Renal sympathetic denervation as second-line therapy in mild resistant hypertension: A pilot study

Treatment of atrial fibrillation in patients with enhanced sympathetic tone by pulmonary vein isolation or pulmonary vein isolation and renal artery denervation: clinical background and study design : The ASAF trial: ablation of sympathetic atrial fibrillation

BACKGROUND

Hypertension is an important, modifiable risk factor for the development of atrial fibrillation (AF). Even after pulmonary vein isolation (PVI), 20-40% experience recurrent AF. Animal studies have shown that renal denervation (RDN) reduces AF inducibility. One clinical study with important limitations suggested that RDN additional to PVI could reduce recurrent AF.

OBJECTIVE

The goal of this multicenter randomized controlled study is to investigate whether RDN added to PVI reduces AF recurrence.

METHODS

The main end point is the time until first AF recurrence according to EHRA guidelines after a blanking period of 3 months. Assuming a 12-month accrual period and 12 months of follow-up, a power of 0.80, a two-sided alpha of 0.05 and an expected drop-out of 10% per group, 69 patients per group are required. We plan to randomize a total of 138 hypertensive patients with AF and signs of sympathetic overdrive in a 1:1 fashion. Patients should use at least two antihypertensive drugs. Sympathetic overdrive includes obesity, exercise-induced excessive blood pressure (BP) increase, significant white coat hypertension, hospital admission or fever induced AF, tachycardia induced AF and diabetes mellitus. The interventional group will undergo PVI + RDN and the control group will undergo PVI.

RESULTS

Patients will have follow-up for 1 year, and continuous loop monitoring is advocated.

CONCLUSION

This randomized, controlled study will elucidate if RDN on top of PVI reduces AF recurrence.

Catheter-based renal denervation in patients with uncontrolled hypertension in the absence of antihypertensive medications (SPYRAL HTN-OFF MED): a randomised, sham-controlled, proof-of-concept trial

BACKGROUND

Previous randomised renal denervation studies did not show consistent efficacy in reducing blood pressure. The objective of our study was to evaluate the effect of renal denervation on blood pressure in the absence of antihypertensive medications.

METHODS

SPYRAL HTN-OFF MED was a multicentre, international, single-blind, randomised, sham-controlled, proof-of-concept trial. Patients were enrolled at 21 centres in the USA, Europe, Japan, and Australia. Eligible patients were drug-naive or discontinued their antihypertensive medications. Patients with an office systolic blood pressure (SBP) of 150 mm Hg or greater and less than 180 mm Hg, office diastolic blood pressure (DBP) of 90 mm Hg or greater, and a mean 24-h ambulatory SBP of 140 mm Hg or greater and less than 170 mm Hg at second screening underwent renal angiography and were randomly assigned to renal denervation or sham control. Patients, caregivers, and those assessing blood pressure were blinded to randomisation assignments. The primary endpoint, change in 24-h blood pressure at 3 months, was compared between groups. Drug surveillance was done to ensure patient compliance with absence of antihypertensive medication. The primary analysis was done in the intention-to-treat population. Safety events were assessed at 3 months. This study is registered with ClinicalTrials.gov, number NCT02439749.

FINDINGS

Between June 25, 2015, and Jan 30, 2017, 353 patients were screened. 80 patients were randomly assigned to renal denervation (n=38) or sham control (n=42) and followed up for 3 months. Office and 24-h ambulatory blood pressure decreased significantly from baseline to 3 months in the renal denervation group: 24-h SBP -5·5 mm Hg (95% CI -9·1 to -2·0; p=0·0031), 24-h DBP -4·8 mm Hg (-7·0 to -2·6; p<0·0001), office SBP -10·0 mm Hg (-15·1 to -4·9; p=0·0004), and office DBP -5·3 mm Hg (-7·8 to -2·7; p=0·0002). No significant changes were seen in the sham-control group: 24-h SBP -0·5 mm Hg (95% CI -3·9 to 2·9; p=0·7644), 24-h DBP -0·4 mm Hg (-2·2 to 1·4; p=0·6448), office SBP -2·3 mm Hg (-6·1 to 1·6; p=0·2381), and office DBP -0·3 mm Hg (-2·9 to 2·2; p=0·8052). The mean difference between the groups favoured renal denervation for 3-month change in both office and 24-h blood pressure from baseline: 24-h SBP -5·0 mm Hg (95% CI -9·9 to -0·2; p=0·0414), 24-h DBP -4·4 mm Hg (-7·2 to -1·6; p=0·0024), office SBP -7·7 mm Hg (-14·0 to -1·5; p=0·0155), and office DBP -4·9 mm Hg (-8·5 to -1·4; p=0·0077). Baseline-adjusted analyses showed similar findings. There were no major adverse events in either group.

