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

Imaging strategies for safety surveillance after renal artery denervation

Renal denervation has emerged as a safe and effective therapy to lower blood pressure in hypertensive patients. In addition to the main renal arteries, branch vessels are also denervated in more contemporary studies. Accurate and reliable imaging in renal denervation patients is critical for long-term safety surveillance due to the small risk of renal artery stenosis that may occur after the procedure. This review summarizes three common non-invasive imaging modalities: Doppler ultrasound (DUS), computed tomography angiography (CTA), and magnetic resonance angiography (MRA). DUS is the most widely used owing to cost considerations, ease of use, and the fact that it is less invasive, avoids ionizing radiation exposure, and requires no contrast media use. Renal angiography is used to determine if renal artery stenosis is present when non-invasive imaging suggests renal artery stenosis. We compiled data from prior renal denervation studies as well as the more recent SPYRAL-HTN OFF MED Study and show that DUS demonstrates both high sensitivity and specificity for detecting renal stenosis de novo and in longitudinal assessment of renal artery patency after interventions. In the context of clinical trials DUS has been shown, together with the use of the baseline angiogram, to be effective in identifying stenosis in branch and accessory arteries and merits consideration as the main screening imaging modality to detect clinically significant renal artery stenosis after renal denervation and this is consistent with guidelines from the recent European Consensus Statement on Renal Denervation.

Cardiovascular autonomic nervous system dysfunction in chronic kidney disease and end-stage kidney disease: disruption of the complementary forces

PURPOSE OF REVIEW

Several nontraditional risk factors have been the focus of research in an attempt to understand the disproportionately high cardiovascular morbidity and mortality in chronic kidney disease (CKD) and end-stage kidney disease (ESKD) populations. One such category of risk factors is cardiovascular autonomic dysfunction. Its true prevalence in the CKD/ESKD population is unknown but existing evidence suggests it is common. Due to lack of standardized diagnostic and treatment options, this condition remains undiagnosed and untreated in many patients. In this review, we discuss current evidence pointing toward the role of autonomic nervous system (ANS) dysfunction in CKD, building off of crucial historical evidence and thereby highlighting the areas in need for future research interest.

RECENT FINDINGS

There are several key mediators and pathways leading to cardiovascular autonomic dysfunction in CKD and ESKD. We review studies exploring the mechanisms involved and discuss the current measurement tools and indices to evaluate the ANS and their pitfalls. There is a strong line of evidence establishing the temporal sequence of worsening autonomic function and kidney function and vice versa. Evidence linking ANS dysfunction and arrhythmia, sudden cardiac death, intradialytic hypotension, heart failure and hypertension are discussed.

SUMMARY

There is a need for early recognition and referral of CKD and ESKD patients suspected of cardiovascular ANS dysfunction to prevent the downstream effects described in this review.There are many unknowns in this area and a clear need for further research.

Arterielle Hypertonie – Was war 2020 wichtig?

Die arterielle Hypertonie bleibt weltweit der prävalenteste Risikofaktor für kardiovaskuläre Erkrankungen und damit einhergehende Behinderungen. Auch im Bereich der arteriellen Hypertonie bestimmte die COVID-19-Pandemie einen Teil der wissenschaftlichen Debatte. Die arterielle Hypertonie ist mit einem schwereren Krankheitsverlauf von COVID-19 assoziiert, wohingegen das SARS-CoV-2-Infektionsrisiko bei Hypertonikern nicht erhöht zu sein scheint. Nach aktueller Datenlage ist die Therapie mit ACE(Angiotensin-Converting-Enzym)-Hemmer und Angiotensin-Typ-1-Rezeptorblocker weder mit einem erhöhten SARS-CoV-2-Infektionsrisiko noch mit einem schwereren Krankheitsverlauf von COVID-19 verbunden. Eine Studie zur antihypertensiven Chronotherapie bestimmte den wissenschaftlichen Diskurs zur medikamentösen Therapie der Hypertonie. Die HYGIA-Studie kam zu der Schlussfolgerung, dass eine abendliche Medikamenteneinnahme das kardiovaskuläre Risiko von Patienten*innen mit arterieller Hypertonie reduziert. Aufgrund einiger Limitationen ist die Datenlage aktuell unzureichend, um eine routinemäßige nächtliche Gabe von antihypertensiven Medikamenten zu empfehlen. Wir werden einige der Aspekte diskutieren. Ein weiterer wissenschaftlicher Schwerpunkt lag auf den neuen Studien zur renalen Denervation. Hier kann man zusammenfassen, dass nach neuer Studienlage die katheterbasierte renale Denervation ein effektives und sicheres Verfahren zur Behandlung der arteriellen Hypertonie darstellt, das sich als alternatives Verfahren zur medikamentösen Blutdrucksenkung weiter etablieren könnte.

Guidance on ambulatory blood pressure monitoring: A statement from the HOPE Asia Network

Hypertension is an important public health issue due to its association with a number of serious diseases, including cardiovascular disease and stroke. The importance of evaluating hypertension taking into account different blood pressure (BP) profiles and BP variability (BPV) is increasingly being recognized, and is particularly relevant in Asian populations given the specific features of hypertension in the region (including greater salt sensitivity and a high rate of nocturnal hypertension). Ambulatory BP monitoring (ABPM) is the gold standard for diagnosing hypertension and assessing 24-hour BP and provides data on several important parameters that cannot be obtained using any other form of BP measurement. In addition, ABPM parameters provide better information on cardio- and cerebrovascular risk than office BP. ABPM should be used in all patients with elevated BP, particularly those with unstable office or home BP, or who are suspected to have white-coat or masked hypertension. ABPM is also an important part of hypertension diagnosis and monitoring in high-risk patients. ABPM needs to be performed using a validated device and good practice techniques, and has a role both in hypertension diagnosis and in monitoring the response to antihypertensive therapy to ensure strict BP control throughout the 24-hour period. Use of ABPM in clinical practice may be limited by cost and accessibility, and practical education of physicians and patients is essential. The ABPM evidence and practice points in this document are based on the Hypertension Cardiovascular Outcome Prevention and Evidence (HOPE) Asia Network expert panel consensus recommendations for ABPM in Asia.

Combined renal and common hepatic artery denervation as a novel approach to reduce cardiometabolic risk: technical approach, feasibility and safety in a pre-clinical model

Background

Cardiovascular and metabolic regulation is governed by neurohumoral signalling in relevant organs such as kidney, liver, pancreas, duodenum, adipose tissue, and skeletal muscle. Combined targeting of relevant neural outflows may provide a unique therapeutic opportunity for cardiometabolic disease.

Objectives

We aimed to investigate the feasibility, safety, and performance of a novel device-based approach for multi-organ denervation in a swine model over 30 and 90 days of follow-up.

Methods

Five Yorkshire cross pigs underwent combined percutaneous denervation in the renal arteries and the common hepatic artery (CHA) with the iRF Denervation System. Control animals (n = 3) were also studied. Specific energy doses were administered in the renal arteries and CHA. Blood was collected at 30 and 90 days. All animals had a pre-terminal procedure angiography. Tissue samples were collected for norepinephrine (NEPI) bioanalysis. Histopathological evaluation of collateral structures and tissues near the treatment sites was performed to assess treatment safety.

