Renal denervation in treatment-resistant essential hypertension. A randomized, SHAM-controlled, double-blinded 24-h blood pressure-based trial

Contemporary Strategies to Manage High Blood Pressure in Patients with Coexistent Resistant Hypertension and Heart Failure With Reduced Ejection Fraction

Resistant hypertension (RH) represents an advanced subtype of hypertension that is complex to diagnose and treat. Compared with general hypertension, RH increases the risk patients will develop more advanced cardiovascular complications, including heart failure with reduced ejection fraction (HFrEF). As expected, the prevalence of RH has increased since the introduction of lower blood pressure targets included in the recent 2017 American blood pressure guidelines. The array of pharmacotherapies available to treat both hypertension and HFrEF has also expanded within the past decade. However, the efficacy of these cutting-edge pharmacotherapies has not come without a more advanced understanding of the important adjunct role non-pharmacological therapies play in helping with the management of both hypertension and HFrEF. In this review, we provide a summary of the latest pharmacological and non-pharmacological strategies that can be used to initiate treatment and optimize long-term blood pressure control in patients with coexistent RH and HFrEF.

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.

Arterial hypertension in adults. Clinical guidelines 2020

Arterial hypertension in adults. Clinical guidelines 2020

Efficacy and safety of renal denervation for the management of arterial hypertension: A systematic review and meta-analysis of randomized, sham-controlled, catheter-based trials

Despite the availability of a numerous antihypertensive agents, hypertension treatment and control rates remain low in many countries. The role of the sympathetic nervous system has long been recognized, but recent sham control renal denervation studies demonstrated conflicting results. In this reviewe paper, the authors performed a systematic review and meta-analysis to examine outcomes of sham-controlled studies utilizing new technologies and procedures. Six published randomized, sham-controlled studies were included in this meta-analysis. Of those, three trials used the first-generation radiofrequency renal denervation device and technique and the other three used second-generation devices and techniques. In total, 981 patients with hypertension were randomized in all 6 trials to undergo renal denervation (n = 585) or sham procedure (n = 396). Overall, renal denervation resulted in a decrease of 24-hours systolic ambulatory blood pressure (ABP) by 3.62 mm Hg (95% CI: -5.28--1.96; I2  = 0%), compared to sham procedure (GRADE: low). Renal denervation also reduced daytime systolic ABP by 5.51 mm Hg (95% CI: -7.79--3.23; I2  = 0%), compared to sham procedure but not nighttime systolic ABP. Office systolic blood pressure was reduced by 5.47 mm Hg (95% CI -8.10--2.84; I2  = 0%), compared to sham control. Further analysis demonstrated that second-generation devices were effective in reducing blood pressure, whereas the first-generation devices were not. These results indicate that effective renal denervation can result in significant and clinically meaningful blood pressure reduction. The second-generation devices provide better renal nerve ablation.

Sham-Controlled Randomized Trials of Catheter-Based Renal Denervation in Patients With Hypertension

BACKGROUND

There are conflicting data regarding the relative effectiveness of renal sympathetic denervation (RSD) in patients with hypertension.

OBJECTIVES

The purpose of this study was to evaluate the blood pressure (BP) response after RSD in sham-controlled randomized trials.

METHODS

Databases were searched through June 30, 2018. Randomized trials (RCTs) with ≥50 patients comparing catheter-based RSD with a sham control were included. The authors calculated summary treatment estimates as weighted mean differences (WMD) with 95% confidence intervals (CIs) using random-effects meta-analysis.

RESULTS

The analysis included 977 patients from 6 trials. The reduction in 24-h ambulatory systolic blood pressure (ASBP) was significantly greater for patients treated with RSD than sham procedure (WMD -3.65 mm Hg, 95% CI: -5.33 to -1.98; p < 0.001). Compared with sham, RSD was also associated with a significant decrease in daytime ASBP (WMD -4.07 mm Hg, 95% CI: -6.46 to -1.68; p < 0.001), office systolic BP (WMD -5.53 mm Hg, 95% CI: -8.18 to -2.87; p < 0.001), 24-h ambulatory diastolic BP (WMD -1.71 mm Hg, 95% CI: -3.06 to -0.35; p = 0.01), daytime ambulatory diastolic BP (WMD -1.57 mm Hg, 95% CI: -2.73 to -0.42; p = 0.008), and office diastolic BP (WMD -3.37 mm Hg, 95% CI: -4.86 to -1.88; p < 0.001). Compared with first-generation trials, a significantly greater reduction in daytime ASBP was observed with RSD in second-generation trials (6.12 mm Hg vs. 2.14 mm Hg; p interaction = 0.04); however, this interaction was not significant for 24-h ASBP (4.85 mm Hg vs. 2.23 mm Hg; p interaction = 0.13).