INTERPRETATION

Results from SPYRAL HTN-OFF MED provide biological proof of principle for the blood-pressure-lowering efficacy of renal denervation.

FUNDING

Medtronic.

Renal Denervation Promotes Atherosclerosis in Hypertensive Apolipoprotein E-Deficient Mice Infused with Angiotensin II

Objective: To determine the effect of renal denervation (RDN) on the severity of atherosclerosis and aortic aneurysm in hypertensive mice. Methods: Hypertension, atherosclerosis and aortic aneurysm were induced by subcutaneous infusion of angiotensin II (1 μg/kg/min) for 28 days in apolipoprotein E-deficient mice. RDN was conducted using combined surgical and local chemical denervation. The norepinephrine concentration in the kidney was measured by high-performance liquid chromatography. Blood pressure was measured by the tail-cuff method. Atherosclerosis was assessed by Sudan IV staining of the aortic arch. The aortic diameter was measured by the morphometric method. The mRNA expression of genes associated with atherosclerosis and aortic aneurysm were analyzed by quantitative PCR. Results: RDN decreased the median norepinephrine content in the kidney by 93.4% (n = 5-7, P = 0.003) 5 days after the procedure, indicating that the RDN procedure was successful. RDN decreased systolic blood pressure in apolipoprotein E-deficient mice. Mice that had RDN had more severe aortic arch atherosclerosis (median percentage of Sudan IV positive area: 13.2% in control mice, n = 12, and 25.4% in mice having RDN, n = 12, P = 0.028). The severity of the atherosclerosis was negatively correlated with the renal norepinephrine content (spearman r = -0.6557, P = 0.005). RDN did not affect the size of aortic aneurysms formed or the incidence of aortic rupture in mice receiving angiotensin II. RDN significantly increased the aortic mRNA expression of matrix metalloproteinase-2 (MMP-2). Conclusion: RDN promoted atherosclerosis in apolipoprotein E-deficient mice infused with angiotensin II associated with upregulation of MMP-2. The higher MMP-2 expression could be the results of the greater amount of atheroma in the RDN mice. The findings suggest further research is needed to assess potentially deleterious effects of RDN in patients.

Impact of renal sympathetic denervation on cardiac sympathetic nerve activity evaluated by cardiac MIBG imaging

AIMS

The objective of the present study was to investigate an effect of renal artery sympathetic denervation (RASD) on patients with resistant hypertension and RASD effect on cardiac sympathetic nerve activity. It is known that an abnormally activated sympathetic tone is associated with progression of heart failure (HF).

METHODS AND RESULTS

We investigated 16 patients with resistant arterial hypertension (mean age 54.88±7.89 years, mean 24-hr ambulatory blood pressure [BP] systolic 161.07±20.12 mmHg, diastolic 97.6±16.25 mmHg, using 6.44±0.96 antihypertensive drugs), who underwent bilateral RASD. Echocardiography, 24-hr ambulatory BP and 123I-metaiodobenzylguanidine (123I-MIBG) scintigraphy were performed before and six months after RASD. There were no significant changes in 24-hr ambulatory systolic and diastolic BP before RASD and six months after it: systolic BP before RASD was 161.07±20.12 mmHg and 144.93±17.27 mmHg after (p=0.050); diastolic BP before RASD was 97.6±16.25 mmHg and 89.87±12.33 mmHg after (p=0.182). We observed a significant change in cardiac sympathetic nerve activity assessed by 123I-MIBG scintigraphy, as an increase of late heart-to-mediastinum (H/M) ratio, varying from 2.21±0.47 to 2.35±0.52 m/s (p=0.02).

