Drug Therapy for Resistant Hypertension: Simplifying the Approach

Metabolomics Signature of Plasma Renin Activity and Linkage with Blood Pressure Response to Beta Blockers and Thiazide Diuretics in Hypertensive European American Patients

Plasma renin activity (PRA) is a predictive biomarker of blood pressure (BP) response to antihypertensives in European–American hypertensive patients. We aimed to identify the metabolic signatures of baseline PRA and the linkages with BP response to β-blockers and thiazides. Using data from the Pharmacogenomic Evaluation of Antihypertensive Responses-2 (PEAR-2) trial, multivariable linear regression adjusting for age, sex and baseline systolic-BP (SBP) was performed on European–American individuals treated with metoprolol (n = 198) and chlorthalidone (n = 181), to test associations between 856 metabolites and baseline PRA. Metabolites with a false discovery rate (FDR) < 0.05 or p < 0.01 were tested for replication in 463 European–American individuals treated with atenolol or hydrochlorothiazide. Replicated metabolites were then tested for validation based on the directionality of association with BP response. Sixty-three metabolites were associated with baseline PRA, of which nine, including six lipids, were replicated. Of those replicated, two metabolites associated with higher baseline PRA were validated: caprate was associated with greater metoprolol SBP response (β = −1.7 ± 0.6, p = 0.006) and sphingosine-1-phosphate was associated with reduced hydrochlorothiazide SBP response (β = 7.6 ± 2.8, p = 0.007). These metabolites are clustered with metabolites involved in sphingolipid, phospholipid, and purine metabolic pathways. The identified metabolic signatures provide insights into the mechanisms underlying BP response.

The efficacy of cognitive behavioral therapy-based interventions on patients with hypertension: A systematic review and meta-analysis

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CBT-based intervention has a positive effect on health outcomes in patients with hypertension.

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CBT-based intervention might be more effective for blood pressure management in hypertension patients when it is group-based, long term, and cognitive therapy based.

Recently, the benefits of cognitive behavioral therapy (CBT)-based interventions for patients with hypertension have been recognized, but there has been no systematic review that has comprehensively analyzed the efficacy of CBT on health outcomes in this population. We aimed to explore the therapeutic effect of CBT-based interventions on hypertension patients through a meta-analysis.

Relevant randomized controlled trials (RCTs) were obtained by searching electronic databases. The primary outcomes were physiological indicators (blood pressure, blood lipid profile). Secondary outcomes were psychological indicators (anxiety, depression), and the quality of sleep. Stata version 15.0 software was used to analyze the results.

A total of 15 RCTs were included. The main analysis revealed that CBT-based interventions reduced systolic pressure: −8.67 (95% CI: −10.67 to −6.67, P = 0.000); diastolic pressure: −5.82 (95% CI: −7.82 to −3.81, P = 0.000); total cholesterol levels: −0.43 (95% CI: −0.76 to −0.10, P = 0.010); depressive symptoms: −3.13 (95% CI: −4.02 to −2.24, P = 0.000); anxiety symptoms: −3.63 (95% CI: −4.40 to −2.87, P = 0.000); and improved quality of sleep: −2.93 (95% CI: −4.40 to −1.47, P = 0.000). Additionally, the results of subgroup analysis indicated that long-term group-based CBT-based interventions were particularly beneficial for blood pressure management in hypertension patients.

CBT-based interventions are effective in reducing systolic pressure, diastolic pressure, total cholesterol levels, anxiety symptoms, depressive symptoms, and improving quality of sleep in hypertension patients.