CONCLUSIONS

RSD significantly reduced blood pressure compared with sham control. Results of this meta-analysis should inform the design of larger, pivotal trials to evaluate the long-term efficacy and safety of RSD in patients with hypertension.

Renal denervation: Alternative treatment options for hypertension?

Hypertension affects millions of Americans and has adverse long-term consequences increasing morbidity and mortality. Resistant hypertension (RH) continues to be difficult to treat with medications alone which may be associated with significant side effects. Alternate therapies have been evaluated for treating RH and renal denervation has been investigated extensively. We review the data from renal denervation trials and other novel technologies which are not FDA approved to date.

Österreichischer Blutdruckkonsens 2019

Erhöhter Blutdruck bleibt eine Hauptursache von kardiovaskulären Erkrankungen, Behinderung und frühzeitiger Sterblichkeit in Österreich, wobei die Raten an Diagnose, Behandlung und Kontrolle auch in rezenten Studien suboptimal sind. Das Management von Bluthochdruck ist eine häufige Herausforderung für Ärztinnen und Ärzte vieler Fachrichtungen. In einem Versuch, diagnostische und therapeutische Strategien zu standardisieren und letztendlich die Rate an gut kontrollierten Hypertoniker/innen zu erhöhen und dadurch kardiovaskuläre Erkrankungen zu verhindern, haben 13 österreichische medizinische Fachgesellschaften die vorhandene Evidenz zur Prävention, Diagnose, Abklärung, Therapie und Konsequenzen erhöhten Blutdrucks gesichtet. Das hier vorgestellte Ergebnis ist der erste Österreichische Blutdruckkonsens. Die Autoren und die beteiligten Fachgesellschaften sind davon überzeugt, daß es einer gemeinsamen nationalen Anstrengung bedarf, die Blutdruck-assoziierte Morbidität und Mortalität in unserem Land zu verringern.

ReferencesEfficiency and safety of renal denervation via cryoablation (Cryo-RDN) in Chinese patients with uncontrolled hypertension: study protocol for a randomized controlled trial

BACKGROUND

Clinical data show that due to the limited effects of lifestyle regulation and unsatisfactory drug adherence, only half of the hypertensive population have their blood pressure (BP) under control. In recent years, catheter-based renal denervation (RDN) has been used as a novel approach for treating uncontrolled hypertension. The safety and efficacy of catheter-based RDN have been confirmed by a number of studies and trials in which the participants were all non-Chinese and RDN was conducted via radiofrequency or ultrasound.

METHODS/DESIGN

This study is a prospective multicenter randomized sham-controlled trial that aims to investigate the safety and efficacy of cryoablation RDN (cryo-RDN) using a novel dedicated cryoablation balloon catheter (Cryofocus, China). A total of 200 Chinese patients who have uncontrolled hypertension despite standard medical treatment will be enrolled. With drug standardization, eligible participants will be randomized in a 1:1 ratio to undergo cryo-RDN treatment or renal angiography alone as a sham treatment. The primary endpoint is defined as the change in 24-h ambulatory systolic blood pressure from baseline to 6 months. Office BP and other 24-h ambulatory BP are included as secondary endpoints. Safety endpoints primarily include any adverse effects.

DISCUSSION

This study was designed to verify the safety and efficacy of cryo-RDN with Cryofocus balloon catheters in uncontrolled hypertensive patients on polypharmacy. The aim is to provide a new way to improve the control of hypertension in China as a complement to drug therapy.

TRIAL REGISTRATION

ChiCTR, ChiCTR1800017707. Registered on 10 August 2018.

New data, new studies, new hopes for renal denervation in patients with uncontrolled hypertension

Background

following the publication of SYMPLICITY HTN-3 the field of renal of denervation was put on hold. Although SYMPLICITY HTN-3 was well-designed and sham-controlled trial it failed to show any meaningful reduction in office or 24 h ambulatory blood pressure. The procedure was however safe and allowed research to continue. Although several pitfalls of the study have been pointed out, incomplete renal denervation was also implicated. Since then, a great deal of basic and clinical research took place and will be briefly commented on in this article.

Methods and results

Before and after SYMPLICITY-HTN-3, numerous uncontrolled, single or unblinded studies have shown substantial office BP reduction ranging from -7.7 to -32 mmHg and ambulatory BP ranging from -2.2 to 10.2 mmHg. Average weighted office systolic BP reduction was -20.8 mmHg and weighted average 24 h ambulatory BPM reduction was -7.8 mmHg. National and international registries have shown similar BP reductions, but results remained unconvincing due to lack of reliable sham controls. In recent years, 5 well-designed sham - controlled studies (beyond, SYMPLICITY-HTN-3) have been published. Of those studies two were single center and three were multicenter international studies. Four studies used single tip or multi-electrode, radiofrequency catheters and one used focused ultrasound. The three multicenter studies reported positive-placebo subtracted results and established BP reductions measured both in the office and by ambulatory monitoring. No serious adverse events were reported.

