Changes in Plasma Renin Activity After Renal Artery Sympathetic Denervation

Long-Term Safety and Efficacy of Renal Denervation: 24-Month Results From the SPYRAL HTN-ON MED Trial

BACKGROUND

Six-month results from the SPYRAL HTN-ON MED trial demonstrated that renal denervation (RDN) reduced office blood pressure (BP), and not 24-hour ambulatory systolic BP, compared with sham control in hypertensive patients. In this prespecified analysis of the ON MED trial, long-term changes in BP, antihypertensive drug use, and safety outcomes through 24 months are compared between RDN and sham control groups.

METHODS

SPYRAL HTN-ON MED is a prospective, randomized, sham-controlled, blinded trial enrolling 337 patients globally from 56 clinical centers. Eligible patients had an office systolic BP of 150 to 180 mm Hg, a diastolic BP ≥90 mm Hg, and a 24-hour ambulatory systolic BP of 140 to 170 mm Hg. Patients were randomized to RDN or a sham control procedure and were prescribed a stable regimen of 1 to 3 antihypertensive medications through 6 months. After 6 months, patients and physicians were unblinded with permitted changes to antihypertensive therapy, and control patients were permitted to crossover. Crossover patients had their last observations carried forward as part of the control group. Statistical analyses were conducted on the population as a randomized.

RESULTS

At 24 months, the RDN group experienced significantly greater mean reductions in ambulatory systolic BP (-12.1±15.3 mm Hg [n=176] versus -7.0±13.1 mm Hg [n=33]; difference: -5.7 mm Hg; P=0.039) and office systolic BP (-17.4±16.1 mm Hg [n=187] versus -9.0±19.4 mm Hg [n=35]; difference: -8.7 mm Hg; P=0.0034) compared with sham controls. At 24 months, antihypertensive medications increased significantly more in the sham group (1.7-2.7) compared with the RDN group (1.8 versus 2.4; P=0.046). Sensitivity analyses accounting for missing sham patient BP values due to crossover yielded consistent results in favor of RDN for 24-hour ambulatory (P=0.023) and office systolic BP (P<0.0001). Clinically adverse events were rare, with no instances of renal artery stenosis through 24 months.

CONCLUSIONS

RDN produced significantly greater ambulatory and office systolic BP reductions at 24 months compared with sham control, despite higher antihypertensive medication use in the control group.

REGISTRATION

URL: https://clinicaltrials.gov/study; unique identifier: NCT02439775.

Renal Denervation: A Review of Current Devices, Techniques, and Evidence

Hypertension is a major contributor to morbidity and mortality in the United States, and its management remains a significant challenge for clinicians. Transcatheter renal denervation targeting sympathetic nervous system overactivity offers an additive benefit to medications for patients with uncontrolled hypertension as well as for patients who are not able or unwilling to be treated with medications. Two devices were recently approved for commercial use that employ radiofrequency ablative and ultrasound energy for renal denervation. Both devices have shown durable treatment effects up to 3 years with minimal device-related safety concerns.

The road to renal denervation for hypertension and beyond (HF): two decades of failed, succeeded, and to be determined

Activation of the sympathetic nervous system has been attributed to the development of hypertension. Two established approaches for treating hypertension are pharmacotherapy and lifestyle changes. With an improved understanding of renal nerve anatomy and physiology, renal denervation has been proposed as an alternative treatment for hypertension. Specifically, it has been shown that the interruption of sympathetic nerves connecting the kidney and the sympathetic nervous system can reduce blood pressure. Here, we present a review on how renal denervation can help hypertension patients, specifically focusing on our novel understanding of renal nerve anatomy, denervation technique, and subsequent clinical trials, and how it may be used to treat other cardiovascular diseases like heart failure.

Predicting blood pressure response to renal denervation based on a new approach

BACKGROUND

Identifying predictors of blood pressure (BP) response to renal denervation (RDN) is crucial for patient selection. According to Wilder's principle, baseline BP predicts BP change after any antihypertensive intervention. Thus, any observed BP change after RDN is the sum of the BP change depending on the baseline BP and the specific BP reduction due to RDN. Based on this concept, we propose a new definition of BP responders.

METHODS

In our center, 148 patients with uncontrolled hypertension underwent RDN, and 24-h ambulatory BP (ABP) was measured at baseline, and 6 months after the procedure. The decrease in 24-h systolic BP (SBP) correlated with baseline SBP ( P  = <0.001, r  = -0.374). We determined the RDN-specific effect by subtracting the predicted SBP decrease from the observed SBP decrease. The cohort was divided into RDN responders, neutral responders, and nonresponders.

RESULTS

Our study population had a mean age of 59 ± 10.4 years and was 74% male. The RDN-specific (residual) 24-h ABP decreased by -14.9 ± 6.3/-8.2 ± 3.8 mmHg (responder group), 1.0 ± 3.2/0.2 ± 1.9 mmHg (neutral group), and 14.2 ± 10.4/8.3 ± 3.9 mmHg (nonresponder group) 6 months after RDN. Responders had fewer antihypertensive medications ( P  = 0.018), higher baseline office heart rate (HR) ( P  = 0.019), higher 24-h ambulatory HR ( P  = 0.003), lower BMI ( P  < 0.038), and absence of type 2 diabetes (T2D) ( P  = 0.020).

CONCLUSION

Our definition of BP responders to RDN separates baseline BP-related changes from RDN-specific changes. Positive predictors for BP response to RDN include low BMI, fewer antihypertensive medications, high baseline office HR, high 24-h ambulatory HR, and absence of T2D.

Long-Term, Patient-Level Analysis of Radiofrequency Renal Denervation in the SYMPLICITY Clinical Trial Program

BACKGROUND

Renal denervation (RDN) lowers blood pressure (BP) in patients with uncontrolled hypertension. Current guidelines recommend RDN for patients with uncontrolled BP despite the use of antihypertensive (AH) medications. Durability of BP reductions and assessment of which patient baseline characteristics correlate with subsequent BP reductions are scarce.

OBJECTIVES

The authors leveraged patient data from the entire SYMPLICITY Clinical program to model long-term BP reductions and assess patient characteristics associated with future BP reductions.

METHODS

Repeated BP measurements from each patient were analyzed using linear mixed models. Models were fitted with office systolic BP (SBP), 24-h ambulatory SBP, office diastolic BP (DBP), and 24-h ambulatory DBP as outcome variables. Baseline BP, baseline number of AH medications, AH medications over time, and other variables were included as fixed effects.

RESULTS

The mixed model included data from 4,155 patients treated with the Symplicity RDN system. The mean age was 60 ± 12 years, 40.4% of whom were female. Estimated, longitudinal office and 24-h ambulatory SBP changes through 36 months, after adjusting for AH medication effects, were biphasic, with a steep reduction after RDN through the first 6 months followed by continuous and steady reductions in office and 24-h SBP and DBP afterward through 36 months. Higher baseline office systolic or 24-h ambulatory SBP were correlated with greater reductions through follow-up in office and 24-h SBP, respectively. Patient characteristics consistent with high sympathetic nerve activity, such as atrial fibrillation and type 2 diabetes, emerged as statistically significant covariates associated with greater office systolic and office and 24-h diastolic BP reductions, respectively.

CONCLUSIONS

Modeling suggested patients have durable BP reductions following RDN, with a steep immediate reduction followed by a steady reduction through 3 years.

Renal denervation for hypertension

Innovative therapies for hypertension are desperately needed given the rising prevalence and falling rates of control of hypertension despite an abundance of available medical therapies. Procedural interventions lower blood pressure without depending on adherence to medications, and endovascular renal denervation (RDN) is the interventional procedure with the best evidence base for the treatment of hypertension. After nearly two decades of study, with major refinements to devices, technique and trial design, two different systems for RDN received approval from the FDA in late 2023 for the treatment of hypertension. These decisions were based on a portfolio of sham-controlled clinical trials demonstrating efficacy and safety of both radiofrequency and ultrasound RDN in treating patients across the spectrum of hypertension, including patients with mild disease taking no or one medication as well as those with moderate and truly resistant hypertension. In this Review, we begin by summarizing the background and scope of the global problem of hypertension control and explore the evolution and mechanism of RDN. We then detail early studies and randomized clinical trials demonstrating the efficacy and safety of RDN procedures, review international statements, and provide practical guidance on patient selection and implementation of RDN, including the crucial aspects of building a hypertension team and of involving patients in shared decision-making.

