Confounding Factors in Renal Denervation Trials: Revisiting Old and Identifying New Challenges in Trial Design of Device Therapies for Hypertension

Diagnosis and management of resistant hypertension

Resistant hypertension is defined as blood pressure that remains above the therapeutic goal despite concurrent use of at least three antihypertensive agents of different classes, including a diuretic, with all agents administered at maximum or maximally tolerated doses. Resistant hypertension is also diagnosed if blood pressure control requires four or more antihypertensive drugs. Assessment requires the exclusion of apparent treatment resistant hypertension, which is most often the result of non-adherence to treatment. Resistant hypertension is associated with major cardiovascular events in the short and long term, including heart failure, ischemic heart disease, stroke, and renal failure. Guidelines from several professional organizations recommend lifestyle modification and antihypertensive drugs. Medications typically include an angiotensin converting enzyme inhibitor or angiotensin receptor blocker, a calcium channel blocker, and a long acting thiazide-type/like diuretic; if a fourth drug is needed, evidence supports addition of a mineralocorticoid receptor antagonist. After a long pause since 2007 when the last antihypertensive class was approved, several novel agents are now under active development. Some of these may provide potent blood pressure lowering in broad groups of patients, such as aldosterone synthase inhibitors and dual endothelin receptor antagonists, whereas others may provide benefit by allowing treatment of resistant hypertension in special populations, such as non-steroidal mineralocorticoid receptor antagonists in patients with chronic kidney disease. Several device based approaches have been tested, with renal denervation being the best supported and only approved interventional device treatment for resistant hypertension.

Impact of Antihypertensive Medication Changes After Renal Denervation Among Different Patient Groups: SPYRAL HTN-ON MED

BACKGROUND

The SPYRAL HTN-ON 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)trial showed significant office and nighttime systolic blood pressure (BP) reductions in patients with hypertension following renal denervation (RDN) compared with sham-control patients, despite similar 24-hour BP reductions. We compared antihypertensive medication and BP changes among prespecified subpopulations.

METHODS

The multicenter, randomized, sham-controlled, blinded SPYRAL HTN-ON MED trial (n=337) evaluated BP changes after RDN compared with a sham procedure in patients with hypertension prescribed 1 to 3 antihypertensive drugs. Most patients (n=187; 54%) were enrolled outside the United States, while 156 (46%) US patients were enrolled, including 60 (18%) Black Americans.

RESULTS

Changes in detected antihypertensive drugs were similar between RDN and sham group patients in the outside US cohort, while drug increases were significantly more common in the US sham group compared with the RDN group. Patients from outside the United States showed significant reductions in office and 24-hour mean systolic BP at 6 months compared with the sham group, whereas BP changes were similar between RDN and sham in the US cohort. Within the US patient cohort, Black Americans in the sham control group had significant increases in medication burden from baseline through 6 months (P=0.003) but not in the RDN group (P=0.44).

CONCLUSIONS

Patients enrolled outside the United States had minimal antihypertensive medication changes between treatment groups and had significant office and 24-hour BP reductions compared with the sham group. Increased antihypertensive drug burden in the US sham cohort, especially among Black Americans, may have diluted the treatment effect in the combined trial population.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02439775.

Patient-Level Pooled Analysis of Endovascular Ultrasound Renal Denervation or a Sham Procedure 6 Months After Medication Escalation: The RADIANCE Clinical Trial Program

BACKGROUND

The randomized, sham-controlled RADIANCE-HTN (A Study of the Recor Medical Paradise System in Clinical Hypertension) SOLO, RADIANCE-HTN TRIO, and RADIANCE II (A Study of the Recor Medical Paradise System in Stage II Hypertension) trials independently met their primary end point of a greater reduction in daytime ambulatory systolic blood pressure (SBP) 2 months after ultrasound renal denervation (uRDN) in patients with hypertension. To characterize the longer-term effectiveness and safety of uRDN versus sham at 6 months, after the blinded addition of antihypertensive treatments (AHTs), we pooled individual patient data across these 3 similarly designed trials.