Conclusions

It can therefore be concluded that the latest sham controlled studies established efficacy and safety of renal denervation.

Joint UK societies' 2019 consensus statement on renal denervation

Improved and durable control of hypertension is a global priority for healthcare providers and policymakers. There are several lifestyle measures that are proven to result in improved blood pressure (BP) control. Moreover, there is incontrovertible evidence from large scale randomised controlled trials (RCTs) that antihypertensive drugs lower BP safely and effectively in the long-term resulting in substantial reduction in cardiovascular morbidity and mortality. Importantly, however, evidence is accumulating to suggest that patients neither sustain long-term healthy behaviours nor adhere to lifelong drug treatment regimens and thus alternative measures to control hypertension warrant further investigation. Endovascular renal denervation (RDN) appears to hold some promise as a non-pharmacological approach to lowering BP and achieves renal sympathectomy using either radiofrequency energy or ultrasound-based approaches. This treatment modality has been evaluated in clinical trials in humans since 2009 but initial studies were compromised by being non-randomised, without sham control and small in size. Subsequently, clinical trial design and rigour of execution has been greatly improved resulting in recent sham-controlled RCTs that demonstrate short-term reduction in ambulatory BP without any significant safety concerns in both medication-naïve and medication-treated hypertensive patients. Despite this, the joint UK societies still feel that further evaluation of this therapy is warranted and that RDN should not be offered to patients outside of the context of clinical trials. This document reviews the updated evidence since our last consensus statement from 2014 and provides a research agenda for future clinical studies.

Effect of Catheter-Based Renal Denervation on Uncontrolled Hypertension: A Systematic Review and Meta-analysis

OBJECTIVE

To assess the efficacy and safety of catheter-based renal denervation (RDN) for the treatment of uncontrolled hypertension by conducting a systematic review and a meta-analysis.

METHODS

The Medline, Cochrane Library, and Embase databases were searched for clinical studies between January 1, 2009, and July 16, 2018. Studies that evaluated the effect of RDN on uncontrolled hypertension were identified. The primary endpoints were changes in 24-hour ambulatory systolic blood pressure (BP) and office systolic BP. The secondary endpoints included changes in 24-hour ambulatory diastolic BP, office diastolic BP, and major adverse events.

RESULTS

After a literature search and detailed evaluation, 12 randomized controlled trials with a total of 1539 individuals were included in the quantitative analysis. Pooled analyses indicated that RDN was associated with a significantly greater reduction of 24-hour systolic BP (mean difference [MD], -4.02 mm Hg; 95% CI, -5.49 to -2.56; P<.001) and office systolic BP (MD, -8.93 mm Hg; 95% CI, -14.03 to -3.83; P<.001) than controls. Similarly, RDN significantly reduced 24-hour diastolic BP (MD, -2.05 mm Hg; 95% CI, -3.05 to -1.05; P<.001) and office diastolic BP (MD, -4.49 mm Hg; 95% CI, -6.46 to -2.52; P<.001). RDN was not associated with an increased risk of major adverse events (relative risk, 1.06; 95% CI, 0.72 to 1.57; P=.76).

CONCLUSIONS

Catheter-based RDN was associated with a significant BP-lowering benefit without increasing major adverse events.

Selective Renal Denervation Guided by Renal Nerve Stimulation in Canine

Renal nerve stimulation (RNS) can result in substantial blood pressure (BP) elevation, and the change was significantly blunted when repeated stimulation after ablation. However, whether RNS could provide a meaningful renal nerve mapping for identification of optimal ablation targets in renal denervation (RDN) is not fully clear. Here, we compared the antihypertensive effects of selective RDN guided by two different BP responses to RNS and explored the nerve innervations at these sites in Kunming dogs. Our data indicated that ablation at strong-response sites showed a more systolic BP-lowering effect than at weak-response sites ( P =0.002), as well as lower levels of tyrosine hydroxylase and norepinephrine in kidney and a greater reduction in plasma norepinephrine ( P =0.004 for tyrosine hydroxylase, P =0.002 for both renal and plasma norepinephrine). Strong-response sites showed a greater total area and mean number of renal nerves than weak-response sites ( P =0.012 for total area and P <0.001 for mean number). Systolic BP-elevation response to RNS before RDN and blunted systolic BP-elevation to RNS after RDN were correlated with systolic BP changes at 4 weeks follow-up ( R =0.649; P =0.012 and R =0.643; P =0.013). Changes of plasma norepinephrine and renal norepinephrine levels at 4 weeks were also correlated with systolic BP changes at 4 weeks ( R =0.837, P <0.001 and R =0.927, P <0.001). These data suggest that selective RDN at sites with strong BP-elevation response to RNS could lead to a more efficient RDN. RNS is an effective method to identify the nerve-enriched area during RDN procedure and improve the efficacy of RDN.

