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

Renal arteries denervation: from the treatment of resistant hypertension to the treatment of atrial fibrillation

Renal denervation (RDN) is a therapeutic strategy for patients with uncontrolled arterial hypertension characterized by considerable fluctuations during its progression. After initial strong enthusiasm, the procedure came to an abrupt halt following the publication of the Symplicity HTN-3 study results. The results of recently published studies highlight the reduction in blood pressure values after RDN and justify the inclusion in the Guidelines of new recommendations for the use of RDN in clinical practice, in selected patients. Additionally, RDN findings are summarized in view of other potential indications such as atrial fibrillation. Six prospective, randomized studies are presented that evaluated RDN as an adjunct therapy to pulmonary vein isolation for the treatment of atrial fibrillation. In five studies, patients had uncontrolled hypertension despite therapy with three antihypertensive drugs. The analysis of these studies showed that RDN reduced the recurrence of atrial fibrillation (AF) by 57% compared to patients with pulmonary vein isolation (PVI) only. Modulation of the autonomic nervous system by RDN has been shown not only to reduce blood pressure but also to have an antiarrhythmic effect in symptomatic AF patients when the strategy is combined with PVI, thus opening up new therapeutic scenarios.

Technical advance in silico and in vitro development of a new bipolar radiofrequency ablation device for renal denervation

Background

Renal denervation with radiofrequency ablation has become an accepted treatment for drug-resistant hypertension. However, there is a continuing need to develop new catheters for high-accuracy, targeted ablation. We therefore developed a radiofrequency bipolar electrode for controlled, targeted ablation through Joule heating induction between 60 and 100 °C. The bipolar design can easily be assembled into a basket catheter for deployment inside the renal artery.

Methods

Finite element modeling was used to determine the optimum catheter design to deliver a minimum ablation zone of 4 mm (W) × 10 mm (L) × 4 mm (H) within 60 s with a 500 kHz, 60 Vp-p signal, and 3 W maximum. The in silico model was validated with in vitro experiments using a thermochromic phantom tissue prepared with polyacrylamide gel and a thermochromic ink additive that permanently changes from pink to magenta when heated over 60 °C.

Results

The in vitro ablation zone closely matched the size and shape of the simulated area. The new electrode design directs the current density towards the artery walls and tissue, reducing unwanted blood temperature increases by focusing energy on the ablation zone. In contrast, the basket catheter design does not block renal flow during renal denervation.

Conclusions

This computational model of radiofrequency ablation can be used to estimate renal artery ablation zones for highly targeted renal denervation in patients with resistant hypertension. Furthermore, this innovative catheter has short ablation times and is one of the lowest power requirements of existing designs to perform the ablation.

Renal nerve stimulation: complete versus incomplete renal sympathetic denervation

PURPOSE

Blood pressure (BP) reduction after renal sympathetic denervation (RDN) is highly variable. Renal nerve stimulation (RNS) can localize sympathetic nerves. The RNS trial aimed to investigate the medium-term BP-lowering effects of the use of RNS during RDN, and explore if RNS can check the completeness of the denervation.

MATERIAL AND METHODS

Forty-four treatment-resistant hypertensive patients were included in the prospective, single-center RNS trial. The primary study endpoint was change in 24-h BP at 6- to 12-month follow-up after RDN. The secondary study endpoints were the acute procedural RNS-induced BP response before and after RDN; number of antihypertensive drugs at follow-up; and the correlation between the RNS-induced BP increase before versus after RDN (delta [Δ] RNS-induced BP).

RESULTS

Before RDN, the RNS-induced systolic BP rise was 43(±21) mmHg, and decreased to 9(±12) mmHg after RDN (p < 0.001). Mean 24-h systolic/diastolic BP decreased from 147(±12)/82(±11) mmHg at baseline to 135(±11)/76(±10) mmHg (p < 0.001/<0.001) at follow-up (10 [6-12] months), with 1 antihypertensive drug less compared to baseline. The Δ RNS-induced BP and the 24-h BP decrease at follow-up were correlated for systolic (R = 0.44, p = 0.004) and diastolic (R = 0.48, p = 0.003) BP. Patients with ≤0 mmHg residual RNS-induced BP response after RDN had a significant lower mean 24-h systolic BP at follow-up compared to the patients with >0 mmHg residual RNS-induced BP response (126 ± 4 mmHg versus 135 ± 10 mmHg, p = 0.04). 83% of the patients with ≤0 mmHg residual RNS-induced BP response had normal 24-h BP at follow-up, compared to 33% in the patients with >0 mmHg residual RNS-induced BP response (p = 0.023).

CONCLUSION

The use of RNS during RDN leads to clinically significant and sustained lowering of 24-h BP with fewer antihypertensive drugs at follow-up. RNS-induced BP changes were correlated with 24-h BP changes at follow-up. Moreover, patients with complete denervation had significant lower BP compared to the patients with incomplete denervation.

Endovascular renal sympathetic denervation to improve heart failure with reduced ejection fraction: the IMPROVE-HF-I study

Introduction

The aim of the present study was to assess the safety and efficacy of renal sympathetic denervation (RDN) in patients with heart failure with reduced ejection fraction (HFrEF).

Methods

We randomly assigned 50 patients with a left ventricular ejection fraction (LVEF) ≤ 35% and NYHA class ≥ II, in a 1:1 ratio, to either RDN and optimal medical therapy (OMT) or OMT alone. The primary safety endpoint was the occurrence of a combined endpoint of cardiovascular death, rehospitalisation for heart failure, and acute kidney injury at 6 months. The primary efficacy endpoint was the change in iodine-123 meta-iodobenzylguanidine (¹²³I‑MIBG) heart-to-mediastinum ratio (HMR) at 6 months.

Results

Mean age was 60 ± 9 years, 86% was male and mean LVEF was 33 ± 8%. At 6 months, the primary safety endpoint occurred in 8.3% vs 8.0% in the RDN and OMT groups, respectively (p = 0.97). At 6 months, the mean change in late HMR was −0.02 (95% CI: −0.08 to 0.12) in the RDN group, versus −0.02 (95% CI: −0.09 to 0.12) in the OMT group (p = 0.95) whereas the mean change in washout rate was 2.34 (95% CI: −6.35 to 1.67) in the RDN group versus −2.59 (95% CI: −1.61 to 6.79) in the OMT group (p-value 0.09).

Conclusion

RDN with the Vessix system in patients with HFrEF was safe, but did not result in significant changes in cardiac sympathetic nerve activity at 6 months as measured using ¹²³I‑MIBG.

Supplementary Information

The online version of this article (10.1007/s12471-021-01633-z) contains supplementary material, which is available to authorized users.

The clinical case of successful combined treatment of refractory arterial hypertension. Case report

In recent years, there has been an increase of patients with arterial hypertension, one of the variants of which is refractory arterial hypertension. This unfavorable clinical variant of the course of hypertension worries clinicians, due to the higher risk of developing cardiovascular complications, realizing the need for a better control of blood pressure. The presented clinical case demonstrates the successful combined treatment of refractory hypertension using antihypertensive therapy and renal denervation.

