Eligibility for Renal Denervation

Medical Measures in Hypertensives Considered Resistant

BACKGROUND

Patients with resistant hypertension are the group of hypertensive patients with the highest cardiovascular risk.

METHODS

All rules and guidelines for treatment of hypertension should be followed strictly to obtain blood pressure (BP) control in resistant hypertension. The mainstay of treatment of hypertension, also for resistant hypertension, is pharmacological treatment, which should be tailored to each patient's specific phenotype. Therefore, it is pivotal to assess nonadherence to pharmacological treatment as this remains the most challenging problem to investigate and manage in the setting of resistant hypertension.

RESULTS

Once adherence has been confirmed, patients must be thoroughly worked-up for secondary causes of hypertension. Until such possible specific causes have been clarified, the diagnosis is apparent treatment-resistant hypertension (TRH). Surprisingly few patients remain with true TRH when the various secondary causes and adherence problems have been detected and resolved. Refractory hypertension is a term used to characterize the treatment resistance in hypertensive patients using ≥5 antihypertensive drugs. All pressor mechanisms may then need blockage before their BPs are reasonably controlled.

CONCLUSIONS

Patients with resistant hypertension need careful and sustained follow-up and review of their medications and dosages at each term since medication adherence is a very dynamic process.

Cross-cultural adaptation of the Spanish MINICHAL instrument into English for use in the United Kingdom

Background

Hypertension is a highly prevalent condition, with optimal treatment to BP targets conferring significant gains in terms of cardiovascular outcomes. Understanding why some patients do not achieve BP targets would be enhanced through greater understanding of their health-related quality of life (HRQoL). However, the only English language disease-specific instruments for measurement of HRQoL in hypertension have not been validated in accordance with accepted standards. It is proposed that the Spanish MINICHAL instrument for the assessment of HRQoL in hypertension could be translated, adapted and validated for use in the United Kingdom. The aim of the study was therefore to complete this process.

Methods

The MINICHAL authors were contacted and the original instrument obtained. This was then translated into English by two independent English-speakers, with these versions then reconciled, before back-translation and subsequent production of a 2nd reconciled version. Thereafter, a final version was produced after cognitive debriefing, for administration and psychometric analysis in the target population of patients living in the Exeter area (Southwest UK) aged 18–80 years with treatment-naïve grade II-III hypertension, before, during and after 18 weeks’ intensive treatment.

Results

The English-language instrument was administered to 30 individuals (median age: 58.5 years, 53% male). Psychometric analysis demonstrated a floor effect, though no ceiling effect. Internal consistency for both state of mind (StM) and somatic manifestations (SM) dimensions of the instrument were acceptable (Cronbach’s alpha = 0.81 and 0.75), as was test–retest reliability (ICC = 0.717 and 0.961) and construct validity, which was measured through co-administration with the EQ-5D-5L and Bulpitt-Fletcher instruments. No significant associations were found between scores and patient characteristics known to affect HRQoL. The EQ-5D-5L instrument found an improvement in HRQoL following treatment, with the StM and SM dimensions of the English language MINICHAL trending to support this (d = 0.32 and 0.02 respectively).

Conclusions

The present study details the successful English translation and validation of the MINICHAL instrument for use in individuals with hypertension. The data reported also supports an improvement in HRQoL with rapid treatment of grade II-III hypertension, a strategy which has been recommended by contemporaneous European guidelines.

Trial registration ISRCTN registry number: 57475376 (assigned 25/06/2015).

Assessment of a strategy combining ambulatory blood pressure, adherence monitoring and a standardised triple therapy in resistant hypertension

PURPOSE

Poor adherence to drug therapy and inadequate drug regimens are two frequent factors responsible for the poor blood pressure (BP) control observed in patients with apparent resistant hypertension. We evaluated the efficacy of an antihypertensive management strategy combining a standardised therapy with three long acting drugs and electronic monitoring of drug adherence in patients with apparent resistant hypertension.

MATERIALS AND METHODS

In this multicentric observational study, adult patients with residual hypertension on 24 h ambulatory BP monitoring (ABMP) despite the use of three or more antihypertensive drugs could be included. Olmesartan/amlodipine (40/10 mg, single pill fixed-dose combination) and chlorthalidone (25 mg) were prescribed for 3 months in two separated electronic pills boxes (EPB). The primary outcome was 24 h ambulatory systolic BP (SBP) control at 3 months, defined as mean SBP <130 mmHg.

RESULTS

We enrolled 48 patients (36.0% women) of whom 35 had complete EPB data. After 3 months, 52.1% of patients had 24 h SBP <130 mmHg. 24 h SBP decreased by respectively -9.1 ± 15.5 mmHg, -22.8 ± 30.6 mmHg and -27.7 ± 16.6 mmHg from the tertile with the lowest adherence to the tertile with the highest adherence to the single pill combination (p = 0.024). A similar trend was observed with tertiles of adherence to chlorthalidone. Adherence superior to 90% was associated with 24 h systolic and diastolic blood pressure control in multiple logistic regression analysis (odds ratio = 14.1 (95% confidence interval 1.1-173.3, p = 0.039).

CONCLUSIONS

A simplified standardised antihypertensive therapy combined with electronic monitoring of adherence normalises SBP in about half of patients with apparent resistant hypertension. Such combined management strategy enables identifying patients who need complementary investigations and those who rather need a long-term support of their adherence.

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.

Hypertension: Do Inflammation and Immunity Hold the Key to Solving this Epidemic?