Renal Denervation for Resistant Hypertension in the contemporary era: A Systematic Review and Meta-analysis

Renal denervation (RDN) is a catheter-based ablation procedure designed to treat resistant hypertension (RH). The objective of our study is to determine the effect of RDN on blood pressure and renal function in patients with RH in comparison to medical therapy alone. We performed an extensive literature search for randomized control trials (RCT) reporting office and 24 hr. blood pressure changes and estimated glomerular filtration rate (eGFR) at baseline and 6 months. We calculated a weighted standardized mean difference of blood pressure and renal outcomes between RDN and control groups using random effects models. Our search yielded 608 studies of which we included 15 studies for the final analysis. A total of 857 patients were treated with RDN and 616 patients treated with medical therapy ± sham procedure. Only 5 studies were double-blinded RCT with sham control. The adjusted standardized mean difference in the change in office based systolic and diastolic pressures (p = 0.18; p = 0.14); 24 hr. systolic and diastolic pressures (p = 0.20; p = 0.18); and eGFR (p = 0.20) from baseline to 6 months is statistically insignificant with significant heterogeneity. Subgroup analysis showed that among sham controlled trials, 24 hr. systolic blood pressure showed a modest but statistically significant benefit favoring renal denervation in patients with RH. Our meta-analysis of 15 RCTs showed no significant benefit of RDN on blood pressure control in patients with resistant hypertension. Subgroup analysis of sham control studies showed a modest benefit in 24 hr. systolic blood pressure at 6 months with RDN.

Renal Denervation in High-risk Patients with Hypertension

Collapse

Effect of renal denervation on coronary flow reserve in patients with resistant hypertension

Renal denervation (RDN) is a potential modality in the treatment of patients with resistant hypertension (RH) and has shown beneficial effect on a variety of cardiovascular surrogate markers. Coronary flow reserve, as assessed by transthoracic Doppler echocardiography (TDE-CFR) is impaired in patients with hypertension and is an independent predictor of cardiac morbidity. However, data on the effect of RDN on TDE-CFR are scarce. The main objective of this study was to assess the effect of RDN on TDE-CFR. Twenty-six consecutive patients with RH (9 female and 17 male; mean age 62 ± 8 years; mean number of antihypertensive drugs 4·2 ± 1·6) underwent bilateral RDN. CFR was assessed at baseline and 6 months after intervention. Mean flow velocity was measured in the left anterior descending artery by transthoracic Doppler echocardiography at baseline and during adenosine infusion (TDE-CFR). Systolic office blood pressure was reduced at follow-up (174 ± 24 versus 162 ± 27 mmHG; P = 0·01). Mean systolic ambulatory blood pressure decreased from 151 ± 21 to 147 ± 18 (P = 0·17). TDE-CFR remained unchanged 6 months after intervention (2·7 ± 0·6 versus 2·7 ± 0·7; P = 0·67). In conclusion, renal denervation was not associated with any changes in regard to coronary flow reserve at 6-month follow-up.

Selective vs. Global Renal Denervation: a Case for Less Is More

PURPOSE OF REVIEW

Review the renal nerve anatomy and physiology basics and explore the concept of global vs. selective renal denervation (RDN) to uncover some of the fundamental limitations of non-targeted renal nerve ablation and the potential superiority of selective RDN.

RECENT FINDINGS

Recent trials testing the efficacy of RDN showed mixed results. Initial investigations targeted global RDN as a therapeutic goal. The repeat observation of heterogeneous response to RDN including non-responders with lack of a BP reduction, or even more unsettling, BP elevations after RDN has raised concern for the detrimental effects of unselective global RDN. Subsequent studies have suggested the presence of a heterogeneous fiber population and the potential utility of renal nerve stimulation to identify sympatho-stimulatory fibers or "hot spots." The recognition that RDN can produce heterogeneous afferent sympathetic effects both change therapeutic goals and revitalize the potential of therapeutic RDN to provide significant clinical benefits. Renal nerve stimulation has emerged as potential tool to identify sympatho-stimulatory fibers, avoid sympatho-inhibitory fibers, and thus guide selective RDN.

Preferred Fourth-Line Pharmacotherapy for Resistant Hypertension: Are We There Yet?