Results

All animals entered and exited the study in good health. No stenosis or vessel abnormalities were present. No significant changes in serum chemistry occurred. NEPI concentrations were significantly reduced in the liver (− 88%, p = 0.005), kidneys (− 78%, p < 0.001), pancreas (− 78%, p = 0.018) and duodenum (− 95%, p = 0.028) following multi-organ denervation treatment compared to control animals. Histologic findings were consistent with favourable tissue responses at 90 days follow-up.

Conclusions

Significant and sustained denervation of the treated organs was achieved at 90 days without major safety events. Our findings demonstrate the feasibility of multi-organ denervation using a novel iRF Denervation System in a single procedure.

Thermal Analysis of Heat Transfer from Catheters and Implantable Devices to the Blood Flow

Implantable devices, ultrasound imaging catheters, and ablation catheters (such as renal denervation catheters) are biomedical instruments that generate heat in the body. The generated heat can be harmful if the body temperature exceeds the limit of almost 315 K. This paper presents a heat-transfer model and analysis, to evaluate the temperature rise in human blood due to the power loss of medical catheters and implantable devices. The dynamic of the heat transfer is modeled for the blood vessel, at different blood flow velocities. The physics and governing equations of the heat transfer from the implanted energy source to the blood and temperature rise are expressed by developing a Non-Newtonian Carreau–Yasuda fluid model. We used a Finite Element method to solve the governing equations of the established model, considering the boundary conditions and average blood flow velocities of 0–1.4 m/s for the flow of the blood passing over the implanted power source. The results revealed a maximum allowable heat flux of 7500 and 15,000 W/m² for the blood flow velocities of 0 and 1.4 m/s, respectively. The rise of temperature around the implant or tip of the catheter is slower and disappeared gradually with the blood flow, which allows a higher level of heat flux to be generated. The results of this analysis are concluded in the equation/correlation T=310+H3000(1+e−7V), to estimate and predict the temperature changes as a function of heat flux, H, and the blood flow velocity, V, at the implant/catheter location.

Renal Denervation for Uncontrolled and Resistant Hypertension: Systematic Review and Network Meta-Analysis of Randomized Trials

Comparative efficacy and safety of renal denervation (RDN) interventions for uncontrolled (UH) and resistant hypertension (RH) is unknown. We assessed the comparative efficacy and safety of existing RDN interventions for UH and RH. Six search engines were searched up to 1 May 2020. Primary outcomes were mean 24-h ambulatory and office systolic blood pressure (SBP). Secondary outcomes were mean 24-h ambulatory and office diastolic blood pressure (DBP), clinical outcomes, and serious adverse events. Frequentist random-effects network meta-analyses were used to evaluate effects of RDN interventions. Twenty randomized controlled trials (RCTs) (n = 2152) were included, 15 in RH (n = 1544) and five in UH (n = 608). Intervention arms included radiofrequency (RF) in main renal artery (MRA) (n = 10), RF in MRA and branches (n = 4), RF in MRA+ antihypertensive therapy (AHT) (n = 5), ultrasound (US) in MRA (n = 3), sham (n = 8), and AHT (n = 9). RF in MRA and branches ranked as the best treatment to reduce 24-h ambulatory, daytime, and nighttime SBP and DBP versus other interventions (p-scores: 0.83 to 0.97); significant blood pressure effects were found versus sham or AHT. RF in MRA+AHT was the best treatment to reduce office SBP and DBP (p-scores: 0.84 and 0.90, respectively). RF in MRA and branches was the most efficacious versus other interventions to reduce 24-h ambulatory SBP and DBP in UH or RH.

The current status of renal denervation for the treatment of arterial hypertension

Despite the availability of safe and effective antihypertensive drugs, blood pressure (BP) control to guideline-recommended target values is poor. Several device-based therapies have been introduced to lower BP. The most extensively investigated approach is catheter-based renal sympathetic denervation (RDN), which aims to interrupt the activity of afferent and efferent renal sympathetic nerves by applying radiofrequency energy, ultrasound energy, or injection of alcohol in the perivascular space. The second generation of placebo-controlled trials have provided solid evidence for the BP-lowering efficacy of radiofrequency- and ultrasound-based RDN in patients with and without concomitant pharmacological therapy. In addition, the safety profile of RDN appears to be excellent in all registries and clinical trials. However, there remain unsolved issues to be addressed. This review summarizes the rationale as well as the current evidence and discusses open questions and possible future indications of catheter-based RDN.

A Systematic Review of Randomized Controlled Trials Comparing Renal Sympathetic Denervation Versus Sham Procedure for the Management of Uncontrolled Hypertension

ABSTRACT

The efficacy of renal sympathetic denervation (RSD) in the treatment of uncontrolled hypertension (HTN) remains uncertain. A systematic review of randomized controlled trials was performed to evaluate the efficacy and safety of RSD for resistant HTN. PubMed, EMBASE, MEDLINE, Cochrane, Directory of Open Access Journals, CINAHL, and Google Scholar were searched from January 01, 2001, through July 30, 2020. Randomized controlled trials comparing RSD with the sham procedure for uncontrolled HTN were selected. The primary efficacy outcome was the reduction in ambulatory systolic blood pressure. We used random-effects models. Nine prospective clinical trials met the inclusion criteria. The ReSet and Symplicity HTN-3 Trial showed no significant changes because of discrepancies in complete circumferential ablation during RSD. The Relief study, The Radiance HTN solo, and the SPYRAL HTN OFF medical trials showed a significant reduction in systolic blood pressure in the group that had undergone the intervention compared with the sham group attributed to rigorous trial design. In conclusion, our systematic review suggests that efficacy of RSD seems to be superior to sham-controlled interventions provided circumferential denervation is performed. However, difference in efficacy is marginal.

Insights on safety and efficacy of renal artery denervation for uncontrolled-resistant hypertension in a high risk population with chronic kidney disease: first Italian real-world experience

Aims

To evaluate the safety and efficacy of catheter-based radiofrequency renal sympathetic denervation (RSD) in a daily practice population of patients with uncontrolled resistant hypertension, on top of medical therapy.

Methods

Consecutive unselected patients with uncontrolled resistant hypertension undergoing RSD were enrolled. Office and ambulatory blood pressure (BP) measurements were collected at baseline and 3, 6 and 12 months after RSD. Efficacy was assessed even in patients with an estimated glomerular filtration rate (eGFR) below 45 mL/min/1.73 m². Patients were defined as responders if systolic BP decreased by at least 5 mmHg at ambulatory BP or by 10 mmHg at office BP at their last follow-up visit.

Results

Forty patients with multiple comorbidities underwent RSD from 2012 to 2019. Baseline office and ambulatory BP was 159.0/84.9 ± 26.2/14.9 mmHg and 155.2/86.5 ± 20.9/14.0 mmHg, respectively. At 12-month follow up a significant reduction in office and ambulatory systolic BP, respectively by − 19.7 ± 27.1 mmHg and by − 13.9 ± 23.6 mmHg, was observed. BP reduction at 12-month follow-up among patients with eGFR < 45 mL/min was similar to that obtained in patients with higher eGFR. Twenty-nine patients (74.4%) were responders. Combined hypertension, higher ambulatory systolic BP and lower E/E’ at baseline emerged as predictors of successful RSD at univariate analysis. No major complications were observed and renal function (was stable up to 12 months), even in patients with the lowest eGFR values at baseline.