METHODS

Patients with mild to moderate hypertension who were not on AHT or with hypertension resistant to a standardized combination triple AHT were randomized to uRDN (n=293) versus sham (n=213); they were to remain off of added AHT throughout 2 months of follow-up unless specified blood pressure (BP) criteria were exceeded. In each trial, if monthly home BP was ≥135/85 mm Hg from 2 to 5 months, standardized AHT was sequentially added to target home BP <135/85 mm Hg under blinding to initial treatment assignment. Six-month outcomes included baseline- and AHT-adjusted change in daytime ambulatory, home, and office SBP; change in AHT; and safety. Linear mixed regression models using all BP measurements and change in AHT from baseline through 6 months were used.

RESULTS

Patients (70% men) were 54.1±9.3 years of age with a baseline daytime ambulatory/home/office SBP of 150.5±9.8/151.0±12.4/155.5±14.4 mm Hg, respectively. From 2 to 6 months, BP decreased in both groups with AHT titration, but fewer uRDN patients were prescribed AHT (P=0.004), and fewer additional AHT were prescribed to uRDN patients versus sham patients (P=0.001). Whereas the unadjusted between-group difference in daytime ambulatory SBP was similar at 6 months, the baseline and medication-adjusted between-group difference at 6 months was -3.0 mm Hg (95% CI, -5.7, -0.2; P=0.033), in favor of uRDN+AHT. For home and office SBP, the adjusted between-group differences in favor of uRDN+AHT over 6 months were -5.4 mm Hg (-6.8, -4.0; P<0.001) and -5.2 mm Hg (-7.1, -3.3; P<0.001), respectively. There was no heterogeneity between trials. Safety outcomes were few and did not differ between groups.

CONCLUSIONS

This individual patient-data analysis of 506 patients included in the RADIANCE trials demonstrates the maintenance of BP-lowering efficacy of uRDN versus sham at 6 months, with fewer added AHTs.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifiers: NCT02649426 and NCT03614260.

Catheter-based renal artery denervation: facts and expectations

Catheter-based renal artery denervation (RAD) is entering a new era. After the disappointing results of SYMPLICITY-HTN 3 trial in year 2014, several technical and methodological advancements led to execution of important SHAM-controlled randomized trials with promising results. Now, the 2023 ESH Guidelines give RAD a class of recommendation II with a Level of Evidence B. Currently, catheter-based RAD has two main areas of application: (a) Hypertensive patients who are still untreated, in whom RAD is a sort of a first-line treatment; (b) Difficult-to-control or true resistant hypertensive patients. Notably, randomized SHAM-controlled trials met their primary end-point in both these conditions. So far, we do not dispose of established predictors of the antihypertensive response to RAD. Some data suggest that younger patients with systo-diastolic hypertension, absence of diffuse atherosclerosis and evidence of sympathetic nervous system overactivity experience a better BP response to the procedure. We reviewed the available data on catheter-based RAD and included an updated meta-analysis of the results of the available SHAM-controlled trials. Overall, the reduction in 24-h systolic blood pressure (BP) after RAD exceeded that after SHAM by 4.58 mmHg (95% CI 3.07-6.10) in untreated patients, and by 3.82 mmHg (95% CI 2.46-5.18) in treated patients, without significant heterogeneity across trials, patient phenotype (untreated versus treated patients) and technique (radiofrequency versus ultrasound). There were no important safety signals related to the procedure. Notably, some data suggest that RAD could be an effective additional approach in patients with atrial fibrillation and other conditions characterized by sympathetic nervous system overactivity.

Clinical event reductions in high-risk patients after renal denervation projected from the global SYMPLICITY registry

AIMS

Renal denervation has been shown to lower blood pressure in sham-controlled trials and represents a device-based treatment option for hypertension. We sought to project clinical event reductions after radiofrequency renal denervation using a novel modelling approach.