Resistant hypertension (RH) is defined as blood pressure (BP) that remains above target levels despite adherence to at least three different antihypertensive medications, typically including a diuretic. Epidemiological studies estimate that RH is increasing in prevalence, and is associated with detrimental health outcomes. The pathophysiology underlying RH is complex, involving multiple, overlapping contributors including activation of the renin-angiotensin aldosterone system and the sympathetic nervous system, volume overload, endothelial dysfunction, behavioural and lifestyle factors. Hypertension guidelines currently recommend specific pharmacotherapy for 1st, 2nd and 3rd-line treatment, however no specific fourth-line pharmacotherapy is provided for those with RH. Rather, five different antihypertensive drug classes are generally suggested as possible alternatives, including: mineralocorticoid receptor antagonists, α1-adrenergic antagonists, α2-adrenergic agonists, β-blockers, and peripheral vasodilators. Each of these drug classes vary in their efficacy, tolerability and safety profile. This review summarises the available data on each of these drug classes as a potential fourth-line drug and reveals a lack of robust clinical evidence for preferred use of most of these classes in the setting of RH. Moreover, there is a lack of direct comparative trials that could assist in identifying a preferred fourth-line pharmacologic approach and in providing evidence for hypertensive guidelines for adequate treatment of RH.

Predictive factors for successful renal denervation: should we use them in clinical trials?

Renal denervation (RDN) is facing various challenges to its initial claimed value in hypertension treatment. Major concerns are the choice of the patients and the technical efficacy of the RDN. Different factors have been described as predicting the capacity of RDN to decrease blood pressure. These factors are related to the patients, the procedure and the tools to confirm successful neural ablation. Their use in future trials should help to improve RDN trials understanding and outcomes. This review summarizes the different predictive factors available and their potential benefits in patient selection and in procedure guidance.

The effect of renal denervation in an experimental model of chronic renal insufficiency, The REmnant kidney Denervation In Pigs study (REDIP study)

BACKGROUND

Renal denervation (RDN) is a promising therapeutic method in cardiology. Its currently most investigated indication is resistant hypertension. Other potential indications are atrial fibrillation, type 2 diabetes mellitus and chronic renal insufficiency among others. Previous trials showed conflicting but promising results, but the real benefits of RDN are still under investigation. Patients with renal insufficiency and resistant hypertension are proposed to be a good target for this therapy due to excessive activation of renal sympathetic drive. However, only limited number of studies showed benefits for these patients. We hypothesize that in our experimental model of chronic kidney disease (CKD) due to ischemia with increased activity of the renin-angiotensin-aldosterone system (RAAS), renal denervation can have protective effects by slowing or blocking the progression of renal injury.

METHODS

An experimental biomodel of chronic renal insufficiency induced by ischemia was developed using selective renal artery embolization (remnant kidney porcine model). 27 biomodels were assessed. Renal denervation was performed in 19 biomodels (denervated group), and the remaining were used as controls (n = 8). The extent of renal injury and reparative process between the two groups were compared and assessed using biochemical parameters and histological findings.

RESULTS

Viable remnant kidney biomodels were achieved and maintained in 27 swine. There were no significant differences in biochemical parameters between the two groups at baseline. Histological assessment proved successful RDN procedure in all biomodels in the denervated group. Over the 7-week period, there were significant increases in serum urea, creatinine, and aldosterone concentration in both groups. The difference in urea and creatinine levels were not statistically significant between the two groups. However, the level of aldosterone in the denervated was significantly lower in comparison to the controls. Histological assessment of renal arteries showed that RDN tends to produce more damage to the arterial wall in comparison to vessels in subjects that only underwent RAE. In addition, the morphological damage of kidneys, which was expressed as a ratio of damaged surface (or scar) to the overall surface of kidney, also did not show significant difference between groups.

CONCLUSIONS

In this study, we were not able to show significant protective effect of RDN alone on ischemic renal parenchymal damage by either laboratory or histological assessments. However, the change in aldosterone level shows some effect of renal denervation on the RAAS system. We hypothesize that a combined blockade of the RAAS and the sympathetic system could provide more protective effects against acute ischemia. This has to be further investigated in future studies.

Effects of renal denervation on coronary flow reserve and forearm dilation capacity in patients with treatment-resistant hypertension. A randomized, double-blinded, sham-controlled clinical trial

BACKGROUND

Microvascular impairment is well documented in hypertension. We investigated the effect of renal sympathetic denervation (RDN) on cardiac and peripheral microvasculature in patients with treatment-resistant essential hypertension (TRH).

METHODS

A randomized, single centre, double-blinded, sham-controlled clinical trial. Fifty-eight patients with TRH (ambulatory systolic BP (ASBP) ≥ 145mmHg) despite stable treatment were randomized to RDN or SHAM. RDN was performed with the unipolar Medtronic Flex catheter. Coronary flow reserve (CFR) and coronary- and forearm minimum vascular resistance (C-Rmin and F-Rmin) were determined using transthoracic Doppler echocardiography and F-Rmin with venous occlusion plethysmography at baseline and at six-months follow-up.