Novel approaches to define responders to interventional treatment in hypertension: insights from the SPYRAL HTN-OFF and HTN-ON MED trials

Multiple sham-controlled clinical trials have demonstrated significant reductions in both office and 24-h blood pressure (BP) following radiofrequency renal denervation (RDN) in the uncontrolled hypertension population. Notably, the blood pressure response varies widely within individual participants, thus showing a clinical need to identify potential RDN "responders" prior to the procedure. Despite multiple analytic efforts, no single parameter, aside from baseline blood pressure, has been consistently associated with BP reduction following RDN. However, this failure may be due to limitations in empiric definitions of responders. Indeed, commonly applied responder definitions based on the difference between two point-in-time BP measurements are fraught due to visit-to-visit variability in office and 24-h blood pressure endpoints. Several factors should be considered to develop a more clinically useful operational definition of procedural response including relative changes in office and 24-h BP, consideration of the temporal response to RDN, as well as adjustment for baseline BP. The current evidence may provide incentives for future expert consensus to precisely define responders to hypertension treatments.

Response of Blood Pressure to Renal Denervation Is Not Associated With Genetic Variants

BACKGROUND

Renal denervation lowers blood pressure (BP) in patients with uncontrolled hypertension. We conducted an unbiased genomic screen to identify genetic variants that may associate with BP response to renal denervation (RDN).

METHODS

Patients (n=268) with uncontrolled resistant hypertension (baseline BP, 166±21/90±15 mm Hg) who underwent endovascular RDN using the Symplicity catheter (Medtronic, Inc, Santa Rosa, CA) were included. Reduction in 24-hour ambulatory systolic BP was assessed at 6 months and divided into 2 groups: above and below the median response of 6.0 mm Hg, taking preintervention 24-hour ambulatory BP and regression to the mean into account. Whole exome sequencing assessing 249 669 variants, was conducted using Illumina NovaSeq technology read on a NovaSeq S4 Flow Cell device.

RESULTS

We did not identify individual gene variants associated with BP response following RDN. These findings were confirmed after adjustment for sex and in a sensitivity analysis looking at tertiles of BP response. We also explored specific variants in AGT, ADD1, ADRB1, ADRB2, and SCNN1A that have been proposed as potential candidate genes for response and found no association (all P>0.13). Gene ontology analysis of variants across the 2 responder groups highlighted differences in biologic processes such as cell adhesion and molecular function such as protein tyrosine kinase activity.

CONCLUSIONS

The response to RDN, in terms of 24-hour BP reduction, was not associated with the genetic profile of patients with resistant hypertension. These data do not support the use of a genetic score to identify potential responders to RDN.

Renal nerves in physiology, pathophysiology and interoception

Sympathetic efferent renal nerves have key roles in the regulation of kidney function and blood pressure. Increased renal sympathetic nerve activity is thought to contribute to hypertension by promoting renal sodium retention, renin release and renal vasoconstriction. This hypothesis led to the development of catheter-based renal denervation (RDN) for the treatment of hypertension. Two RDN devices that ablate both efferent and afferent renal nerves received FDA approval for this indication in 2023. However, in animal models, selective ablation of afferent renal nerves resulted in comparable anti-hypertensive effects to ablation of efferent and afferent renal nerves and was associated with a reduction in sympathetic nerve activity. Selective afferent RDN also improved kidney function in a chronic kidney disease model. Notably, the beneficial effects of RDN extend beyond hypertension and chronic kidney disease to other clinical conditions that are associated with elevated sympathetic nerve activity, including heart failure and arrhythmia. These findings suggest that the kidney is an interoceptive organ, as increased renal sensory nerve activity modulates sympathetic activity to other organs. Future studies are needed to translate this knowledge into novel therapies for the treatment of hypertension and other cardiorenal diseases.

Aspects of renal function and renal artery anatomy as indications for renal denervation

Renal denervation (RDN) is a minimally invasive, endovascular catheter-based procedure using radiofrequency, ultrasound, or alcohol-mediated ablation to treat resistant hypertension. As more attention is focused on the renal sympathetic nerve as a cause and treatment target of hypertension, understanding the anatomy of the renal artery may have important implications for determining endovascular treatment strategies as well as for future selection of devices and appropriate candidates for RDN treatment. However, the anatomical structure of the renal artery (RA) is complex, and standardized morphological evaluations of the RA structure are lacking. Computed tomography angiography or magnetic resonance angiography imaging is useful for assessing RA anatomy before conducting RDN. RA echocardiography is an established noninvasive screening method for significant stenosis. Major randomized controlled trials have limited enrollment to patients with preserved renal function, usually defined as an estimated glomerular filtration rate (eGFR) ≥ 45 mL/min/1.73 m2. Therefore, the level of renal function at which RDN is indicated has not yet been determined. This mini-review summarizes the characteristics of renal artery anatomy and renal function that constitute indications for renal denervation. (Role of Clinical Trials: K. Kario is an Executive Committee Principal Investigator for the Spyral OFF MED, the Spyral ON MED, the DUO and the REQUIRE; a Coordinating investigator for the TCD-16164 study; a Site Principal Investigator for the HTN-J, the Spyral OFF MED, the Spyral ON MED, the DUO, the REQUIRE and the TCD-16164 study). Evaluation of renal arteries for radiofrequency renal denervation. A Simultaneous quadrantal ablations at four sites in the main renal artery or the equivalent renal artery to the main renal artery. B If there is a renal artery branch with a diameter >3 mm in the middle of the main renal artery, this branch is the distal end of the main renal artery. In this case, four simultaneous and quadrantal ablations can be performed on the equivalent renal arteries. C Four simultaneous and quadrantal ablations can be performed in the branch renal artery. D Sonication should be spaced at least 5 mm (one transducer*) apart. Perform 2 to 3 mm proximal to the arterial bifurcation. Perform 2 to 3 mm distal to the abdominal aortic inlet.

Effects of renal denervation on the kidney: albuminuria, proteinuria, and renal function

Renal denervation has attracted attention as a novel antihypertensive treatment for hypertensive patients who are poorly controlled by medicine. Clinical studies have shown the antihypertensive effects of renal denervation in patients with treatment-resistant hypertension. However, renal denervation potentially has other beneficial effects, such as improving glucose metabolism and cardioprotection beyond its antihypertensive effects. In this mini-review article, we summarize and discuss the effects of renal denervation on proteinuria, albuminuria, and renal function based on the recent findings of clinical studies, and review the renoprotective effects of renal denervation.

Comparison of the effects of renal denervation at early or advanced stages of hypertension on cardiac, renal, and adipose tissue pathology in Dahl salt-sensitive rats

Renal denervation (RDN) has emerged as a novel therapy for drug-resistant hypertension. We here examined the effects of RDN at early versus advanced stages of hypertension on blood pressure and organ pathology in rats with salt-sensitive hypertension. Dahl salt-sensitive (DahlS) rats fed an 8% NaCl diet from 6 weeks of age were subjected to RDN (surgical ablation and application of 10% phenol in ethanol) or sham surgery at 7 (early stage) or 9 (advanced stage) weeks and were studied at 12 weeks. RDN at early or advanced stages resulted in a moderate lowering of blood pressure. Although RDN at neither stage affected left ventricular (LV) and cardiomyocyte hypertrophy, it ameliorated LV diastolic dysfunction, fibrosis, and inflammation at both stages. Intervention at both stages also attenuated renal injury as well as downregulated the expression of angiotensinogen and angiotensin-converting enzyme (ACE) genes and angiotensin II type 1 receptor protein in the kidney. Furthermore, RDN at both stages inhibited proinflammatory gene expression in adipose tissue. The early intervention reduced both visceral fat mass and adipocyte size in association with downregulation of angiotensinogen and ACE gene expression. In contrast, the late intervention increased fat mass without affecting adipocyte size as well as attenuated angiotensinogen and ACE gene expression. Our results thus indicate that RDN at early or late stages after salt loading moderately alleviated hypertension and substantially ameliorated cardiac and renal injury and adipose tissue inflammation in DahlS rats. They also suggest that cross talk among the kidney, cardiovascular system, and adipose tissue may contribute to salt-sensitive hypertension. Supposed mechanism for the beneficial effects of RDN on hypertension and target organ damage in DahlS rats. RDN at early or late stages after salt loading moderately alleviated hypertension and substantially ameliorated renal injury in DahlS rats. Cross talk among the kidney, cardiovascular system, and adipose tissue possibly mediated by circulating RAS may contribute to salt-sensitive hypertension. LV; left ventricular, NE; norepinephrine, RAS; renin-angiotensin system, RDN; renal denervation.