METHODS AND RESULTS

The Global SYMPLICITY Registry is a global, prospective all-comer registry to evaluate safety and efficacy after renal denervation. For this analysis, change in office systolic blood pressure from baseline was calculated from reported follow-up in the Global SYMPLICITY Registry. Relative risks for death and other cardiovascular events as well as numbers needed to treat for event avoidance were obtained for the respective blood pressure reductions based on previously reported meta-regression analyses for the full cohort and high-risk subgroups including type 2 diabetes, chronic kidney disease, resistant hypertension, and high basal cardiovascular risk. Average baseline office systolic blood pressure and reduction estimates for the full cohort (N = 2651) were 166±25 and -14.8 ± 0.4 mmHg, respectively. Mean reductions in blood pressure ranged from -11.0--21.8 mmHg for the studied high-risk subgroups. Projected relative risks ranged from 0.57 for stroke in the resistant hypertension cohort to 0.92 for death in the diabetes cohort. Significant absolute reductions in major adverse cardiovascular events over 3 years compared with the projected control (8.6 ± 0.7% observed vs. 11.7 ± 0.9% for projected control; P < 0.01) were primarily due to reduced stroke incidence. The robustness of findings was confirmed in sensitivity and scenario analyses.

CONCLUSION

Model-based projections suggest radiofrequency renal denervation for patients with uncontrolled hypertension adds considerable clinical benefit across a spectrum of different cohort characteristics.

Emerging topics on renal denervation in hypertension: anatomical and functional aspects of renal nerves

Inappropriate sympathetic activation is closely associated with the development and progression of hypertension. Renal denervation (RDN) is a neuromodulation therapy performed using an intraarterial catheter in patients with hypertension. Recent randomized sham-operated controlled trials have shown that RDN has significant antihypertensive effects that last for at least 3 years. Based on this evidence, RDN is nearly ready for general clinical application. On the other hand, there are remaining issues to be addressed, including elucidation of the precise antihypertensive mechanisms of RDN, the appropriate endpoint of RDN during the procedure, and the association between reinnervation after RDN and the long-term effects of RDN. This mini review focuses on studies implicating anatomy of the renal nerves, which consist of afferent or efferent and sympathetic or parasympathetic nerves, the response of blood pressure to renal nerve stimulation, and reinnervation of renal nerves after RDN. A comprehensive understanding of the anatomical and functional aspects of the renal nerves and the antihypertensive mechanisms of RDN, including its long-term effects, will enhance our ability to incorporate RDN into strategies to treat hypertension in clinical practice. This mini review focuses on studies implicating anatomy of the renal nerves, which consist of afferent or efferent and sympathetic or parasympathetic nerves, the response of blood pressure to renal nerve stimulation, and reinnervation of renal nerves after renal denervation. Whether the ablation site is sympathetic dominant or parasympathetic dominant, and afferent dominant or efferent dominant, would in turn determine the final output of renal denervation. BP: blood pressure.

Renal Denervation: A Practical Guide for Health Professionals Managing Hypertension

Growing evidence demonstrates the suitability of renal denervation in a broad population of patients; however, questions remain over its suitability and practical implementation. Given the rapidity of emerging data, this has been a challenging field for potential adopters to navigate. The purpose of this article is twofold: to provide navigation through emerging clinical data and evolving guidance; and to provide physicians with practical, evidence-based advice for identifying eligible patients and providing appropriate management in the pre- and postintervention settings. Although many of these recommendations are based on existing published guidance documents, we reflect equally on our own experiences of using this technology.

Endovascular Ultrasound Renal Denervation to Treat Hypertension: The RADIANCE II Randomized Clinical Trial

Importance

Two initial sham-controlled trials demonstrated that ultrasound renal denervation decreases blood pressure (BP) in patients with mild to moderate hypertension and hypertension that is resistant to treatment.

Objective

To study the efficacy and safety of ultrasound renal denervation without the confounding influence of antihypertensive medications in patients with hypertension.

Design, Setting, and Participants

Sham-controlled, randomized clinical trial with patients and outcome assessors blinded to treatment assignment that was conducted between January 14, 2019, and March 25, 2022, at 37 centers in the US and 24 centers in Europe, with randomization stratified by center. Patients aged 18 years to 75 years with hypertension (seated office systolic BP [SBP] ≥140 mm Hg and diastolic BP [DBP] ≥90 mm Hg despite taking up to 2 antihypertensive medications) were eligible if they had an ambulatory SBP/DBP of 135/85 mm Hg or greater and an SBP/DBP less than 170/105 mm Hg after a 4-week washout of their medications. Patients with an estimated glomerular filtration rate of 40 mL/min/1.73 m2 or greater and with suitable renal artery anatomy were randomized 2:1 to undergo ultrasound renal denervation or a sham procedure. Patients were to abstain from antihypertensive medications until the 2-month follow-up unless prespecified BP criteria were exceeded and were associated with clinical symptoms.