Conclusion

RSD is safe and feasible in patients with uncontrolled resistant hypertension on top of medical therapy, even in a high-risk CKD population with multiple comorbidities, with a significant reduction in systolic BP and a trend towards a reduction in diastolic BP lasting up to 12 months.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s40620-021-00966-7.

Changes in sympathetic nervous system activity after renal denervation: results from the randomised Oslo RDN study

PURPOSE

Sympathetic nervous system (SNS) over-activity is associated with essential hypertension. Renal sympathetic denervation (RDN) possibly lowers office- and ambulatory blood pressure (BP) in patients with treatment-resistant hypertension (TRH). We aimed to assess the effect of RDN compared to drug adjustment on SNS activity among patients with TRH by measuring plasma catecholamines and heart rate variability (HRV) during stress tests.

MATERIALS AND METHODS

Patients with TRH were randomised to RDN (n = 9) or Drug Adjustment (DA) (n = 10). We measured continuous HRV and beat-to-beat-BP using FinaPres® and obtained plasma catecholamines during standardised orthostatic- and cold-pressor stress tests (CPT) before- and six months after randomisation.

RESULTS

CPT revealed no differences between groups at baseline in peak adrenaline concentration (69.3 pg/mL in the DA group vs. 70.0 pg/mL in the RDN group, p = 0.38) or adrenaline reactivity (Δ23.1 pg/mL in the DA group vs. Δ29.3 pg/mL in the RDN group, p = 0.40). After six months, adrenaline concentrations were statistically different between groups after one minute (66.9 pg/mL in the DA group vs. 55.3 pg/mL in the RDN group, p = 0.03), and six minutes (62.4 pg/mL in the DA group vs. 50.1 pg/mL in the RDN group, p = 0.03). There was a tendency of reduction in adrenaline reactivity after six months in the RDN group (Δ26.3 pg/mL at baseline vs. Δ12.8 pg/ml after six months, p = 0.08), while it increased in the DA group (Δ13.6 pg/mL at baseline vs. Δ19.9 pg/mL after six months, p = 0.53). We also found a difference in the Low Frequency band at baseline following the CPT (667µs² in the DA group vs. 1628µs² in the RDN group, p = 0.03) with a clear tendency of reduction in the RDN group to 743µs² after six months (p = 0.07), compared to no change in the DA group (1052µs^2, p = 0.39).

CONCLUSION

Our data suggest that RDN reduces SNS activity after six months. This finding warrants investigation in a larger study. Clinical Trial Number registered at www.clinicaltrials.gov: NCT01673516.

Novel approaches to management of hypertension

PURPOSE OF REVIEW

Of the roughly 1.4 billion people with hypertension worldwide, only about one in seven has their blood pressure (BP) successfully treated and adequately controlled. This review will focus on new therapeutic approaches of hypertension.

RECENT FINDINGS

Several recent clinical studies and guidelines have favoured the assessment of target organ damage and cardiovascular risk scores for the diagnosis and treatment approach of hypertension. Paradigm shifts recommended in the guidelines are the initiation of antihypertensive treatment with combination (not mono) therapy and the recommendation of single-pill combinations (SPC), which improve adherence and result in rapid and effective BP control. In clinical trials with optimized design and renal denervation (RDN) technology, the biological proof of concept has been established. Consistent, durable ambulatory and office BP reductions without procedure associated serious adverse events have been documented. The challenges are now to identify patients who respond best to interventional treatment.

SUMMARY

Major key points in the treatment strategy for hypertension are: individualization of the therapy according to total cardiovascular risk, combination therapy as initial step, recommendation of SPC and RDN as promising interventional therapy.

An Open-label, Single-arm, Multicenter Feasibility Study Evaluating the Safety of Catheter-based Renal Denervation with DENEX™ in Patients with Uncontrolled Hypertension on Standard Medical Therapy

Background and Objectives

DENEX™ is a novel renal sympathetic denervation (RDN) system that is equipped with 3 electrodes that deliver radiofrequency energy to the renal nerves along renal arteries. The purpose of this study was to evaluate the safety and efficacy of RDN with DENEX™ in resistant hypertension.

Methods

This was an open-label, single-arm, multicenter, first-in-man pilot study. Between November 2016 and May 2018, a total of 16 patients were enrolled at 4 centers in South Korea. The inclusion criteria were systolic blood pressure (SBP) ≥150 mmHg and use of 3 or more antihypertensive medications, including diuretics. The primary objective was the safety outcome of RDN with the DENEX™ system. The secondary objective was efficacy outcome based on changes of office, and 24-hour ambulatory SBP from baseline to 3 months. The patients underwent abdominal computed tomography (CT) or duplex ultrasonogram before and 6 months after RDN.

Results

No major adverse events occurred after RDN for 6 month of follow-up period. There was no vascular complication either by CT or duplex ultrasonogram. The office SBP was significantly reduced from 164.6±11.6 mmHg at baseline to 142.0±20.4 mmHg (−24.4±24.4 mmHg, p=0.003) at 3 months. The ambulatory SBP was reduced from 151.44±12.85 mmHg at baseline to 140.0±16.5 mmHg (−13.1±18.9 mmHg, p=0.056) at 3 months.

Conclusion

RDN with the DENEX™ system showed a favorable safety profile in resistant hypertension. A significant reduction in office SBP and a borderline reduction in ambulatory SBP were observed.

Trial Registration

ClinicalTrials.gov Identifier: NCT04248530

Differences in patient and physician perspectives on pharmaceutical therapy and renal denervation for the management of hypertension

OBJECTIVE

To study patient and physician attitudes to pharmaceutical therapy and renal denervation for the management of hypertension.

METHODS

Data were analyzed from 19 market research studies in Western Europe and the United States conducted between 2010 and 2019 to obtain quantitative and qualitative perspectives. The analysis incorporated insights from 2768 patients and the experiences of 1902 physicians either actively performing or interested to perform device procedures, or hypertension specialists who would refer patients for a device-based intervention.

RESULTS

Referring cardiologists and proceduralists were more likely to recommend the renal denervation procedure to patients with higher BP levels and a greater number of antihypertensive medications. Physicians perceived patient reluctance towards a procedure as an important obstacle to recommending renal denervation as a treatment option for uncontrolled hypertension. Patient interest in the renal denervation procedure did not correlate with BP severity (P = NS), and the highest preference for the procedure was in patients diagnosed with hypertension but not receiving treatment (P < 0.001). Patients who perceived high BP as a major problem (P = 0.029) and those who experienced side effects attributed to their BP medications (P = 0.006) had a higher preference for renal denervation.

CONCLUSION

Patients with hypertension often regard the choice of renal denervation to lower BP differently from physicians. A considerable proportion of hypertensive patients, especially those not taking medications, may prefer a device-based approach to reduce their BP.