Elevated cardiovascular risk including stroke, heart failure, and heart attack is present even after normalization of blood pressure in patients with hypertension. Underlying immune cell activation is a likely culprit. Although immune cells are important for protection against invading pathogens, their chronic overactivation may lead to tissue damage and high blood pressure. Triggers that may initiate immune activation include viral infections, autoimmunity, and lifestyle factors such as excess dietary salt. These conditions activate the immune system either directly or through their impact on the gut microbiome, which ultimately produces chronic inflammation and hypertension. T cells are central to the immune responses contributing to hypertension. They are activated in part by binding specific antigens that are presented in major histocompatibility complex molecules on professional antigen-presenting cells, and they generate repertoires of rearranged T-cell receptors. Activated T cells infiltrate tissues and produce cytokines including interleukin 17A, which promote renal and vascular dysfunction and end-organ damage leading to hypertension. In this comprehensive review, we highlight environmental, genetic, and microbial associated mechanisms contributing to both innate and adaptive immune cell activation leading to hypertension. Targeting the underlying chronic immune cell activation in hypertension has the potential to mitigate the excess cardiovascular risk associated with this common and deadly disease.

Adherence in Hypertension

The global epidemic of hypertension is largely uncontrolled and hypertension remains the leading cause of noncommunicable disease deaths worldwide. Suboptimal adherence, which includes failure to initiate pharmacotherapy, to take medications as often as prescribed, and to persist on therapy long-term, is a well-recognized factor contributing to the poor control of blood pressure in hypertension. Several categories of factors including demographic, socioeconomic, concomitant medical-behavioral conditions, therapy-related, healthcare team and system-related factors, and patient factors are associated with nonadherence. Understanding the categories of factors contributing to nonadherence is useful in managing nonadherence. In patients at high risk for major adverse cardiovascular outcomes, electronic and biochemical monitoring are useful for detecting nonadherence and for improving adherence. Increasing the availability and affordability of these more precise measures of adherence represent a future opportunity to realize more of the proven benefits of evidence-based medications. In the absence of new antihypertensive drugs, it is important that healthcare providers focus their attention on how to do better with the drugs they have. This is the reason why recent guidelines have emphasize the important need to address drug adherence as a major issue in hypertension management.

Rapid treatment of moderate to severe hypertension using a novel protocol in a single-centre, before and after interventional study

Rapid treatment to target in hypertension may have beneficial effects on long-term outcomes. This has led to a new recommendation in the 2018 European hypertension guidelines for patients with grade II/III hypertension to be treated to target within three months. However, whether it is feasible and safe to quickly manage treatment-naïve grade II/III hypertension to target was unclear. We examined this using a single-centre before and after interventional study, treating newly diagnosed, never-treated, grade II/III hypertensive patients with a daytime average systolic ABP ≥ 150 mmHg to target within 18 weeks. The proportion at office target BP at 18 weeks was determined, together with office and ambulatory BP change from baseline to after the intervention. The protocol was designed to maximise medication adherence, including a low threshold for treatment adaptation. Safety was evaluated through close monitoring of adverse events and protocol discontinuation. Fifty-five participants were enrolled with 54 completing the protocol. 69 ± 12.3% were at office target BP at their final visit, despite a high average starting BP of 175/103 mmHg, as a consequence of significant reductions in both office and ambulatory BP. Of those at office target BP, 51% were above target on ambulatory measurement. Adherence testing demonstrated that 92% of participants were adherent to treatment at their final visit. Therefore we conclude that the accelerated management of treatment-naïve grade II/III hypertension is feasible and safe to implement in routine practice and there is no evidence to suggest it causes harm. Further large-scale randomised studies of rapid, adaptive treatment, including a cost-effectiveness analysis, are required.

Arterial Hypertension

BACKGROUND

Essential arterial hypertension is one of the main treatable cardiovascular risk factors. In Germany, approximately 13% of women and 18% of men have uncontrolled high blood pressure (≥ 140/90 mmHg).

METHODS

This review is based on pertinent publications retrieved by a selective literature search in PubMed.

RESULTS

Arterial hypertension is diagnosed when repeated measurements in a doctor's office yield values of 140/90 mmHg or higher. The diagnosis should be confirmed by 24-hour ambulatory blood pressure monitoring or by home measurement. Further risk factors and end-organ damage should be considered as well. According to the current European guidelines, the target blood pressure for all patients, including those with diabetes mellitus or renal failure, is <140/90 mmHg. If the treatment is well tolerated, further lowering of blood pressure, with a defined lower limit, is recommended for most patients. The main non-pharmacological measures against high blood pressure are reduction of salt in the diet, avoidance of excessive alcohol consumption, smoking cessation, a balanced diet, physical exercise, and weight loss. The first-line drugs for arterial hypertension include long-acting dihydropyridine calcium channel blockers, angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers, and thiazide-like diuretics. Mineralocorticoid-receptor blockers are effective in patients whose blood pressure cannot be brought into acceptable range with first-line drugs.

CONCLUSION

In most patients with essential hypertension, the blood pressure can be well controlled and the cardiovascular risk reduced through a combination of lifestyle interventions and first-line antihypertensive drugs.