Interventions

Ultrasound renal denervation vs a sham procedure.

Main Outcomes and Measures

The primary efficacy outcome was the mean change in daytime ambulatory SBP at 2 months. The primary safety composite outcome of major adverse events included death, kidney failure, and major embolic, vascular, cardiovascular, cerebrovascular, and hypertensive events at 30 days and renal artery stenosis greater than 70% detected at 6 months. The secondary outcomes included mean change in 24-hour ambulatory SBP, home SBP, office SBP, and all DBP parameters at 2 months.

Results

Among 1038 eligible patients, 150 were randomized to ultrasound renal denervation and 74 to a sham procedure (mean age, 55 years [SD, 9.3 years]; 28.6% female; and 16.1% self-identified as Black or African American). The reduction in daytime ambulatory SBP was greater with ultrasound renal denervation (mean, -7.9 mm Hg [SD, 11.6 mm Hg]) vs the sham procedure (mean, -1.8 mm Hg [SD, 9.5 mm Hg]) (baseline-adjusted between-group difference, -6.3 mm Hg [95% CI, -9.3 to -3.2 mm Hg], P < .001), with a consistent effect of ultrasound renal denervation throughout the 24-hour circadian cycle. Among 7 secondary BP outcomes, 6 were significantly improved with ultrasound renal denervation vs the sham procedure. No major adverse events were reported in either group.

Conclusions and Relevance

In patients with hypertension, ultrasound renal denervation reduced daytime ambulatory SBP at 2 months in the absence of antihypertensive medications vs a sham procedure without postprocedural major adverse events.

Trial Registration

ClinicalTrials.gov Identifier: NCT03614260.

Consensus and inconsistency between different consensus documents on renal denervation worldwide: the way forward

ABSTRACT

Given the unsatisfactory hypertension control rates and high rates of non-adherence to antihypertensive medications worldwide, device therapy which can safely provide durable blood pressure-lowering effects can fulfill the unmet need. A series of second-generation randomized sham-controlled renal denervation (RDN) trials have demonstrated the efficacy and safety of RDN in a wide range of hypertensive patients. The four representative consensus documents on RDN (from the Chinese Taiwan Hypertension Society and Taiwan Society of Cardiology [THS/TSOC 2019], Asia Renal Denervation Consortium 2019, European Society of Hypertension [ESH 2021], and Society for Cardiovascular Angiography & Intervention and National Kidney Foundation [SCAI/NKF 2021]) consistently recommend RDN as an alternative or complementary treatment strategy for patients with uncontrolled hypertension. In addition, both documents from Asia further recommend that RDN can be considered as an initial treatment strategy for drug-naïve hypertensive patients. There is still inconsistency regarding whether ambulatory blood pressure monitoring should be used routinely both before and after RDN, and whether patients with a secondary cause of hypertension could be treated with RDN if their blood pressure remains uncontrolled after definitive treatment (treatment-resistant secondary hypertension). The THS/TSOC consensus provides acronyms to summarize key aspects of patient selection (RDNi2) and pre-RDN assessments (RAS). The ESH and SCAI/NKF documents recommend establishing structured pathways for clinical practice and issues regarding reimbursement. All documents identify knowledge gaps in RDN, from identifying predictors of super-responders to demonstrating effects on cardiovascular events. These gaps should be urgently filled to facilitate the wider application of this device therapy for patients with hypertension.

C, Renkin J, Maes F, Beauloye C, Lengelé JP, Huyberechts D, Bouvie A, Witkowski A, Januszewicz A, Kądziela J, Prejbisj A, Hering D, Ciecwierz D, Jaguszewski MJ, Owczuk R. Effects of Renal Denervation vs Sham in Resistant Hypertension After Medication Escalation: Prespecified Analysis at 6 Months of the RADIANCE-HTN TRIO Randomized Clinical Trial

Importance

Although early trials of endovascular renal denervation (RDN) for patients with resistant hypertension (RHTN) reported inconsistent results, ultrasound RDN (uRDN) was found to decrease blood pressure (BP) vs sham at 2 months in patients with RHTN taking stable background medications in the Study of the ReCor Medical Paradise System in Clinical Hypertension (RADIANCE-HTN TRIO) trial.