CONCLUSIONS

Selective RASD significantly reduces cardiac sympathetic overdrive assessed by 123I-MIBG scintigraphy. Presumably, this positively affects HF progression in patients with resistant arterial hypertension.

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

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

Predictors of blood pressure response: Obesity is associated with a less pronounced treatment response after renal denervation

OBJECTIVES

The purpose of this study was to identify predictors of BP response.

BACKGROUND

Catheter-based renal denervation (RDN) causes significant blood pressure (BP) reductions in a large number of patients with resistant hypertension.

METHODS

One hundred one consecutive patients with resistant hypertension who underwent RDN with the Symplicity™ catheter were included in this retrospective study. Primary endpoint was the change in office systolic BP after 6 months. Uni- and multivariate logistic regression analyses were performed to detect baseline predictors of a significant BP response 6 months after RDN (age, gender, office and ambulatory BP, renal function, body mass index [BMI], diabetes mellitus, antihypertensive medication, number of ablations).

RESULTS

The procedure was technically uneventful in all patients. Mean BP at baseline was 166.6/90.2 ± 22.5/16.4 mmHg and decreased by -14.7 (P < 0.0001)/-5.3 (P < 0.001) ± 22.8/14.1 mm Hg at 6-month follow-up. Similarly, paired analysis of 24-hr-ambulatory BP measurement (n = 71) showed a significant reduction of mean systolic BP by 6.8 ± 14.4 mm Hg (P < 0.0002). Upon univariate analyses, a higher baseline office systolic BP (P < 0.0001) and lower BMI (P = 0.014) were identified as significant predictors of the magnitude of BP response after 6 months. Importantly, on multivariate analysis, baseline office systolic BP (standardized ß = -0.46; r = -0.47; P < 0.0001) and BMI (standardized ß = 0.21; r = 0.95; P = 0.019) remained significant.

CONCLUSION

Blood pressure reductions after RDN were more pronounced in patients with higher baseline blood pressure and lower BMI. These findings may have implications regarding patient selection for renal denervation. © 2015 Wiley Periodicals, Inc.

Deep brain stimulation for the treatment of resistant hypertension

Hypertension is a leading risk factor for the development of several cardiovascular diseases. As the global prevalence of hypertension increases, so too has the recognition of resistant hypertension. Whilst figures vary, the proportion of hypertensive patients that are resistant to multiple drug therapies have been reported to be as high as 16.4 %. Resistant hypertension is typically associated with elevated sympathetic activity and abnormal homeostatic reflex control and is termed neurogenic hypertension because of its presumed central autonomic nervous system origin. This resistance to conventional pharmacological treatment has stimulated a plethora of medical devices to be investigated for use in hypertension, with varying degrees of success. In this review, we discuss a new therapy for drug-resistant hypertension, deep brain stimulation. The utility of deep brain stimulation in resistant hypertension was first discovered in patients with concurrent neuropathic pain, where it lowered blood pressure and improved baroreflex sensitivity. The most promising central target for stimulation is the ventrolateral periaqueductal gray, which has been well characterised in animal studies as a control centre for autonomic outflow. In this review, we will discuss the promise and potential mechanisms of deep brain stimulation in the treatment of severe, resistant hypertension.