Cardiovascular morbidity of severe resistant hypertension among treated uncontrolled hypertensives: a 4-year follow-up study

Data regarding the prognosis of resistant hypertension (RHTN) with respect to its severity is limited. We investigated the cardiovascular risk of severe RHTN in a prospective observational study. A cohort of 1700 hypertensive patient with treated uncontrolled HTN was followed for a mean period of 3.6 ± 1.8 years. At baseline, standard clinical and laboratory workup was performed, including testing for secondary causes of RHT where applicable. Three groups were identified depending on presence of RHTN (office-based uncontrolled HTN under at least three drugs including a diuretic) and levels of office systolic blood pressure (BP): 1187 patients (70%) without RHTN, 313 (18%) with not-severe RHTN (systolic BP < 160 mmHg) and 200 (12%) with severe RHTN (systolic BP ≥ 160 mmHg). Endpoint of interest was cardiovascular morbidity set as the composite of coronary heart disease and stroke. During follow-up, incidence rates of cardiovascular events per 1000 person-years were 7.1 cases in the non-RHTN group, 12.4 cases in the not-severe RHTN group and 18 cases in the severe RHTN group. Unadjusted analysis showed that compared to uncontrolled patients without RHTN, patients with not-severe RHTN exhibited a similar risk but patients with severe RHTN had a significantly higher risk, by 2.5 times (CI: 1.28-4.73, p = 0.007). Even after multivariate adjustment for established risk factors including BP levels and isolated systolic HTN, severe RHTN remained as an independent predictor of the cardiovascular outcome (OR: 2.30, CI: 1.00-5.29, p = 0.05). In conclusion, among treated yet uncontrolled hypertensive patients, severe RHTN exhibits a significantly higher cardiovascular risk indicating the need for prompt management.

Personalised Single-Pill Combination Therapy in Hypertensive Patients: An Update of a Practical Treatment Platform

Despite the improvements in the management of hypertension during the last three decades, it continues to be one of the leading causes of cardiovascular morbidity and mortality worldwide. Effective and sustained reductions in blood pressure (BP) reduce the incidence of myocardial infarction, stroke, congestive heart failure and cardiovascular death. However, the proportion of patients who achieve the recommended BP goal (< 140/90 mmHg) is persistently low, worldwide. Poor adherence to therapy, complex therapeutic regimens, clinical inertia, drug-related adverse events and multiple risk factors or comorbidities contribute to the disparity between the potential and actual BP control rate. Previously we published a practical therapeutic platform for the treatment of hypertension based on clinical evidence, guidelines, best practice and clinical experience. This platform provides a personalised treatment approach and can be used to improve BP control and simplify treatment. It uses long-acting, effective and well-tolerated angiotensin receptor blocker (ARB) olmesartan, in combination with a calcium channel blocker amlodipine, and/or a thiazide diuretic hydrochlorothiazide. These drugs were selected based on the availability in most European Countries of single-pill, fixed formulations in a wide range of doses for both dual- and triple-drug combinations. The platform approach could be applied to other ARBs or angiotensin-converting enzyme inhibitors available in single-pill, fixed-dose combinations. Here, we present an update, which takes into account the results of the recently published studies and extends the applicability of the platform to common conditions that are often neglected or poorly considered in clinical practice guidelines.

Renal vascular calcification and response to renal nerve denervation in resistant hypertension

Renal sympathetic nerve denervation (RDN) is accepted as a treatment option for patients with resistant hypertension. However, results on decline in ambulatory blood pressure (BP) measurement (ABPM) are conflicting. The high rate of nonresponders may be related to increased systemic vascular stiffness rather than sympathetic overdrive. A single center, prospective registry including 26 patients with treatment resistant hypertension who underwent RDN at the Isala Hospital in the Netherlands. Renal perivascular calcium scores were obtained from noncontrast computed tomography scans. Patients were divided into 3 groups based on their calcium scores (group I: low 0-50, group II: intermediate 50-1000, and group III: high >1000). The primary end point was change in 24-hour ABPM at 6 months follow-up post-RDN compared to baseline. Seven patients had low calcium scores (group I), 13 patients intermediate (group II), and 6 patients had high calcium scores (group III). The groups differed significantly at baseline in age and baseline diastolic 24-hour ABPM. At 6-month follow-up, no difference in 24-hour systolic ABPM response was observed between the 3 groups; a systolic ABPM decline of respectively -9 ± 12, -6 ± 12, -12 ± 10 mm Hg was found. Also the decline in diastolic ambulatory and office systolic and diastolic BP was not significantly different between the 3 groups at follow-up. Our preliminary data showed that the extent of renal perivascular calcification is not associated with the ABPM response to RDN in patients with resistant hypertension.

Renal artery and parenchymal changes after renal denervation: assessment by magnetic resonance angiography

Objectives

Relatively little is known about the incidence of long-term renal damage after renal denervation (RDN), a potential new treatment for hypertension. In this study the incidence of renal artery and parenchymal changes, assessed with contrast-enhanced magnetic resonance angiography (MRA) after RDN, is investigated.

Methods

This study is an initiative of ENCOReD, a collaboration of hypertension expert centres. Patients in whom an MRA was performed before and after RDN were included. Scans were evaluated by two independent, blinded radiologists. Primary outcome was the change in renal artery morphology and parenchyma.

Results

MRAs from 96 patients were analysed. Before RDN, 41 renal anomalies were observed, of which 29 mostly mild renal artery stenoses. After a median time of 366 days post RDN, MRA showed a new stenosis (25–49% lumen reduction) in two patients and progression of pre-existing lumen reduction in a single patient. No other renal changes were observed and renal function remained stable.

Conclusions

We observed new or progressed renal artery stenosis in three out of 96 patients, after a median time of 12 months post RDN (3.1%). Procedural angiographies showed that ablations were applied near the observed stenosis in only one of the three patients.

Key Points

• The incidence of vascular changes 12 months post RDN was 3.1%.