Ambulatory Blood Pressure Monitoring to Predict Response to Renal Denervation: A Post Hoc Analysis of the RADIANCE-HTN SOLO Study

Renal denervation (RDN) is effective in lowering blood pressure (BP) in patients with hypertension. The issue remains how to best identify potential responders. Ambulatory BP monitoring may be useful. Baseline nighttime systolic BP (SBP) ≥136 mm Hg and its variability (SD) ≥12 mm Hg in DENER-HTN trial or 24-hour heart rate ≥73.5 bpm in SPYRAL HTN-OFF MED Trial were shown to predict the BP response to RDN. We applied these criteria to the patients with hypertension in the sham-controlled RADIANCE-HTN SOLO trial to predict the BP response to ultrasound RDN at 2 months while patients were maintained off medications. BP responders were defined as: clinical with 24-hour SBP <130 mm Hg (RDN: 22/64 versus sham: 7/58); meaningful with 24-hour SBP reduction ≥10 mm Hg (RDN: 24/64, sham: 7/58); and extreme with 24-hour SBP reduction above mean+2 SD of the SBP decrease in the sham group, that is, ≥16.5 mm Hg (RDN: 10/64 versus sham: 2/58). The predictive criteria reported above were tested for sensitivity, specificity, and positive and negative predictive values. The predictive value varied according to the definition of response, with the clinical definition being strongly influenced by regression to the mean. Baseline nighttime SBP and its variability, especially when combined, offered good specificity (>90% irrespective of definition) but low sensitivity (from 9.1% to 30% depending on the definition) to predict responders; the heart rate criterion had insufficient predictive value. This analysis suggests the potential role of nighttime SBP and its variability to predict BP response to RDN in patients with hypertension. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02649426.

Resistant hypertension: new insights and therapeutic perspectives

Resistant hypertension (RH) is a concept that currently goes beyond the classical definition of blood pressure ≥140/90 mmHg in subjects receiving three or more drugs of different classes at maximally tolerated doses. Here, we review the clinical relevance of RH and the different types of RH-associated phenotypes, namely refractory hypertension, controlled resistant hypertension, and masked uncontrolled hypertension. We also discuss current drug strategies and future treatments for these high-risk phenotypes.

Renal arteries denervation with second generation systems: a remedy for resistant hypertension?

Initial studies on renal denervation (RDN) for the treatment of non-controlled arterial hypertension (HTN) through radiofrequency ablation of renal arteries demonstrated that RDN is an effective therapeutic strategy to reduce arterial blood pressure (BP). Nonetheless, the first randomized study, SYMPLICITY-HTN-3, failed to demonstrate a clear benefit for RND over the control group. Technologic evolution, with the introduction of new second generation multi-electrode devices, allowed deep energy delivery along the full circumference of the vessel. Two recent randomized studies involving patients assuming (SPYRAL HTN-ON MED) or not (SPYRAL HTN-OFF MED) antihypertensive pharmacologic treatment, demonstrated the efficacy and safety of RDN using second generation systems for radiofrequency ablation. Another recent randomized study demonstrated that RDN with ultrasounds (RADIANCE-HTN SOLO) of the main renal arteries led to a significant BP reduction compared to the control group. These studies have once again raised the interest of the scientific community towards attempting to define the appropriate role of RDN in the treatment of hypertension. Nonetheless, larger and longer clinical trials will be necessary to draw further conclusions.

Renal denervation: where do we stand and what is the relevance to the nephrologist?

Catheter-based renal denervation to reduce high blood pressure (BP) has received well-deserved attention after a recent series of sham-controlled trials reported significant antihypertensive efficacy and very favourable tolerability and safety of the intervention. This emerging treatment option is of high relevance to nephrologists. Patients with chronic kidney disease (CKD) are at elevated risk of cardiovascular adverse events and often present with hypertension, which is very difficult to control with medication. Renal denervation promises a new tool to reduce BP and to prevent loss of renal function in this population. The current review considers the role of the kidney and neurohormonal activation in the development of hypertension and the rationale for renal denervation. The current state of the evidence for the effectiveness and tolerability of the procedure is considered from the nephrologists’ perspective, with a focus on the potential future role of renal denervation in the management of CKD patients with hypertension.

The state of renal sympathetic denervation for the management of patients with hypertension: A systematic review and meta-analysis

BACKGROUND

Sympathetic nervous system plays a central role in the development and persistence of essential hypertension. In recent years renal sympathetic denervation (RSD) has emerged as a promising option for the treatment of patients with hypertension.

METHODS

We conducted a literature search of PubMed, EMBASE, Cochrane library and Clinicaltrials.gov from inception through April 20, 2020. Outcomes of interest were change in 24-hour ambulatory systolic (ASBP) or diastolic blood pressure (ADBP) and change in office systolic (OSBP) or diastolic blood pressure (ODBP). We pooled data from randomized controlled trials (RCTS) comparing RSD to sham procedures in the management of hypertension using the random effect model.

RESULTS

A total of 1,363 patients from eight studies were included in the current meta-analysis. The mean age of the included patients was 56 ± 2.6 years, 29% were women and the median duration of maximum follow up was 6-month (range 3-12 month). There was more reduction favoring RSD in ASBP (Weighted mean difference [WMD] -3.55; 95% CI -4.91 - -2.19, p < .001, I² = 0%), ADBP (WMD -1.87; 95% CI -3.07 - -0.66, p = .002, I² = 43%), OSBP (WMD -5.5; 95% CI -7.59 - -3.40, p < .001, I² = 7%) and ODBP (WMD -3.20; 95% CI -4.47 - -1.94, p < .001, I² = 14%).

CONCLUSION

The use of RSD for the management of hypertension resulted in effective reduction in the ambulatory and office blood pressure compared to sham procedure. Adequately powered RCTs of RSD are needed to confirm safety, reproducibility and assess the impact on clinical outcomes.

Recent advances in managing primary hypertension

Hypertension remains a leading risk factor for cardiovascular mortality and morbidity globally despite the availability of effective and well-tolerated antihypertensive medications. Accumulating evidence suggests a more aggressive blood pressure regulation aimed at lower targets, particularly for selected patient groups. Our concepts of the optimal method for blood pressure measurement have radically changed, maintaining appropriate standard office measurements for initial assessment but relying on out-of-office measurement to better guide our decisions. Thorough risk stratification provides guidance in decision making; however, an individualized approach is highly recommended to prevent overtreatment. Undertreatment, on the other hand, remains a major concern and is mainly attributed to poor adherence and resistant or difficult-to-control forms of the disease. This review aims to present modern perspectives, novel treatment options, including innovative technological applications and developing interventional and pharmaceutical therapies, and the major concerns emerging from several years of research and epidemiological observations related to hypertension management.

A drug-induced hypotensive challenge to verify catheter-based radiofrequency renal denervation in an obese hypertensive swine model

Objective

Sham-controlled trials provided proof-of-principle for the blood pressure-lowering effect of catheter-based renal denervation (RDN). However, indicators for the immediate assessment of treatment success are lacking. This study sought to investigate the impact of RDN on renal renin arteriovenous difference (renal renin AV-Δ) following a hypotensive challenge (HC).

Methods

Twelve hypertensive Ossabaw swine underwent either combined surgical and chemical (n = 3) or catheter-based RDN (n = 9). A telemetry monitor was implanted to acquire hemodynamic data continuously. Before and after RDN, a sodium nitroprusside-induced HC was performed. Renal renin AV-Δ was calculated as the difference of plasma renin concentrations drawn from the renal artery and vein.