Randomized sham-controlled trial of renal sympathetic denervation in mild resistant hypertension

Few data are available with regard to the effectiveness of renal sympathetic denervation in patients with resistant hypertension yet only mildly elevated blood pressure (BP). Patients with resistant hypertension and slightly elevated BP (day-time systolic pressure, 135-149 and diastolic pressure, 90-94 mm Hg on 24-hour ambulatory measurement) were randomized in a 1:1 ratio to renal sympathetic denervation with the Symplicity Flex Catheter (Medtronic) or an invasive sham procedure. The primary efficacy end point was the change in 24-hour systolic BP at 6 months between groups in the intention to treat population. A total of 71 patients underwent randomization. Baseline day-time systolic BP was 144.4±4.8 mm Hg in patients assigned to denervation and 143.0±4.7 mm Hg in patients randomized to the sham procedure. The mean change in 24-hour systolic BP in the intention to treat cohort at 6 months was -7.0 mm Hg (95% confidence interval, -10.8 to -3.2) for patients undergoing denervation and -3.5 mm Hg (95% confidence interval, -6.7 to -0.2) in the sham group (P=0.15). In the per protocol population, the change in 24-hour systolic BP at 6 months was -8.3 mm Hg (95% confidence interval, -11.7 to -5.0) for patients undergoing denervation and -3.5 mm Hg (95% confidence interval, -6.8 to -0.2) in the sham group (P=0.042). In patients with mild resistant hypertension, renal sympathetic denervation failed to show a significant reduction in the primary end point of 24-hour systolic BP at 6 months between groups in the intention to treat analysis.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01656096.

[Position paper on the results of Symplicity HTN-3 trial. Grupo de estudio de la hipertensión arterial resistente]

Renal artery denervation has shown to be an effective treatment for resistant hypertension. Symplicity HTN 1 and 2 trials showed in small and uncontrolled groups, significant systolic blood pressure reductions down to 30 mm Hg. Symplicity HTN-3, a double blind, randomized, placebo controlled clinical trial shaded this initial enthusiasm. Surprisingly, their results showed that renal denervation has a similar effect to placebo. Pre-specified subgroup analysis showed that non-black race individuals, younger than 65 years and with normal renal function, had a statistically significant systolic blood pressure decrease. This manuscript critically appraises the Symplicity HTN-3 trial, proposing possible explanations for the results. Also declares our group position and future actions regarding renal denervation.

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.

Where and when device therapy may be useful in the management of drug-resistant hypertension

Device therapy for the treatment of uncontrolled and resistant hypertension has evolved significantly over the past several decades. Both renal artery disease and sympathetic hyperactivity have been linked to resistant hypertension. This manuscript will review the current evidence base supporting device therapy (e.g., renal artery revascularization, sympathetic nervous system modulation) for resistant hypertension.

Renal sympathetic nerve ablation for the management of resistant hypertension: an update

PURPOSE OF REVIEW

The aim is to provide clinicians with a concise update on renal sympathetic nerve ablation in the management of resistant hypertension. The review will specifically discuss the latest clinical trial findings, technological advancements in ablation modalities and expert guidelines for patient eligibility. Novel therapeutic applications beyond blood pressure (BP) control will also be discussed.

RECENT FINDINGS

Follow-up data from the Symplicity Clinical Trials Program provides further evidence for the safety of the procedure and substantiates a sustained reduction in BP in most patients with resistant hypertension. Recently published expert consensus statements recommend that only patients with resistant hypertension should undergo the procedure at this stage. Several alternative treatment modalities for renal denervation have been developed to improve efficacy, procedure time and safety. Initial findings suggest comparable BP reductions amongst technical approaches. Several pilot studies, although predominantly uncontrolled, indicate additional benefits of renal sympathetic nerve ablation on regression of hypertensive end-organ damage, heart failure, cardiac arrhythmias and other disturbances commonly associated with resistant hypertension.

SUMMARY

Catheter-based renal nerve ablation is emerging as a well tolerated, effective and cost-effective treatment to control BP in patients with resistant hypertension. Further studies are required to determine the long-term impact of this novel therapeutic option.