Targeting Brain Aminopeptidase A: A New Strategy for the Treatment of Hypertension and Heart Failure

The pathophysiology of heart failure (HF) and hypertension are thought to involve brain renin-angiotensin system (RAS) hyperactivity. Angiotensin III, a key effector peptide in the brain RAS, provides tonic stimulatory control over blood pressure (BP) in hypertensive rats. Aminopeptidase A (APA), the enzyme responsible for generating brain angiotensin III, constitutes a potential therapeutic target for hypertension treatment. We focus here on studies of RB150/firibastat, the first prodrug of the specific and selective APA inhibitor EC33 able to cross the blood-brain barrier. We consider its development from therapeutic target discovery to clinical trials of the prodrug. After oral administration, firibastat crosses the gastrointestinal and blood-brain barriers. On arrival in the brain, it is cleaved to generate EC33, which inhibits brain APA activity, lowering BP in various experimental models of hypertension. Firibastat was clinically and biologically well tolerated, even at high doses, in phase I trials conducted in healthy human subjects. It was then shown to decrease BP effectively in patients of various ethnic origins with hypertension in phase II trials. Brain RAS hyperactivity leads to excessive sympathetic activity, which can contribute to HF after myocardial infarction (MI). Chronic treatment with oral firibastat (4 or 8 weeks after MI) has been shown to normalize brain APA activity in mice. This effect is accompanied by a normalization of brain RAS and sympathetic activities, reducing cardiac fibrosis and hypertrophy and preventing cardiac dysfunction. Firibastat may therefore represent a novel therapeutic advance in the clinical management of patients with hypertension and potentially with HF after MI.

Evolution of a New Class of Antihypertensive Drugs: Targeting the Brain Renin-Angiotensin System

In addition to the circulating renin-angiotensin system, activation of the brain renin-angiotensin system plays an important role in the pathophysiology of hypertension. One of the major components of the brain renin-angiotensin system implicated in the development of hypertension is Ang III (angiotensin III). Brain Ang III, produced from Ang II (angiotensin II) by APA (aminopeptidase A), exerts a tonic stimulatory control over blood pressure in hypertensive rats. Targeting Ang III by inhibiting brain APA is now considered a potentially important target in the management of hypertension. This has led to development of RB150, an orally active prodrug of the specific and selective APA inhibitor, EC33. Orally administered RB150 crosses the gastrointestinal and blood-brain barriers, enters the brain where it generates 2 active molecules of EC33 that block brain APA activity. This results in decreased brain Ang III formation and reduced blood pressure in hypertensive rats. The RB150-induced blood pressure decrease is due to a reduced vasopressin release, which increases diuresis, reducing extracellular volume, a decrease in sympathetic tone, leading to a reduction of vascular resistances, and the improvement of the baroreflex function. RB150 was renamed firibastat by the World Health Organization. Phase Ia/Ib clinical trials showed that firibastat is clinically and biologically well tolerated in healthy volunteers. Clinical efficacy of firibastat in hypertensive patients was, therefore, demonstrated in 2 phase II studies. Accordingly, firibastat could represent the first drug of a novel class of antihypertensive drugs targeting the brain renin-angiotensin system.

Additivity of nebivolol/valsartan single-pill combinations versus other single-pill combinations for hypertension

The single‐pill combination (SPC) comprising nebivolol (5 mg), a vasodilatory β₁‐selective antagonist/β₃‐agonist, and valsartan (80 mg), a renin‐angiotensin‐aldosterone system inhibitor, is the only Food and Drug Administration–approved β‐blocker/renin‐angiotensin‐aldosterone system inhibitor SPC for hypertension. Additive effects of four nebivolol/valsartan SPC doses (5 mg/80 mg, 5/160 mg, 10/160 mg, 10/320 mg nebivolol/valsartan) were compared with five Food and Drug Administration–approved non–β‐blocker/renin‐angiotensin‐aldosterone system inhibitor SPCs (aliskiren/hydrochlorothiazide, aliskiren/amlodipine, valsartan/amlodipine, aliskiren/valsartan, and telmisartan/amlodipine). Additivity is the ratio of placebo‐adjusted SPC blood pressure (BP) reduction to the placebo‐adjusted monotherapy component BP reduction sums. A weighted average of comparator scores was calculated and compared vs nebivolol/valsartan. Additivity ratio scores for nebivolol/valsartan SPCs (diastolic BP range: 0.735–0.866; systolic BP range: 0.717–0.822) were similar to the comparator weighted average (diastolic BP: 0.837; systolic BP: 0.825). Among the nebivolol/valsartan SPCs, 5/80 mg had the greatest additivity (diastolic BP: 0.866; systolic BP: 0.822). BP reduction contributions with monotherapy were similar for nebivolol/valsartan 5/80 mg SPC. Additivity scores for nebivolol/valsartan and select non–β‐blocker/renin‐angiotensin‐aldosterone system inhibitor SPCs were comparable.