• No renal vascular or parenchymal changes other than stenoses were observed.

• Ablations were applied near the stenosis in only one of three patients.

Electronic supplementary material

The online version of this article (doi:10.1007/s00330-017-4770-7) contains supplementary material, which is available to authorized users.

A perspective on sympathetic renal denervation in chronic congestive heart failure

Medical therapy has indisputably been the mainstay of management for chronic congestive heart failure. However, a significant percentage of patients continue to experience worsening heart failure (HF) symptoms despite treatment with multiple therapeutic agents. Recently, catheter-based interventional strategies that interrupt the renal sympathetic nervous system have shown promising results in providing better symptom control in patients with HF. In this article, we will review the pathophysiology of HF for better understanding of the interplay between the cardiovascular system and the kidney. Subsequently, we will briefly discuss pivotal renal denervation (RDN) therapy trials in patients with resistant hypertension and then present the available evidence on the role of RDN in HF therapy.

Guest Editorial Challenges in Resistant Hypertension

Hypertension is the major risk factor for disease and premature death. Although the efficacy of antihypertensive therapy is undisputed, few patients reach target blood pressure. Steps to improve treatment and control include assessment of global cardiovascular risk for the individual patient, improving caregiver support, education and organisation, increasing treatment persistence, using out of office blood pressure monitoring more often, detecting secondary hypertension forms, and referring patients with remaining uncontrolled hypertension to a specialist hypertension centre. In conclusion, there is room for improvement of blood pressure control in hypertensive patients. The clinical benefit of improved blood pressure control may be considerable. This may be particularly true for patients with resistant hypertension.

Chronic Kidney Disease As a Potential Indication for Renal Denervation

Renal denervation is being used as a blood pressure lowering therapy for patients with apparent treatment resistant hypertension. However, this population does not represent a distinct disease condition in which benefit is predictable. In fact, the wide range in effectiveness of renal denervation could be a consequence of this heterogeneous pathogenesis of hypertension. Since renal denervation aims at disrupting sympathetic nerves surrounding the renal arteries, it seems obvious to focus on patients with increased afferent and/or efferent renal sympathetic nerve activity. In this review will be argued, from both a pathophysiological and a clinical point of view, that chronic kidney disease is particularly suited to renal denervation.

Renal denervation in the era of HTN-3. Comprehensive review and glimpse into the future

The pathophysiological role of sympathetic overactivity in conditions such as hypertension has been well documented. Catheter-based renal denervation (RDN) is a minimally invasive percutaneous procedure which aims to disrupt sympathetic nerve afferent and efferent activity through the application of radiofrequency energy directly within the renal artery wall. This technique has emerged as a very promising treatment with dramatic effects on refractory hypertension but also in other conditions in which a sympathetic influence is present. Several studies have evaluated the safety and efficacy of this procedure, presently surrounded by controversy since the recent outcome of Symplicity HTN-3, the first randomized, sham-control trial, which failed to confirm RDN previous reported benefits on BP and cardiovascular risk lowering. Consequently, although some centers halted their RDN programs, research continues and both the concept of denervation and treatment strategies are being redefined to identify patients who can drive the most benefit from this technology. In the United States, the Food and Drug Administration (FDA) has appropriately mandated that RDN remains an investigative procedure and a new generation of sham-controlled trials are ongoing and aimed to assess not only its efficacy against pharmacotherapy but also trials in drug free patients with the objective of demonstrating once and for all whether the procedure actually does lower BP in comparison to a placebo arm. In this article, we present an overview of the sympathetic nervous system and its role in hypertension, examine the current data on RDN, and share some insights and future expectations.

Adherence to medication and drug monitoring in apparent treatment-resistant hypertension

Poor drug adherence is one of the main reasons for the failure to achieve treatment targets in hypertensive patients. In patients who receive pharmacological treatment, assessment of drug adherence is of the utmost importance. The aim of this review is to present an update of the methods available to reveal and monitor non-adherence in patients with apparent treatment-resistant hypertension. Methods for monitoring adherence are divided into indirect and direct methods. The indirect methods are mainly based on self-reported adherence and can easily be manipulated by the patient. Directly observed therapy and therapeutic drug monitoring are examples of direct methods. There are limitations and advantages to all of the methods, and because of the patient's ability to manipulate the outcome of indirect methods, direct methods should be preferred. Therapeutic drug monitoring and directly observed therapy with subsequent ambulatory blood pressure measurement are considered to be reliable methods and should be used more in the routine assessment of patients with apparent treatment-resistant hypertension.

Retrospective morphometric study of the suitability of renal arteries for renal denervation according to the Symplicity HTN2 trial criteria

OBJECTIVE

The aim of this study was to describe the renal arteries of humans in vivo, as precisely as possible, and to formulate an expected value for the exclusion of renal denervation due to the anatomical situation based on the criteria of the Symplicity HTN trials.

DESIGN AND SETTING

In a retrospective cohort study, the renal arteries of 126 patients (57 women, 69 men, mean age 60 ± 17.2 years (CI 57.7 to 63.6)) were segmented semiautomatically from high-contrast CT angiographies.