Objectives

To report the prespecified analysis of the persistence of the BP effects and safety of uRDN vs sham at 6 months in conjunction with escalating antihypertensive medications.

Design, Setting, and Participants

This randomized, sham-controlled, clinical trial with outcome assessors and patients blinded to treatment assignment, enrolled patients from March 11, 2016, to March 13, 2020. This was an international, multicenter study conducted in the US and Europe. Participants with daytime ambulatory BP of 135/85 mm Hg or higher after 4 weeks of single-pill triple-combination treatment (angiotensin-receptor blocker, calcium channel blocker, and thiazide diuretic) with estimated glomerular filtration rate (eGFR) of 40 mL/min/1.73 m2 or greater were randomly assigned to uRDN or sham with medications unchanged through 2 months. From 2 to 5 months, if monthly home BP was 135/85 mm Hg or higher, standardized stepped-care antihypertensive treatment starting with aldosterone antagonists was initiated under blinding to treatment assignment.

Interventions

uRDN vs sham procedure in conjunction with added medications to target BP control.

Main Outcomes and Measures

Six-month change in medications, change in daytime ambulatory systolic BP, change in home systolic BP adjusted for baseline BP and medications, and safety.

Results

A total of 65 of 69 participants in the uRDN group and 64 of 67 participants in the sham group (mean [SD] age, 52.4 [8.3] years; 104 male [80.6%]) with a mean (SD) eGFR of 81.5 (22.8) mL/min/1.73 m2 had 6-month daytime ambulatory BP measurements. Fewer medications were added in the uRDN group (mean [SD], 0.7 [1.0] medications) vs sham (mean [SD], 1.1 [1.1] medications; P = .045) and fewer patients in the uRDN group received aldosterone antagonists at 6 months (26 of 65 [40.0%] vs 39 of 64 [60.9%]; P = .02). Despite less intensive standardized stepped-care antihypertensive treatment, mean (SD) daytime ambulatory BP at 6 months was 138.3 (15.1) mm Hg with uRDN vs 139.0 (14.3) mm Hg with sham (additional decreases of -2.4 [16.6] vs -7.0 [16.7] mm Hg from month 2, respectively), whereas home SBP was lowered to a greater extent with uRDN by 4.3 mm Hg (95% CI, 0.5-8.1 mm Hg; P = .03) in a mixed model adjusting for baseline and number of medications. Adverse events were infrequent and similar between groups.

Conclusions and Relevance

In this study, in patients with RHTN initially randomly assigned to uRDN or a sham procedure and who had persistent elevation of BP at 2 months after the procedure, standardized stepped-care antihypertensive treatment escalation resulted in similar BP reduction in both groups at 6 months, with fewer additional medications required in the uRDN group.

Trial Registration

ClinicalTrials.gov Identifier: NCT02649426.

Identifying and treating resistant hypertension in PRECISION: A randomized long-term clinical trial with aprocitentan

The design and baseline data of the PRECISION study, which evaluates the effect of the dual endothelin receptor antagonist aprocitentan on blood pressure (BP) in patients with resistant hypertension (RHT) are presented. The study is a blinded, randomized, parallel-group Phase 3 study and its three-part design assesses the short-term and sustained long-term effects of aprocitentan on BP. Results are expected in 2022. Patients with uncontrolled BP (measured as unattended automated office BP) despite the use of three or more antihypertensive medications for at least 1 year were screened. They were switched to a single-tablet triple fixed combination antihypertensive therapy for at least 4 weeks before entering a single-blind placebo run-in period. The 4-week placebo run-in period further excluded placebo responders. The randomization period consisted of three sequential parts: (1) a 4-week double-blind part with aprocitentan 12.5 mg, 25 mg, or placebo (1:1:1 ratio); (2) a 32-week single-blind part with aprocitentan 25 mg; and (3) a 12-week randomized withdrawal part with aprocitentan 25 mg or placebo (1:1 ratio). The purpose was to demonstrate the BP lowering effect of aprocitentan in RHT (Part 1) and the persistence of this effect (Parts 2 and 3). Out of 1965 screened patients, 730 were randomized resulting in an overall inclusion failure rate of 62.8%. The most common reason for exclusion (44.4% of all screened patients) was failure to meet the BP inclusion criteria. These results underline the high proportion of pseudoresistant hypertension among patients referred for RHT.

