medications has not been assessed in the Saudi population. The aim of this study was to address and evaluate the magnitude of nonadherence among hypertensive patients and the risk factors associated with it.

METHODS

A cross-sectional survey was conducted on hypertensive patients who attended the general internal medicine clinics at King Abdulaziz Medical City, Riyadh, Saudi Arabia, using a questionnaire that was modified after reviewing the literature. Hypertensive patients were labeled as nonadherent if they missed their medications for a total of 7 days during the previous month.

RESULTS

A total of 302 patients participated in the study, of whom 63% were females with a mean age of 64 years, and 64% were illiterate. The prevalence of nonadherence to medications among hypertensive patients was found to be 12.3%. Poor disease knowledge was reported in 80% of patients, while 66% of the patients had poor monitoring of their disease. Younger age (≤65 years), poor monitoring, and uncontrolled blood pressure (BP ≥140/90 mmHg) were the predictor factors associated with nonadherence (odds ratio [OR] =2.04, P=0.025; OR=2.39, P=0.004; and OR=2.86, P=0.003, respectively).

CONCLUSION

Nonadherence to antihypertensive medications is lower than that previously reported in the literature. Younger age, uncontrolled BP, and poor monitoring are the main risk factors associated with nonadherence.

Medication Routines and Adherence Among Hypertensive African Americans

Poor adherence to prescribed medication regimens remains an important challenge preventing successful treatment of cardiovascular diseases such as hypertension. While studies have documented differences in the time of day or weekday vs weekend on medication adherence, no study has examined whether having a medication-taking routine contributes to increased medication adherence. The purpose of this study was to: (1) identify patients' sociodemographic factors associated with consistent medication-taking routine; (2) examine associations between medication-taking consistency, medication adherence, and blood pressure (BP) control. The study included black patients with hypertension (n = 190; 22 men and 168 women; age, mean±standard deviation 54 ± 12.08 years) who completed a practice-based randomized controlled trial. Findings showed that medication-taking consistency was significantly associated with better medication adherence (F = 9.54, P = .002). Associations with the consistency index were not statistically significant for diastolic BP control (odds ratio, 1.319; 95% confidence interval, 0.410-4.246; P = .642) and systolic BP control (odds ratio, 0.621; 95% confidence interval, 0.195-1.974; P = .419).

Systematic review and meta-analysis of the prevalence of resistant hypertension in treated hypertensive populations

BACKGROUND

Although treatment-resistant hypertension (RH) is a serious burden on population health, there exists uncertainty about its prevalence. Hence, the objectives of this work were to systematically review and critically appraise the literature and to conduct a meta-analysis on the prevalence of RH in treated hypertensive populations.

METHODS

PubMed, Cochrane Library, CRD York databases, and study bibliographies were systematically searched for observational and interventional studies that report disease frequency in adult populations. The pooled prevalence was obtained through random-effect modeling. Furthermore, quality assessment, publication bias diagnostics, meta-regression, subgroup analysis by sex, and sensitivity analysis were performed.

RESULTS

Out of 318 retrieved studies, 20 observational studies and 4 randomized control trials (RCTs) with a total population of 961,035 were included. The random-effect method for observational studies and RCTs yielded RH prevalence ratios of 13.72% (95% confidence interval (CI) = 11.19%-16.24%) and 16.32% (95% CI = 10.68%-21.95%), respectively. Yet, most studies were incapable of ruling out pseudo-resistance caused by white-coat effect, poor medication adherence, and suboptimal dosing. Differences in RH prevalence by sex were negligible. Meta-regression analysis showed that study-level characteristics had no statistically significant influence on RH prevalence. The inclusion of further studies in the sensitivity analysis concurred with the baseline results (13.19%; 95% CI = 10.89%-15.49%).

CONCLUSIONS

Researchers should enhance comparability of future empirical evidence through homogeneous methodologies and comparable baseline populations. This meta-analysis concludes that RH is a frequent phenomenon and further harmonization in terms of RH definition and measurement would be necessary to clearly distinguish true treatment resistance from pseudo-resistance.

Renal denervation for resistant hypertension and beyond

Despite the availability of more than 125 approved antihypertensive medications, 36 million (48%) of 75 million people with hypertension, including 16 million treated with antihypertensive medications in the United States, do not achieve guideline blood pressure goals known to reduce cardiovascular morbidity and mortality and progression of kidney disease; 3% to 6% of these 75 million hypertensive individuals are estimated to have resistant hypertension. A major contributing factor for poor blood pressure control, besides inadequate diuretic therapy, is failure of antihypertensive agents to inhibit the sympathetic nervous system effectively. Consequently, alternative device-driven approaches have been developed. Recent technical advances targeting renal sympathetic nerves, that is, renal denervation therapy, are the focus of more invasive therapies to treat resistant hypertension. Encouraging results from the SYMPLICITY HTN-2 trial, regarding efficacy and safety of renal denervation therapy, were countered by disappointing efficacy results of SYMPLICITY HTN-3. Reasons for these divergent results and the future of the field are discussed.