RESULTS

Among the 300 renal arteries, there were three arteries with fibromuscular dysplasia and one with ostial renal artery stenosis. The first left renal artery was shorter than the right (34 ± 11.4 mm (CI 32 to 36) vs 45.9 ± 15 mm (CI 43.2 to 48.6); p<0.0001), but had a slightly larger diameter (5.2 ± 1.4 mm (CI 4.9 to 5.4) vs 4.9 ± 1.2 mm (CI 4.6 to 5.1); p>0.05). The first left renal arteries were 1.1 ± 0.4 mm (CI 0.9 to 1.3), and the first right renal arteries were 0.3 ± 0.6 mm (CI 0.1 to 0.5) thinner in women than in men (p<0.05). Ostial funnels were up to 14 mm long. The cross-sections were elliptical, more pronounced on the right side (p<0.05). In 23 cases (18.3%), the main artery was shorter than 2 cm; in 43 cases (34.1%), the diameter was not >4 mm. Some 46% of the patients, or 58.7% when variants and diseases were taken into consideration, were theoretically not suitable for denervation.

CONCLUSIONS

Based on these precise measurements, the anatomical situation as a reason for ruling out denervation appears to be significantly more common than previously suspected. Since this can be the cause of the failure of treatment in some cases, further development of catheters or direct percutaneous approaches may improve success rates.

Role of Adding Spironolactone and Renal Denervation in True Resistant Hypertension: One-Year Outcomes of Randomized PRAGUE-15 Study

This randomized, multicenter study compared the relative efficacy of renal denervation (RDN) versus pharmacotherapy alone in patients with true resistant hypertension and assessed the effect of spironolactone addition. We present here the 12-month data. A total of 106 patients with true resistant hypertension were enrolled in this study: 52 patients were randomized to RDN and 54 patients to the spironolactone addition, with baseline systolic blood pressure of 159±17 and 155±17 mm Hg and average number of drugs 5.1 and 5.4, respectively. Twelve-month results are available in 101 patients. The intention-to-treat analysis found a comparable mean 24-hour systolic blood pressure decline of 6.4 mm Hg, P=0.001 in RDN versus 8.2 mm Hg, P=0.002 in the pharmacotherapy group. Per-protocol analysis revealed a significant difference of 24-hour systolic blood pressure decline between complete RDN (6.3 mm Hg, P=0.004) and the subgroup where spironolactone was added, and this continued within the 12 months (15 mm Hg, P= 0.003). Renal artery computed tomography angiograms before and after 1 year post-RDN did not reveal any relevant changes. This study shows that over a period of 12 months, RDN is safe, with no serious side effects and no major changes in the renal arteries. RDN in the settings of true resistant hypertension with confirmed compliance is not superior to intensified pharmacological treatment. Spironolactone addition (if tolerated) seems to be more effective in blood pressure reduction.

Sympathetic overactivity occurs before hypertension in the two-kidney, one-clip model

Our knowledge of mechanisms responsible for both the development and the maintenance of hypertension remains incomplete in the Goldblatt (two-kidney, one-clip; 2K1C) model. We tested the hypothesis that elevated sympathetic nerve activity (SNA) occurs before the onset of hypertension in 2K1C rats, considering the time course of the increase in SNA in relationship to the onset of the hypertension. We used a decorticated in situ working heart-brainstem preparation of three groups of male Wistar rats, namely sham-operated animals (SHAM, n = 7) and animals 3 weeks post-2K1C, of which some were hypertensive (2K1C-H, n = 6) and others normotensive (2K1C-N, n = 9), as determined in vivo a priori. Perfusion pressure was higher in both 2K1C groups (2K1C-H, 76 ± 1 mmHg; 2K1C-N, 74 ± 3 mmHg; versus SHAM, 60 ± 2 mmHg, P < 0.05). The SNA was significantly elevated in both 2K1C groups (2K1C-H, 47.7 ± 6.1 μV; 2K1C-N, 32.8 ± 2.8 μV; versus SHAM, 20.5 ± 2.5 μV, P < 0.05) owing to its increased respiratory modulation; the chemoreflex was augmented and baroreflex depressed. Precollicular transection reduced SNA in all groups (2K1C-H, -32.5 ± 7.5%; 2K1C-NH, -48 ± 6.9%; versus SHAM, -13.2 ± 1%, P < 0.05). Subsequent medullary spinal cord transection abolished SNA in both SHAM and 2K1C-N groups, but decreased it by only 57 ± 5.5% in 2K1C-H preparations. Thus, SNA is raised before the onset of hypertension, by the third week after renal artery clipping, and this originates, in part, from its enhanced respiratory modulation. Spinal circuits contribute to the elevation of SNA in the 2K1C model, but only after hypertension has developed.

Screening for non-adherence to antihypertensive treatment as a part of the diagnostic pathway to renal denervation

Renal denervation is a potential therapeutic option for resistant hypertension. A thorough clinical assessment to exclude reversible/spurious causes of resistance to antihypertensive therapy is required prior to this procedure. The extent to which non-adherence to antihypertensive treatment contributes to apparent resistance to antihypertensive therapy in patients considered for renal denervation is not known. Patients (n=34) referred for renal denervation entered the evaluation pathway that included screening for adherence to antihypertensive treatment by high-performance liquid chromatography-tandem mass spectrometry-based urine analysis. Biochemical non-adherence to antihypertensive treatment was the most common cause of non-eligibility for renal denervation-23.5% of patients were either partially or completely non-adherent to prescribed antihypertensive treatment. About 5.9% of those referred for renal denervation had admitted non-adherence prior to performing the screening test. Suboptimal pharmacological treatment of hypertension and 'white-coat effect' accounted for apparently resistant hypertension in a further 17.7 and 5.9% of patients, respectively. Taken together, these three causes of pseudo-resistant hypertension accounted for 52.9% of patients referred for renal denervation. Only 14.7% of referred patients were ultimately deemed eligible for renal denervation. Without biochemical screening for therapeutic non-adherence, the eligibility rate for renal denervation would have been 38.2%. Non-adherence to antihypertensive treatment and other forms of therapeutic pseudo-resistance are by far the most common reason of 'resistant hypertension' in patients referred for renal denervation. We suggest that inclusion of biochemical screening for non-adherence to antihypertensive treatment may be helpful in evaluation of patients with 'resistant hypertension' prior to consideration of renal denervation.