Russian Medical Society for Arterial Hypertension expert consensus. Resistant hypertension: detection and management

The diagnosis of resistant arterial hypertension allows us to single out a separate group of patients in whom it is necessary to use special diagnostic methods and approaches to treatment. Elimination of reversible factors leading to the development of resistant arterial hypertension, such as non-adherence to therapy, inappropriate therapy, secondary forms of arterial hypertension, leads to an improvement in the patient's prognosis. Most patients with resistant hypertension should be evaluated to rule out primary aldosteronism, renal artery stenosis, chronic kidney disease, and obstructive sleep apnea. The algorithm for examining patients, recommendations for lifestyle changes and a step-by-step therapy plan can improve blood pressure control. It is optative to use the most simplified treatment regimen and long-acting combined drugs. For a separate category of patients, it is advisable to perform radiofrequency denervation of the renal arteries.

Effect of Heart Rate on the Outcome of Renal Denervation in Patients With Uncontrolled Hypertension

BACKGROUND

Sham-controlled trials demonstrated safety and efficacy of renal denervation (RDN) to lower blood pressure (BP). Association of baseline heart rate with BP reduction after RDN is incompletely understood.

OBJECTIVES

The purpose of this analysis was to evaluate the impact of baseline heart rate on BP reduction without antihypertensive medications in the SPYRAL HTN-OFF MED (Global Clinical Study of Renal Denervation With the Symplicity Spyral Multi-electrode Renal Denervation System in Patients With Uncontrolled Hypertension in the Absence of Antihypertensive Medications) Pivotal trial.

METHODS

Patients removed from any antihypertensive medications were enrolled with office systolic blood pressure (SBP) ≥150 and <180 mm Hg and randomized 1:1 to RDN or sham control. Patients were separated according to baseline office heart rate <70 or ≥70 beats/min. BP changes from baseline to 3 months between treatment arms were adjusted for baseline SBP using analysis of covariance.

RESULTS

Scatter plots of 3-month changes in 24-hour and office SBP illustrate a wide range of changes in SBP for different baseline heart rates. Treatment difference at 3 months between RDN and sham control with baseline office heart rate ≥70 beats/min for 24-hour SBP was -6.2 mm Hg (95% CI: -9.0 to -3.5 mm Hg) (P < 0.001) and for baseline office heart rate <70 beats/min it was -0.1 mm Hg (-3.8 to 3.6 mm Hg) (P = 0.97) with an interaction P value of 0.008. Results were similar for changes in office, daytime, and nighttime SBP at 3 months, with a greater reduction in SBP with baseline office heart rate ≥70 beats/min.

CONCLUSIONS

Reduction in mean office, 24-hour, daytime, and nighttime SBP for RDN at 3 months was greater with baseline office heart rate ≥70 than <70 beats/min, suggesting an association between baseline heart rate and BP reduction after RDN. (SPYRAL PIVOTAL-SPYRAL HTN-OFF MED Study; NCT02439749).

Catheter-based alcohol-mediated renal denervation for the treatment of uncontrolled hypertension: design of two sham-controlled, randomized, blinded trials in the absence (TARGET BP OFF-MED) and presence (TARGET BP I) of antihypertensive medications

BACKGROUND

Arterial hypertension is a common and life-threatening condition and poses a large global health burden. Device-based treatments have been developed as adjunctive or alternative therapy, to be used with or without antihypertensive medication for treating uncontrolled hypertension. The safety and feasibility of chemical renal denervation (RDN) using the Peregrine Catheter and alcohol were demonstrated in a first-in-man and open-label clinical trials, prompting the initiation of the ongoing TARGET BP OFF-MED and TARGET BP I trials.

DESIGN

The TARGET BP trials are randomized, blinded, sham-controlled trials designed to assess the safety and efficacy of alcohol-mediated RDN for the treatment of uncontrolled hypertension in the absence of antihypertensive medications (TARGET BP OFF-MED) or in addition to prescribed antihypertensive medications (TARGET BP I). Subjects with confirmed uncontrolled hypertension and suitable renal artery anatomy are randomized (1:1) to receive either RDN using the Peregrine Kit with alcohol (0.6 mL per renal artery) infused through the Peregrine Catheter or diagnostic renal angiography only (sham procedure). TARGET BP OFF-MED completed enrollment and randomized 96 subjects. TARGET BP I will randomize approximately 300 subjects and will transition to an open-label safety cohort of approximately 300 subjects receiving RDN once the primary efficacy endpoint of the Randomized Controlled Trial (RCT) cohort has been met. Primary endpoints are change in mean 24-hour ambulatory systolic blood pressure from baseline to 8 weeks (TARGET BP OFF-MED) and 3 months (TARGET BP I) post-procedure.

CONCLUSION

The TARGET BP trials are the first large-scale, international, randomized trials aimed to investigate the safety and BP lowering efficacy of a novel RDN method, with perivascular alcohol delivery using the Peregrine Kit.

Erythrocyte membranes beta-adrenoreactivity changes after renal denervation in patients with resistant hypertension, relationship with antihypertensive and cardioprotective intervention efficacy

Aim      To study the functional condition of sympathoadrenal system as evaluated by beta-adrenoreactivity of erythrocyte membranes (beta-ARM) during two years following renal denervation (RD) in patients with resistant arterial hypertension (RAH) and to determine the relationship of this index with long-term antihypertensive and cardioprotective effectivity of this invasive treatment.Material and methods  The study included 48 patients (mean age, 57.2±8.7 years, 18 men) with RAH on a stable antihypertensive therapy. Averaged daily systolic and diastolic blood pressure (SBP and DBP) and levels of beta-ARM were determined at baseline and in 7 days and 2 years following RD. Measurement of beta-ARM was based on beta-adrenoblocker inhibition of erythrocyte hemolysis induced by exposure to hypo-osmotic environment. The beta-adrenoblocker binds to erythrocyte membrane beta-adrenoceptors to prevent the erythrocyte destruction. Increased values of beta-ARM reflect a decrease in the number of functionally active erythrocyte membrane beta-adrenoceptors associated with long-term sympathetic hyperactivity.Results For two years of follow-up, values of average daily BP decreased from 160.4±16.0 / 88.1±14.6 to 145.3±19.3 / 79.4±13.6 mm Hg. At 7 days, the number of beta-ARM had decreased in the group of RD responders (р=0.028) who at two years had decreased their BP by 10 mm Hg or more, while in the group of non-responders, the number of beta-ARM remained unchanged. At one week, beta-ARM values correlated with changes in SBP and DBP (r= -0.54; р&lt;0.05) and with left ventricular myocardial mass (LVMM) (r= -0.36; р&lt;0.05) at two years of follow-up whereas beta-ARM delta at one week was interrelated with the renin concentration in the long-term (r= -0.44; р&lt;0.05). At two years, the content of beta-ARM was increased in both groups.Conclusion      The decrease in beta-ARM content at 7 days after RD shows the procedure efficacy and allows an expectation of clinically significant decreases in BP and LVMM in the long-term after the surgical treatment. At two years after the intervention, the content of beta-ARM increased, and the BP decrease was apparently due to some other mechanisms.