Reinnervation following catheter-based radio-frequency renal denervation

NEW FINDINGS

What is the topic of this review? Does catheter-based renal denervation effectively denervate the afferent and efferent renal nerves and does reinnervation occur? What advances does it highlight? Following catheter-based renal denervation, the afferent and efferent responses to electrical stimulation were abolished, renal sympathetic nerve activity was absent, and levels of renal noradrenaline and immunohistochemistry for tyrosine hydroxylase and calcitonin gene-related peptide were significantly reduced. By 11 months after renal denervation, both the functional responses and anatomical markers of afferent and efferent renal nerves had returned to normal, indicating reinnervation. Renal denervation reduces blood pressure in animals with experimental hypertension and, recently, catheter-based renal denervation was shown to cause a prolonged decrease in blood pressure in patients with resistant hypertension. The randomized, sham-controlled Symplicity HTN-3 trial failed to meet its primary efficacy end-point, but there is evidence that renal denervation was incomplete in many patients. Currently, there is little information regarding the effectiveness of catheter-based renal denervation and the extent of reinnervation. We assessed the effectiveness of renal nerve denervation with the Symplicity Flex catheter and the functional and anatomical reinnervation at 5.5 and 11 months postdenervation. In anaesthetized, non-denervated sheep, there was a high level of renal sympathetic nerve activity, and electrical stimulation of the renal nerve increased blood pressure and reduced heart rate (afferent response) and caused renal vasoconstriction and reduced renal blood flow (efferent response). Immediately after renal denervation, renal sympathetic nerve activity and the responses to electrical stimulation were absent, indicating effective denervation. By 11 months after denervation, renal sympathetic nerve activity was present and the responses to electrical stimulation were normal, indicating reinnervation. Anatomical measures of renal innervation by sympathetic efferent nerves (tissue noradrenaline and tyrosine hydroxylase) and afferent sensory nerves (calcitonin gene-related peptide) demonstrated large decreases at 1 week postdenervation, but normal levels at 11 months postdenervation. In summary, catheter-based renal denervation is effective, but reinnervation occurs. Studies of central and renal changes postdenervation are required to understand the causes of the prolonged hypotensive response to catheter-based renal denervation in human hypertension.

Resistant hypertension, patient characteristics, and risk of stroke

Background

Little is known about the prognosis of resistant hypertension (RH) in Asian population. This study aimed to evaluate the impacts of RH in Taiwanese patients with hypertension, and to ascertain whether patient characteristics influence the association of RH with adverse outcomes.

Methods and Results

Patients aged ≥45 years with hypertension were identified from the National Health Insurance Research Database. Medical records of 111,986 patients were reviewed in this study, and 16,402 (14.6%) patients were recognized as having RH (continuously concomitant use of ≥3 anti-hypertensive medications, including a diuretic, for ≥2 years). Risk of major adverse cardiovascular events (MACE, a composite of all-cause mortality, acute coronary syndrome, and stroke [included both fatal and nonfatal events]) in patients with RH and non-RH was analyzed. A total of 11,856 patients experienced MACE in the follow-up period (average 7.1±3.0 years). There was a higher proportion of females in the RH group, they were older than the non-RH (63.1 vs. 60.5 years) patients, and had a higher prevalence of cardiovascular co-morbidities. Overall, patients with RH had higher risks of MACE (adjusted HR 1.17; 95%CI 1.09–1.26; p<0.001). Significantly elevated risks of stroke (10,211 events; adjusted HR 1.17; 95%CI 1.08–1.27; p<0.001), especially ischemic stroke (6,235 events; adjusted HR 1.34; 95%CI 1.20–1.48; p<0.001), but not all-cause mortality (4,594 events; adjusted HR 1.06; 95%CI 0.95–1.19; p = 0.312) or acute coronary syndrome (2,145 events; adjusted HR 1.17; 95%CI 0.99–1.39; p = 0.070) were noted in patients with RH compared to those with non-RH. Subgroup analysis showed that RH increased the risks of stroke in female and elderly patients. However, no significant influence was noted in young or male patients.

Conclusions

Patients with RH were associated with higher risks of MACE and stroke, especially ischemic stroke. The risks were greater in female and elderly patients than in male or young patients.