Impact of renal denervation on quality of life (How does renal denervation contribute to improving hypertension treatment affected by poor medication adherence?)

The US Food and Drug Administration has approved renal denervation (RDN) as a new treatment option for hypertension (HT) because it not only has antihypertensive effects but also improves the quality of blood pressure (BP) reduction. RDN is expected to be increasingly used in clinical practice in the future. This review summarizes the impact of RDN on quality of life (QOL). Although the treatment of HT aims to improve life prognosis, the use of antihypertensive agents can impair QOL because of adverse effects and lifestyle changes associated with long-term medication use. Consequently, poor adherence to antihypertensive agents is a common problem and may be the most important issue affecting patient QOL. In RDN trials in patients taking antihypertensive agents, approximately 40% of patients had poor adherence to the drugs. Poor adherence is often the cause of resistant hypertension. Therefore, RDN should be well suited to treating HT and improving QOL. Studies have shown that approximately 30% of HT patients prefer RDN to drug treatment. Patients who prefer RDN are typically male and younger and have high BP, poor adherence, and a history of adverse effects of antihypertensive agents. We hope that RDN will improve not only life prognosis but also QOL in HT patients because of its benefits for adherence. Furthermore, we expect that in the future, RDN will be used in other sympathetic nervous system-related diseases, such as heart failure, atrial fibrillation, and sleep apnea syndrome.

Renal Denervation for the Treatment of Hypertension: A Scientific Statement From the American Heart Association

Hypertension is a leading risk factor for cardiovascular morbidity and mortality. Despite the widespread availability of both pharmacological and lifestyle therapeutic options, blood pressure control rates across the globe are worsening. In fact, only 23% of individuals with high blood pressure in the United States achieve treatment goals. In 2023, the US Food and Drug Administration approved renal denervation, a catheter-based procedure that ablates the renal sympathetic nerves, as an adjunctive treatment for patients in whom lifestyle modifications and antihypertensive medications do not adequately control blood pressure. This approval followed the publication of multiple randomized clinical studies using rigorous trial designs, all incorporating renal angiogram as the sham control. Most but not all of the new generation of trials reached their primary end point, demonstrating modest efficacy of renal denervation in lowering blood pressure across a spectrum of hypertension, from mild to truly resistant. Individual patient responses vary, and further research is needed to identify those who may benefit most. The initial safety profile appears favorable, and multiple ongoing studies are assessing longer-term efficacy and safety. Multidisciplinary teams that include hypertension specialists and adequately trained proceduralists are crucial to ensure that referrals are made appropriately with full consideration of the potential risks and benefits. Incorporating patient preferences and engaging in shared decision-making conversations will help patients make the best decisions given their individual circumstances. Although further research is clearly needed, renal denervation presents a novel treatment strategy for patients with uncontrolled blood pressure.

Renal sympathetic denervation 2024 in Austria: recommendations from the Austrian Society of Hypertension : Endorsed by the Austrian Society of Nephrology and the Working Group of Interventional Cardiology of the Austrian Society of Cardiology

Renal sympathetic denervation (RDN) is an interventional supplement to medical treatment in patients with arterial hypertension. While the first sham-controlled trial, SYMPLICITY HTN‑3 was neutral, with improved procedural details, patient selection and follow-up, recent randomized sham-controlled trials of second-generation devices show a consistent blood pressure lowering effect of RDN, as compared to sham controls. These new data and the recent U.S. Food and Drug Administration (FDA) premarket approval of two RDN devices are the basis for the present recommendations update.This joint position paper from the Austrian Society of Hypertension, together with the Austrian Society of Nephrology and the Working Group of Interventional Cardiology from the Austrian Society of Cardiology includes an overview about the available evidence on RDN and gives specific recommendations for the work-up, patient selection, pretreatment, procedural management and follow-up in patients undergoing RDN in Austria. Specifically, RDN may be used in clinical routine care, together with lifestyle measures and antihypertensive drugs, in patients with resistant hypertension (i.e. uncontrolled blood pressure on 3 antihypertensive drugs) and in those with uncontrolled hypertension, after adequate work-up, if institutional, patient-related and procedural conditions are fulfilled.

Italian Society of Interventional Cardiology (GISE) and Italian Society of Arterial Hypertension (SIIA) Position Paper on the role of renal denervation in the management of the difficult-to-treat hypertension

Renal denervation (RDN) is a safe and effective strategy for the treatment of difficult to treat hypertension. The blood pressure (BP)-lowering efficacy of RDN is comparable to those of many single antihypertensive medications and it allows to consider the RDN as a valuable option for the treatment of difficult to treat hypertension together with lifestyle modifications and medical therapy. A multidisciplinary team is of pivotal importance from the selection of the patient candidate for the procedure to the post-procedural management. Further studies are needed to investigate the effect of RDN on clinical outcomes and to better identify the predictors of BP response to RDN in order to recognize the patients who are more likely to benefit from the procedure.

Effects of Renal Denervation on Ouabain-Induced Hypertension in Rats

Background

Ouabain, a Na+, K+-ATPase inhibitor, is elevated in hypertensive patients. Evidence suggests ouabain contributes to hypertension mainly through activation of the sympathetic nervous system (SNS). Renal nerves play a vital role in the regulation of SNS activity, so we hypothesize that renal denervation may attenuate the development of ouabain-induced hypertension.

Methods and Results

Forty Sprague-Dawley rats were divided into following groups (n = 10 each): control group (sham surgery plus intraperitoneal saline injection), RDN group (renal denervation (RDN) plus intraperitoneal saline injection), ouabain group (sham surgery plus intraperitoneal ouabain injection), and ouabain + RDN group (RDN plus intraperitoneal ouabain injection). After eight weeks, compared with the control group, rats in the ouabain group exhibited elevated blood pressure (P < 0.05), increased plasma epinephrine, norepinephrine, angiotensin II, and aldosterone levels (P < 0.05). These indexes could be significantly ameliorated by RDN. RDN also reduced the thickening of aortic tunica media and downregulated the expression of proliferating cell nuclear antigen (PCNA) in the thoracic aorta induced by ouabain. Masson staining and echocardiography showed that myocardial fibrosis and increased left ventricular mass in the ouabain group could be attenuated by RDN.

Conclusions

The present study reveals that renal nerves play an important role in the development of ouabain-induced hypertension. RDN could inhibit the pressor effect and the myocardial remodeling induced by ouabain potentially via inhibiting catecholamine release and vascular smooth muscle cell proliferation. Clinical studies are needed to explore whether RDN may exhibit better antihypertensive effects on hypertensive patients with high plasma ouabain levels as compared to those with normal plasma ouabain levels.

Bilateral Nephrectomy for Resistant Hypertension and Secondary Aldosteronism in a Hemodialysis Patient: A Case Report

A 42-year-old Japanese woman with end-stage renal failure due to hypertension presented with a systolic blood pressure of 160-200 mmHg despite treatment with 4 different antihypertensive agents. The plasma aldosterone concentration (PAC) and plasma renin activity (PRA) were elevated. Adrenal vein sampling suggested bilateral excessive aldosterone secretion, whereas adrenocortical scintigraphy showed right-dominant accumulation. Open bilateral nephrectomy and right adrenalectomy improved the systolic blood pressure, PAC, and PRA. A pathological examination revealed zona glomerulosa hyperplasia but not microaldosteronoma. This report shows that bilateral nephrectomy, not unilateral adrenalectomy, is a potentially effective treatment option for resistant hypertension with an elevated renin-angiotensin-aldosterone system in hemodialysis patients.