The Effect of Renal Denervation on Cardiac Diastolic Function in Patients with Hypertension and Paroxysmal Atrial Fibrillation

Objective

Renal artery denervation (RDN) can treat hypertension and paroxysmal atrial fibrillation (PAF). Hypertension and PAF can affect cardiac diastolic function. The study aimed to evaluate the effect of RDN on cardiac diastolic function in patients with refractory hypertension and PAF.

Methods

190 consecutive patients with hypertension and PAF were recruited. The levels of NT-proBNP and metrics of echocardiography were measured before and after RDN in patients with refractory hypertension and PAF. The 190 patients were divided into the decreasing HR and nondecreasing HR group, the decreasing MAP and nondecreasing MAP group, the HFPEF group, and the normal diastolic function group, respectively.

Results

Before RDN, the indices about cardiac diastolic function were out of the normal range. After RDN, the diastolic function improved in the indices of NT-proBNP, E/e′, e′. The diastolic function about the indices of NT-proBNP, E/e′, e′ was improved in the decreasing HR group, the decreasing mean arterial pressure (MAP) group, and the HFPEF group, correspondingly compared to the nondecreasing HR group, the non-decreasing MAP group, and the preoperative normal diastolic function group. In the multivariate analysis, the MAP and HR were the only two indicators significantly associated with the improvement of diastolic function.

Conclusion

RDN could improve the diastolic function in patients with refractory hypertension and PAF. Patients with HFPEF could receive benefits through RDN. It was speculated that RDN improved the diastolic function mainly through decreasing HR and MAP.

Clinical Trial Design Principles and Outcomes Definitions for Device-Based Therapies for Hypertension: A Consensus Document From the Hypertension Academic Research Consortium

The clinical implications of hypertension in addition to a high prevalence of both uncontrolled blood pressure and medication nonadherence promote interest in developing device-based approaches to hypertension treatment. The expansion of device-based therapies and ongoing clinical trials underscores the need for consistency in trial design, conduct, and definitions of clinical study elements to permit trial comparability and data poolability. Standardizing methods of blood pressure assessment, effectiveness measures beyond blood pressure alone, and safety outcomes are paramount. The Hypertension Academic Research Consortium (HARC) document represents an integration of evolving evidence and consensus opinion among leading experts in cardiovascular medicine and hypertension research with regulatory perspectives on clinical trial design and methodology. The HARC document integrates the collective information among device-based therapies for hypertension to better address existing challenges and identify unmet needs for technologies proposed to treat the world’s leading cause of death and disability. Consistent with the Academic Research Consortium charter, this document proposes pragmatic consensus clinical design principles and outcomes definitions for studies aimed at evaluating device-based hypertension therapies.

Estratificação de Risco e Avaliação da Atividade Simpática Cardíaca Utilizando Imagem Miocárdica com [123I] MIBG na Denervação Renal

A hiperativação do sistema nervoso simpático desempenha um papel central na fisiopatologia da hipertensão. O objetivo deste estudo foi avaliar a atividade simpática cardíaca e investigar o papel da cintigrafia miocárdica com metaiodobenzilguanidina com ¹²³I ([¹²³I] MIBG) na estratificação de risco cardiovascular de pacientes com hipertensão resistente tratados com denervação renal (DR). Dezoito pacientes foram incluídos neste estudo prospectivo (média de idade de 56 ± 10 anos, 27,8% mulheres). Ecocardiograma transtorácico, análise geral do sangue e cintilografia miocárdica com [(¹²³I) MIBG] foram realizados antes e seis meses após a DR. Um paciente era considerado respondedor (R) se uma diminuição ≥ 5 mmHg na pressão arterial sistólica (PAS) média ambulatorial fosse observada no seguimento de seis meses. 66,7% dos pacientes foram R (diminuição na PAS de 20,6 ± 14,5 mmHg, vs. menos 8 ± 11,6 mmHg em não-respondedores (NR), p = 0,001). A relação coração-mediastino (RCM) inicial foi significativamente menor na linha basal no grupo R (1,6 ± 0,1 vs. 1,72 ± 0,1, p <0,02), mas semelhante em seis meses. Considerando os dois momentos no tempo, o grupo R teve valores iniciais de RCM mais baixos do que o grupo NR (p <0,05). Tanto o RCM tardio quanto a taxa de washout foram idênticos e nenhuma correlação significativa entre a resposta à DR ou qualquer índice de imagem com MIBG foi encontrada. A denervação renal efetivamente reduziu a pressão arterial na maioria dos pacientes, mas a imagem com [¹²³I] MIBG não foi útil na previsão da resposta. Entretanto, houve evidência de overdrive do sistema nervoso simpático e, tanto a RCM inicial quanto tardia estavam reduzidas em geral, provavelmente colocando essa população em um risco maior de eventos adversos.