A Japan nationwide web-based survey of estimation on patients for renal denervation based on blood pressure level and the number of antihypertensives (J-NEEDs survey)

Catheter‐based renal denervation (RDN) is currently being developed as a new complementary treatment option for hypertension. RDN has not yet received approval in Japan and so the number of possible candidates for RDN in Japan also remains unknown. A total of 10 756 hypertensive patients who regularly visit medical institutions and reported their latest home blood pressure (BP) values were identified from registrants at an online research company. They filled out a survey regarding their prescribed antihypertensives and latest BP values in March 2020 in Japan. The mean age of the patients was 61.3 years old (83.5% male). According to JSH 2019, the prevalence of resistant hypertension (RHT) was estimated to be 1.4% (0.52% having an office BP of 140/90 mm Hg or more while taking three antihypertensives, including diuretics; 0.84% taking four or more antihypertensives regardless of BP level). Assuming the indication for RDN was RHT with morning home systolic BP (HSBP) ≥ 135 mm Hg and office systolic BP (OSBP) ≥ 140 mm Hg, the number of candidates for RDN was estimated to be approximately 340 000 and 372 000, respectively. When hypertensive patients prescribed three or more, two, one, and no antihypertensives were included, the estimated number based on uncontrolled HSBP and OSBP cumulatively increased 2.6, 14.2, 40.6, and 58.0‐fold; 1.8, 8.6, 25.3, and 36.4‐fold, respectively. These findings revealed that a substantial number of hypertensive patients are unable to adequately control their BP level with existing treatments, and new complemental therapies, such as RDN, would alleviate the burden of hypertension in this population.

Renal denervation as a management strategy for hypertension: current evidence and recommendations

INTRODUCTION

The concept of targeting the renal sympathetic nerves therapeutically to lower blood pressure (BP) is based on their crucial role in regulating both renal and cardiovascular control. These effects are mainly mediated via three major mechanisms including alteration of renal blood flow, renin-release, and Na⁺ retention. Initial surgical approaches applying crude and unselected sympathectomy, while rendering significant BP lowering and cardiovascular event reducing properties, where plagued by side effects. More modern selective catheter-based denervation approaches selectively targeting the renal nerves have been shown to be safe and effective in reducing BP in various forms of hypertension and multiple comorbidities.

AREAS COVERED

This article covers the background relevant for the concept of renal denervation (RDN), the evidence obtained from relevant randomized controlled trials to substantiate the safety and efficacy of RDN, and recently published clinical recommendations.

EXPERT OPINION

Catheter-based RDN is safe and has now been shown in sham-controlled randomized clinical trials to result in clinically meaningful BP lowering in both drug naïve hypertensive patients and those on concomitant antihypertensive therapy. Real world data from a large global registry further supports the clinical utility of RDN. It now seems time to embed renal denervation into routine clinical care.

Pacemaker-Based Cardiac Neuromodulation Therapy in Patients With Hypertension: A Pilot Study

Background In prior unblinded studies, cardiac neuromodulation therapy (CNT) employing a sequence of variably timed short and longer atrioventricular intervals yielded sustained reductions of systolic blood pressure (SBP) in patients with hypertension. The effects of CNT on SBP were investigated in this double-blind randomized pilot study. Methods and Results Eligible patients had daytime ambulatory SBP (aSBP) ≥130 mm Hg and office SBP ≥140 mm Hg despite taking ≥1 antihypertensive medication, and an indication for a dual-chamber pacemaker. Patients underwent Moderato device implantation, which was programmed as a standard pacemaker during a 1-month run-in phase. Patients whose daytime aSBP was ≥125 mm Hg at the end of this period were randomized (1:1, double blind) to treatment (CNT) or control (CNT inactive). The primary efficacy end point was the between-group difference of the change in 24-hour aSBP at 6 months. Of 68 patients initially enrolled and who underwent implantation with the Moderato system, 47 met criteria for study continuation and were randomized (26 treatment, 21 control). The mean age was 74.0±8.7 years, 64% were men, left ventricular ejection fraction was 59.2%±5.7%, and aSBP averaged 141.0±10.8 mm Hg despite the use of 3.3±1.5 antihypertensive medications; 81% had isolated systolic hypertension. Six months after randomization, aSBP was 11.1±10.5 mm Hg (95% CI, -15.2 to -8.1 mm Hg) lower than prerandomization in the treatment group compared with 3.1±9.5 mm Hg (-7.4 to 1.2 mm Hg) lower in controls, yielding a net treatment effect of 8.1±10.1 mm Hg (-14.2 to -1.9 mm Hg) (P=0.012). There were no Moderato device- or CNT-related adverse events. Conclusions CNT significantly reduced 24-hour aSBP in patients with hypertension with a clinical indication for a pacemaker. The majority of patients had isolated systolic hypertension, a particularly difficult group of patients to treat. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02837445.

Renal Denervation by Noninvasive Stereotactic Radiotherapy Induces Persistent Reduction of Sympathetic Activity in a Hypertensive Swine Model

Background

We have previously reported the feasibility of noninvasive stereotactic body radiotherapy (SBRT) as a novel approach for renal denervation.

Methods and Results

Herein, from a translational point of view, we assessed the antihypertensive effect and chronological evolution of SBRT‐induced renal nerve injury within 6 months in a hypertensive swine model. Hypertension was induced in swine by subcutaneous implantation of deoxycorticosterone acetate pellets in combination with a high‐salt diet. A single dose of 25 Gy with SBRT was delivered for renal denervation in 9 swine within 3.4±1.0 minutes. Blood pressure levels at baseline and 1 and 6 months post‐SBRT were comparable to control (n=5), whereas renal norepinephrine was significantly lower at 6 months (P<0.05). Abdominal computed tomography, performed before euthanasia and renal function assessment, remained normal. Standard semiquantitative histological assessment showed that compared with control (1.4±0.4), renal nerve injury was greater at 1 month post‐SBRT (2.3±0.3) and peaked at 6 months post‐SBRT (3.2±0.8) (P<0.05), along with a higher proportion of active caspase‐3–positive nerves (P<0.05). Moreover, SBRT resulted in continuous dysfunction of renal sympathetic nerves and low level of nerve regeneration in 6 months by immunohistochemistry analysis.

Conclusions

SBRT delivering 25 Gy for renal denervation was safe and related to sustained reduction of sympathetic activity by aggravating nerve damage and inhibiting nerve regeneration up to 6 months; however, its translation to clinical trial should be cautious because of the negative blood pressure response in the deoxycorticosterone acetate–salt hypertensive swine model.

Blunted natriuretic response to saline loading in sheep with hypertensive kidney disease following radiofrequency catheter-based renal denervation

Renal sympathetic nerves contribute to renal excretory function during volume expansion. We hypothesized that intact renal innervation is required for excretion of a fluid/electrolyte load in hypertensive chronic kidney disease (CKD) and normotensive healthy settings. Blood pressure, kidney hemodynamic and excretory response to 180 min of isotonic saline loading (0.13 ml/kg/min) were examined in female normotensive (control) and hypertensive CKD sheep at 2 and 11 months after sham (control-intact, CKD-intact) or radiofrequency catheter-based RDN (control-RDN, CKD-RDN) procedure. Basal blood pressure was ~ 7 to 9 mmHg lower at 2, and 11 months in CKD-RDN compared with CKD-intact sheep. Saline loading did not alter glomerular filtration rate in any group. At 2 months, in response to saline loading, total urine and sodium excretion were ~ 40 to 50% less, in control-RDN and CKD-RDN than intact groups. At 11 months, the natriuretic and diuretic response to saline loading were similar between control-intact, control-RDN and CKD-intact groups but sodium excretion was ~ 42% less in CKD-RDN compared with CKD-intact at this time-point. These findings indicate that chronic withdrawal of basal renal sympathetic activity impairs fluid/electrolyte excretion during volume expansion. Clinically, a reduced ability to excrete a saline load following RDN may contribute to disturbances in body fluid balance in hypertensive CKD.