Ten-year follow-up of very-high risk hypertensive patients undergoing renal sympathetic denervation

OBJECTIVES

Renal denervation (RDN) has been proven to be effective in lowering blood pressure (BP) in patients, but previous studies have had short follow-ups and have not examined the effects of RDN on major cardiovascular outcomes. This study aimed to demonstrate the effectiveness and safety of RDN in the long-term treatment of hypertension and to determine if it has an effect on cardiovascular outcomes.

METHODS

All patients with resistant hypertension who underwent RDN between 2011 and 2015 at Tianjin First Central Hospital were included in the study. Patients were followed up at 1,5 and 10 years and the longest follow-up was 12 years. Data were collected on office BP, home BP, ambulatory BP monitoring (ABPM), renal function, antihypertensive drug regimen, major adverse events (including acute myocardial infarction, stroke, cardiovascular death and all cause death) and safety events.

RESULTS

A total of 60 participants with mean age 50.37 ± 15.19 years (43.33% female individuals) completed long-term follow-up investigations with a mean of 10.02 ± 1.72 years post-RDN. Baseline office SBP and DBP were 179.08 ± 22.05 and 101.17 ± 16.57 mmHg under a mean number of 4.22 ± 1.09 defined daily doses (DDD), with a reduction of -35.93/-14.76 mmHg as compared with baseline estimates ( P  < 0.0001). Compared with baseline, ambulatory SBP and DBP after 10-years follow-up were reduced by 14.31 ± 10.18 ( P  < 0.001) and 9 ± 4.35 ( P  < 0.001) mmHg, respectively. In comparison to baseline, participants were taking fewer antihypertensive medications ( P  < 0.001), and their mean heart rate had decreased ( P  < 0.001). Changes in renal function, as assessed by estimated glomerular filtration rate (eGFR) and creatinine, were within the expected rate of age-related decline. No major adverse events related to the RDN procedure were observed in long-term consequences. All-cause mortality and cardiovascular mortality rates were 10 and 8.34%, respectively, for the 10-year period.

CONCLUSION

The BP-lowering effect of RDN was safely sustained for at least 10 years post-procedure. More importantly, to the best of my knowledge, this is the first study to explore cardiovascular and all-cause mortality at 10 years after RDN.

Salt sensitivity risk derived from nocturnal dipping and 24-h heart rate predicts long-term blood pressure reduction following renal denervation

BACKGROUND

Renal denervation (RDN) has been consistently shown in recent sham-controlled clinical trials to reduce blood pressure (BP). Salt sensitivity is a critical factor in hypertension pathogenesis, but cumbersome to assess by gold-standard methodology. Twenty-four-hour average heart rate (HR) and mean arterial pressure (MAP) dipping, taken by ambulatory blood pressure monitoring (ABPM), stratifies patients into high, moderate, and low salt sensitivity index (SSI) risk categories.

OBJECTIVES

We aimed to assess whether ABPM-derived SSI risk could predict the systolic blood pressure reduction at long-term follow-up in a real-world RDN patient cohort.

METHODS

Sixty participants had repeat ABPM as part of a renal denervation long-term follow-up. Average time since RDN was 8.9 ± 1.2 years. Based on baseline ABPM, participants were stratified into low (HR < 70 bpm and MAP dipping > 10%), moderate (HR ≥70 bpm or MAP dipping ≤ 10%), and high (HR ≥ 70 bpm and MAP dipping ≤ 10%) SSI risk groups, respectively.

RESULTS

One-way ANOVA indicated a significant treatment effect ( P  = 0.03) between low ( n  = 15), moderate ( n  = 35), and high ( n  = 10) SSI risk with systolic BP reduction of 9.6 ± 3.7 mmHg, 8.4 ± 3.5 mmHg, and 28.2 ± 9.6 mmHg, respectively. Baseline BP was not significantly different between SSI Risk groups ( P  = 0.18). High SSI risk independently correlated with systolic BP reduction ( P  = 0.02).

CONCLUSIONS

Our investigation indicates that SSI risk may be a simple and accessible measure for predicting the BP response to RDN. However, the influence of pharmacological therapy on these participants is an important extraneous variable requiring testing in prospective or drug naive RDN cohorts.

Neuromodulation interventions in the management of heart failure

Despite remarkable improvements in the management of heart failure (HF), HF remains one of the most rapidly growing cardiovascular condition resulting in a substantial burden on healthcare systems worldwide. In clinical practice, however, a relevant proportion of patients are treated with suboptimal combinations and doses lower than those recommended in the current guidelines. Against this background, it remains important to identify new targets and investigate additional therapeutic options to alleviate symptoms and potentially improve prognosis in HF. Therefore, non-pharmacological interventions targeting autonomic imbalance in HF have been evaluated. This paper aims to review the physiology, available clinical data, and potential therapeutic role of device-based neuromodulation in HF.

Mechanisms and treatment of obesity-related hypertension-Part 1: Mechanisms

The prevalence of obesity has tripled over the past five decades. Obesity, especially visceral obesity, is closely related to hypertension, increasing the risk of primary (essential) hypertension by 65%-75%. Hypertension is a major risk factor for cardiovascular disease, the leading cause of death worldwide, and its prevalence is rapidly increasing following the pandemic rise in obesity. Although the causal relationship between obesity and high blood pressure (BP) is well established, the detailed mechanisms for such association are still under research. For more than 30 years sympathetic nervous system (SNS) and kidney sodium reabsorption activation, secondary to insulin resistance and compensatory hyperinsulinemia, have been considered as primary mediators of elevated BP in obesity. However, experimental and clinical data show that severe insulin resistance and hyperinsulinemia can occur in the absence of elevated BP, challenging the causal relationship between insulin resistance and hyperinsulinemia as the key factor linking obesity to hypertension. The purpose of Part 1 of this review is to summarize the available data on recently emerging mechanisms believed to contribute to obesity-related hypertension through increased sodium reabsorption and volume expansion, such as: physical compression of the kidney by perirenal/intrarenal fat and overactivation of the systemic/renal SNS and the renin-angiotensin-aldosterone system. The role of hyperleptinemia, impaired chemoreceptor and baroreceptor reflexes, and increased perivascular fat is also discussed. Specifically targeting these mechanisms may pave the way for a new therapeutic intervention in the treatment of obesity-related hypertension in the context of 'precision medicine' principles, which will be discussed in Part 2.

Effects of renal denervation on kidney function in patients with chronic kidney disease: a systematic review and meta-analysis

The present study aims to evaluate the clinical outcomes following renal denervation (RDN) for hypertensive patients with chronic kidney disease (CKD). Prospective studies published between January 1, 2010 and November 15, 2022 where systematically identified for RDN outcomes on office and ambulatory blood pressure, estimated glomerular filtration rate (eGFR), creatinine and procedural characteristics from three online databases (Medline, PubMed, EMBASE). Random effects model to combine risk ratios and mean differences was used. Where possible, clinical outcomes were pooled and analyzed at 6, 12 and 24 months. Significance was set at p ≤ 0.05. 11 prospective trials, with a total of 226 patients with treatment resistant HTN receiving RDN met the inclusion criteria. Age ranged from 42.5 ± 13.8 to 66 ± 9. Main findings of this review included a reduction in systolic and diastolic office blood pressure at 6 [-19.8 (p < 0.00001)/-15.2 mm Hg (p < 0.00001)] and 12 months [-21.2 (p < 0.00001)/-9.86 mm Hg (p < 0.0005)] follow-up compared to baseline. This was also seen in systolic and diastolic 24-hour ambulatory blood pressure at 6 [-9.77 (p = 0.05)/-3.64 mm Hg (p = 0.09)] and 12 months [-13.42 (p = 0.0007)/-6.30 mm Hg (p = 0.001)] follow-up compared to baseline. The reduction in systolic and diastolic 24-hour ambulatory blood pressure was maintained to 24 months [(-16.30 (p = 0.0002)/-6.84 mm Hg (p = 0.0010)]. Analysis of kidney function through eGFR demonstrated non-significant results at 6 (+1.60 mL/min/1.73 m2, p = 0.55), 12 (+5.27 mL/min/1.73 m2, p = 0.17), and 24 months (+7.19 mL/min/1.73 m2, p = 0.36) suggesting an interruption in natural CKD progression. Similar results were seen in analysis of serum creatinine at 6 (+0.120 mg/dL, p = 0.41), 12 (+0.100 mg/dL, p = 0.70), and 24 months (+0.07 mg/dL, p = 0.88). Assessment of procedural complications deemed RDN in a CKD cohort to be safe with an overall complication rate of 4.86%. With the current advances in RDN and its utility in multiple chronic diseases beyond hypertension, the current study summarizes critical findings that further substantiate the literature regarding the potential of such an intervention to be incorporated as an effective treatment for resistant hypertension and CKD.