Blood pressure response to metoprolol and chlorthalidone in European and African Americans with hypertension

Despite the availability of many antihypertensive drug classes, half of patients with hypertension have uncontrolled blood pressure (BP). The authors sought to assess the effect of age on BP response in European American and African American patients with hypertension. Clinic BP from the PEAR2 (Pharmacogenomics Evaluation of Antihypertensive Responses 2) study was used to estimate BP responses from baseline following sequential treatment with metoprolol 100 mg twice daily and chlorthalidone 25 mg daily for 8 to 9 weeks each, with a minimum 4-week washout between treatments. BP responses to both drugs were compared in 159 European Americans and 119 African Americans by age with adjustment for baseline BP and sex. European Americans younger than 50 years responded better to metoprolol than chlorthalidone (diastolic BP: -9.6 ± 8.0 vs -5.9 ± 6.8 mm Hg, adjusted P = .003), whereas patients 50 years and older responded better to chlorthalidone than metoprolol (systolic BP: -18.7 ± 13.8 vs -13.6 ± 14.8 mm Hg, adjusted P = .008). African Americans younger than 50 years responded similarly to both drugs, whereas those 50 years and older responded better to chlorthalidone than metoprolol (-17.0 ± 13.2/-9.6 ± 7.5 vs -7.0 ± 18.6/-6.7 ± 9.3 mm Hg, adjusted P<.0001/.008). Therefore, age should be considered when selecting antihypertensive therapy in European and African American populations with hypertension.

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.

Clinical Diagnosis and Management of Resistant Hypertension

Resistant hypertension (RHT) is variably defined as insufficient blood pressure (BP) response to multiple drug treatment. Prevalence of RHT has been thoroughly studied in the recent years, ranging from about 5 to 30 % in various cohorts. Initial management of patients with apparent RHT requires identification of true treatment resistance by out-of-office BP measurements, assessment of adherence and screening for treatable causes of uncontrolled BP. Endorsement of lifestyle modifications and maximisation of the doses of a suitable regimen, preferably with the further addition of an aldosterone antagonist, are the mainstay of treatment. An invasive approach to RHT, mainly represented by renal nerve ablation, should be kept for persistently severe cases managed in a specialised hypertension centre.

Resistant hypertension: what the cardiologist needs to know

Treatment-resistant hypertension (TRH) affects between 3 and 30% of hypertensive patients, and its presence is associated with increased cardiovascular morbidity and mortality. Until recently, the interest on these patients has been limited, because providing care for them is difficult and often frustrating. However, the arrival of new treatment options [i.e. catheter-based renal denervation (RDN) and baroreceptor stimulation] has revitalized the interest in this topic. The very promising results of the initial uncontrolled studies on the blood pressure (BP)-lowering effect of RDN in TRH seemed to suggest that this intervention might represent an easy solution for a complex problem. However, subsequently, data from controlled studies have tempered the enthusiasm of the medical community (and the industry). Conversely, these new studies emphasized some seminal aspects on this topic: (i) the key role of 24 h ambulatory BP and arterial stiffness measurement to identify 'true' resistant patients; (ii) the high prevalence of secondary hypertension among this population; and (iii) the difficulty to identify those patients who may profit from device-based interventions. Accordingly, for those patients with documented TRH, the guidelines suggest to refer them to a hypertension specialist/centre in order to perform adequate work-up and treatment strategies. The aim of this review is to provide guidance for the cardiologist on how to identify patients with TRH and elucidate the prevailing underlying pathophysiological mechanism(s), to define a strategy for the identification of patients with TRH who may benefit from device-based interventions and discuss results and limitations of these interventions, and finally to briefly summarize the different drug-based treatment strategies.