Renal sympathetic denervation: early impact on ambulatory resistant hypertension

Although guidelines recommend ambulatory blood pressure (BP) monitoring (ABPM), few data are available regarding the effects of renal denervation (RDN) on 24-hour ABPM values. A total of 44 patients with mean systolic BP ≥135 mm Hg on ABPM despite adequate therapy were included. Basal systolic BP (SBP) and diastolic BP (DBP) were 154±11 mm Hg and 86±12 mm Hg, respectively. At 1 month, SBP and DBP were reduced to 146±18 mm Hg (P=.01) and 82±14 mm Hg and showed no further decrease up to 6 months. Only 55% of the patients responded to RDN (≥-5 mm Hg SBP), with a mean responder rate drop of 21/11 mm Hg. Neither the number of ablation points nor the amount of impedance drop was predictive of response. Only approximately half of patients with resistant hypertension responded to RDN. However, in these responders, a remarkable reduction of 24-hour BP occurred as early as 1 month after RDN.

Renal sympathetic denervation for blood pressure control: a review of the current evidence and ongoing studies

Hypertensive heart disease is the leading cause of mortality and morbidity in the United States. Despite widespread availability of medical therapy, it remains a challenge to treat. Autonomic nervous system imbalance resulting in overactivity of the sympathetic nervous system is integral to the development of hypertension and ultimately the development of hypertensive heart disease. Although the results with renal sympathetic denervation so far have been encouraging, optimism has recently been tempered with the broadcast alert from Medtronic, the sponsor of Symplicity HTN-3, that the trial did not meet its primary efficacy endpoint. The principal focus of this article is to review the developments in renal sympathetic denervation for the treatment of resistant hypertension.

Renal denervation in the treatment of hypertension

Despite advances in nonpharmacologic and pharmacologic therapy, blood pressure control rates in hypertension are low. About 10 % of patients with hypertension fulfill the criteria of therapy resistance, which is defined as noncontrolled blood pressure despite treatment with ≥3 antihypertensive drugs of different classes, including a diuretic, at optimal or maximal tolerated doses. Although the pathogenesis of resistant hypertension is multifactorial, an interaction between renal afferent and efferent sympathetic nerves and the central nervous system plays a key role, leading to increased renal and central sympathetic activity. Catheter-based renal sympathetic denervation (RDN) is a novel therapeutic technique for the treatment of resistant hypertension. Clinical trials of RDN have shown a significant and sustained reduction of blood pressure as well as renal and central sympathetic activity. In clinical practice, appropriate patient selection is crucial to ensure successful and safe treatment. Beyond hypertension, RDN was associated with reduction of heart rate, regression of left ventricular mass, and improvements in glucose metabolism and severity of sleep apnea. Further studies addressing open questions in the treatment of resistant hypertension and evaluating potential new indications such as metabolic syndrome or heart failure (RE-ADAPT-HF) are necessary to prove effectiveness and safety of RDN in these patients. By modulating sympathetic activity, RDN has the potential to provide benefit in a variety of diseases, but these concepts have to be evaluated in well-designed prospective controlled clinical trials.

Renal Sympathetic Denervation - A Review of Applications in Current Practice

Resistant hypertension is associated with high morbidity and mortality despite numerous pharmacological strategies. A wealth of preclinical and clinical data have demonstrated that resistant hypertension is associated with elevated renal and central sympathetic tone. The development of interventional therapies to modulate the sympathetic nervous system potentially represents a paradigm shift in the strategy for blood pressure control in this subset of patients. Initial first-in-man and pivotal, randomised controlled trials of endovascular, radio-frequency renal sympathetic denervation have spawned numerous iterations of similar technology, as well as many novel concepts for achieving effective renal sympatholysis. This review details the current knowledge of these devices and the evidence base behind each technology.