Renal Denervation in the Treatment of Resistant Hypertension and Difficult-to-Control Hypertension - Consensus Document of the Croatian Hypertension League - Croatian Society of Hypertension, Croatian Cardiac Society, Croatian Endovascular Initiative, Croatian Society for Diabetes and Metabolic Diseases, Croatian Renal Association, and Croatian Society of Family Physicians of the Croatian Medical Association

Renal denervation (RDN) as a method of treating arterial hypertension (AH) was introduced in Croatia in 2012. A multidisciplinary team and a network of hospitals that diagnose and treat patients with severe forms of AH were established, and a very strict diagnostic-treatment algorithm was prepared. At monthly meetings patients with truly resistant hypertension who were candidates for RDN were discussed. According to the 2021 ESH position statement and 2023 ESH guidelines, RDN is considered an alternative and additional, not a competitive method of treating patients with various forms of AH which must be performed by following a structured procedure and the patient's preference should be considered. In view of the changes in the global scientific community, the Croatian Hypertension League brings this consensus document on RDN conducted with radiofrequency-based catheter, the only currently available method in Croatia. In this document, exclusion and inclusion criteria are shown, as well as three groups of patients in whom RDN could be considered. The new diagnostic-treatment algorithm is prepared and follow-up procedure is explained. In Croatia, RDN is reimbursed by the national insurance company, thus pharmacoeconomic analyses is also shown. Criteria required by an individual centre to be approved of RDN are listed, and plans for prospective research on RDN in Croatia, including the Croatian registry for RDN, are discussed.

Current problems in renal denervation and a hope to break the stage

Renal denervation (RDN) is currently confronted with the considerable heterogeneity of different post-procedural blood pressure responses. The challenges predominantly arise from not only the lack of selection of appropriate responders but also the absence of detection for the successful endpoints of intervention. In this paper, we summarize the significant characteristics of potentially appropriate hypertensive patients and propose a hopeful way to improve the accuracy of RDN, that is, the application of three-dimensional reconstruction technology combined with electrical renal nerve stimulation to guide the radiofrequency catheter ablation, which may promote the development of selective and accurate RDN in real-world clinical practice. This paper focuses on two current critical concerns of renal denervation (RDN): appropriate patient selection and the improvement in the accuracy of selective RDN. A hopeful way of accurate RDN may be the combination of 3D electroanatomic mapping systems for the renal artery with modified renal nerve stimulation (RNS) techniques and technology for appropriate hypertensive candidates.

Histological examination of renal nerve distribution, density, and function in humans

BACKGROUND

Renal denervation is optimised when guided by knowledge of nerve distribution.

AIMS

We aimed to assess sympathetic nerve distribution along the renal arteries, especially in post-bifurcation vessel segments.

METHODS

Renal arteries and surrounding tissue from 10 body donors were collected and examined histologically. Immunohistochemical staining was used to analyse nerve distribution and to identify afferent and efferent sympathetic nerves.

RESULTS

A total of 6,781 nerves surrounding 18 renal arteries were evaluated. The mean lumen-nerve distance of the left renal artery (2.32±1.95 mm) was slightly greater than the right (2.29±2.03 mm; p=0.161); this varied across the arteries' courses: 3.7±2.3 mm in proximal segments, 2.5±2.0 mm in middle segments, 1.9±1.6 mm in distal prebifurcation segments and 1.3±1.0 mm in post-bifurcation segments (p<0.001). The number of nerves per quadrant was highest in the proximal segments (13.7±18.6), followed by the middle (9.7±7.9), distal prebifurcation (8.0±7.6), and distal post-bifurcation (4.3±4.0) segments (p<0.001). Circumferentially, the number of nerves was highest in the superior (7.8±9.4) and the ventral (7.6±13.1) quadrants (p=0.638). The mean tyrosine hydroxylase (TH) to calcitonin gene-related peptide (CGRP) ratio increased from proximal (37.5±33.5) to distal (72.0±7.2 in the post-bifurcation segments; p<0.001). Thirty-eight neuroganglia were identified along 14 (78%) renal arteries.

CONCLUSIONS

Nerves converge to the renal arteries' lumen in the distal segments and along branches, resulting in the lowest number of nerves per quadrant and the shortest lumen-nerve distance in the distal post-bifurcation segments. Efferent nerves occur predominantly, and the ratio of efferent to afferent nerves continues to increase in the vessels' course.

Controversies in Hypertension IV: Renal Denervation

Renal denervation is not a cure for hypertension. Although more recent sham-controlled trials were positive, a significant minority of patients in each trial were unresponsive. The optimal patient or patients need to be defined. Combined systolic/diastolic hypertension appears more responsive than isolated systolic hypertension. It remains uncertain whether patients with comorbidities associated with higher adrenergic tone should be targeted, including obesity, diabetes, sleep apnea, and chronic kidney disease. No biomarker can adequately predict response. A key to a successful response is the adequacy of denervation, which currently cannot be assessed in real time. It is uncertain what is the optimal denervation methodology: radiofrequency, ultrasound, or ethanol injection. Radiofrequency requires targeting the distal main renal artery plus major branches and accessory arteries. Although denervation appears to be safe, conclusive data on quality of life, improved target organ damage, and reduced cardiovascular events/mortality are required before denervation can be generally recommended.

Renal Denervation as a Complementary Treatment Option for Uncontrolled Arterial Hypertension: A Situation Assessment

Uncontrolled arterial hypertension is a major global health issue. Catheter-based renal denervation has shown to lower blood pressure in sham-controlled trials and represents a device-based, complementary treatment option for hypertension. In this situation assessment, the authors, who are practicing experts in hypertension, nephrology, general practice and cardiology in the Republic of Ireland, discuss the current evidence base for the BP-lowering efficacy and safety of catheter-based renal denervation with different modalities. Although important questions remain regarding the identification of responders, and long-term efficacy and safety of the intervention, renal denervation has the potential to provide much-needed help to address hypertension and its adverse consequences. The therapeutic approach needs to be multidisciplinary and personalised to take into account the perspective of patients and healthcare professionals in a shared decision-making process.

Radio frequency-based renal denervation: a story of simplicity?

Radio frequency-based renal denervation is a safe and effective way of lowering blood pressure, a common condition associated with high cardiovascular risk. Several catheters have been developed to administer energy to the renal arteries and their side branches, thereby modulating sympathetic renal activity. The Symplicity Flex™ and Symplicity Spyral™ are first- and second-generation devices, respectively, for radio frequency-based renal denervation. There is a continuous need to further improve and adjust interventional antihypertensive therapies. Several randomized controlled trials have been conducted to investigate the safety and efficacy of these catheters and most were able to show radio frequency-based renal denervation to be feasible, safe and effective in lowering blood pressure in hypertensive patients with and without concomitant antihypertensive medication. Herein, the authors discuss the pathophysiologic concepts of renal denervation and its procedural approaches, report catheter designs, summarize clinical trials outcomes and, finally, discuss real-world evidence.

Efficacy of Antihypertensive Drugs of Different Classes After Renal Denervation in Spontaneously Hypertensive Rats

BACKGROUND

Renal denervation (RDN) lowers blood pressure (BP) in patients with uncontrolled hypertension. Limited data exist on the effectiveness of different antihypertensive medications following RDN on BP and maladaptive cardiac phenotypes.