Treatment resistant hypertension--investigation and conservative management

BACKGROUND

The introduction of invasive treatments, some of which are irreversible, for the entity called treatment-resistant hypertension (TRH) creates the need for a comprehensive discussion of the diagnostic evaluation that TRH requires and the available options for its conservative treatment.

METHOD

The pertinent literature is selectively reviewed in the light of the authors' longstanding clinical experience.

RESULTS

Our review of the literature suggests that the high prevalence of TRH in Germany (ca. 20%) can be nearly halved with the aid of more thorough diagnostic evaluation. Such an evaluation should include a review of the patient's antihypertensive drugs (adherence, daily dosing, concomitant medication), investigation for other vascular changes that might affect blood pressure measurement, and exclusion of white-coat hypertension, sleep apnea syndrome, and secondary rather than essential hypertension. As there have been no randomized trials of treatment for TRH, the physician confronted with such cases must devise treatments on the basis of observational data and pathophysiological reasoning (volume status considering renin levels, sympathetic blockade, vasodilatation). Such measures can presumably lower the number of truly treatment-resistant cases still further.

CONCLUSION

To save patients from preventable harm, patients should undergo a thorough diagnostic evaluation and-under close monitoring for side effects-conservative pharmacological and nonpharmacological treatments should be deployed before any invasive treatment is performed.

Detection, evaluation, and treatment of severe and resistant hypertension: proceedings from an American Society of Hypertension Interactive forum held in Bethesda, MD, U.S.A., October 10th 2013

The epidemiology, evaluation, and management of severe and resistant hypertension in the United States (US) are evolving. The American Society of Hypertension held a multi-disciplinary forum in October 2013 to review the available evidence related to the management of resistant hypertension with both drug and device therapies. There is strong evidence that resistant hypertension is an important clinical problem in the US and many other regions of the world. Complex drug therapy is effective in most of the patients with severe and resistant hypertension, but there are certain individuals who may be refractory to multiple-drug regimens or have adverse effects that make adherence to the regimen difficult. When secondary forms of hypertension and pseudo-resistance, such as medication nonadherence, or white-coat hypertension based on marked differences between clinic and 24-hour ambulatory blood pressure monitoring, have been excluded, the impact of device therapy is under evaluation through clinical trials in the US and from clinical practice registries in Europe and Australia. Clinical trial data have been obtained primarily in patients whose resistant hypertension is defined as systolic clinic blood pressures of ≥160 mm Hg (or ≥ 150 mm Hg in type 2 diabetes) despite pharmacologic treatment with at least three antihypertensive drugs (one of which is a thiazide or loop diuretic). Baroreceptor stimulation therapy has shown modest benefit in a moderately sized sham-controlled study in drug-resistant hypertension. Patients selected for renal denervation have typically been restricted to those with preserved kidney function (estimated glomerular filtration rate ≥ 45 mL/min/1.73 m2). The first sham-controlled safety and efficacy trial for renal denervation (SYMPLICITY HTN-3) did not show benefit in this population when used in addition to an average of five antihypertensive medications. Analyses of controlled clinical trial data from future trials with novel designs will be of critical importance to determine the effectiveness of device therapy for patients with severe and resistant hypertension and will allow for proper determination of patient selection and whether it will be acceptable for clinical practice. At present, the focus on the management of severe and resistant hypertension will be through careful evaluation for pseudo-resistance and secondary forms of hypertension, appropriate use of combination pharmacologic therapy, and greater utility of specialists in hypertension.