Renal denervation for the treatment of resistant hypertension: review and clinical perspective

When introduced clinically 6 years ago, renal denervation was thought to be the solution for all patients whose blood pressure could not be controlled by medication. The initial two studies, SYMPLICITY HTN-1 and HTN-2, demonstrated great magnitudes of blood pressure reduction within 6 mo of the procedure and were based on a number of assumptions that may not have been true, including strict adherence to medication and absence of white-coat hypertension. The SYMPLICITY HTN-3 trial controlled for all possible factors believed to influence the outcome, including the addition of a sham arm, and ultimately proved the demise of the initial overly optimistic expectations. This trial yielded a much lower blood pressure reduction compared with the previous SYMPLICITY trials. Since its publication in 2014, there have been many analyses to try and understand what accounted for the differences. Of all the variables examined that could influence blood pressure outcomes, the extent of the denervation procedure was determined to be inadequate. Beyond this, the physiological mechanisms that account for the heterogeneous fall in arterial pressure following renal denervation remain unclear, and experimental studies indicate dependence on more than simply reduced renal sympathetic activity. These and other related issues are discussed in this paper. Our perspective is that renal denervation works if done properly and used in the appropriate patient population. New studies with new approaches and catheters and appropriate controls will be starting later this year to reassess the efficacy and safety of renal denervation in humans.

Optimum and stepped care standardised antihypertensive treatment with or without renal denervation for resistant hypertension (DENERHTN): a multicentre, open-label, randomised controlled trial

BACKGROUND

Conflicting blood pressure-lowering effects of catheter-based renal artery denervation have been reported in patients with resistant hypertension. We compared the ambulatory blood pressure-lowering efficacy and safety of radiofrequency-based renal denervation added to a standardised stepped-care antihypertensive treatment (SSAHT) with the same SSAHT alone in patients with resistant hypertension.

METHODS

The Renal Denervation for Hypertension (DENERHTN) trial was a prospective, open-label randomised controlled trial with blinded endpoint evaluation in patients with resistant hypertension, done in 15 French tertiary care centres specialised in hypertension management. Eligible patients aged 18-75 years received indapamide 1·5 mg, ramipril 10 mg (or irbesartan 300 mg), and amlodipine 10 mg daily for 4 weeks to confirm treatment resistance by ambulatory blood pressure monitoring before randomisation. Patients were then randomly assigned (1:1) to receive either renal denervation plus an SSAHT regimen (renal denervation group) or the same SSAHT alone (control group). The randomisation sequence was generated by computer, and stratified by centres. For SSAHT, after randomisation, spironolactone 25 mg per day, bisoprolol 10 mg per day, prazosin 5 mg per day, and rilmenidine 1 mg per day were sequentially added from months two to five in both groups if home blood pressure was more than or equal to 135/85 mm Hg. The primary endpoint was the mean change in daytime systolic blood pressure from baseline to 6 months as assessed by ambulatory blood pressure monitoring. The primary endpoint was analysed blindly. The safety outcomes were the incidence of acute adverse events of the renal denervation procedure and the change in estimated glomerular filtration rate from baseline to 6 months. This trial is registered with ClinicalTrials.gov, number NCT01570777.

FINDINGS

Between May 22, 2012, and Oct 14, 2013, 1416 patients were screened for eligibility, 106 of those were randomly assigned to treatment (53 patients in each group, intention-to-treat population) and 101 analysed because of patients with missing endpoints (48 in the renal denervation group, 53 in the control group, modified intention-to-treat population). The mean change in daytime ambulatory systolic blood pressure at 6 months was -15·8 mm Hg (95% CI -19·7 to -11·9) in the renal denervation group and -9·9 mm Hg (-13·6 to -6·2) in the group receiving SSAHT alone, a baseline-adjusted difference of -5·9 mm Hg (-11·3 to -0·5; p=0·0329). The number of antihypertensive drugs and drug-adherence at 6 months were similar between the two groups. Three minor renal denervation-related adverse events were noted (lumbar pain in two patients and mild groin haematoma in one patient). A mild and similar decrease in estimated glomerular filtration rate from baseline to 6 months was observed in both groups.

INTERPRETATION

In patients with well defined resistant hypertension, renal denervation plus an SSAHT decreases ambulatory blood pressure more than the same SSAHT alone at 6 months. This additional blood pressure lowering effect may contribute to a reduction in cardiovascular morbidity if maintained in the long term after renal denervation.

FUNDING

French Ministry of Health.