Mapping Renal Innervations by Renal Nerve Stimulation and Characterizations of Blood Pressure Response Patterns

Increased sympathetic nervous activity is one of main contributors to pathogenesis and progression of hypertension. Renal denervation (RDN) has been demonstrated as a potential therapy for treatment of hypertension; however, lack of indicators of intra-/post-procedure results in inconsistent clinical outcomes. Renal nerve stimulation (RNS), a simple and promising method, could evoke elevated blood pressure as an intraoperative indicator for RDN. But related researches on patterns of blood pressure responses to RNS are still incomplete. To investigate and categorize the phenotypes of blood pressure response to RNS and heart rate alteration before and after RNS, 24 Chinese Kunming dogs were used to perform RNS from bifurcation to ostium of renal arteries after angiography, and a total of 483 stimulated sites were complete. We identified five different patterns of blood pressure response to RNS in 483 stimulated sites, (1) continuous ascending and finally keeping steady above baseline (26.9%), (2) declining and then rising over baseline (11.8%), (3) declining and then rising but below baseline (14.5%), (4) fluctuating in the vicinity of baseline (39.5%), and (5) continuous declining and finally keeping steady below baseline (7.2%), and found no difference in RR intervals among five blood pressure responses before and after renal nerve stimulation. Renal nerve stimulation could elicit different patterns of blood pressure response, which could potentially assist in distinguishing sympathetic-excitatory sites and sympathetic-inhibitory sites from mixed nerve components, which might help to improve the efficacy of RDN.

Arterial hypertension

Arterial hypertension is the most important contributor to the global burden of disease; however, disease control remains poor. Although the diagnosis of hypertension is still based on office blood pressure, confirmation with out-of-office blood pressure measurements (ie, ambulatory or home monitoring) is strongly recommended. The definition of hypertension differs throughout various guidelines, but the indications for antihypertensive therapy are relatively similar. Lifestyle adaptation is absolutely key in non-pharmacological treatment. Pharmacologically, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, calcium channel blockers, and diuretics are the first-line agents, with advice for the use of single-pill combination therapy by most guidelines. As a fourth-line agent, spironolactone should be considered. The rapidly evolving field of device-based therapy, especially renal denervation, will further broaden therapeutic options. Despite being a largely controllable condition, the actual rates of awareness, treatment, and control of hypertension are disappointingly low. Further improvements throughout the process of patient screening, diagnosis, treatment, and follow-up need to be urgently addressed.

Renal Denervation for Patients With Atrial Fibrillation

PURPOSE OF REVIEW

During the last decade, several case series and small reports have indicated that pulmonary vein isolation (PVI) in combination with renal denervation (RDN) may increase the rate of atrial fibrillation (AF) freedom in patients with hypertension. We aimed to provide a contemporary systematic overview on the techniques, and the efficacy/safety of RDN on AF recurrence, and the current landscape of ongoing investigation.

RECENT FINDINGS

The recent Evaluate Renal Denervation in Addition to Catheter Ablation to Eliminate Atrial Fibrillation (ERADICATE-AF) trial has demonstrated convincingly that among patients with paroxysmal AF and poorly controlled (but not "resistant") hypertension, RDN added to catheter ablation, compared with catheter ablation alone, significantly increased the likelihood of freedom from AF at 12 months. RDN has proven to be a unique, effective and safe interventional therapy for the management of AF. Future investigation will likely focus on confirming current findings; expanding the population of eligible patients (eg., non-hypertensives, well controlled hypertensives); determining long-term maintenance of effect and therapeutics.

Effect of renal denervation on catecholamines and the renin-angiotensin-aldosterone system

Introduction:

The effect of renal sympathetic denervation (RDN) on neurohormonal responses is largely unknown. We aimed to assess the effect of RDN on the renin–angiotensin–aldosterone system (RAAS) and endogenous catecholamines.

Methods:

A total of 60 patients with hypertension underwent RDN and remained on a stable antihypertensive drug regimen. Samples for plasma aldosterone, plasma renin and urine (nor)metanephrine were collected at baseline and at 6 months post procedure. Ambulatory blood pressure (BP) recordings were obtained at baseline and at 6 months post procedure.

Results:

Mean age was 64±9 years, and 30/60 patients were male. At 6 months, average daytime systolic and diastolic ambulatory BP decreased by 10 and 6 mmHg, respectively (p<0.001). No significant change was observed in plasma aldosterone (median=248.0 pmol/L (interquartile range (IQR) 113.3–369.5 pmol/L) vs. median=233.0 pmol/L (IQR 110.3–360.8 pmol/L); p=0.66); renin (median=19.5 µIU/mL (IQR 6.8–119.5 µIU/mL) vs. median=14.3 µIU/mL (IQR 7.2–58.0 µIU/mL); p=0.32), urine metanephrine (median=0.46 µmol/L (IQR 0.24–0.77 µmol/L) vs. median=0.46 µmol/L (IQR 0.22–0.88 µmol/L); p=0.75) and normetanephrine (median=1.41 µmol/L (IQR 0.93–2.00 µmol/L vs. median =1.56 (IQR 0.74–2.50 µmol/L); p=0.58) between baseline and 6 months, respectively. No correlation was found between the decrease in mean systolic daytime BP and changes in RAAS hormones or endogenous catecholamines.

Conclusion:

Despite significant reductions in ambulatory BP, RDN did not result in a significant change in endogenous catecholamines or in RAAS hormones at 6 months.

Impact of anesthesia and sex on sympathetic efferent and hemodynamic responses to renal chemo- and mechanosensitive stimuli

Activation of renal sensory nerves by chemo- and mechanosensitive stimuli produces changes in efferent sympathetic nerve activity (SNA) and arterial blood pressure (ABP). Anesthesia and sex influence autonomic function and cardiovascular hemodynamics, but it is unclear to what extent anesthesia and sex impact SNA and ABP responses to renal sensory stimuli. We measured renal, splanchnic, and lumbar SNA and ABP in male and female Sprague-Dawley rats during contralateral renal infusion of capsaicin and bradykinin or during elevation in renal pelvic pressure. Responses were evaluated with a decerebrate preparation or Inactin, urethane, or isoflurane anesthesia. Intrarenal arterial infusion of capsaicin (0.1-30.0 μM) increased renal SNA, splanchnic SNA, or ABP but decreased lumbar SNA in the Inactin group. Intrarenal arterial infusion of bradykinin (0.1-30.0 μM) increased renal SNA, splanchnic SNA, and ABP but decreased lumbar SNA in the Inactin group. Elevated renal pelvic pressure (0-20 mmHg, 30 s) significantly increased renal SNA and splanchnic SNA but not lumbar SNA in the Inactin group. In marked contrast, SNA and ABP responses to every renal stimulus were severely blunted in the urethane and decerebrate groups and absent in the isoflurane group. In the Inactin group, the magnitude of SNA responses to chemo- and mechanosensory stimuli were not different between male and female rats. Thus, chemo- and mechanosensitive stimuli produce differential changes in renal, splanchnic, and lumbar SNA. Experimentally, future investigations should consider Inactin anesthesia to examine sympathetic and hemodynamic responses to renal sensory stimuli.NEW & NOTEWORTHY The findings highlight the impact of anesthesia, and to a lesser extent sex, on sympathetic efferent and hemodynamic responses to chemosensory and mechanosensory renal stimuli. Sympathetic nerve activity (SNA) and arterial blood pressure (ABP) responses were present in Inactin-anesthetized rats but largely absent in decerebrate, isoflurane, or urethane preparations. Renal chemosensory stimuli differentially changed SNA: renal and splanchnic SNA increased, but lumbar SNA decreased. Future investigations should consider Inactin anesthesia to study SNA and hemodynamic responses to renal sensory nerve activation.