METHODS

Eighty-nine male spontaneously hypertensive rats with continuous BP recording underwent RDN or sham operation. Ten days postsurgery, spontaneously hypertensive rats were randomized to receive no antihypertensive medication, amlodipine, olmesartan, hydrochlorothiazide, bisoprolol, doxazosin, or moxonidine for 28 days. Cardiac remodeling was determined histologically, and activation of the renin-angiotensin-aldosterone system was explored.

RESULTS

Before initiation of antihypertensive drugs, RDN reduced mean arterial pressure (-12.6 mm Hg [95% CI, -14.4 to -10.8]; P<0.001). At study end, mean arterial pressure was lower in RDN compared with sham operation in drug-naïve controls (P=0.006), olmesartan (P=0.002), amlodipine (P=0.0004), hydrochlorothiazide (P=0.006), doxazosin (P=0.001), and bisoprolol (P=0.039) but not in animals receiving moxonidine (P=0.122). Compared with pooled BP change of all other drug classes, mean arterial pressure change was largest for olmesartan (-15.9 mm Hg [95% CI, -18.6 to -13.2]; P<0.001) and amlodipine (-12.0 mm Hg [95% CI, -14.7 to -9.3]; P<0.001). In drug-naïve controls, RDN reduced plasma renin activity (-5.6%¸ P=0.03) and aldosterone concentration (-53.0%; P=0.005). In the presence of antihypertensive medication, plasma renin activity and aldosterone remained unchanged after RDN. Cardiac remodeling was not affected by RDN alone. In animals receiving olmesartan after RDN, cardiac perivascular fibrosis was attenuated. Amlodipine and bisoprolol following RDN reduced cardiomyocyte diameter.

CONCLUSIONS

Following RDN, treatment with amlodipine and olmesartan resulted in the largest BP reduction. Antihypertensive medications mediated heterogeneous effects on renin-angiotensin-aldosterone system activity and cardiac remodeling.

Renal Denervation: A Practical Guide for Health Professionals Managing Hypertension

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

Effects of Renal Denervation on Sympathetic Nerve Traffic and Correlates in Drug-Resistant and Uncontrolled Hypertension: A Systematic Review and Meta-Analysis

BACKGROUND

Whether and to what extent the reported blood pressure (BP) lowering effects of renal denervation (RDN) are associated with a central sympathoinhibition is controversial. We examined this issue by performing a meta-analysis of the microneurographic studies evaluating the BP and muscle sympathetic nerve activity (MSNA) responses to RDN in drug-resistant or uncontrolled hypertension (RHT).

METHODS

This analysis comprised 11 studies including a total of >400 RHT patients undergoing RDN and were followed up for 6 months. Evaluation was extended to the relationships of MSNA with clinic heart rate and BP changes associated with RDN.

RESULTS

MSNA showed a significant reduction after RDN (-4.78 bursts/100 heart beats; P<0.04), which was also accompanied by a significant systolic (-11.45 mm Hg; P<0.002) and diastolic (-5.24 mm Hg; P=0.0001) BP decrease. No significant quantitative relationship was found between MSNA and systolic (r=-0.96, P=0.19) or diastolic BP (r=-0.97, P=0.23) responses to RDN. This was also the case for clinic heart rate (r=0.53, P=0.78, respectively), whose post RDN values were not significant different from the pre-RDN ones. More than 10 renal nerves ablations were found to be needed for obtaining a significant sympathoinhibition.

CONCLUSIONS

This meta-analysis, the first ever done on the MSNA responses to RDN, shows that in a consistent number of RHT patients RDN is associated with a significant, although modest, central sympathoinhibition, which appears to be unrelated to the BP lowering effects of the procedure. Thus factors other than the central sympathetic outflow inhibition may concur at the BP lowering effects of RDN.

Disparate Clinical Characteristics and Prognosis of HFpEF versus HFrEF Phenotype of Diabetic Cardiomyopathy

AIMS

Diabetic cardiomyopathy (DCM) is an ill-defined entity. This study aims to explore the clinical characteristics and prognosis of diabetic patients that disparately develop heart failure (HF) with preserved ejection fraction (HFpEF) other than HF with reduced ejection fraction (HFrEF).

PATIENTS AND METHODS

A total of 911 patients diagnosed with diabetes mellitus were identified in the ChiHFpEF cohort (NCT05278026). DCM was defined as diabetic patients diagnosed with HF, absent from flow obstructive coronary artery disease (CAD), uncontrolled refractory hypertension and hemodynamics significant heart valvular diseases, arrhythmia and congenital heart diseases. The primary endpoint was a composite of all-cause death and rehospitalization due to HF.

RESULTS

As compared to DCM-HFrEF patients, DCM-HFpEF patients had a longer duration of diabetes, were older and more noticeable in hypertension and non-obstructive CAD. After a median follow-up of 45.5 months, survival analysis showed that DCM-HFpEF patients had a better composite endpoint. Cox regression implicated that non-obstructive CAD was a negative (HR 0.101, 95% CI 0.028-0.373, p = 0.001) predictor for the composite endpoint of DCM-HFrEF patients. Age was a positive predictor for the composite endpoint of DCM-HFpEF patients (HR 1.044, 95% CI 1.007-1.082, p = 0.018).

CONCLUSION

DCM-HFpEF is a disparate entity from DCM-HFrEF. Additional phenomic studies are needed to explore the molecular mechanisms and develop targeted therapies.

The intrarenal blood pressure modulation system is differentially altered after renal denervation guided by different intensities of blood pressure responses

The aim of this study was to investigate alterations in the intrarenal blood pressure (BP) regulation system after renal denervation (RDN) guided by renal nerve stimulation (RNS). Twenty-one dogs were randomized to receive RDN at strong (SRA group, n = 7) or weak (WRA group, n = 7) BP-elevation response sites identified by RNS or underwent RNS only (RNS-control, RSC, n = 7). After 4 weeks of follow-up, renal sympathetic components, the main components of renin-angiotensin system (RAS) and the major transporters involved in sodium and water reabsorption were assessed by immunohistochemical analysis. Compared with RSC treatment, RDN therapy significantly reduced renal norepinephrine and tyrosine hydroxylase levels, decreased the renin content and inhibited the onsite generation of angiotensinogen. Moreover, the expression of exciting axis components, including angiotensin-converting enzyme (ACE), angiotensin II and angiotensin II type-1 receptor, was downregulated, while protective axis components for the cardiovascular system, including ACE2 and Mas receptors, were upregulated in both WRA and SRA groups. Moreover, RDN reduced the abundance of aquaporin-1 and aquaporin-2 in kidneys. Although RDN had a minimal effect on overall NKCC2 expression, its activation (p-NKCC2) and directional enrichment in the apical membrane (mNKCC2) were dramatically blunted. All these changes were more obvious in the SRA group than WRA group. Selective RDN guided by RNS effectively reduced systemic BP by affecting the renal neurohormone system, as well as the sodium and water transporter system, and these effects at sites with a strong BP response were more superior.

Differential effects of renal denervation on skin and muscle sympathetic nerve traffic in resistant and uncontrolled hypertension

PURPOSE

Renal denervation (RDN) exerts sympathoinhibitory effects. No information is available, however, on whether these effects have a regional or a more generalized behavior.

METHODS

In 14 patients with resistant hypertension (RHT, age 58.3 ± 2.2 years, mean ± SEM), we recorded muscle and skin sympathetic nerve traffic (MSNA and SSNA, respectively) using the microneurographic technique, before, 1 month, and 3 months after RDN. Measurements included clinic blood pressure (BP), heart rate (HR), 24-h BP and HR, as well as routine laboratory and echocardiographic variables. Ten age-matched RHT patients who did not undergo RDN served as controls.

RESULTS

MSNA, but not SSNA, was markedly higher in RHT. RDN caused a significant reduction in MSNA 1 month after RDN, with this reduction increasing after 3 months (from 68.1 ± 2.5 to 64.8 ± 2.4 and 63.1 ± 2.6 bursts/100 heartbeats, P < 0.05). This effect was not accompanied by any significant change in SSNA (from 13.1 ± 0.5 to 13.4 ± 0.6 and 13.3 ± 0.4 bursts/min, P = NS). No quantitative or, in some cases, qualitative relationship was found between BP and the MSNA reduction induced by RDN. No significant changes in various sympathetic markers were detected in the control group who did not undergo RDN and were followed for 3-months observation.