RESULTS

RDN was performed with 5.3±0.2 lesions in the right renal artery and 5.4±0.2 lesions in the left. Baseline ASBP was 152±2mmHg (RDN, n=29) and 154±2mmHg (SHAM, n=29). Similar reductions in MAP were seen at follow up (-3.5±2.0 vs. -3.2±1.8, P=0.92). Baseline CFR was 2.9±0.1 (RDN) and 2.4±0.1 (SHAM), with no significant change at follow-up (0.2±0.2 vs. -0.1±0.2, P=0.57). C-Rmin was 1.9±0.3 (RDN) and 2.7±0.6 (SHAM) (mmHgmin/ml pr. 100g) and did not change significantly (0.3±0.5 vs. -0.4±0.8, P=0.48). F-Rmin was 3.6±0.2 (RDN) and 3.6±0.3 (SHAM) (mmHgmin/ml pr. 100ml tissue) and unchanged at follow-up (4.2±0.4 vs. 3.8±0.2, P=0.17). Left ventricular mass index was unchanged following RDN (-4±7 (RDN) vs. 3±5 (SHAM) (g/m²) P=0.38).

CONCLUSION

The current study does not support positive effects of RDN on microvascular impairment in TRH.

Salt intake and blood pressure response to percutaneous renal denervation in resistant hypertension

The effect of lowering sympathetic nerve activity by renal denervation (RDN) is highly variable. With the exception of office systolic blood pressure (BP), predictors of the BP-lowering effect have not been identified. Because dietary sodium intake influences sympathetic drive, and, conversely, sympathetic activity influences salt sensitivity in hypertension, we investigated 24-hour urinary sodium excretion in participants of the SYMPATHY trial. SYMPATHY investigated RDN in patients with resistant hypertension. Both 24-hour ambulatory and office BP measurements were end points. No relationship was found for baseline sodium excretion and change in BP 6 months after RDN in multivariable-adjusted regression analysis. Change in the salt intake-measured BP relationships at 6 months vs baseline was used as a measure for salt sensitivity. BP was 8 mm Hg lower with similar salt intake after RDN, suggesting a decrease in salt sensitivity. However, the change was similar in the control group, and thus not attributable to RDN.

Renal Sympathetic Denervation: A Viable Option for Treating Resistant Hypertension

Accumulating evidence from mainly uncontrolled clinical studies with various types of ablation catheters have shown that renal denervation (RDN) can be applied safely and is effective in lowering blood pressure (BP) in patients with treatment-resistant hypertension. Sustained BP lowering has been documented up to 3 years. Furthermore, RDN has been associated with regression of target organ damage, such as left ventricular hypertrophy, arterial stiffness, and others. Several studies indicate potential benefit in other common clinical conditions associated with increased sympathetic tone including chronic kidney disease and heart failure. However, the recently published Symplicity HTN-3 study, the largest and most rigorously designed sham-controlled clinical trial, while confirming the safety of the procedure, failed to demonstrate a BP lowering effect beyond that of a sham procedure in patients with resistant hypertension. Efforts to unravel the reasons for the discrepant results from Symplicity HTN-3 have focused on a range of potential confounders including anatomical and procedural aspects. Indeed, data from post-hoc analyses indicate that sufficient RDN may not have been achieved in the majority of patients in Symplicity HTN-3. Furthermore, recent evidence from human postmortem and functional animal studies revealed new insights into the anatomical distribution of renal nerves and their accessibility by intravascular approaches. Initial results from recent clinical trials integrating these important findings indeed seem to confirm that RDN remains a viable option for the treatment of hypertension. Thorough further investigations will be key to determine the true potential of RDN in clinical conditions characterized by increased sympathetic drive.

[Invasive treatment of hypertension : Update 2016]

Invasive treatment methods-more specifically renal denervation and baroreceptor activator therapy-have been used for the treatment of therapy-resistant hypertension for several years now. In particular, renal denervation has aroused great interest because it was easy to perform and the first studies provided very promising results. Meanwhile, however, three randomized, blinded studies have been published, and none showed a significant benefit of renal denervation compared to a sham procedure. In addition, in several studies it was demonstrated that intensification of drug therapy, particularly with spironolactone, is at least comparable. Carotid sinus node baroreceptor activator therapy tends to be superior to renal denervation, but the probe currently used is not optimal. The first results by inserting an arteriovenous shunt between the iliac artery and vein are promising, but lack long-term safety data. Currently, all invasive treatment procedures should be performed within the framework of studies or accurate register surveys.

The effect of renal denervation on arterial stiffness, central blood pressure and heart rate variability in treatment resistant essential hypertension: a substudy of a randomized sham-controlled double-blinded trial (the ReSET trial)

OBJECTIVES

To investigate, whether renal denervation (RDN) improves arterial stiffness, central blood pressure (C-BP) and heart rate variability (HRV) in patients with treatment resistant hypertension.