European Society of Hypertension position paper on renal denervation 2021

This ESH Position Paper 2021 with updated proposed recommendations was deemed necessary after the publication of a set of new pivotal sham-controlled randomized clinical trials (RCTs), which provided important information about the efficacy and safety of endovascular device-based renal denervation (RDN) for hypertension treatment. RDN is effective in reducing or interrupting the sympathetic signals to the kidneys and decreasing whole body sympathetic activity. Five independent, fully completed, sham-controlled RCTs provide conclusive evidence that RDN lowers ambulatory and office blood pressure (BP) to a significantly greater extent than sham treatment. BP-lowering efficacy is evident both in patients with and without concomitant antihypertensive medication. The average decrease of 10 mmHg in office BP is estimated to lower the incidence of cardiovascular events by 25-30%, based on meta-analyses of RCTs using pharmacological treatment. Neither peri-procedural, nor short-term or long-term adverse events or safety signals (available up to 3 years) have been observed. Implementing RDN as an innovative third option in the armamentarium of antihypertensive treatment requires a structured process that ensures the appropriate performance of the endovascular RDN procedure and adequate selection of hypertensive patients. The latter should also incorporate patients' perspective and preference that needs to be respected in a shared decision-making process.

Responsiveness of afferent renal nerve units in renovascular hypertension in rats

Previous data suggest that renal afferent nerve activity is increased in hypertension exerting sympathoexcitatory effects. Hence, we wanted to test the hypothesis that in renovascular hypertension, the activity of dorsal root ganglion (DRG) neurons with afferent projections from the kidneys is augmented depending on the degree of intrarenal inflammation. For comparison, a nonhypertensive model of mesangioproliferative nephritis was investigated. Renovascular hypertension (2-kidney, 1-clip [2K1C]) was induced by unilateral clipping of the left renal artery and mesangioproliferative glomerulonephritis (anti-Thy1.1) by IV injection of a 1.75-mg/kg BW OX-7 antibody. Neuronal labeling (dicarbocyanine dye [DiI]) in all rats allowed identification of renal afferent dorsal root ganglion (DRG) neurons. A current clamp was used to characterize neurons as tonic (sustained action potential [AP] firing) or phasic (1–4 AP) upon stimulation by current injection. All kidneys were investigated using standard morphological techniques. DRG neurons exhibited less often tonic response if in vivo axonal input from clipped kidneys was received (30.4% vs. 61.2% control, p < 0.05). However, if the nerves to the left clipped kidneys were cut 7 days prior to investigation, the number of tonic renal neurons completely recovered to well above control levels. Interestingly, electrophysiological properties of neurons that had in vivo axons from the right non-clipped kidneys were not distinguishable from controls. Renal DRG neurons from nephritic rats also showed less often tonic activity upon current injection (43.4% vs. 64.8% control, p < 0.05). Putative sympathoexcitatory and impaired sympathoinhibitory renal afferent nerve fibers probably contribute to increased sympathetic activity in 2K1C hypertension.

Effect of Renal Denervation on Cardiac Function and Inflammatory Factors in Heart Failure After Myocardial Infarction

Supplemental Digital Content is Available in the Text.

Heart failure (HF) affects around 100 million people and is a staggering burden for health care system worldwide. Rapid and sustained activation of inflammatory response is an important feature of HF after myocardial infarction. Sympathetic overactivation is also an important factor in the occurrence and progression of HF. The beneficial effect of renal denervation (RDN) has been demonstrated in HF. In the current study, we hypothesized that RDN improves cardiac function in HF canine models due to acute myocardial infarction (AMI) and reduced inflammation might be involved. Twenty-four beagles were randomized into the control (n = 8), HF (n = 8), and HF + RDN group (n = 8). The HF model after AMI was established by embolization the anterior descending distal artery with anhydrous ethanol in the HF and HF + RDN group. Bilateral renal artery ablation was performed in the HF + RDN group. Cardiac function, serum creatine kinase, creatine kinase-MB and NT-Pro BNP level, and expression of inflammation-related proteins in myocardial were examined. Because the paraventricular nucleus of the hypothalamus might be involved in inflammation-induced central neural excitation in HF and plays an important role in regulating extracellular fluid volume and sympathetic activity, expression of inflammation-related proteins in hypothalamus was also examined. AMI and post-AMI HF model was created successfully. Compared with the HF group, dogs in the HF + RDN group showed better cardiac function 4 weeks after AMI: lower left ventricular end-diastolic pressure, left ventricular end-diastolic dimension, and left ventricular end-systolic dimension and higher LEVF and left ventricular systolic pressure (P < 0.05 for all) were observed in the HF + RDN group. In addition, dogs in the HF + RDN group had slightly less ventricular fibrosis. Interestingly, RDN had lower expression of inflammation-related proteins including interleukin-6, tumor necrosis factors-α, nuclear factor κB, and monocyte chemotactic protein 1 (P < 0.05 for all) in both myocardial tissue and hypothalamus. RDN can improve cardiac function in dogs with HF after myocardial infarction. Our results suggested that RDN might affect cytokine-induced central neural excitation in HF and later affect sympathetic activity. Our results suggested a potential beneficial mechanism of RDN independent of mechanism involving renal afferent and efferent sympathetic nerves.

Nocturnal Hypertension and Heart Failure: Mechanisms, Evidence, and New Treatments

Heart failure (HF) is a common condition with an increasing prevalence. Despite a variety of evidence-based treatments for patients with HF with reduced ejection fraction, morbidity and mortality rates remain high. Furthermore, there are currently no treatments that have yet been shown to reduce complication and death rates in patients who have HF with preserved ejection fraction. Hypertension is a common comorbidity in patients with HF, contributing to disease development and prognosis. For example, hypertension is closely associated with the development of left ventricular hypertrophy, which an important precursor of HF. In particular, nighttime blood pressure (BP) appears to be an important, modifiable risk factor. Both nighttime BP and an abnormal circadian pattern of nighttime BP dipping have been shown to predict development of HF and the occurrence of cardiovascular events, independent of office BP. Key mechanisms for this association include sodium handling/salt sensitivity and increased sympathetic activation. These pathogenic mechanisms are targeted by several new treatment options, including sodium-glucose cotransporter 2 inhibitors, angiotensin receptor neprilysin inhibitors, mineralocorticoid receptor antagonists, and renal denervation. All of these could form part of antihypertensive strategies designed to control nighttime BP and contribute to the goal of achieving perfect 24-hour BP management. Nevertheless, additional research is needed to determine the effects of reducing nighttime BP and improving the circadian BP profile on the rate of HF, other cardiovascular events, and mortality.

Renal denervation therapy for hypertension: truths and half-truths: Renal denervation therapy for hypertension

Systemic hypertension is a major contributing factor for excessive morbidity and mortality globally. Experimental studies and early clinical trials showed excellent therapeutic responses to renal denervation (RDN) in patients with hypertension. However meta-analyses and objective assessments have failed to show that RDN therapy has any significant effect on blood pressure.  The aim of this review is to introduce the different methods that can be used in RDN, along with the benefits and disadvantages of these methods. Radiofrequency (RF) ablation (of renal nerves) is the most com-mon method of RDN, and we discuss the clinical evaluation of this method in the SYMPLICITY RDN trials. Finally, the development of second-generation RF devices and more comprehensive RDN procedures lead us to consider the current status and future path for RDN.