The effect of renal denervation added to standard pharmacologic treatment versus standard pharmacologic treatment alone in patients with resistant hypertension: rationale and design of the SYMPATHY trial

The first studies on renal denervation (RDN) suggest that this treatment is feasible, effective, and safe in the short term. Presently available data are promising, but important uncertainties exist; therefore, SYMPATHY has been initiated. SYMPATHY is a multicenter, randomized, controlled trial in patients randomized to RDN in addition to usual care (intervention group) or to continued usual care (control group). Randomization will take place in a ratio of 2 to 1. At least 300 participants will be included to answer the primary objective. Sample size may be extended to a maximum of 570 to address key secondary objectives. The primary objective is to assess whether RDN added to usual care compared with usual care alone reduces blood pressure (BP) (ambulatory daytime systolic BP) in subjects with an average daytime systolic BP ≥135, despite use of ≥3 BP-lowering agents, 6 months after RDN. Key secondary objectives are evaluated at 6 months and at regular intervals during continued follow-up and include the effect of RDN on the use of BP-lowering agents, in different subgroups (across strata of estimated glomerular filtration rate and of baseline BP), on office BP, quality of life, and cost-effectiveness.

Response and non-response to renal denervation: who is the ideal candidate?

Catheter-based renal denervation (RDN) leads to a considerable decrease of blood pressure in the vast majority of patients with resistant hypertension. However, only minor or no blood pressure change is achieved in some patients. This non-reponse is defined as a reduction of office systolic blood pressure of less than 10 mmHg following RDN. The rates of non-response vary between 8-37%. Here several causes are discussed such as inappropriate patient selection, an ineffective procedure, the subordinate contribution of sympathetic activation for the maintenance of hypertension, and patient conditions such as non-adherence to drug therapy. Based on current evidence, an ideal candidate for RDN has high baseline blood pressure, which is known to be the best predictor for blood pressure reduction after RDN. In order to ensure treatment success further criteria have to be fulfilled, such as exclusion of secondary hypertension and optimised medical therapy.

Effect of catheter-based renal sympathetic denervation on 24-h ambulatory blood pressure in patients with resistant hypertension

We investigated the effect of renal denervation on office blood pressure (OBP) and 24-h ambulatory blood pressure (BP) measurement (ABPM) at baseline and 6 months after intervention in 25 consecutive patients with resistant hypertension. Mean baseline 24-h ABPM and OBP were 158/88 mmHg and 169/96 mmHg, respectively. Patients were treated with an average of 4 ± 1 antihypertensive drugs. Among the 22 patients included in data analysis, mean ambulatory systolic and diastolic BP were reduced by 6 mmHg from 158 ± 17 to 152 ± 20 mmHg (p < 0.05) and by 3 mmHg from 88 ± 12 to 85 ± 14 mmHg (p = ns) after 6 months follow-up, respectively. Blood pressure reduction was most pronounced during daytime with a decrease of 9 mmHg from 164 ± 17 to 155 ± 19 (p < 0.05) in systolic (SBP) and 6 mmHg from 94 ± 14 to 88 ± 14 mmHg in diastolic BP (DBP) (p < 0.05). Night-time SBP mmHg and DBP were similar at baseline compared with follow-up. Systolic and diastolic OBP during follow-up were significantly reduced by 17 mmHg from 169 ± 20 to 152 ± 21 (p < 0.05) and by 9 mmHg from 96 ± 16 to 87 ± 13 mmHg (p < 0.05), respectively. These results provide new insight into the effect of renal denervation on ABPM day- and night-time blood pressure profile in comparison with OBP. The decrease in ABPM was identified during daytime registration and was less pronounced compared with reduction of OBP.

Renal sympathetic denervation therapy in the real world: results from the Heidelberg registry

INTRODUCTION

Renal sympathetic denervation (RDN) is a novel treatment option in patients with treatment-resistant arterial hypertension. A subset of recently published randomized and non-randomized trials indicates that RDN leads to sustained lowering of blood pressure (BP) under controlled study conditions. However, registry data that allow evaluation of safety and efficacy in a real-world setting are largely missing.

METHODS

Sixty-three consecutive patients with treatment-resistant hypertension underwent RDN with the radiofrequency-based Symplicity™ catheter. As part of our prospective registry, treatment efficacy and safety were monitored after 3, 6, and 12 months.