Results

In total, complete renal renin AV data were obtained in eight animals at baseline and six animals at baseline and 3 months of follow-up. Baseline renal renin AV-Δ correlated inversely with change in 24-h minimum systolic (− 0.764, p = 0.02), diastolic (r = − 0.679, p = 0.04), and mean (r = − 0.663, p = 0.05) blood pressure. In the animals with complete renin secretion data at baseline and follow-up, the HC increased renal renin AV-Δ at baseline, while this effect was attenuated following RDN (0.55 ± 0.34 pg/ml versus − 0.10 ± 0.16 pg/ml, p = 0.003). Renin urinary excretion remained unchanged throughout the study (baseline 0.286 ± 0.187 pg/ml versus termination 0.305 ± 0.072 pg/ml, p = 0.789).

Conclusion

Renin secretion induced by HC was attenuated following RDN and may serve as an indicator for patient selection and guide successful RDN procedures.

Interventional Approaches for Loin Pain Hematuria Syndrome and Kidney-Related Pain Syndromes

PURPOSE OF REVIEW

Loin pain hematuria syndrome (LPHS) frequently presents with severe chronic pain that poses a clinical challenge. Current treatment approaches are mostly empirical and include a wide range of therapeutic strategies such as physical therapy, local and systemic analgesia, interventional and surgical approaches usually flanked by psycho-behavioral therapy, and other strategies. LPHS often impacts negatively on quality of life particularly in patients who are refractory to treatment.

RECENT FINDINGS

With recent advances in catheter-based treatment approaches and better understanding of the pathophysiology of LPHS, intraluminal renal denervation (RDN) has been proposed as a valuable treatment option for kidney-related pain syndromes. The present review provides a brief overview of the clinical challenges associated with LPHS, highlights recent insights into its underlying mechanisms, and summarizes currently available data on the use of RDN in the context of LPHS and kidney-related pain syndromes. Renal denervation via various approaches including surgical and catheter-based techniques has shown promise in alleviating kidney-related pain syndromes. Randomized controlled trials are now required to better define its role in the management of these conditions.

Renal Sympathetic Denervation as Upstream Therapy During Atrial Fibrillation Ablation: Pilot HFIB Studies and Meta-Analysis

OBJECTIVES

This study sought to determine the impact of adjunctive renal sympathetic denervation to catheter ablation in patients with atrial fibrillation (AF) and history of hypertension.

BACKGROUND

There are limited data regarding the impact of upstream adjunctive renal sympathetic denervation (RSDN) to pulmonary vein isolation (PVI) in patients with symptomatic atrial fibrillation (AF) and hypertension.

METHODS

The data for this study were obtained from 2 prospective randomized pilot studies, the HFIB (Adjunctive Renal Denervation to Modify Hypertension and Sympathetic tone as Upstream Therapy in the Treatment of Atrial Fibrillation)-1 (n = 30) and HFIB (Adjunctive Renal Denervation to Modify Hypertension and Sympathetic tone as Upstream Therapy in the Treatment of Atrial Fibrillation)-2 (n = 50) studies, and we performed a meta-analysis including all published studies comparing RSDN+PVI versus PVI alone up to January 25, 2020, in patients with AF and hypertension.

RESULTS

At 24 months, AF recurrence occurred in 53% and 38% in the PVI and PVI+RSDN groups (p = 0.43) in the HFIB-1 study, respectively, and 27% and 25% in the PVI and PVI+RSDN groups (p = 0.80) in the HFIB-2 study, respectively. When combined in a meta-analysis including 6 studies (n = 725), adjunctive RSDN significantly decreased the risk of AF recurrence (risk ratio [RR]: 0.68; 95% confidence interval [CI]: 0.55 to 0.83; p = 0.0002; I² = 0%) when compared with PVI. Six renal artery complications occurred in the HFIB-1 study and none occurred in the HFIB-2 study with RSDN. However, in the meta-analysis, there were no significant differences in overall complications between both groups (RR: 1.43; 95% CI: 0.63 to 3.22; p = 0.40; I² = 7%). When compared with baseline, RDSN significantly reduced the systolic blood pressure (-12.1 mm Hg; 95% CI: -20.9 to -3.3 mm Hg; p < 0.007; I² = 99%) and diastolic blood pressure (-5.60 mm Hg; 95% CI: -10.05 to -1.10 mm Hg; p = 0.01; I² = 98%) on follow-up.

CONCLUSIONS

The pilot HFIB-1 and HFIB-2 studies did not demonstrate a benefit with RSDN as an adjunctive upstream therapy during PVI. However, in the meta-analysis, adjunctive RSDN to PVI appears to be safe, and improves clinical outcomes in AF patients with a history of hypertension.

Renal Denervation to Treat Heart Failure

Heart failure (HF) is a global pandemic with a poor prognosis after hospitalization. Despite HF syndrome complexities, evidence of significant sympathetic overactivity in the manifestation and progression of HF is universally accepted. Confirmation of this dogma is observed in guideline-directed use of neurohormonal pharmacotherapies as a standard of care in HF. Despite reductions in morbidity and mortality, a growing patient population is resistant to these medications, while off-target side effects lead to dismal patient adherence to lifelong drug regimens. Novel therapeutic strategies, devoid of these limitations, are necessary to attenuate the progression of HF pathophysiology while continuing to reduce morbidity and mortality. Renal denervation is an endovascular procedure, whereby the ablation of renal nerves results in reduced renal afferent and efferent sympathetic nerve activity in the kidney and globally. In this review, we discuss the current state of preclinical and clinical research related to renal sympathetic denervation to treat HF.

Neurogenic tachykinin mechanisms in experimental nephritis of rats

We demonstrated earlier that renal afferent pathways combine very likely “classical” neural signal transduction to the central nervous system and a substance P (SP)–dependent mechanism to control sympathetic activity. SP content of afferent sensory neurons is known to mediate neurogenic inflammation upon release. We tested the hypothesis that alterations in SP-dependent mechanisms of renal innervation contribute to experimental nephritis. Nephritis was induced by OX-7 antibodies in rats, 6 days later instrumented for recording of blood pressure (BP), heart rate (HR), drug administration, and intrarenal administration (IRA) of the TRPV1 agonist capsaicin to stimulate afferent renal nerve pathways containing SP and electrodes for renal sympathetic nerve activity (RSNA). The presence of the SP receptor NK-1 on renal immune cells was assessed by FACS. IRA capsaicin decreased RSNA from 62.4 ± 5.1 to 21.6 ± 1.5 mV s (*p < 0.05) in controls, a response impaired in nephritis. Suppressed RSNA transiently but completely recovered after systemic administration of a neurokinin 1 (NK1-R) blocker. NK-1 receptors occurred mainly on CD11⁺ dendritic cells (DCs). An enhanced frequency of CD11c⁺NK1R⁺ cell, NK-1 receptor⁺ macrophages, and DCs was assessed in nephritis. Administration of the NK-1R antagonist aprepitant during nephritis reduced CD11c⁺NK1R⁺ cells, macrophage infiltration, renal expression of chemokines, and markers of sclerosis. Hence, SP promoted renal inflammation by weakening sympathoinhibitory mechanisms, while at the same time, substance SP released intrarenally from afferent nerve fibers aggravated immunological processes i.e. by the recruitment of DCs.