A new strategy for treating hypertension by blocking the activity of the brain renin-angiotensin system with aminopeptidase A inhibitors

Hypertension affects one-third of the adult population and is a growing problem due to the increasing incidence of obesity and diabetes. Brain RAS (renin-angiotensin system) hyperactivity has been implicated in the development and maintenance of hypertension in several types of experimental and genetic hypertension animal models. We have identified in the brain RAS that APA (aminopeptidase A) and APN (aminopeptidase N), two membrane-bound zinc metalloproteases, are involved in the metabolism of AngII (angiotensin II) and AngIII (angiotensin III) respectively. The present review summarizes the main findings suggesting that AngIII plays a predominant role in the brain RAS in the control of BP (blood pressure). We first explored the organization of the APA active site by site-directed mutagenesis and molecular modelling. The development and the use in vivo of specific and selective APA and APN inhibitors EC33 and PC18 respectively, has allowed the demonstration that brain AngIII generated by APA is one of the main effector peptides of the brain RAS, exerting a tonic stimulatory control over BP in conscious hypertensive rats. This identified brain APA as a potential therapeutic target for the treatment of hypertension, which has led to the development of potent orally active APA inhibitors, such as RB150. RB150 administered orally in hypertensive DOCA (deoxycorticosteroneacetate)-salt rats or SHRs (spontaneously hypertensive rats) crosses the intestinal, hepatic and blood-brain barriers, enters the brain, generates two active molecules of EC33 which inhibit brain APA activity, block the formation of brain AngIII and normalize BP for several hours. The decrease in BP involves two different mechanisms: a decrease in vasopressin release into the bloodstream, which in turn increases diuresis resulting in a blood volume reduction that participates in the decrease in BP and/or a decrease in sympathetic tone, decreasing vascular resistance. RB150 constitutes the prototype of a new class of centrally acting antihypertensive agents and is currently being evaluated in a Phase Ib clinical trial.

[Renal denervation a treatment for resistant hypertension: a French experience]

Arterial hypertension is the largest single contributor to global mortality, and is poorly controlled in approximately 50% of patients despite lifestyle and pharmacologic interventions. Randomized clinical trials have demonstrated that catheter-based renal sympathetic denervation reduces blood pressure (BP) in patients with resistant hypertension. We sought to evaluate the efficacy of this novel therapy in "Real World" clinical practice. Consecutive patients with treatment-resistant primary hypertension, as defined as home BP>160 mmHg despite treatment with ≥3 antihypertensive drugs, were selected for denervation following renal artery screening. Ambulatory and home BP monitoring was performed in all patients prior to and following percutaneous renal sympathetic denervation. In total, 35 patients were selected for catheter-based renal sympathetic denervation. The mean age was 63.6 ± 11.7 years, 37.1% were women, 37.1% were diabetic, and 11.4% had renal impairment (GFR<45 mL/min). The basal BP (home or ambulatory) was 179.1 ± 20.75/99.66 ± 19.76 mmHg, despite an average of 4.91 ± 0.98 medications per patient. Successful bilateral sympathetic denervation was performed in 33/35 patients (1 renal artery stenosis on angiography [not ablated], 1 patient with renal artery spasm [unilateral denervation]), with an average 5.9 ± 1.6 ablations per renal artery. No procedural complications occurred. At 6 months, blood pressure was 15.5 ± 22.37/87.76 ± 13.97 mmHg (P<0.01). At 2 years follow-up, systolic blood pressure (ABPM or Home BP) was 143.8 ± 15.30 mmHg (P<0.0001) and diastolic 83.42 ± 12.80 mmHg (P=0.0004). There were no adverse events during follow-up, and no deterioration in renal function was observed. Catheter-based renal denervation is safe and efficacious treatment, which results in significant reductions in blood pressure in patients with treatment-resistant hypertension, stable at 2 years follow-up. These results are applicable to real-world patient populations.