Renal interventions in the management of hypertension

PURPOSE OF REVIEW

In the present comprehensive review, we describe the pathophysiology, indications, and evidence for both renal artery stenting and renal artery denervation. We also discuss the procedural techniques, risks, benefits, and future directions of renal intervention in the management of hypertension (HTN).

RECENT FINDINGS

Hemodynamic confirmation of lesion severity in severe renal artery stenosis is a resting or hyperemic translesional systolic gradient >20, resting or hyperemic mean translesional gradient >10 and/or renal fractional flow reserve <0.8 are considered severe. Knowing that correct stent size was used is the best predictor of restenosis, intravascular ultrasound is effective and well tolerated for stent sizing. The main categories of renal denervation: radiofrequency ablation, ultrasound, chemical ablation, and brachytherapy have shown impressive outcomes in treating resistant HTN.

SUMMARY

Over the past decade, several studies have shown the safety and benefit of catheter-based renal interventions in managing HTN. Renal artery stenting and renal artery denervation are the leading alternative invasive treatment employed in managing HTN.

New Drugs and Interventional Strategies for the Management of Hypertension

Essential hypertension is an important cause of cardiovascular morbidity and mortality worldwide with significant clinical and economic implications. The field of antihypertensive treatment already numbers numerous agents and classes of drugs. However, patients are still developing uncontrolled hypertension. Hence there is a continuous need for novel agents with good tolerability. Advances in this field are focusing both on pharmacotherapy, with the developments in traditional and non-traditional targets, as well as interventional techniques such as renal denervation and baroreflex activation therapy. It is likely that future strategies may involve a tailored approach to the individual patient, with genetic modulation playing a key role.

[Second chance for renal artery denervation]

The article is a review of contemporary randomized studies on radiofrequency denervation of renal arteries, followed by critical assessment of their advantages and disadvantages for possible optimization of endovascular treatment of resistant arterial hypertension.

Aorticorenal ganglion as a novel target for renal neuromodulation

BACKGROUND

Clinical trials for renal artery (RA) ablation have shown limited efficacy.

OBJECTIVE

The purpose of this study was to investigate whether the aorticorenal ganglion (ARG) can be targeted for renal denervation.

METHODS

Twenty-eight pigs were studied under isoflurane or alpha-chloralose to examine hemodynamic responses and catecholamine release in response to RA or ARG stimulation. To assess the efficacy of ARG ablation, we randomized 16 pigs to either sham, RA, or ARG ablation, followed by occlusion of the left anterior descending coronary artery (LAD). Hemodynamic responses, cardiac electrophysiological parameters, and arrhythmias/sudden cardiac death were assessed following LAD occlusion. Absent hemodynamic responses to stimulation confirmed ARG or RA ablation. In vivo stellate ganglion neural activity was recorded to assess cardiac sympathetic signaling. Cadaveric dissections were performed to localize the ARG in humans for comparison to swine.

RESULTS

The ARG is a purely sympathetic ganglion with cholinergic inputs and pass-through sensory afferent fibers. Compared to RA stimulation, ARG stimulation yielded greater hemodynamic responses during alpha-chloralose anesthesia. However, neither site yielded significant responses under isoflurane. Radiofrequency ablation of the ARG eliminated responses to both RA and ARG stimulation, whereas RA ablation did not eliminate responses to ARG stimulation. Ablation of the ARG did not impact the kidneys or adrenal glands. Compared to control and RA ablation, ARG ablation was protective against ventricular arrhythmias and sudden death. Human and swine ARG are similarly located in the aorticorenal region.

CONCLUSION

Our findings indicate that the ARG may be a novel target for renal neuromodulation. Further studies are warranted to validate these findings.

Long-term outcomes after renal denervation in an Asian population: results from the Global SYMPLICITY Registry in South Korea (GSR Korea)

The objective of this work was to investigate the long-term safety and efficacy of renal denervation in Korean patients from the Global SYMPLICITY Registry (GSR). GSR Korea is a substudy of GSR with additional inclusion and exclusion criteria compared to GSR, including inclusion criteria of office systolic blood pressure ≥160 mmHg, or ≥150 mmHg for type 2 diabetes patients, while receiving 3 or more antihypertensive medications without changes for 2 weeks prior to enrollment. Renal denervation was performed using a Symplicity Flex catheter for ablation in the main renal arteries. Changes in office systolic blood pressure and adverse events were collected for up to 36 months of follow-up for 102 patients in GSR Korea. In addition, adverse events and reductions in office systolic blood pressure were analyzed for patients with and without type II diabetes mellitus. Renal denervation led to mean (± standard deviation) reductions in office systolic blood pressure at 12, 24, and 36 months in GSR Korea (-26.7 ± 18.5, -30.1 ± 21.6 mmHg, and -32.5 ± 18.8, respectively). The proportion of patients with a ≥10 mmHg office systolic blood pressure reduction from baseline was 86.3% at 12 months, 86.5% at 24 months, and 89.7% at 36 months. Adverse events at 3 years were rare. In addition, reductions in office systolic blood pressure were similar for patients with vs. without diabetes mellitus (p > 0.05 at all timepoints). Office systolic blood pressure was safely reduced at up to 36 months post-renal denervation in GSR Korea, and adverse events were rare. In addition, patients with and without diabetes had similar office systolic blood pressure reductions.

Current Status and Future Perspectives of Renal Denervation

Despite the availability of numerous antihypertensive medications, hypertension treatment and control rates remain low, and uncontrolled hypertension is well-known to be one of the most important cardiovascular risk factors. Endovascular catheter-based renal denervation (RDN) has been developed to be a complementary or alternative treatment option for patients who cannot take medication, poor adherence, or have resistant hypertension despite the use of maximal doses of medications. Recently, several randomized trials for evaluating the efficacy and safety of second-generation RDN devices consistently show solid evidence for their blood pressure-lowering efficacy. This review summarizes the current evidence and future perspectives of RDN.

Catheter-based renal denervation (RDN) therapy, a new procedure that uses radiofrequency ablation to interrupt efferent and afferent renal sympathetic nerve fibers, is a complementary or alternative treatment to antihypertensive medications for optimal control of blood pressure (BP). Although several single-arm early proof-of-concept studies showed significant BP reduction, the largest sham-controlled study using the first-generation RDN device (SYMPLICITY HTN-3) failed to significantly reduce BP in patients with resistant hypertension who were taking the guideline-based combination of antihypertensive medications. Since then, new devices and techniques have been developed to improve the efficacy and safety of RDN procedures. Sham-controlled trials using second-generation RDN devices (radiofrequency- and ultrasound-based) have provided solid evidence for their BP-lowering efficacy with and without the use of concomitant antihypertensive medication. Moreover, the safety profile of RDN in several registries and clinical trials appears to be excellent. This review summarizes the current evidence for RDN and discusses its current issues, future trials, Asian perspectives, and potential roles in both hypertension and other morbidities.

Effect of renal denervation on long-term outcomes in patients with resistant hypertension

Increasing studies strongly prove that renal denervation, a minimally invasive surgery, is a promising new non-drug treatment method that can effectively control blood pressure in patients with resistant hypertension, but the evaluation of the long-term blood pressure control effect of renal denervation for resistant hypertension is still lacking. Here, we critically review current long-term follow-up data about the use of renal denervation for RH to comprehensively evaluate the effectiveness of renal denervation for RH, and to provide practical guidance for practitioners who are establishing a renal denervation service. Limited by the current research, many problems need to be solved before renal denervation is applied to RH. In addition, ambulatory blood pressure should be the first choice for the evaluation of blood pressure. Finally, the continuous antihypertensive effect of renal denervation in different renal denervation systems also needs to be strictly compared.