Global- and renal-specific sympathoinhibition in aldosterone hypertension

Recent technology for chronic electric activation of the carotid baroreflex and renal nerve ablation provide global and renal-specific suppression of sympathetic activity, respectively, but the conditions for favorable antihypertensive responses in resistant hypertension are unclear. Because inappropriately high plasma levels of aldosterone are prevalent in these patients, we investigated the effects of baroreflex activation and surgical renal denervation in dogs with hypertension induced by chronic infusion of aldosterone (12 μg/kg per day). Under control conditions, basal values for mean arterial pressure and plasma norepinephrine concentration were 100±3 mm Hg and 134±26 pg/mL, respectively. By day 7 of baroreflex activation, plasma norepinephrine was reduced by ≈40% and arterial pressure by 16±2 mm Hg. All values returned to control levels during the recovery period. Arterial pressure increased to 122±5 mm Hg concomitant with a rise in plasma aldosterone concentration from 4.3±0.4 to 70.0±6.4 ng/dL after 14 days of aldosterone infusion, with no significant effect on plasma norepinephrine. After 7 days of baroreflex activation at control stimulation parameters, the reduction in plasma norepinephrine was similar but the fall in arterial pressure (7±1 mm Hg) was diminished (≈55%) during aldosterone hypertension when compared with control conditions. Despite sustained suppression of sympathetic activity, baroreflex activation did not have central actions to inhibit either the stimulation of vasopressin secretion or drinking induced by increased plasma osmolality during chronic aldosterone infusion. Finally, renal denervation did not attenuate aldosterone hypertension. These findings suggest that aldosterone excess may portend diminished blood pressure lowering to global and especially renal-specific sympathoinhibition during device-based therapy.

Renal denervation--hypes and hopes

Catheter-based renal denervation (RDN) is a novel invasive approach in the treatment of resistant hypertension. It is considered a minimally invasive and safe procedure which, as shown by initial experimental and clinical trials, is able not only to reduce blood pressure but also to modify its risk factors by modulation of autonomic nervous system. Recently published results of a randomized Symplicity HTN-3 trial, which failed to demonstrate RDN-induced reduction of blood pressure at six months, decreased the initial enthusiasm regarding RDN and raised a question about real efficacy of this procedure. Nevertheless, still there are some other conditions characterized by increased sympathetic tone such as heart failure, atrial fibrillation, or ventricular arrhythmias that may benefit from RDN. Furthermore, novel therapeutical approach toward RDN using adapted electrophysiological or new specially designed electrodes may improve effectiveness of RDN procedure.

Renal denervation

PURPOSE OF REVIEW

Renal denervation (RDN) has, within recent years, been suggested as a novel treatment option for patients with resistant hypertension. This review summarizes the current knowledge on this procedure as well as limitations and questions that remain to be answered.

RECENT FINDINGS

The Symplicity HTN-1 (2009) and HTN-2 (2010) studies re-introduced an old treatment approach for resistant hypertension and showed that catheter-based RDN was feasible and resulted in substantial blood pressure (BP) reductions. However, they also raised questions of durability of BP reduction, correct patient selection, anatomical and physiological effects of RDN as well as possible beneficial effects on other diseases with increased sympathetic activity. The long awaited Symplicity HTN-3 (2014) results illustrated that the RDN group and the sham-group had similar reductions in BP.

SUMMARY

Initial studies demonstrated that RDN in patients with resistant hypertension was both feasible and safe and indicated that RDN may lead to impressive reductions in BP. However, recent controlled studies question the BP lowering effect of RDN treatment. Large-scale registry data still supports the favorable BP reducing effect of RDN. We suggest that, in the near future, RDN should not be performed outside clinical studies. The degree of denervation between individual operators and between different catheters and techniques used should be clarified. The major challenge ahead is to identify which patients could benefit from RDN, to clarify the lack of an immediate procedural success parameter, and to establish further documentation of overall effect of treatment such as long-term cardiovascular morbidity and mortality.

Renal denervation after Symplicity HTN-3: an update

After three years of excessive confidence, overoptimistic expectations and performance of 15 to 20,000 renal denervation procedures in Europe, the failure of a single well-designed US trial—Symplicity HTN-3—to meet its primary efficacy endpoint has cast doubt on renal denervation as a whole. The use of a sound methodology, including randomisation and blinded endpoint assessment was enough to see the typical 25–30 mmHg systolic blood pressure decrease observed after renal denervation melt down to less than 3 mmHg, the rest being likely explained by Hawthorne and placebo effects, attenuation of white coat effect, regression to the mean and other physician and patient-related biases. The modest blood pressure benefit directly assignable to renal denervation should be balanced with unresolved safety issues, such as potentially increased risk of renal artery stenosis after the procedure (more than ten cases reported up to now, most of them in 2014), unclear long-term impact on renal function and lack of morbidity–mortality data. Accordingly, there is no doubt that renal denervation is not ready for clinical use. Still, renal denervation is supported by a strong rationale and is occasionally followed by major blood pressure responses in at-risk patients who may otherwise have remained uncontrolled. Upcoming research programmes should focus on identification of those few patients with truly resistant hypertension who may derive a substantial benefit from the technique, within the context of well-designed randomised trials and independent registries. While electrical stimulation of baroreceptors and other interventional treatments of hypertension are already “knocking at the door”, the premature and uncontrolled dissemination of renal denervation should remain an example of what should not be done, and trigger radical changes in evaluation processes of new devices by national and European health authorities.

Renal sympathetic denervation after Symplicity HTN-3 and therapeutic drug monitoring in severe hypertension

Renal sympathetic denervation (RDN) has been and is still proposed as a new treatment modality in patients with apparently treatment resistant hypertension (TRH), a condition defined as persistent blood pressure elevation despite prescription of at least 3 antihypertensive drugs including a diuretic. However, the large fall in blood pressure after RDN reported in the first randomized study, Symplicity HTN-2 and multiple observational studies has not been confirmed in five subsequent prospective randomized studies and may be largely explained by non-specific effects such as improvement of drug adherence in initially poorly adherent patients (the Hawthorne effect), placebo effect and regression to the mean. The overall blood-pressure lowering effect of RDN seems rather limited and the characteristics of true responders are largely unknown. Accordingly, RDN is not ready for clinical practice. In most patients with apparently TRH, drug monitoring and improvement of drug adherence may prove more effective and cost-beneficial to achieve blood pressure control. In the meantime, research should aim at identifying characteristics of those patients with truly TRH who may respond to RDN.