Effects of renal denervation on kidney function and long-term outcomes: 3-year follow-up from the Global SYMPLICITY Registry

Aims

Several studies and registries have demonstrated sustained reductions in blood pressure (BP) after renal denervation (RDN). The long-term safety and efficacy after RDN in real-world patients with uncontrolled hypertension, however, remains unknown. The objective of this study was to assess the long-term safety and efficacy of RDN, including its effects on renal function.

Methods and results

The Global SYMPLICITY Registry is a prospective, open-label registry conducted at 196 active sites worldwide in hypertensive patients receiving RDN treatment. Among 2237 patients enrolled and treated with the SYMPLICITY Flex catheter, 1742 were eligible for follow-up at 3 years. Baseline office and 24-h ambulatory systolic BP (SBP) were 166 ± 25 and 154 ± 18 mmHg, respectively. SBP reduction after RDN was sustained over 3 years, including decreases in both office (−16.5 ± 28.6 mmHg, P < 0.001) and 24-h ambulatory SBP (−8.0 ± 20.0 mmHg; P < 0.001). Twenty-one percent of patients had a baseline estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m². Between baseline and 3 years, renal function declined by 7.1 mL/min/1.73 m² in patients without chronic kidney disease (CKD; eGFR ≥60 mL/min/1.73 m²; baseline eGFR 87 ± 17 mL/min/1.73 m²) and by 3.7 mL/min/1.73 m² in patients with CKD (eGFR <60 mL/min/1.73 m²; baseline eGFR 47 ± 11 mL/min/1.73 m²). No long-term safety concerns were observed following the RDN procedure.

Conclusion

Long-term data from the Global SYMPLICITY Registry representing the largest available cohort of hypertensive patients receiving RDN in a real-world clinical setting demonstrate both the safety and efficacy of the procedure with significant and sustained office and ambulatory BP reductions out to 3 years.

The randomised Oslo study of renal denervation vs. Antihypertensive drug adjustments: efficacy and safety through 7 years of follow-up

PURPOSE

The blood pressure (BP) lowering effect of renal sympathetic denervation (RDN) in treatment-resistant hypertension shows variation amongst the existing randomised studies. The long-term efficacy and safety of RDN require further investigation. For the first time, we report BP changes and safety up to 7 years after RDN, compared to drug adjustment in the randomised Oslo RDN study.

MATERIALS AND METHODS

Patients with treatment-resistant hypertension, defined as daytime systolic ambulatory BP ≥135 mmHg after witnessed intake of ≥3 antihypertensive drugs including a diuretic, were randomised to either RDN (n = 9) or drug adjustment (n = 10). The initial primary endpoint was the change in office BP after 6 months. The RDN group had their drugs adjusted after 1 year using the same principles as the Drug Adjustment group. Both groups returned for long-term follow-up after 3 and 7 years.

RESULTS

The decrease in office BP and ambulatory BP (ABPM) after 6 months did not persist, but gradually increased in both groups. From 6 months to 7 years follow-up, mean daytime systolic ABPM increased from 142 ± 10 to 145 ± 15 mmHg in the RDN group, and from 133 ± 11 to 137 ± 13 mmHg in the Drug Adjustment group, with the difference between them decreasing. In a mixed factor model, a significantly different variance was found between the groups in daytime systolic ABPM (p = .04) and diastolic ABPM (p = .01) as well as office diastolic BP (p<.01), but not in office systolic BP (p = .18). At long-term follow-up we unveiled no anatomical- or functional renal impairment in either group.

CONCLUSIONS

BP changes up to 7 years show a tendency towards a smaller difference in BPs between the RDN and drug adjustment patients. Our data support RDN as a safe procedure, but it remains non-superior to intensive drug adjustment 7 years after the intervention.

Afferent renal innervation in anti-Thy1.1 nephritis in rats

Afferent renal nerves exhibit a dual function controlling central sympathetic outflow via afferent electrical activity and influencing intrarenal immunological processes by releasing peptides such as calcitonin gene-related peptide (CGRP). We tested the hypothesis that increased afferent and efferent renal nerve activity occur with augmented release of CGRP in anti-Thy1.1 nephritis, in which enhanced CGRP release exacerbates inflammation. Nephritis was induced in Sprague-Dawley rats by intravenous injection of OX-7 antibody (1.75 mg/kg), and animals were investigated neurophysiologically, electrophysiologically, and pathomorphologically 6 days later. Nephritic rats exhibited proteinuria (169.3 ± 10.2 mg/24 h) with increased efferent renal nerve activity (14.7 ± 0.9 bursts/s vs. control 11.5 ± 0.9 bursts/s, n = 11, P < 0.05). However, afferent renal nerve activity (in spikes/s) decreased in nephritis (8.0 ± 1.8 Hz vs. control 27.4 ± 4.1 Hz, n = 11, P < 0.05). In patch-clamp recordings, neurons with renal afferents from nephritic rats showed a lower frequency of high activity following electrical stimulation (43.4% vs. 66.4% in controls, P < 0.05). In vitro assays showed that renal tissue from nephritic rats exhibited increased CGRP release via spontaneous (14 ± 3 pg/mL vs. 6.8 ± 2.8 pg/ml in controls, n = 7, P < 0.05) and stimulated mechanisms. In nephritic animals, marked infiltration of macrophages in the interstitium (26 ± 4 cells/mm²) and glomeruli (3.7 ± 0.6 cells/glomerular cross-section) occurred. Pretreatment with the CGRP receptor antagonist CGRP_8-37 reduced proteinuria, infiltration, and proliferation. In nephritic rats, it can be speculated that afferent renal nerves lose their ability to properly control efferent sympathetic nerve activity while influencing renal inflammation through increased CGRP release.

Microdissection of the Human Renal Nervous System

Despite the use of renal denervation to treat hypertension, the anatomy of the renal nervous system remains poorly understood. We performed a detailed quantitative analysis of the human renal nervous system anatomy with the goal of optimizing renal denervation procedural safety and efficacy. Sixty kidneys from 30 human cadavers were systematically microdissected to quantify anatomic variations in renal nerve patterns. Contrary to current clinical perception, not all renal innervation followed the main renal artery. A significant portion of the renal nerves (late arriving nerves) frequently reached the kidney (73% of the right kidney and 53% of the left kidney) bypassing the main renal artery. The ratio of the main renal artery length/aorta-renal hilar distance proved to be a useful variable to identify the presence/absence of these late arriving nerves (odds ratio, 0.001 (95% CI, 0.00002–0.0692; P : 0.001) with a cutoff of 0.75 (sensitivity: 0.68, specificity: 0.83, area under ROC curve at threshold: 0.76). When present, polar arteries were also highly associated with the presence of late arriving nerve. Finally, the perivascular space around the proximal main renal artery was frequently occupied by fused ganglia from the solar plexus (right kidney: 53%, left kidney: 83%) and/or by the lumbar sympathetic chain (right kidney: 63%, left kidney: 60%). Both carried innervation to the kidneys but importantly also to other abdominal and pelvic organs, which can be accidentally denervated if the proximal renal artery is targeted for ablation. These novel anatomic insights may help guide future procedural treatment recommendations to increase the likelihood of safely reaching and destroying targeted nerves during renal denervation procedures.