Renal denervation: basic and clinical evidence

Renal nerves have critical roles in regulating blood pressure and fluid volume, and their dysfunction is closely related with cardiovascular diseases. Renal nerves are composed of sympathetic efferent and sensory afferent nerves. Activation of the efferent renal sympathetic nerves induces renin secretion, sodium absorption, and increased renal vascular resistance, which lead to increased blood pressure and fluid retention. Afferent renal sensory nerves, which are densely innervated in the renal pelvic wall, project to the hypothalamic paraventricular nucleus in the brain to modulate sympathetic outflow to the periphery, including the heart, kidneys, and arterioles. The effects of renal denervation on the cardiovascular system are mediated by both efferent denervation and afferent denervation. The first half of this review focuses on basic research using animal models of hypertension and heart failure, and addresses the therapeutic effects of renal denervation for hypertension and heart failure, including underlying mechanisms. The second half of this review focuses on clinical research related to catheter-based renal denervation in patients with hypertension. Randomized sham-controlled trials using second-generation devices, endovascular radiofrequency-based devices and ultrasound-based devices are reviewed and their results are assessed. This review summarizes the basic and clinical evidence of renal denervation to date, and discusses future prospects and potential developments in renal denervation therapy for cardiovascular diseases.

Catheter-Based Renal Denervation Therapy: Evolution of Evidence and Future Directions

Motivated by the persistence of uncontrolled blood pressure and its public health impact, the development and evaluation of device-based therapies for hypertension has advanced at an accelerated pace to complement pharmaceutical and lifestyle intervention strategies. Countering widespread interest from early studies, the lack of demonstrable efficacy for renal denervation (RDN) in a large, sham-controlled randomized trial motivated revision of trial design and conduct to account for confounding variables of procedural technique, medication variability, and selection of both patients and end points. Now amidst varied trial design and methods, several sham-controlled, randomized trials have demonstrated clinically meaningful reductions in blood pressure with RDN. With this momentum, additional studies are underway to position RDN as a potential part of standard therapy for the world's leading cause of death and disability. In parallel, further studies will address unresolved issues including durability of blood pressure lowering and reduction in antihypertensive medications, late-term safety, and impact on clinical outcomes. Identifying predictors of treatment effect and surveys of patient-reported outcomes and treatment preferences are also evolving areas of investigation. Aside from confirmatory studies of safety and effectiveness, these additional studies will further inform patient selection, expand experience with RDN in broader populations with hypertension, and provide guidance to how RDN may be incorporated into treatment pathways.

Renal denervation based on experimental rationale

Excessive activation of the sympathetic nervous system is one of the pathophysiological hallmarks of hypertension and heart failure. Within the central nervous system, the paraventricular nucleus (PVN) of the hypothalamus and the rostral ventrolateral medulla in the brain stem play critical roles in the regulation of sympathetic outflow to peripheral organs. Information from the peripheral circulation, including serum concentrations of sodium and angiotensin II, is conveyed to the PVN via adjacent structures with a weak blood-brain barrier. In addition, signals from baroreceptors, chemoreceptors and cardiopulmonary receptors as well as afferent input via the renal nerves are all integrated at the level of the PVN. The brain renin-angiotensin system and the balance between nitric oxide and reactive oxygen species in these brain areas also determine the final sympathetic outflow. Additionally, brain inflammatory responses have been shown to modulate these processes. Renal denervation interrupts both the afferent inputs from the kidney to the PVN and the efferent outputs from the PVN to the kidney, resulting in the suppression of sympathetic outflow and eliciting beneficial effects on both hypertension and heart failure.