Definition, identification and treatment of resistant hypertension in chronic kidney disease patients

Resistant hypertension, the inability to achieve goal blood pressure despite the use of three or more appropriately dosed antihypertensive drugs (including a diuretic), remains a common clinical problem, especially in patients with chronic kidney disease (CKD). While the exact prevalence and prognosis of resistant hypertension in CKD patients remain unknown, resistant hypertension likely contributes significantly to increased cardiovascular risk and progression of kidney disease in this population. We review the identification and evaluation of patients with resistant hypertension, including the importance of 24-h ambulatory blood pressure monitoring in the identification of 'white-coat', 'masked' and 'non-dipper' hypertension, the latter of which has particular clinical and therapeutic importance in patients with resistant hypertension and CKD. We then discuss treatment strategies for resistant hypertension that target the pathophysiologic mechanisms underlying resistance to treatment, including persistent volume excess, incomplete renin-angiotensin-aldosterone system blockade and inadequate nocturnal blood pressure control. Finally, we propose a treatment algorithm for evaluation and treatment of resistant hypertension in patients with CKD.

Effectiveness of the direct renin inhibitor, aliskiren, in patients with resistant hypertension

Currently there is no consensus regarding which add-on therapy to use in resistant hypertension. We have conducted an open observational study of the use of aliskiren in resistant hypertensive patients. Forty-three patients with resistant hypertension were included in the study. The inclusion criteria were as follows: 1) office blood pressure (BP) > 140/90 mmHg despite treatment with at least three or more antihypertensive drugs; 2) no prior therapy with aliskiren; and 3) no renal insufficiency. Follow-up BP was determined at 1 and 3 months. Baseline BP was 153 ± 12/79 ± 12 mmHg. After 3 months, systolic BP (SBP) and diastolic BP (DBP) dropped significantly: 140 ± 19/73 ± 13 mmHg (P < 0.0001). Twenty-one patients (49%) had an office BP < 140/90 mmHg, and these patients were assigned to the good BP control group. Another 22 were placed into the poor BP control group. BP reductions from baseline in the good BP control group (SBP/ DBP: 19 ± 11/8 ± 7 mmHg) were larger than those in the poor BP control group (5 ± 15/3 ± 9 mmHg, P < 0.05). Mean BP (MBP) values at baseline, 1, and 3 months were higher in the poor BP control group. There was no significant difference in pulse pressure at baseline between the 2 groups. In multivariate analysis, only MBP at baseline correlated with lack of BP control. Aliskiren administration to resistant hypertensive patients was effective in reducing BP. The present findings suggest aliskiren may be useful as a fourth-line or fifth-line treatment added to other drugs in the treatment of resistant hypertension.

Treatment of hypertension in obese patients

Obesity is a global pandemic and with its rise, its associated co-morbidities are increasing in prevalence, particularly uncontrolled hypertension. Lifestyle changes should be an anchor for the management of obesity-related hypertension; however, they are difficult to sustain. Drug therapy is often necessary to achieve blood pressure control. Diuretics, inhibitors of the renin-angiotensin system, and dihydropyridine calcium channel blockers are often used as first trio, with subsequent additions of mineralocorticoid receptor antagonists and/or dual alpha/beta blocking agents. While a number of agents are currently available, 50 % of hypertensive patients remain uncontrolled. A number of novel drug and invasive therapies are in development and hold significant potential for the effective management of obesity-related hypertension.

The assessment and importance of hypertension in the dental setting

Many patients with hypertension have uncontrolled disease. The dental visit presents a unique opportunity to screen patients for undiagnosed and undertreated hypertension, which may lead to improved monitoring and treatment. Although there are no clinical studies, it is generally recommended that nonemergent procedures be avoided in patients with a blood pressure of greater than 180/110 mm Hg. Because of the high prevalence of disease and medication use for hypertension, dentists should be aware of the oral side effects of antihypertensive medications as well as the cardiovascular effects of medications commonly used during dental visits.