RESULTS

At 6 months follow-up, office systolic BP significantly improved by 19 + 23 mmHg as compared to baseline, while diastolic BP values reduced by 6 + 13 mmHg (p < 0.05). One year after RDN, office BP levels further improved (26 + 25 mmHg in systolic BP and 9 + 13 mmHg in diastolic BP, respectively), even though 19 patients had reduced the number and/or dosage of antihypertensive agents. The response rate, defined as reduction of office systolic BP of ≥ 10 mmHg, was 73% after 6 months. Baseline BP was the only significant predictor of blood pressure response, whereas no correlation was found between the number of ablation points and the individual changes in office blood pressure. Interestingly, patients with challenging renal anatomy profited somewhat less from the procedure than those with "normal" renal anatomy. Procedure related adverse events occurred in three patients (4.7%) and were limited to vascular access complications.

CONCLUSIONS

RDN with the Symplicity™ system is safe and effective in patients with treatment-resistant hypertension also in a real-world setting.

International expert consensus statement: Percutaneous transluminal renal denervation for the treatment of resistant hypertension

Catheter-based radiofrequency ablation technology to disrupt both efferent and afferent renal nerves has recently been introduced to clinical medicine after the demonstration of significant systolic and diastolic blood pressure reductions. Clinical trial data available thus far have been obtained primarily in patients with resistant hypertension, defined as standardized systolic clinic blood pressure ≥ 160 mm Hg (or ≥ 150 mm Hg in patients with type 2 diabetes) despite appropriate pharmacologic treatment with at least 3 antihypertensive drugs, including a diuretic agent. Accordingly, these criteria and blood pressure thresholds should be borne in mind when selecting patients for renal nerve ablation. Secondary forms of hypertension and pseudoresistance, such as nonadherence to medication, intolerance of medication, and white coat hypertension, should have been ruled out, and 24-h ambulatory blood pressure monitoring is mandatory in this context. Because there are theoretical concerns with regard to renal safety, selected patients should have preserved renal function, with an estimated glomerular filtration rate ≥ 45 ml/min/1.73 m(2). Optimal periprocedural management of volume status and medication regimens at specialized and experienced centers equipped with adequate infrastructure to cope with potential procedural complications will minimize potential patient risks. Long-term safety and efficacy data are limited to 3 years of follow-up in small patient cohorts, so efforts to monitor treated patients are crucial to define the long-term performance of the procedure. Although renal nerve ablation could have beneficial effects in other conditions characterized by elevated renal sympathetic nerve activity, its potential use for such indications should currently be limited to formal research studies of its safety and efficacy.

Renal sympathetic denervation: applications in hypertension and beyond

Renal afferent and efferent sympathetic nerves are involved in the regulation of blood pressure and have a pathophysiological role in hypertension. Renal sympathetic denervation is a novel therapeutic technique for the treatment of patients with resistant hypertension. Clinical trials of renal sympathetic denervation have shown significant reductions in blood pressure in these patients. Renal sympathetic denervation also reduces heart rate, which is a surrogate marker of cardiovascular risk. Conditions that are comorbid with hypertension, such as heart failure and myocardial hypertrophy, obstructive sleep apnoea, atrial fibrillation, renal dysfunction, and metabolic syndrome are closely associated with enhanced sympathetic activity. In experimental models and case-control studies, renal denervation has had beneficial effects on these conditions. Renal denervation could become a commonly used procedure to treat resistant hypertension and chronic diseases associated with enhanced sympathetic activation. Current work is focused on refining the techniques and interventional devices to provide safe and effective renal sympathetic denervation. Controlled studies in patients with mild-to-moderate, nonresistant hypertension and comorbid conditions such as heart failure, diabetes mellitus, sleep apnoea, and arrhythmias are needed to investigate the capability of renal sympathetic denervation to improve cardiovascular outcomes.

Effectiveness of renal denervation therapy for resistant hypertension: a systematic review and meta-analysis

OBJECTIVES

This study sought to determine the current effectiveness and safety of sympathetic renal denervation (RDN) for resistant hypertension.