METHODS

ReSET was a randomized, sham-controlled, double-blinded trial (NCT01459900). RDN was performed by a single experienced operator using the Medtronic unipolar Symplicity Flex^TM catheter. C-BP, carotid-femoral pulse wave velocity (PWV), and HRV were obtained at baseline and after six months with the SphygmoCor^®-device.

RESULTS

Fifty-three patients (77% of the ReSET-cohort) were included in this substudy. The groups were similar at baseline (SHAM/RDN): n = 27/n = 26; 78/65% males; age 59 ± 9/54 ± 8 years (mean ± SD); systolic brachial BP 158 ± 18/154 ± 17 mmHg; systolic 24-hour ambulatory BP 153 ± 14/151 ± 13 mmHg. Changes in PWV (0.1 ± 1.9 (SHAM) vs. -0.6 ± 1.3 (RDN) m/s), systolic C-BP (-2 ± 17 (SHAM) vs. -8 ± 16 (RDN) mmHg), diastolic C-BP (-2 ± 9 (SHAM) vs. -5 ± 9 (RDN) mmHg), and augmentation index (0.7 ± 7.0 (SHAM) vs. 1.0 ± 7.4 (RDN) %) were not significantly different after six months. Changes in HRV-parameters were also not significantly different. Baseline HRV or PWV did not predict BP-response after RDN.

CONCLUSIONS

In a sham-controlled setting, there were no significant effects of RDN on arterial stiffness, C-BP and HRV. Thus, the idea of BP-independent effects of RDN on large arteries and cardiac autonomic activity is not supported.

The innervation of the kidney in renal injury and inflammation: a cause and consequence of deranged cardiovascular control

Extensive investigations have revealed that renal sympathetic nerves regulate renin secretion, tubular fluid reabsorption and renal haemodynamics which can impact on cardiovascular homoeostasis normally and in pathophysiological states. The significance of the renal afferent innervation and its role in determining the autonomic control of the cardiovascular system is uncertain. The transduction pathways at the renal afferent nerves have been shown to require pro-inflammatory mediators and TRPV1 channels. Reno-renal reflexes have been described, both inhibitory and excitatory, demonstrating that a neural link exists between kidneys and may determine the distribution of excretory and haemodynamic function between the two kidneys. The impact of renal afferent nerve activity on basal and reflex regulation of global sympathetic drive remains opaque. There is clinical and experimental evidence that in states of chronic kidney disease and renal injury, there is infiltration of T-helper cells with a sympatho-excitation and blunting of the high- and low-pressure baroreceptor reflexes regulating renal sympathetic nerve activity. The baroreceptor deficits are renal nerve-dependent as the dysregulation can be relieved by renal denervation. There is also experimental evidence that in obese states, there is a sympatho-excitation and disrupted baroreflex regulation of renal sympathetic nerve activity which is mediated by the renal innervation. This body of information provides an important basis for directing greater attention to the role of renal injury/inflammation causing an inappropriate activation of the renal afferent nerves as an important initiator of aberrant autonomic cardiovascular control.

A Network Meta-Analysis of Clinical Management Strategies for Treatment-Resistant Hypertension: Making Optimal Use of the Evidence

BACKGROUND

With the addition of surgical interventions to current medicinal treatments, it is increasingly challenging for clinicians to rationally choose among the various options for treating patients with apparent treatment-resistant hypertension (ATRHTN). This study aims to establish the comparative effectiveness of mineralocorticoid receptor antagonists (MRA), renal denervation (RDN), darusentan and central arteriovenous anastomosis (CAA) for patients with ATRHTN by performing a network meta-analysis.

METHODS

Data Sources: Studies from recent meta-analyses for RDN and placebo effect were supplemented with a systematic search for MRAs in ATRHTN in the Pubmed, EMBASE, CINAHL and Cochrane databases through November 2016.

STUDY SELECTION

Randomized controlled trials comparing treatment options for patients with ATRHTN.

DATA EXTRACTION AND SYNTHESIS

Data were extracted using predefined data extraction forms, including the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria. A Bayesian random effects model was used to conduct a network meta-analysis. Spironolactone was used as the main comparator. Main Outcomes and Measures: Reduction in 24-h ambulatory blood pressure measurement (ABPM).

RESULTS

Twenty articles met our inclusion criteria, and seven treatment alternatives were compared. Compared to MRA, CAA had the highest probability of being more effective, further reducing 24-h SBP (-4.8 mmHg [-13.0, 3.7]) and 24-h DBP (-9.7 mmHg [-18, -0.63]). This difference is likely to be clinically meaningful, with a probability of 78 and 96% at a threshold of a 2-mmHg reduction in blood pressure.