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.

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.

Ultrasound renal denervation for hypertension resistant to a triple medication pill (RADIANCE-HTN TRIO): a randomised, multicentre, single-blind, sham-controlled trial

BACKGROUND

Endovascular renal denervation reduces blood pressure in patients with mild-to-moderate hypertension, but its efficacy in patients with true resistant hypertension has not been shown. We aimed to assess the efficacy and safety of endovascular ultrasound renal denervation in patients with hypertension resistant to three or more antihypertensive medications.

METHODS

In a randomised, international, multicentre, single-blind, sham-controlled trial done at 28 tertiary centres in the USA and 25 in Europe, we included patients aged 18-75 years with office blood pressure of at least 140/90 mm Hg despite three or more antihypertensive medications including a diuretic. Eligible patients were switched to a once daily, fixed-dose, single-pill combination of a calcium channel blocker, an angiotensin receptor blocker, and a thiazide diuretic. After 4 weeks of standardised therapy, patients with daytime ambulatory blood pressure of at least 135/85 mm Hg were randomly assigned (1:1) by computer (stratified by centres) to ultrasound renal denervation or a sham procedure. Patients and outcome assessors were masked to randomisation. Addition of antihypertensive medications was allowed if specified blood pressure thresholds were exceeded. The primary endpoint was the change in daytime ambulatory systolic blood pressure at 2 months in the intention-to-treat population. Safety was also assessed in the intention-to-treat population. This study is registered with ClinicalTrials.gov, NCT02649426.

FINDINGS

Between March 11, 2016, and March 13, 2020, 989 participants were enrolled and 136 were randomly assigned to renal denervation (n=69) or a sham procedure (n=67). Full adherence to the combination medications at 2 months among patients with urine samples was similar in both groups (42 [82%] of 51 in the renal denervation group vs 47 [82%] of 57 in the sham procedure group; p=0·99). Renal denervation reduced daytime ambulatory systolic blood pressure more than the sham procedure (-8·0 mm Hg [IQR -16·4 to 0·0] vs -3·0 mm Hg [-10·3 to 1·8]; median between-group difference -4·5 mm Hg [95% CI -8·5 to -0·3]; adjusted p=0·022); the median between-group difference was -5·8 mm Hg (95% CI -9·7 to -1·6; adjusted p=0·0051) among patients with complete ambulatory blood pressure data. There were no differences in safety outcomes between the two groups.

INTERPRETATION

Compared with a sham procedure, ultrasound renal denervation reduced blood pressure at 2 months in patients with hypertension resistant to a standardised triple combination pill. If the blood pressure lowering effect and safety of renal denervation are maintained in the long term, renal denervation might be an alternative to the addition of further antihypertensive medications in patients with resistant hypertension.

FUNDING

ReCor Medical.

Device Therapy of Hypertension

In the past decade, efforts to improve blood pressure control have looked beyond conventional approaches of lifestyle modification and drug therapy to embrace interventional therapies. Based upon animal and human studies clearly demonstrating a key role for the sympathetic nervous system in the etiology of hypertension, the newer technologies that have emerged are predominantly aimed at neuromodulation of peripheral nervous system targets. These include renal denervation, baroreflex activation therapy, endovascular baroreflex amplification therapy, carotid body ablation, and pacemaker-mediated programmable hypertension control. Of these, renal denervation is the most mature, and with a recent series of proof-of-concept trials demonstrating the safety and efficacy of radiofrequency and more recently ultrasound-based renal denervation, this technology is poised to become available as a viable treatment option for hypertension in the foreseeable future. With regard to baroreflex activation therapy, endovascular baroreflex amplification, carotid body ablation, and programmable hypertension control, these are developing technologies for which more human data are required. Importantly, central nervous system control of the circulation remains a poorly understood yet vital component of the hypertension pathway and mandates further investigation. Technology to improve blood pressure control through deep brain stimulation of key cardiovascular control territories is, therefore, of interest. Furthermore, alternative nonsympathomodulatory intervention targeting the hemodynamics of the circulation may also be worth exploring for patients in whom sympathetic drive is less relevant to hypertension perpetuation. Herein, we review the aforementioned technologies with an emphasis on the preclinical data that underpin their rationale and the human evidence that supports their use.