Updated ESH position paper on interventional therapy of resistant hypertension

Out of the overall hypertensive population it is estimated that approximately 10% have treatment resistant hypertension (TRH). Percutaneous catheter-based transluminal renal ablation (renal denervation [RDN] by delivery of radiofrequency energy) has emerged as a new approach to achieve sustained blood pressure reduction in patients with TRH. This innovative interventional technique is now available across Europe for severe TRH for those patients in whom pharmacologic strategies and lifestyle changes have failed to control blood pressure below target (usually <140/90 mmHg). In 2012, the "ESH position paper: renal denervation - an interventional therapy of resistant hypertension" was published to facilitate a better understanding of the effectiveness, safety, limitation and unresolved issues. We have now updated this position paper since numerous studies have been published over the last year providing more data about the rationale, therapeutic efficacy and safety of RDN. In the upcoming ESH/ESC guidelines for the management of arterial hypertension, therapeutic options of treatment resistant hypertension will be addressed, but only briefly, and thus it is the focus of this paper to provide detailed and updated information on this innovative interventional technique.

Renal denervation in patients with resistant hypertension: six-month results

INTRODUCTION

Increased activation of the sympathetic nervous system plays a central role in the pathophysiology of hypertension (HTN). Catheter-based renal denervation (RDN) was recently developed for the treatment of resistant HTN.

AIM

To assess the safety and efficacy of RDN for blood pressure (BP) reduction at six months in patients with resistant HTN.

METHODS

In this prospective registry of patients with essential resistant HTN who underwent RDN between July 2011 and May 2013, the efficacy of RDN was defined as ≥ 10 mm Hg reduction in office systolic blood pressure (SBP) six months after the intervention.

RESULTS

In a resistant HTN outpatient clinic, 177 consecutive patients were evaluated, of whom 34 underwent RDN (age 62.7 ± 7.6 years; 50.0% male). There were no vascular complications, either at the access site or in the renal arteries. Of the 22 patients with complete six-month follow-up, the response rate was 81.8% (n=18). The mean office SBP reduction was 22 mm Hg (174 ± 23 vs. 152 ± 22 mm Hg; p<0.001) and 9 mm Hg in diastolic BP (89 ± 16 vs. 80 ± 11 mm Hg; p=0.006). The number of antihypertensive drugs (5.5 ± 1.0 vs. 4.6 ± 1.1; p=0.010) and pharmacological classes (5.4 ± 0.7 vs. 4.6 ± 1.1; p=0.009) also decreased significantly. Of the 24-hour ambulatory BP monitoring and echocardiographic parameters analyzed, there were significant reductions in diastolic load (45 ± 29 vs. 27 ± 26%; p=0.049) and in left ventricular mass index (174 ± 56 vs. 158 ± 60 g/m(2); p=0.014).

CONCLUSION

In this cohort of patients with resistant HTN, RDN was safe and effective, with a significant BP reduction at six-month follow-up.

[Renal sympathetic denervation in treatment-resistant hypertension]

BACKGROUND

Renal denervation (RDN) has been introduced as a potential new treatment for patients with treatment-resistant hypertension, defined as a blood pressure above 140/90 mm Hg despite treatment with at least three antihypertensive drugs. We present an overview of this type of treatment, describe the method and discuss its possible future uses.

METHOD

The review is based on a discretionary selection of relevant articles from our archive, our own experience and a literature search in PubMed.

RESULTS

The use of RDN for treatment-resistant hypertension is based on a single randomised study with a total of 104 patients, in which the intervention group experienced a fall in blood pressure of 32/12 mm Hg, while blood pressure in the control group remained unchanged. More than 16,000 patients, particularly in Germany, have been treated on this basis. In the USA, data from a larger randomised study (n = 530) that includes sham surgery are awaited before any decision is made on whether to approve the method for use.

INTERPRETATION

Before RDN can become recommended treatment in Norway, more evidence is required that the method lowers blood pressure, and that this reduces morbidity and mortality.

Refractory hypertension: determination of prevalence, risk factors, and comorbidities in a large, population-based cohort

Refractory hypertension is an extreme phenotype of antihypertensive treatment failure. Participants in the REasons for Geographic And Racial Differences in Stroke (REGARDS) Study, a large (n=30 239), population-based cohort were evaluated to determine the prevalence of refractory hypertension and associated cardiovascular risk factors and comorbidities. Refractory hypertension was defined as uncontrolled blood pressure (systolic/diastolic, ≥140/90 mm Hg) on ≥5 antihypertensive drug classes. Participants with resistant hypertension (systolic/diastolic, ≥140/90 mm Hg on ≥3 or <140/90 mm Hg on ≥4 antihypertensive classes) and all participants treated for hypertension served as comparator groups. Of 14 809 REGARDS participants receiving antihypertensive treatment, 78 (0.5%) had refractory hypertension. The prevalence of refractory hypertension was 3.6% among participants with resistant hypertension (n=2144) and 41.7% among participants on ≥5 antihypertensive drug classes. Among all participants with hypertension, black race, male sex, living in the stroke belt or buckle, higher body mass index, lower heart rate, reduced estimated glomerular filtration rate, albuminuria, diabetes mellitus, and history of stroke and coronary heart disease were associated with refractory hypertension. Compared with resistant hypertension, prevalence ratios for refractory hypertension were increased for blacks (3.00; 95% confidence interval, 1.68-5.37) and those with albuminuria (2.22; 95% confidence interval, 1.40-3.52) and diabetes mellitus (2.09; 95% confidence interval, 1.32-3.31). The median 10-year Framingham risk for coronary heart disease and stroke was higher among participants with refractory hypertension when compared with those with either comparator group. These data indicate that although resistant hypertension is relatively common among treated patients with hypertension, true antihypertensive treatment failure is rare.