Treatment of hypertension in patients undergoing coronary artery by-pass grafting

Hypertension occurs in up to 80% of patients scheduled to coronary artery by-pass grafting (CABG). In hemodynamically stable patients all anti-hypertensive drugs should be continued till a day of surgery. For vast majority of patients there is no need to use blood pressure lowering agents during CABG, however it is necessary to maintain blood pressure level and avoid extreme blood pressure variations. Upon CABG hypotensive therapy should be modified to the needs of the individual patient and should be monitored individually. Treatment of hypertension ought to be started with caution with lowest possible dosage. Aggressive therapy is strongly discouraged to avoid hemodynamic collapse. Beta-blockers should be administered to all CABG patients unless contraindicated.

Resistant hypertension: concepts and approach to management

Resistant hypertension (RH), defined simply, is blood pressure (BP) requiring the use of four or more antihypertensive agents, whether controlled or uncontrolled. RH is an increasingly common problem in elderly patients and may affect as many as 20% of the hypertensive population. Unfortunately, at least 30% of patients evaluated for RH are actually adequately controlled when more carefully assessed by home BP monitoring or ambulatory BP monitoring, thus representing a white coat effect. It is also essential to exclude pseudoresistance resulting from improper BP recording techniques or failure of the patient to adhere to the prescribed treatment regimen. Concurrent use of drugs that may interfere with prescribed antihypertensive agents, including many over the counter herbal preparations, must also be excluded. The underlying mechanisms principally driving true RH include pathophysiologic abnormalities of aldosterone signaling, sodium and water retention, excessive sympathetic nervous system activity, and obstructive sleep apnea. Appropriate treatment regimens will usually include an inhibitor of the renin-angiotensin-aldosterone system, a calcium channel blocker, and a diuretic. An aldosterone receptor blocker can be instituted at any step, and is very effective as a fourth drug. Beta-blockers can also be integrated into these treatment plans and may be especially helpful when excessive sympathetic nervous system activity is suspected. Novel device therapies that interrupt sympathetic nerve stimulation at the carotid sinus and kidney are under investigation, and may add entirely new directions in the management of RH. What is most important is that treatment regimens should be targeted to specific patient profiles.

[Renal artery denervation for treating refractory hypertension]

Arterial hypertension is a major healthcare issue affecting between 30 and 40% of the adult population in industrialized countries. Despite the availability of numerous pharmaceutical treatments, arterial hypertension often remains uncontrolled. A non-negligible percentage of patients are refractory to multiple-drug therapy, which exposes them to an increased risk of cardiovascular events. Percutaneous, renal denervation using a catheter connected to a low energy radiofrequency generator has proven effective in decreasing arterial pressure in patients resistant to medical therapy, by reducing afferent nerve activity. In order to be eligible for this therapeutic approach, patients must have uncontrolled essential hypertension despite treatment with a combination of three anti-hypertensive drugs including a diuretic agent, and ≥ 45mL/min glomerular filtration rate. The initial registry study demonstrated that catheter-based sympathetic renal denervation was a simple and safe procedure resulting in a significant and durable reduction in arterial pressure. Subsequently, a randomized controlled trial (the Symplicity HTN-2 trial) showed a mean 32/12 mmHg decrease in blood pressure measurements in the group of patients who underwent renal denervation whereas no difference was observed in the control group. The reduction in blood pressure was still present at 24-month follow-up. No procedure-related complications were reported and no instances of renal artery stenosis or aneurysmal dilatation were evidenced during the follow-up period. No cases of renal function impairment or deterioration were recorded. This technique seems to be a promising strategy in patients suffering from this serious condition. In order to demonstrate the actual benefit of this technique, we report the case of two patients who underwent renal denervation in our institution.