Impact of renal sympathetic denervation on cardiac magnetic resonance-derived cardiac indices in hypertensive patients - A meta-analysis

BACKGROUND

Renal sympathetic denervation (RDN) is a safe device-based option for the treatment of hypertension although current guidelines do not recommend its use in routine clinical practice. In this meta-analysis, we investigated the effects of RDN in cardiac magnetic resonance (CMR)-derived cardiac indices.

METHODS

This meta-analysis was performed in accordance with the PRISMA statement. A comprehensive systematic search of MEDLINE database and Cochrane library through to January 2021 was performed. The inclusion criteria were studies that enrolled patients undergoing RDN in whom CMR data were provided for left ventricular end-diastolic volume indexed to body surface area (BSA) (LVEDVI), left ventricular end-systolic volume indexed (LVESVI), left ventricular mass indexed (LVMI), and left ventricular ejection fraction (LVEF) pre and post RDN. A random effects model was used for the analyses.

RESULTS

Our search strategy revealed 9 studies that were finally included in the meta-analysis (n=300 patients, mean age: 60 years old, males: 59%). Compared to control group, RDN patients showed significantly lower values in the attained volumes (LVEDVI: -6.70 ml/m², p=0.01; LVESVI: -3.63 ml/m², p=0.006). Moreover, RDN group achieved a statistically significant higher attained LVEF (3.49%, p=0.01). A non-significant difference was found in the attained LVMI between RDN and control groups (-2.59 g/m², p=0.39). Compared to pre-RDN values, RDN reduces significantly the LVMI, the LVEDVI, and the LVESVI while a non-significant change of LVEF was found.

CONCLUSIONS

In conclusion, the current study demonstrates the potential beneficial role of RDN in CMR-derived cardiac indices that reflect adverse remodeling. However, large, randomized studies are needed to elucidate the role of RDN in cardiac remodeling in hypertension, heart failure, and other clinical settings.

[Update on treatment resistant hypertension and secondary hypertension]

Resistant hypertension (RH) is defined in patients who do not meet their blood pressure targets despite the daily intake of three antihypertensive drugs in maximally tolerated dosages. This triple treatment should comprise (1) an angiotensin-converting enzyme inhibitor (ACE-I) or angiotensin receptor blocker (ARB), (2) a calcium channel blocker and (3) a diuretic. RH should also be diagnosed in patients on four or more antihypertensive drug classes. Of note, the diagnosis of RH requires the exclusion of non-adherence, "white coat effect", and incorrect BP-measurement.After diagnosing RH, it is important to recommend lifestyle interventions (e. g. low dietary salt intake, regular physical activity), to pause BP-elevating substances, and to consider the presence of secondary hypertension.Such secondary forms of hypertension primarily include endocrine disorders and renal disease (both acute kidney injury and chronic kidney disease). The leading endocrine cause is primary hyperaldosteronism, the management of which was highlighted in a recent guideline. Other endocrine causes - such as phaeochromocytoma or hypercortisolism - are much less frequent. In contrast, sleep apnoea disorders are now mostly considered as a comorbidity rather than as a cause of secondary hypertension.Treatment options for RH include lifestyle optimisation and escalation of antihypertensive medication. In most patients on triple treatment (ACE-I or ARB plus calcium channel blocker plus diuretic), mineralocorticoid receptor antagonists (MRA) should be the next treatment choice. As MRA may be associated with hyperkalemia (particularly in patients with chronic kidney disease), the concurrent use of potassium-lowering agents such as patiromer may allow a safe long-term treatment. In contrast, novel interventional treatment options in RH such as renal denervation are still controversially discussed.

Predictors of blood pressure response to ultrasound renal denervation in the RADIANCE-HTN SOLO study

The blood pressure (BP) lowering response to renal denervation (RDN) remains variable with about one-third of patients not responding to ultrasound or radiofrequency RDN. Identification of predictors of the BP response to RDN is needed to optimize patient selection for this therapy. This is a post-hoc analysis of the RADIANCE-HTN SOLO study. BP response to RDN was measured by the change in daytime ambulatory systolic blood pressure (dASBP) at 2 months post procedure. Univariate regression was used initially to assess potential predictors of outcome followed by multivariate regression analysis. In the univariate analysis, predictors of response to RDN were higher baseline daytime ambulatory diastolic blood pressure (dADBP), the use of antihypertensive medications at screening, and presence of orthostatic hypertension (OHTN) whilst the presence of untreated accessory arteries was a negative predictor of response. Multivariate analysis determined that dADBP and use of antihypertensive medications were predictors of response to RDN with a trend for OHTN to predict response. Obese females also appeared to be better responders to RDN in an interaction model. RDN is more effective in patients with elevated baseline dADBP and those with OHTN, suggesting increased peripheral vascular resistance secondary to heightened sympathetic tone. These assessments are easy to perform in clinical setting and may help in phenotyping patients who will respond better to RDN.

The Road to Better Management in Resistant Hypertension-Diagnostic and Therapeutic Insights

Resistant hypertension (R-HTN) implies a higher mortality and morbidity compared to non-R-HTN due to increased cardiovascular risk and associated adverse outcomes—greater risk of developing chronic kidney disease, heart failure, stroke and myocardial infarction. R-HTN is considered when failing to lower blood pressure below 140/90 mmHg despite adequate lifestyle measures and optimal treatment with at least three medications, including a diuretic, and usually a blocker of the renin-angiotensin system and a calcium channel blocker, at maximally tolerated doses. Hereby, we discuss the diagnostic and therapeutic approach to a better management of R-HTN. Excluding pseudoresistance, secondary hypertension, white-coat hypertension and medication non-adherence is an important step when diagnosing R-HTN. Most recently different phenotypes associated to R-HTN have been described, specifically refractory and controlled R-HTN and masked uncontrolled hypertension. Optimizing the three-drug regimen, including the diuretic treatment, adding a mineralocorticoid receptor antagonist as the fourth drug, a β-blocker as the fifth drug and an α1-blocker or a peripheral vasodilator as a final option when failing to achieve target blood pressure values are current recommendations regarding the correct management of R-HTN.

Renal denervation prevents myocardial structural remodeling and arrhythmogenicity in a chronic kidney disease rabbit model

BACKGROUND

The electrophysiological (EP) effects and safety of renal artery denervation (RDN) in chronic kidney disease (CKD) are unclear.

OBJECTIVE

The purpose of this study was to investigate the arrhythmogenicity of RDN in a rabbit model of CKD.

METHODS

Eighteen New Zealand white rabbits were randomized to control (n = 6), CKD (n = 6), and CKD-RDN (n = 6) groups. A 5/6 nephrectomy was selected for the CKD model. RDN was applied in the CKD-RDN group. All rabbits underwent cardiac EP studies for evaluation. Immunohistochemistry, myocardial fibrosis, and renal catecholamine levels were evaluated.