CONCLUSIONS

These data provide the first evidence that RDN exerts heterogeneous effects on sympathetic cardiovascular drive, inducing a marked reduction in MSNA but not in SSNA, which appears to be within the normal range in this condition.These effects may depend on the different reflex modulation regulating neuroadrenergic drive in these cardiovascular districts.

Effects of catheter-based renal denervation on renin-aldosterone system, catecholamines, and electrolytes: A systematic review and meta-analysis

In recent years, catheter-based renal denervation (RDN) has emerged as a promising instrumental therapy for hypertension. The interruption of sympathetic nervous system was regarded as a possible mechanism for RDN regulating blood pressure. While the results reflected by renin-angiotensin-aldosterone system (RAAS), catecholamines and electrolytes remained inconsistent and was never systematically assessed. Pubmed, Embase, and Web of Science were comprehensively searched from inception to September 5, 2021. Studies that evaluated the effects of RDN on RAAS, catecholamines, and electrolytes were identified. Primary outcomes were changes in RAAS hormones after RDN, and secondary outcomes involved changes in plasma norepinephrine, serum, and urinary sodium and potassium. Out of 6391 retrieved studies, 20 studies (two randomized controlled studies and 18 observational studies) involving 771 persons were eventually included. Plasma renin activity had a statistically significant reduction after RDN (0.24 ng/mL/h, 95% CI 0.04 to 0.44, P = .02). While no significant change was found regarding plasma aldosterone (1.53 ng/dL, 95% CI -0.61 to 3.67, P = .16), norepinephrine (0.42 nmol/L, 95% -0.51 to 1.35, P = 0.38), serum sodium and potassium (0.16 mmol/L, 95% CI -0.17 to 0.49, P = .34; -0.02 mmol/L, 95% CI -0.09 to 0.04, P = .48, respectively), and urinary sodium and potassium (3.95 mmol/24 h, 95% CI -29.36 to 37.26, P = .82; 10.22 mmol/24 h, 95% CI -12.11 to 32.54, P = .37, respectively). In conclusion, plasma renin activity significantly decreased after RDN, while no significant change was observed in plasma aldosterone, plasma norepinephrine, and serum and urinary electrolytes.

Long-term follow-up of patients undergoing renal sympathetic denervation

OBJECTIVES

Renal denervation (RDN) proved to significantly lower blood pressure (BP) at 2-6 months in patients on and off antihypertensive drugs. Given a lack of longer-term follow-up data, our aim was to assess the safety and efficacy of RDN up to five years taking into account antihypertensive drug regimen changes over time.

METHODS

In the present single-center study, patients underwent RDN for (therapy resistant) hypertension. Patients underwent protocolized yearly follow-up out to five years. Data were collected on 24-h ambulatory BP and office BP monitoring, renal function, antihypertensive drug regimen, and safety events, including non-invasive renal artery imaging at 6/12 months. Efficacy analyses were performed using linear mixed-effects models.

RESULTS

Seventy-two patients with mean age 63.3 ± 9.5 (SD) years (51% female) were included. Median follow-up time was 3.5 years and Clark's Completeness Index was 72%. Baseline ambulatory daytime BP was 146.1/83.7 ± 17.4/12.2 mmHg under a mean number of 4.9 ± 2.7 defined daily doses (DDD). At five years, ambulatory daytime systolic BP as calculated from the mixed model was 120.8 (95% CI 114.2-127.5) mmHg and diastolic BP was 73.3 (95% CI 69.4-77.3) mmHg, implying a reduction of -20.9/-8.3 mmHg as compared to baseline estimates (p < 0.0001). The number of DDDs remained stable over time (p = 0.87). No procedure-related major adverse events resulting in long-term consequences were observed.

CONCLUSIONS

The BP-lowering effect of RDN was safely maintained at least five years post-procedure as reflected by a significant decrease in ambulatory daytime BP in the absence of escalating antihypertensive drug therapy over time.

Advances in pathogenesis and treatment of essential hypertension

Hypertension is a significant risk factor for cardiovascular and cerebrovascular diseases and the leading cause of premature death worldwide. However, the pathogenesis of the hypertension, especially essential hypertension, is complex and requires in-depth studies. Recently, new findings about essential hypertension have emerged, and these may provide important theoretical bases and therapeutic tools to break through the existing bottleneck of essential hypertension. In this review, we demonstrated important advances in the different pathogenesis areas of essential hypertension, and highlighted new treatments proposed in these areas, hoping to provide insight for the prevention and treatment of the essential hypertension.

Renal Denervation: A Review

Uncontrolled hypertension persists as an important health issue despite the availability of many medications and nondrug therapies that lower blood pressure. Increasingly, nonadherence to medication is found in approximately 2 of every 5 patients with uncontrolled hypertension. In the search for interventions that lower blood pressure that do not rely on adherence to a regimen requiring daily ingestion of medication or repeated physical activity, device-based methods that denervate the renal arteries have emerged as a potential complement to standard antihypertensive treatments. At least 3 different approaches to renal artery denervation are under active investigation, including the use of radiofrequency energy, ultrasound, or the injection of neurolytic agents into the renal perivascular tissue. In this review, we cover what is currently known about the mechanisms of antihypertensive effects of renal denervation, summarize the efficacy and safety of renal denervation using recent controlled trial publications in a number of hypertensive populations, and conclude with some thoughts about challenges in the field, including the optimization of patient selection for the procedure and what the reader can expect in the near future in this rapidly developing field.

Transvenous Right Greater Splanchnic Nerve Ablation in Heart Failure and Preserved Ejection Fraction: First-in-Human Study

BACKGROUND

Ablation of the right-sided greater splanchnic nerve (GSN) can reduce excessive splanchnic vasoconstriction, potentially improving the handling of volume shifts in patients with heart failure with preserved ejection fraction (HFpEF).

OBJECTIVES

The purpose of this study was to assess a novel catheter procedure of right-sided GSN ablation to treat HFpEF: splanchnic ablation for volume management.

METHODS

This trial included 11 HFpEF patients (8 women, age 70 ± 8 years) with New York Heart Association functional class II or III symptoms, ejection fraction ≥50%, and elevated pulmonary capillary wedge pressure at rest or with exercise. After splanchnic ablation for volume management, follow-up at 1, 3, 6, and 12 months included 6-minute walk test, Kansas City Cardiomyopathy Questionnaire (KCCQ), and echocardiography.

RESULTS

There were no device-related adverse cardiac events or clinical sequelae following right GSN ablation through 12 months. Patients experienced clinical improvements by 1 month that were sustained through 12 months. KCCQ score improved from baseline median 48 (IQR: 35-52) to 65 (IQR: 58-77) at 1 month and 80 (IQR: 77-88) at 12 months (P &lt; 0.05). The 6-minute walk test distance increased from baseline 292 ± 82 m to 341 ± 88 m at 1 month and 359 ± 75 m at 12 months (P &lt; 0.05). The NT-proBNP decreased from a baseline mean of 1,292 ± 1,186 pg/mL to 1,202 ± 797 pg/mL (P = 0.585) at 1 month, to 472 ± 226 pg/mL (P = 0.028) at 6 months, and to 379 ± 165 pg/mL (P = 0.039) at 12 months.

CONCLUSIONS

In this open-label, single-arm feasibility study, right-sided GSN ablation was safe and improved mostly subjective clinical metrics in patients with HFpEF over 12 months. (Endovascular GSN Ablation in Subjects With HFpEF; NCT04287946).