Renal Denervation: History and Current Status

This review examines the early roots of renal denervation from its conceptualization and the creation of a percutaneous catheter system from a start-up company. As excitement began to grow with early animal experiments and human trials, renal denervation began to focus on the treatment of hypertension, culminating in a disappointing pivotal trial. Lessons learned from this trial are pushed forward, and renal denervation begins to gain clinical momentum as a new set of successful clinical trials emerge. The future for renal denervation eventually may extend beyond hypertension.

Renal denervation improves vascular endothelial dysfunction by inducing autophagy via AMPK/mTOR signaling activation in a rat model of type 2 diabetes mellitus with insulin resistance

BACKGROUND

Recent clinical and animal studies have shown that renal denervation (RDN) improves insulin sensitivity and endothelial dysfunction. However, the specific mechanism remains incompletely understood. The purpose of this study is to investigate the effects of RDN on endothelial dysfunction of type 2 diabetes mellitus (T₂DM) rat models with insulin resistance and to explore the underlying molecular mechanisms.

METHODS

Male Sprague-Dawley rats were fed with or without high-fat diet allocated in different groups, combined with low-dose streptozotocin which induces a rat model to develop T₂DM with insulin resistance. RDN was conducted 1 week after the rat models fully developed T₂DM. The animals were sub-divided into four groups randomly: control group (CON, n = 6), diabetic group (T₂DM, n = 6), diabetic with sham surgery group (Sham, n = 6) and diabetic with RDN group (RDN, n = 6). Rats in all groups were studied at baseline, both preoperatively and 4 weeks after RDN, respectively. Western blot was used to detect the expression of angiotensin-converting enzyme 2 (ACE2) protein and the expression of autophagy-related proteins Beclin1, LC3 and p62 and autophagy signaling pathway AMPK/mTOR proteins and apoptosis-related protein caspase-3 in the aorta endothelial cells. In addition, the effects of ACE2 on autophagy of human umbilical vein insulin resistance endothelial cell culture in vitro were also studied.

RESULTS

RDN decreased plasma and renal tissue norepinephrine levels. The Von Willebrand factor level was also decreased, while the plasma level of nitric oxide (NO) was significantly increased after RDN. Compared with the T₂DM group and the Sham group, the endothelium-dependent and endothelium-independent diastolic function of the RDN group was improved significantly, the expression of Beclin1, LC3, ACE2 and eNOS proteins was higher, and the level of p62 protein was decreased. Furthermore, we found that RDN can activate the expression of p-AMPK and inhibit the expression of p-mTOR. In cell culture experiment, ACE2 activated p-AMPK and inhibited p-mTOR, thus promoting autophagy.

CONCLUSIONS

RDN may not only increase the expression of ACE2 in the vascular endothelium, but also can via ACE2 activate p-AMPK and inhibit p-mTOR, thus promoting autophagy and improving endothelial dysfunction.

Emerging therapies for right ventricular dysfunction and failure

Therapeutic options for right ventricular (RV) dysfunction and failure are strongly limited. Right heart failure (RHF) has been mostly addressed in the context of pulmonary arterial hypertension (PAH), where it is not possible to discern pulmonary vascular- and RV-directed effects of therapeutic approaches. In part, opposing pathomechanisms in RV and pulmonary vasculature, i.e., regarding apoptosis, angiogenesis and proliferation, complicate addressing RHF in PAH. Therapy effective for left heart failure is not applicable to RHF, e.g., inhibition of adrenoceptor signaling and of the renin-angiotensin system had no or only limited success. A number of experimental studies employing animal models for PAH or RV dysfunction or failure have identified beneficial effects of novel pharmacological agents, with most promising results obtained with modulators of metabolism and reactive oxygen species or inflammation, respectively. In addition, established PAH agents, in particular phosphodiesterase-5 inhibitors and soluble guanylate cyclase stimulators, may directly address RV integrity. Promising results are furthermore derived with microRNA (miRNA) and long non-coding RNA (lncRNA) blocking or mimetic strategies, which can target microvascular rarefaction, inflammation, metabolism or fibrotic and hypertrophic remodeling in the dysfunctional RV. Likewise, pre-clinical data demonstrate that cell-based therapies using stem or progenitor cells have beneficial effects on the RV, mainly by improving the microvascular system, however clinical success will largely depend on delivery routes. A particular option for PAH is targeted denervation of the pulmonary vasculature, given the sympathetic overdrive in PAH patients. Finally, acute and durable mechanical circulatory support are available for the right heart, which however has been tested mostly in RHF with concomitant left heart disease. Here, we aim to review current pharmacological, RNA- and cell-based therapeutic options and their potential to directly target the RV and to review available data for pulmonary artery denervation and mechanical circulatory support.

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

Recent randomized sham-controlled trials have demonstrated significant blood pressure reductions following renal denervation (RDN) in patients with hypertension, both in the presence and absence of antihypertensive therapy. These new data encouraged us to revisit previously published insights into potential clinical trial confounding factors that informed the design and conduct of forthcoming trials. Initially identified confounders related to procedural technique, medication variability, and selected patient subgroups have been addressed in contemporary trial design. Regarding procedural method and technology, blood pressure reductions may be improved by ensuring circumferential lesion creation in the distal renal arteries and branch vessels. Safety of the RDN procedure has been demonstrated in multiple independent meta-analyses including thousands of treated patients with low reported rates of renal vessel complications and maintenance of renal function. However, a newer generation of RDN trials has also introduced insights related to medication adherence, patient selection, and the definition of treatment response. Evolving evidence indicates that RDN therapy may be considered in higher risk populations of uncontrolled hypertension regardless of ethnicity and in patients expressing a strong preference for a nondrug therapy option. Despite advances in procedural technique and clinical trial conduct, inconsistent antihypertensive-drug adherence behavior remains perhaps the most critical clinical trial design issue for device-based hypertension therapies. As the balance in clinical equipoise increasingly favors RDN, justification of sham-controlled trial designs will be revisited, and novel study designs may be required to evaluate the safety and efficacy of novel devices and procedures intended to address the escalating prevalence of poorly controlled hypertension.

Distal renal denervation: cardioprotection in patients with resistant hypertension

Aim. To study the effectiveness of using the anatomically optimized distal renal denervation (RDN) in comparison with the standard approach for reducing myocardial damage and left ventricular (LV) hypertrophy in patients with resistant hypertension (HTN).

Material and methods. The randomized double-blind study of the efficacy and safety of distal RDN compared to conventional main renal artery intervention (ClinicalTrials.gov NCT02667912) for the treatment of resistant HTN included 26 patients. All patients were divided into two groups: group 1 (n=16) — distal RDN, group 2 (n=10) — conventional RDN. In addition to 24-hour blood pressure (BP) monitoring, initially and 12 months after the intervention, contrast- enhanced cardiac magnetic resonance imaging was performed to determine the left ventricular mass and non-coronary myocardial damage area. All patients signed informed consent. Twenty-four patients completed the present study.