The possibility of resistant hypertension during the treatment of hypertensive patients

Patients with poorly controlled hypertension despite taking at least three different kinds of anti-hypertensive drugs, including diuretics, are considered to have resistant hypertension (RH). The prevalence of RH was reported to be 13% in the Japanese J-HOME study. The incidences of RH in younger and older Japanese individuals should be prospectively investigated in the near future. RH is associated with poor outcomes and various cardiovascular events. In addition, it is frequently associated with older age, obesity, sleep apnea, long-term hypertension, diabetes, dyslipidemia, reduced renal function, microalbuminuria and left ventricular hypertrophy. Some cases of RH exhibit high levels of aldosterone and cortisol, suggesting that endocrine hypertension should be ruled out among RH patients. Carotid baroreceptor activation and renal sympathetic denervation have recently been developed as treatments for RH. In conclusion, we should consider the possibility of RH during the treatment of hypertensive patients who do not achieve appropriate blood pressure control, in order to avoid the early onset of fatal cardiovascular events and reduce medical costs.

Dysfunctional brain-bone marrow communication: a paradigm shift in the pathophysiology of hypertension

It is widely accepted that the pathophysiology of hypertension involves autonomic nervous system dysfunction, as well as a multitude of immune responses. However, the close interplay of these systems in the development and establishment of high blood pressure and its associated pathophysiology remains elusive and is the subject of extensive investigation. It has been proposed that an imbalance of the neuro-immune systems is a result of an enhancement of the "proinflammatory sympathetic" arm in conjunction with dampening of the "anti-inflammatory parasympathetic" arm of the autonomic nervous system. In addition to the neuronal modulation of the immune system, it is proposed that key inflammatory responses are relayed back to the central nervous system and alter the neuronal communication to the periphery. The overall objective of this review is to critically discuss recent advances in the understanding of autonomic immune modulation, and propose a unifying hypothesis underlying the mechanisms leading to the development and maintenance of hypertension, with particular emphasis on the bone marrow, as it is a crucial meeting point for neural, immune, and vascular networks.

From bad behaviour to bad biology: pitfalls and promises in the management of resistant hypertension

Control rates for hypertension have dramatically improved during the past 2 decades-especially in Canada. However, hypertension remains one of the top risk factors for premature death globally. Furthermore, one-third of Canadians with hypertension have not obtained adequate blood pressure control. Most of these patients have resistant hypertension with uncontrolled blood pressure despite therapy. The etiology of resistant hypertension is multifactorial but includes both behavioural and biological factors. Among behavioural factors, nonadherence on the part of patients and especially clinical inertia on the part of health care professionals are contributing causes. An understanding of the root causes underlying the failure to control an individual's blood pressure is central to optimal subsequent management. Further advances in blood pressure control rates in this group of patients will depend on improvements in health care delivery systems and the further development of innovative therapies. Drugs combining multiple antihypertensive agents in a single pill and the development of new technologies to lower blood pressure, primarily by disruption of the sympathetic nervous system, have the potential to be useful strategies in this effort.

Rationale for establishing a mechanism to increase reimbursement to hypertension specialists

Hypertension is an important public health problem both in the United States and worldwide, contributing to many forms of cardiovascular and renal diseases. Although great strides have been made in the proportion of the US population that achieves recommended blood pressure targets, many Americans still have undertreated and uncontrolled blood pressure that increases the risk of expensive strokes, heart attacks, heart failure, and dialysis. Because hypertension is a common but heterogeneous and sometimes complex condition, the American Society of Hypertension (ASH) has, since 1999, designated physicians as "ASH Hypertension Specialists." Such Hypertension Specialists (as defined by ASH's Specialist Program) are fully licensed physicians with a primary board certification who are competent in all aspects of the diagnosis and treatment of hypertension, as evidenced by passing a specific examination on these topics offered by ASH's Specialist Program. These physicians have a proven track record of controlling blood pressure in "resistant hypertensive" patients, the general population whom they serve, and educating other physicians to help them achieve higher blood pressure control rates among their patient populations. This report sets out a rationale for increased reimbursement for care of hypertensive patients by ASH-Designated Hypertension Specialists.