Renal denervation for atrial fibrillation: a comprehensive updated systematic review and meta-analysis

The study aims to compare clinical outcomes following renal denervation (RDN) in hypertensive patients with atrial fibrillation (AF). Three online databases were searched (MEDLINE, EMBASE and PubMed) for literature related to outcomes of RDN on hypertension and AF, between January 1, 2010, and June 1, 2021. Where possible, risk ratios (RR) and mean differences (MD) were combined using a random effects model. Significance was set at p ≤ 0.05. Seven trials were included that assessed the effect of adding RDN to pulmonary vein isolation (PVI) in patients with hypertension and AF. A total of 711 patients (329 undergoing PVI + RDN and 382 undergoing PVI alone), with an age range of 56 ± 6 to 68 ± 9 years, were included. Pooled analysis showed a significant lowering of AF recurrence in the PVI + RDN (31.3%) group compared to the PVI-only (52.9%) group (p < 0.00001). Pooled analysis of patients with resistant hypertension showed a significant mean reduction of systolic blood pressure (SBP) (-9.42 mm Hg, p = 0.05), but not diastolic blood pressure (DBP) (-4.11 mm Hg, p = 0.16) in favor of PVI + RDN. Additionally, the pooled analysis showed that PVI + RDN significantly improved estimated glomerular filtration rate (eGFR) (+10.2 mL/min per 1.73 m2, p < 0.001) compared to PVI alone. RDN procedures in these trials have proven to be both safe and efficacious with an overall complication rate of 6.32%. Combined PVI and RDN is beneficial for patients with hypertension and AF. Combined therapy showed improvement in SBP and eGFR, reducing the risk of AF recurrence. RDN may serve as an innovative intervention in the treatment of AF.

The role of renal nerve stimulation in percutaneous renal denervation for hypertension: A mini-review

Recent trials have demonstrated the efficacy and safety of percutaneous renal sympathetic denervation (RDN) for blood pressure (BP)-lowering in patients with uncontrolled hypertension. Nevertheless, major challenges exist, such as the wide variation of BP-lowering responses following RDN (from strong response to no response) and lack of feasible and reproducible peri-procedural predictors for patient response. Both animal and human studies have demonstrated different patterns of BP responses following renal nerve stimulation (RNS), possibly related to varied regional proportions of sympathetic and parasympathetic nerve tissues along the renal arteries. Animal studies of RNS have shown that rapid electrical stimulation of the renal arteries caused renal artery vasoconstriction and increased norepinephrine secretion with a concomitant increase in BP, and the responses were attenuated after RDN. Moreover, selective RDN at sites with strong RNS-induced BP increases led to a more efficient BP-lowering effect. In human, when RNS was performed before and after RDN, blunted changes in RNS-induced BP responses were noted after RDN. The systolic BP response induced by RNS before RDN and blunted systolic BP response to RNS after RDN, at the site with maximal RNS-induced systolic BP response before RDN, both correlated with the 24-h ambulatory BP reductions 3-12 months following RDN. In summary, RNS-induced BP changes, before and after RDN, could be used to assess the immediate effect of RDN and predict BP reductions months following RDN. More comprehensive, large-scale and long term trials are needed to verify these findings.

Present Evidence of Determinants to Predict the Efficacy of Renal Denervation

Sympathetic overactivation is one of the main contributors to development and progress of hypertension. Renal denervation (RDN) has been evidenced by series of clinical trials for its efficacy and safety to treat overactivated sympathetic nervous system induced diseases. However, the results were inconsistent and not all patients benefited from RDN. Appropriate patient selection and intraoperative factors to improve the efficacy of RDN need to be solved urgently. Over the decade, research studies on the correlations between indicators and the antihypertensive effects have been conducted and made a fairly well progress. Herein, we comprehensively reviewed the research studies on how to make RDN more predictable or improve the efficacy of RDN and summarized these potential indicators or devices which might be applied in clinical settings.

Update on Renal Sympathetic Denervation for the Treatment of Hypertension

PURPOSE OF REVIEW

Hypertension is a leading risk factor for all-cause mortality in adults; however, medication non-adherence and intolerance present an enormous treatment challenge. Given the critical role of renal sympathetic nerves in neurogenic control of blood pressure and pathophysiology of hypertension, renal sympathetic denervation (RDN) has been explored as a therapeutic strategy in hypertension treatment over the last 15 years. In this review, we will discuss the role of renal sympathetic nerves in the pathophysiology of hypertension, provide an update on the available evidence regarding the short- and long-term safety and effectiveness of RDN in the treatment of hypertension, and consider its future perspectives.

RECENT FINDINGS

RDN is a percutaneous endovascular catheter-based neuromodulation approach that enables ablation of renal sympathetic nerve fibers within the adventitial layer of the renal arteries using radiofrequency (most extensively studied), ultrasound energy, or neurolytics (e.g., alcohol). In the last decade, advancements in procedural techniques and well-designed sham-controlled trials utilizing 24-h ambulatory blood pressure measurements have demonstrated that RDN has an excellent safety profile and results in a modest reduction of blood pressure, in a wide range of hypertensive phenotypes (mild to resistant), irrespective of antihypertensive drug use and this effect is sustained over a 3-year period. Superiority of a particular RDN modality has not been yet established. Despite strong evidence demonstrating efficacy and safety of RDN, current data does not support its use as a primary approach in the treatment of hypertension due to its modest treatment effect and concerns around long-term sustainability. Perhaps the best utility of RDN is in hypertensives intolerant to antihypertensive medications or as an adjunct to aldosterone antagonists in the management of resistant hypertension. Patient selection will be critical to demonstrate a meaningful benefit of RDN. Future well-designed studies are necessary to determine predictors and measures of response to RDN, long-term efficacy given question of renal nerve regeneration, comparison of available technologies, safety in patients with advanced kidney disease, and improvement in patient quality of life measures.

Twenty-Four-Hour Pulsatile Hemodynamics Predict Brachial Blood Pressure Response to Renal Denervation in the SPYRAL HTN-OFF MED Trial

Renal denervation (RDN) lowers blood pressure (BP), but BP response is variable in individual patients. We investigated whether measures of pulsatile hemodynamics, obtained during 24-hour ambulatory BP monitoring, predict BP drop following RDN.

Intravascular Renal Denervation Reduces Ambulatory and Office Blood Pressure in Patients with Essential Hypertension: A Meta-Analysis of Randomized Sham-Controlled Trials

BACKGROUND

This meta-analysis was designed to evaluate the antihypertensive efficacy of intravascular renal denervation (RDN) in patients with essential hypertension, especially to determine the magnitude of blood pressure (BP) reduction with RDN therapy using second-generation catheters.

METHODS

PubMed was searched to identify randomized sham-controlled trials from inception through August 2021. The endpoints were changes in 24-h ambulatory BP or office BP. This meta-analysis was performed by calculating the weighted mean difference (WMD) with 95% confidence interval (CI) using the random-effects model when the I2 index was <50%. A fixed-effects model was used when the I2 index was ≥50%.

RESULTS

A total of 1,297 patients were included in 8 randomized, sham-controlled trials in this meta-analysis. Intravascular RDN reduced 24-h ambulatory systolic BP (SBP) -3.02 (WMD, 95% CI: -4.95, -1.10, p < 0.01) and diastolic BP (DBP) -1.66 (WMD, 95% CI: -2.44, -0.88, p < 0.001) mm Hg, respectively. In the studies using first-generation catheters, the WMDs of 24-h ambulatory SBP and DBP changes between intravascular RDN and sham control were -2.67 (95% CI: -5.08, -0.27; p < 0.05; I2 = 0%, p = 0.53) and -0.82 (95% CI: -2.19, 0.56; p > 0.05; I2 = 0%, p = 0.64) mm Hg. In the studies using second-generation catheters, the WMDs of 24-h ambulatory SBP and DBP changes between intravascular RDN and sham control were -3.14 (95% CI: -5.94, -0.33, p < 0.05; I2 = 71%, p = 0.008) and -2.06 (95% CI: -3.02, -1.11, p < 0.001; I2 = 50%, p = 0.09) mm Hg. Intravascular RDN using second-generation catheters reduced office SBP -6.30 (WMD, 95% CI: -7.67, -4.93, p < 0.001; I2 = 43%, p = 0.14) and DBP -3.88 (WMD, 95% CI: -4.44, -3.33, p < 0.001; I2 = 42%, p = 0.14) mm Hg, respectively.

CONCLUSIONS

Intravascular RDN using second-generation catheters reduces ambulatory and office BP in patients with essential hypertension. The selection of appropriate hypertensive patients may be the major challenge for the performance of intravascular RDN in routine clinical practice.