Results. After 12 months, the mean 24-hour BP significantly decreased after both distal RDN (from 167,2±28,5/93,2±19,3 to 147,0±13,7/81,5±9,3 mm Hg (p<0,05)) and conventional RDN (from 157,5±22,5/90,6±23,9 to 139,9±17,7/80,0±16,7 (p<0,05)). Also in both cases, a trend to LV mass decrease was revealed: from 252,6±85,2 to 221,0±60,3 gm (p=0,096) after the distal RDN; from 214,3±54,1 to 186,4±48,1 gm (p=0,071) after the conventional RDN. In contrast, the myocardial damage area decreased only after distal RDN (from 2,33±1,33 to 1,35±0,67 cm3 (p=0,02)) and did not change after conventional RDN.

Conclusion. In comparison with the conventional main renal artery intervention, distal RDN in patients with resistant HTN has an additional cardioprotective effect — a decrease in LV myocardial damage area.

Cost-effectiveness of Interventional therapies for management of Treatment-resistant hypertension: systematic review of pharmacoeconomic studies

Background

Treatment resistant hypertension (TRH) is defined as uncontrolled blood pressure (&gt;140/90 mm Hg) after treatment with the intensified dose of three standard antihypertensive drugs. Management of TRH involves addition of fourth line drugs on standard care or interventional therapies (Renal denervation, Baroreceptor activation, Central venous anastomosis). However, evidence concerning cost-effectiveness of interventional therapies is inconclusive. Objective: This systematic review was conducted to extract the level of evidence on cost-effectiveness of interventional therapies for TRH.

Method

We systematically searched articles written in English language since January 2000 to January 2020 from the following databases: PubMed/Medline, Ovid/Medline, Embase, Scopus, Web of Science, Google scholar and other relevant sources.

Key findings

Twelve pharmacoeconomic studies were included in this systematic review. Renal denervation (RDN) is the most commonly studied intervention therapy for treatment of TRH. Participants included in the study vary from age 18-99 years. The incremental cost-effectiveness ratio (ICER) of RDN ranged from $1,709.84 per QALY gained in Netherlands to 66,380.3 per QALY gained in Australia. RDN was cost-effective in high-risk patients in UK, Australia, Canada, Netherlands, USA, Germany, Russia and Korea. The cost-effectiveness was influenced by the magnitude of effect of RDN on systolic blood pressure, the rate of RDN nonresponders, and the procedure costs of RDN and assumption of long-term time horizon. However, the ICER of RDN in Mexico was above MXN$ 139,000 GDP/capita of the country. The ICER of implantable carotid body stimulator was $64,400 per QALYs gained. The cost-effectiveness of baroreceptor activation didn’t improve with age.

Conclusion

Overall cost-effectiveness of interventional therapies for treatment of TRH was inconclusive based on the current available evidence. Therefore, strong clinical trials and pharmacoeconomic evaluations from different perspectives in various candidate populations are needed to generate adequate clinical and cost-effectiveness evidence for using interventional therapies in treatment of treatment resistant hypertension.

Renal Denervation for Resistant Hypertension: Where Do We Stand?

PURPOSE OF REVIEW

To review the data about the use of renal denervation (RDN), a minimally invasive surgery, for resistant hypertension (RH) and to provide practical guidance for practitioners who are establishing an RDN service.

RECENT FINDINGS

RDN can selectively ablate renal sympathetic nerve fibres, block the transmission of nerve impulses between central sympathetic nerve and kidney, to control blood pressure to as a novel promising non-drug treatment option for RH. At present, there are many researches on the treatment of RH by RDN, but there are some controversies. This review summarises and critically examines the evidence for RDN in the treatment of RH and identifies areas for future research. With the development of RDN, the continuous innovation of RDN technology and methods, the development about better evaluating the real-time success of RDN and the improvement for identifying individuals who are most likely to benefit from RDN will ultimately determine whether RDN represents a feasible way to manage RH in the future.

Successful renal denervation decreases the platelet activation status in hypertensive patients

AIMS

To determine whether renal denervation (RDN) in hypertensive patients affects the platelet activation status.

METHODS AND RESULTS

We investigated the effect of RDN on the platelet activation status in 41 hypertensive patients undergoing RDN. Ambulatory blood pressure (BP), plasma sympathetic neurotransmitter Neuropeptide Y, and platelet activation markers were measured at baseline, at 3 months, and 6 months after RDN. RDN significantly decreased BP at 3 months (150.6 ± 11.3/80.9 ± 11.4 mmHg to 144.7 ± 12.0/77.1 ± 11.1 mmHg; P < 0.01) and at 6 months (144.3 ± 13.8/78.3 ± 11.1 mmHg; P < 0.01). Plasma levels of the sympathetic neurotransmitter Neuropeptide Y, an indicator of sympathetic nerve activity, were significantly decreased at 3 months (0.29 ± 0.11 ng/mL to 0.23 ± 0.11 ng/mL; P < 0.0001) and at 6 months (0.22 ± 0.12 ng/mL; P < 0.001) after RDN. This was associated with a reduction in platelet membrane P-selectin expression (3 months, P < 0.05; 6 months, P < 0.05), soluble P-selectin (6 months, P < 0.05), circulating numbers of platelet-derived extracellular vesicles (EVs) (3 months, P < 0.001; 6 months, P < 0.01), and phosphatidylserine expressing EVs (3 months, P < 0.001; 6 months, P < 0.0001), indicative of a reduction in platelet activation status and procoagulant activity. Only patients who responded to RDN with a BP reduction showed inhibition of P-selectin expression at 3 months (P < 0.05) and 6 months (P < 0.05) as well as reduction of glycoprotein IIb/IIIa activation at 3 months (P < 0.05). Notably, 13 patients who took aspirin did not show significant reduction in platelet P-selectin expression following RDN.

CONCLUSION

Our results imply a connection between the sympathetic nervous system and the platelet activation status and provide a potential mechanistic explanation by which RDN can have favourable effects towards reducing cardiovascular complications.

Resistant Hypertension: Where are We Now and Where Do We Go from Here?

Resistant hypertension is an important subtype of hypertension that leads to an increased risk of cerebrovascular, cardiovascular, and kidney disease. The revised guidelines from the American College of Cardiology and American Heart Association now define resistant hypertension as blood pressure that remains above goal despite use of three maximally titrated anti-hypertensive medications including a diuretic or as a hypertensive patient who requires 4 or more agents for adequate BP control. These agents typically include a calcium-channel blocker, a renin-angiotensin system inhibitor, and a diuretic at maximal or maximally tolerated doses. As recognition of resistant hypertension increases, it is important to distinguish pseudo-resistant or apparent hypertension from true resistant hypertension. Etiologies of apparent resistant hypertension include measurement error and medication non-adherence. The prevalence of true resistant hypertension is likely much lower than reported in the literature when accounting for patients with apparent resistant hypertension. Evaluation of patients with true resistant hypertension includes screening for causes of secondary hypertension and interfering medications. Successful management of resistant hypertension includes lifestyle modification and optimization of medical therapy, often including the use of mineralocorticoid receptor antagonists. Looking ahead at developments in hypertension management, a slew of new device-based therapies are under active development. Of these, renal denervation is the closest to routine clinical application. Further study is needed before these devices can be recommended in the routine treatment of resistant hypertension.