CONCLUSIONS

When compared to MRA as anchor, darusentan, CAA and RDN are not more effective in achieving a clinically significant reduction in ambulatory blood pressure in individuals with apparent treatment-resistant hypertension.

Account for Clinical Heterogeneity in Assessment of Catheter-based Renal Denervation among Resistant Hypertension Patients: Subgroup Meta-analysis

Background:

Catheter-based renal denervation (RDN) is a novel treatment for resistant hypertension (RH). A recent meta-analysis reported that RDN did not significantly reduce blood pressure (BP) based on the pooled effects with mild to severe heterogeneity. The aim of the present study was to identify and reduce clinical sources of heterogeneity and reassess the safety and efficacy of RDN within the identified homogeneous subpopulations.

Methods:

This was a meta-analysis of 9 randomized clinical trials (RCTs) among patients with RH up to June 2016. Sensitivity analyses and subgroup analyses were extensively conducted by baseline systolic blood pressure (SBP) level, antihypertensive medication change rates, and coronary heart disease (CHD).

Results:

In all patients with RH, no statistical differences were found in mortality, severe cardiovascular events rate, and changes in 24-h SBP and office SBP at 6 and 12 months. However, subgroup analyses showed significant differences between the RDN and control groups. In the subpopulations with baseline 24-h SBP ≥155 mmHg (1 mmHg = 0.133 kPa) and the infrequently changed medication, the use of RDN resulted in a significant reduction in 24-h SBP level at 6 months (P = 0.100 and P = 0.009, respectively). Subgrouping RCTs with a higher prevalent CHD in control showed that the control treatment was significantly better than RDN in office SBP reduction at 6 months (P < 0.001).

Conclusions:

In all patients with RH, the catheter-based RDN is not more effective in lowering ambulatory or office BP than an optimized antihypertensive drug treatment at 6 and 12 months. However, among RH patients with higher baseline SBP, RDN might be more effective in reducing SBP.

Impact of Medication Adherence on the Effect of Renal Denervation

Randomized trials of catheter-based renal denervation (RDN) as therapy for resistant hypertension showed conflicting results in blood pressure (BP) lowering effect. Adherence to medication is modest in this patient group and may importantly drive these conflicting results. SYMPATHY is a prospective open label multicenter trial in Dutch patients with resistant hypertension. Primary outcome was change in daytime systolic ambulatory BP at 6 months. Patients were randomly assigned to RDN on top of usual care. Adherence to BP lowering drugs was assessed at baseline and follow-up, using blood samples drawn synchronously with BP measurements. Patients and physicians were unaware of the adherence assessment. Primary analyses showed a mean difference between RDN (n=95) and control (n=44) in changes in daytime systolic ambulatory BP after 6 months of 2.0 mm Hg (95% confidence interval, −6.1 to 10.2 mm Hg) in favor of control. In 80% of patients, fewer medications were detected than prescribed and adherence changed during follow-up in 31%. In those with stable adherence during follow-up, mean difference between RDN and control for daytime systolic ambulatory BP was −3.3 mm Hg (−13.7 to 7.2 mm Hg) in favor of RDN. RDN as therapy for resistant hypertension was not superior to usual care. Objective assessment of medication use shows that medication adherence is extremely poor, when patients are unaware of monitoring. Changes over time in adherence are common and affect treatment estimates considerably. Objective measurement of medication adherence during follow-up is strongly recommended in randomized trials.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01850901.

Effects of Renal Denervation on Insulin Sensitivity and Inflammatory Markers in Nondiabetic Patients with Treatment-Resistant Hypertension

Increased sympathetic activity is important in the pathogenesis of hypertension and insulin resistance. Afferent signaling from the kidneys elevates the central sympathetic drive. We investigated the effect of catheter-based renal sympathetic denervation (RDN) on glucose metabolism, inflammatory markers, and blood pressure in nondiabetic patients with treatment-resistant hypertension. Eight subjects were included in an open-labelled study. Each patient was studied before and 6 months after RDN. Endogenous glucose production was assessed by a 3-³H glucose tracer, insulin sensitivity was examined by hyperinsulinemic euglycemic clamp, hormones and inflammatory markers were analyzed, and blood pressure was measured by office blood pressure readings and 24-hour ambulatory blood pressure monitoring. Insulin sensitivity (M-value) increased nonsignificantly from 2.68 ± 0.28 to 3.07 ± 0.41 (p = 0.12). A significant inverse correlation between the increase in M-value and BMI 6 months after RDN (p = 0.03) was found, suggesting beneficial effects on leaner subjects. Blood pressure decreased significantly, but there were no changes in hormones, inflammatory markers, or endogenous glucose production. Our results indicate that RDN may improve insulin sensitivity in some patients with treatment-resistant hypertension, albeit confirmation of these indications of beneficial effects on leaner subjects awaits the outcome of larger randomized controlled studies.