BACKGROUND

RDN is a novel approach that has been evaluated in multiple small studies.

METHODS

We performed a systematic review and meta-analysis of published studies evaluating the effect of RDN in patients with resistant hypertension. Studies were stratified according to controlled versus uncontrolled design and analyzed using random-effects meta-analysis models.

RESULTS

We identified 2 randomized controlled trials, 1 observational study with a control group, and 9 observational studies without a control group. In controlled studies, there was a reduction in mean systolic and diastolic blood pressure (BP) at 6 months of -28.9 mm Hg (95% confidence interval [CI]: -37.2 to -20.6 mm Hg) and -11.0 mm Hg (95% CI: -16.4 to -5.7 mm Hg), respectively, compared with medically treated patients (for both, p < 0.0001). In uncontrolled studies, there was a reduction in mean systolic and diastolic BP at 6 months of -25.0 mm Hg (95% CI: -29.9 to -20.1 mm Hg) and -10.0 mm Hg (95% CI: -12.5 to -7.5 mm Hg), respectively, compared with pre-RDN values (for both, p < 0.00001). There was no difference in the effect of RDN according to the 5 catheters employed. Reported procedural complications included 1 renal artery dissection and 4 femoral pseudoaneurysms.

CONCLUSIONS

RDN resulted in a substantial reduction in mean BP at 6 months in patients with resistant hypertension. The decrease in BP was similar irrespective of study design and type of catheter employed. Large randomized controlled trials with long-term follow-up are needed to confirm the sustained efficacy and safety of RDN.

Extreme Elevations in Blood Pressure and All-Cause Mortality in a Referred CKD Population: Results from the CRISIS Study

Hypertension frequently complicates chronic kidney disease (CKD), with studies showing clinical benefit from blood pressure lowering. Subgroups of patients with severe hypertension exist. We aimed to identify patients with the greatest mortality risk from uncontrolled hypertension to define the prevalence and phenotype of patients who might benefit from adjunctive therapies. 1691 all-cause CKD patients from the CRISIS study were grouped by baseline blood pressure—target (<140/80 mmHg); elevated (140–190/80–100 mmHg); extreme (>190 and/or 100 mmHg). Groups were well matched for age, eGFR, and comorbidities. 77 patients had extreme hypertension at recruitment but no increased mortality risk (HR 0.9, P = 0.9) over a median follow-up period of 4.5 years. The 1.2% of patients with extreme hypertension at recruitment and at 12-months had a significantly increased mortality risk (HR 4.3, P = 0.01). This association was not seen in patients with baseline extreme hypertension and improved 12-month blood pressures (HR 0.86, P = 0.5). Most CKD patients with extreme hypertension respond to pharmacological blood pressure control, reducing their risk for death. Patients with extreme hypertension in whom blood pressure control cannot be achieved have an approximate prevalence of 1%. These patients have an increased mortality risk and may be an appropriate group to consider for further therapies, including renal nerve ablation.

[Treatment resistant hypertension. Value of a new treatment concept]

Sympathetic overexpression can be found in a majority of hypertensive patients. Resistant arterial hypertension requires a targeted diagnostic procedure in order to exclude secondary causes of hypertension which can be treated specifically with established therapies. If secondary reasons are not identified, the antihypertensive medication is already optimal and lifestyle changes have been realized, but still the goal of antihypertensive therapy cannot be achieved, alternative invasive therapy strategies such as renal sympathetic denervation and baroreflex activation have been developed to achieve blood pressure control. These therapies are restricted to specialized centers which treat well-defined patients with therapy-resistant hypertension. Little long-term data concerning safety and efficacy are available for the two strategies. However, they should preferably be used as an ultima-ratio and add-on pathway to conservative procedures when established medication fails to achieve blood pressure control. To date, the effectiveness of the interventional antihypertensive therapies has only been shown on patients with systolic blood pressure over 160 mmHg and a mean oral medication of five drugs.