RESULTS

The CKD group (34.8% ± 9.2%) had a significantly higher ventricular arrhythmia (VA) inducibility than the control (8.6% ± 3.8%; P <.01) and CKD-RDN (19.5% ± 6.3%; P = .01) groups. In the CKD-RDN group, ventricular fibrosis was significantly decreased compared to the CKD group (7.4% ± 2.0 % vs 10.4% ± 3.7%; P = .02). Sympathetic innervation in the CKD group was significantly increased compared to the control and CKD-RDN groups [left ventricle: 4.1 ± 1.8 vs 0.8 ± 0.5 (10² μm²/mm²), P <.01; 4.1 ± 1.8 vs 0.9± 0.6 (10² μm²/mm²), P <.01; right ventricle: 3.6 ± 1.0 vs 1.0 ± 0.4 (10² μm²/mm²), P <.01; 3.6 ± 1.0 vs 1.0 ± 0.5 (10² μm²/mm²), P <.01].

CONCLUSION

Neuromodulation by RDN demonstrated protective effects with less structural and electrical remodeling, leading to attenuated VAs. In a rabbit model of CKD, RDN plays a therapeutic role by lowering the risk of VA caused by autonomic dysfunction.

Changes in Plasma Renin Activity After Renal Artery Sympathetic Denervation

BACKGROUND

The renin-angiotensin-aldosterone system plays a key role in blood pressure (BP) regulation and is the target of several antihypertensive medications. Renal denervation (RDN) is thought to interrupt the sympathetic-mediated neurohormonal pathway as part of its mechanism of action to reduce BP.

OBJECTIVES

The purpose of this study was to evaluate plasma renin activity (PRA) and aldosterone before and after RDN and to assess whether these baseline neuroendocrine markers predict response to RDN.

METHODS

Analyses were conducted in patients with confirmed absence of antihypertensive medication. Aldosterone and PRA levels were compared at baseline and 3 months post-procedure for RDN and sham control groups. Patients in the SPYRAL HTN-OFF MED Pivotal trial were separated into 2 groups, those with baseline PRA ≥0.65 ng/ml/h (n = 110) versus <0.65 ng/ml/h (n = 116). Follow-up treatment differences between RDN and sham control groups were adjusted for baseline values using multivariable linear regression models.

RESULTS

Baseline PRA was similar between RDN and control groups (1.0 ± 1.1 ng/ml/h vs. 1.1 ± 1.1 ng/ml/h; p = 0.37). Change in PRA at 3 months from baseline was significantly greater for RDN compared with control subjects (-0.2 ± 1.0 ng/ml/h; p = 0.019 vs. 0.1 ± 0.9 ng/ml/h; p = 0.14), p = 0.001 for RDN versus control subjects, and similar differences were seen for aldosterone: RDN compared with control subjects (-1.2 ± 6.4 ng/dl; p = 0.04 vs. 0.4 ± 5.4 ng/dl; p = 0.40), p = 0.011. Treatment differences at 3 months in 24-h and office systolic blood pressure (SBP) for RDN versus control patients were significantly greater for patients with baseline PRA ≥0.65 ng/ml/h versus <0.65 ng/ml/h, despite similar baseline BP. Differences in office SBP changes according to baseline PRA were also observed earlier at 2 weeks post-RDN.

CONCLUSIONS

Plasma renin activity and aldosterone levels for RDN patients were significantly reduced at 3 months when compared with baseline as well as when compared with sham control. Higher baseline PRA levels were associated with a significantly greater reduction in office and 24-h SBP. (SPYRAL PIVOTAL - SPYRAL HTN-OFF MED Study; NCT02439749).

Renal Arteries Revisited: Anatomy, Pathologic Entities, and Implications for Endovascular Management

The renal arteries (RAs) are important vessels that usually arise from the abdominal aorta and supply the kidneys; thus, these arteries play a vital role in physiologic functions such as hemofiltration and blood pressure regulation. An understanding of the basis for embryologic development and the frequently variable anatomy of the RAs is necessary to fully appreciate the range of diseases and the implications for procedural planning. Hemorrhage from an RA is relatively common and is typically traumatic or spontaneous, with the latter form often seen in association with underlying tumors or arteriopathy. Accurate diagnostic evaluation of RA disease due to conditions such as atherosclerosis, fibromuscular dysplasia, vasculitis, aneurysm, arteriovenous shunt, embolic disease, and dissection is dependent on the use of multimodality imaging and is essential for selecting appropriate clinical management, with endovascular therapy having a key role in treatment. Surgical considerations include extra-anatomic renal bypass, which remains an important treatment option even in this era of endovascular therapy, and RA embolization as an adjunct to tumor surgery. A novel area of research interest is the potential role of RA denervation in the management of refractory hypertension. ^©RSNA, 2021.

Joint ESH excellence centers' national meeting on renal sympathetic denervation: A Greek experts' survey

OBJECTIVE

The efficacy of renal sympathetic denervation (RDN) has been affirmed by a number of recent clinical studies, despite controversies in this field over the last five years. Therefore, it is of paramount importance that hypertension experts debate the merits of RDN by revealing and expressing their personal beliefs and perspectives regarding this procedure.

METHODS

A cross-sectional survey was conducted among Greek leaders of the Hypertension Excellence Centers with the use of a closed-type questionnaire specifically designed to elicit information and evaluate the respondent's views and perspectives about RDN efficacy, safety and ideal target patient population.

RESULTS

A total of 36 participants completed the survey. Based on the results, RDN was considered efficient (91.7%) and safe (94.5%), while the overwhelming majority of the participants felt confident in the long-term efficacy (88.9%) of the intervention and that it lacks reliable predictors of blood pressure response (94.5%). Patients with resistant (91.7%), ultra-resistant (94.4%), and uncontrolled hypertension (80.6%) were suggested as ideal candidates for RDN. Establishing a close co-operation between interventionalists and hypertension experts was considered essential to ensure the efficacy (97.2%) as well as the safety (97.3%) of the procedure.

CONCLUSION

The vast majority of Greek hypertension experts surveyed were convinced of the efficacy and safety of RDN based on the preponderance of available scientific and clinical data. Identification of the ideal patient group remains controversial. Respondents generally agreed on the necessity of building close collaborative relationships between interventionalists and hypertension experts in order to improve RDN clinical outcome.

Renal denervation for the treatment of ventricular arrhythmias: A systematic review and meta-analysis

INTRODUCTION

Ventricular arrhythmias (VAs) are a major cause of morbidity and mortality in patients with heart disease. Recent studies evaluated the effect of renal denervation (RDN) on the occurrence of VAs. We conducted a systematic review and meta-analysis to determine the efficacy and safety of this procedure.

METHODS AND RESULTS

A systematic search of the literature was performed to identify studies that evaluated the use of RDN for the management of VAs. Primary outcomes were reduction in the number of VAs and implantable cardioverter-defibrillator (ICD) therapies. Secondary outcomes were changes in blood pressure and renal function. Ten studies (152 patients) were included in the meta-analysis. RDN was associated with a reduction in the number of VAs, antitachycardia pacing, ICD shocks, and overall ICD therapies of 3.53 events/patient/month (95% confidence interval [CI] = -5.48 to -1.57), 2.86 events/patient/month (95% CI = -4.09 to -1.63), 2.04 events/patient/month (95% CI = -2.12 to -1.97), and 2.68 events/patient/month (95% CI = -3.58 to -1.78), respectively. Periprocedural adverse events occurred in 1.23% of patients and no significant changes were seen in blood pressure or renal function.

CONCLUSIONS

In patients with refractory VAs, RDN was associated with a reduction in the number of VAs and ICD therapies, and was shown to be a safe procedure.