Renal Denervation After Symplicity HTN-3 - Back to Basics. Review of the Evidence

Renal sympathetic denervation (RDN) has been proposed as a new treatment modality in patients with apparent treatment resistant hypertension, a condition defined as office blood pressure elevation despite prescription of at least three antihypertensive drugs including a diuretic. However, the impressive fall in blood pressure reported after RDN in Symplicity HTN-2, the first randomised study, and multiple observational studies has not been confirmed in the US sham-controlled trial Symplicity HTN-3 and four subsequent prospective randomised studies, all published or presented in 2014. The blood pressure reduction documented in earlier studies may be largely due to non-specific effects such as improvement of drug adherence in initially poorly adherent patients (Hawthorne effect), placebo effect and regression to the mean. The overall blood pressure lowering effect of RDN seems rather limited and the characteristics of true responders remain largely unknown. Accordingly, RDN is not ready for clinical practice. In most patients with apparent drug-resistant hypertension, drug monitoring and subsequent improvement of drug adherence may prove more effective and cost-beneficial to achieve blood pressure control. In the meantime, research should aim at identifying characteristics of those few patients adherent to drug treatment and with true resistant hypertension who may respond to RDN.

Joint UK societies' 2014 consensus statement on renal denervation for resistant hypertension

Resistant hypertension continues to pose a major challenge to clinicians worldwide and has serious implications for patients who are at increased risk of cardiovascular morbidity and mortality with this diagnosis. Pharmacological therapy for resistant hypertension follows guidelines-based regimens although there is surprisingly scant evidence for beneficial outcomes using additional drug treatment after three antihypertensives have failed to achieve target blood pressure. Recently there has been considerable interest in the use of endoluminal renal denervation as an interventional technique to achieve renal nerve ablation and lower blood pressure. Although initial clinical trials of renal denervation in patients with resistant hypertension demonstrated encouraging office blood pressure reduction, a large randomised control trial (Symplicity HTN-3) with a sham-control limb, failed to meet its primary efficacy end point. The trial however was subject to a number of flaws which must be taken into consideration in interpreting the final results. Moreover a substantial body of evidence from non-randomised smaller trials does suggest that renal denervation may have an important role in the management of hypertension and other disease states characterised by overactivation of the sympathetic nervous system. The Joint UK Societies does not recommend the use of renal denervation for treatment of resistant hypertension in routine clinical practice but remains committed to supporting research activity in this field. A number of research strategies are identified and much that can be improved upon to ensure better design and conduct of future randomised studies.

Randomized comparison of renal denervation versus intensified pharmacotherapy including spironolactone in true-resistant hypertension: six-month results from the Prague-15 study

This prospective, randomized, open-label multicenter trial evaluated the efficacy of catheter-based renal denervation (Symplicity, Medtronic) versus intensified pharmacological treatment including spironolactone (if tolerated) in patients with true-resistant hypertension. This was confirmed by 24-hour ambulatory blood pressure monitoring after excluding secondary hypertension and confirmation of adherence to therapy by measurement of plasma antihypertensive drug levels before enrollment. One-hundred six patients were randomized to renal denervation (n=52), or intensified pharmacological treatment (n=54) with baseline systolic blood pressure of 159±17 and 155±17 mm Hg and average number of drugs 5.1 and 5.4, respectively. A significant reduction in 24-hour average systolic blood pressure after 6 months (-8.6 [95% cofidence interval: -11.8, -5.3] mm Hg; P<0.001 in renal denervation versus -8.1 [95% cofidence interval: -12.7, -3.4] mm Hg; P=0.001 in pharmacological group) was observed, which was comparable in both groups. Similarly, a significant reduction in systolic office blood pressure (-12.4 [95% cofidence interval: -17.0, -7.8] mm Hg; P<0.001 in renal denervation versus -14.3 [95% cofidence interval: -19.7, -8.9] mm Hg; P<0.001 in pharmacological group) was present. Between-group differences in change were not significant. The average number of antihypertensive drugs used after 6 months was significantly higher in the pharmacological group (+0.3 drugs; P<0.001). A significant increase in serum creatinine and a parallel decrease of creatinine clearance were observed in the pharmacological group; between-group difference were borderline significant. The 6-month results of this study confirmed the safety of renal denervation. In conclusion, renal denervation achieved reduction of blood pressure comparable with intensified pharmacotherapy.

Increasing role of interventional cardiologists for peripheral vascular disease

Improvements in the design of endovascular devices and technical skills of interventionalists have opened new possibilities for patients with a wide range of peripheral vascular diseases. In lower extremity peripheral artery disease, percutaneous treatments have become the predominant revascularization strategy for simple and complex lesions. Newer generations of stents and drug-coated balloons have demonstrated strong potential in the treatment of femoropopliteal and infrainguinal diseases. One of the most dramatic advances in the recent past has been endovascular repair of thoracic and abdominal aortic aneurysms, which has become the preferred approach in lieu of open surgical repair. Contemporary trials have established the safety and effectiveness of carotid stenting in selected patients with severe stenosis. Endovascular treatments for venous occlusive disease have long been underutilized, but their effectiveness is being increasingly recognized. This review covers new endovascular procedures performed by interventional cardiologists for peripheral vascular diseases.