Baroreflex activation therapy lowers blood pressure in patients with resistant hypertension: results from the double-blind, randomized, placebo-controlled rheos pivotal trial

Baroreflex activation therapy in advanced heart failure: A long-term follow-up

AIMS

Baroreceptor activation therapy (BAT) is a promising new treatment strategy for patients with heart failure with reduced ejection fraction (HFrEF). It provides symptomatic relief, improvement in left ventricular function and reduction of cardiac biomarkers. Data regarding the long-term effect of BAT on HFrEF are scarce. This retrospective, monocentric study aimed to assess long-term outcome in patients who underwent BAT.

METHODS

Patients with HFrEF who received BAT at Hannover Medical School between 2014 and 2023 were followed until the latest available follow-up. Symptom burden, echocardiography and laboratory testing were assessed before BAT implantation and in subsequent follow-ups.

RESULTS

Twenty-three patients (mean age 66 ± 10 years, 83% male) with HFrEF were included in the study. Aetiology of heart failure was ischaemic in 70%. The majority of patients (96%) suffered from New York Heart Association (NYHA) III with a mean left ventricular ejection fraction (LVEF) of 23 ± 8% and N-terminal pro-B-type natriuretic peptide (NT-proBNP) of 2463 ± 2922 pg/mL. A complication occurred in one patient during BAT implantation (4%). The mean follow-up was 3 ± 2 (max. 7.5) years. BAT reduced NYHA classification in 12 patients (52%) after 1 year, of which one patient remained in ameliorated NYHA for 7.5 years. Echocardiographic evaluation revealed significant improvement in LVEF by 9 ± 9% after 1 year (P < 0.001) and by 11 ± 9% (P = 0.005) after 2 years. In addition, BAT mildly reduced NT-proBNP in the first 2 years [non-significantly after 1 year by 396 ± 1006 pg/mL and significantly after 2 years by 566 ± 651 pg/mL (P = 0.039)]. Seven patients reaching the recommended replacement time underwent device exchange. Four patients died during observation time.

CONCLUSIONS

BAT resulted in a substantial reduction in NYHA classification and improvement in LVEF that lasted over long-term follow-up in many patients. NT-proBNP level decreased interim in long-term follow-up. These findings highlight the long-term efficacy and potential benefits of BAT as a therapeutic intervention for patients with HFrEF.

Effects of baroreflex activation therapy on cardiac function and morphology

AIMS

Arterial hypertension (aHTN) plays a fundamental role in the pathogenesis and prognosis of heart failure with preserved ejection fraction (HFpEF). The risk of heart failure increases with therapy-resistant arterial hypertension (trHTN), defined as inadequate blood pressure (BP) control ≥140/90 mmHg despite taking ≥3 antihypertensive medications including a diuretic. This study investigates the effects of the BP lowering baroreflex activation therapy (BAT) on cardiac function and morphology in patients with trHTN with and without HFpEF.

METHODS

Sixty-four consecutive patients who had been diagnosed with trHTN and received BAT implantation between 2012 and 2016 were prospectively observed. Office BP, electrocardiographic and echocardiographic data were collected before and after BAT implantation.

RESULTS

Mean patients' age was 59.1 years, 46.9% were male, and mean body mass index (BMI) was 33.2 kg/m2. The prevalence of diabetes mellitus was 38.8%, atrial fibrillation was 12.2%, and chronic kidney disease (CKD) stage ≥3 was 40.8%. Twenty-eight patients had trHTN with HFpEF, and 21 patients had trHTN without HFpEF. Patients with HFpEF were significantly older (64.7 vs. 51.6 years, P < 0.0001), had a lower BMI (30.0 vs. 37.2 kg/m2, P < 0.0001), and suffered more often from CKD-stage ≥3 (64 vs. 20%, P = 0.0032). After BAT implantation, mean office BP dropped in patients with and without HFpEF (from 169 ± 5/86 ± 4 to 143 ± 4/77 ± 3 mmHg [P = 0.0019 for systolic BP and 0.0403 for diastolic BP] and from 170 ± 5/95 ± 4 to 149 ± 6/88 ± 5 mmHg [P = 0.0019 for systolic BP and 0.0763 for diastolic BP]), while a significant reduction of the intake of calcium-antagonists, α2-agonists and direct vasodilators, as well as a decrease in average dosage of ACE-inhibitors and α2-agonists could be seen. Within the study population, a decrease in heart rate from 74 ± 2 to 67 ± 2 min-1 (P = 0.0062) and lengthening of QRS-time from 96 ± 3 to 106 ± 4 ms (P = 0.0027) and QTc-duration from 422 ± 5 to 432 ± 5 ms (P = 0.0184) were detectable. The PQ duration was virtually unchanged. In patients without HF, no significant changes of echocardiographic parameters could be seen. In patients with HFpEF, posterior wall diameter decreased significantly from 14.0 ± 0.5 to 12.7 ± 0.3 mm (P = 0.0125), left ventricular mass (LVM) declined from 278.1 ± 15.8 to 243.9 ± 13.4 g (P = 0.0203), and e' lateral increased from 8.2 ± 0.4 to 9.0 ± 0.4 cm/s (P = 0.0471).

CONCLUSIONS

BAT reduced systolic and diastolic BP and was associated with morphological and functional improvement of HFpEF.

Low-Level Tragus Stimulation Attenuates Blood Pressure in Young Individuals With Hypertension: Results From a Small-Scale Single-Blind Controlled Randomized Clinical Trial

BACKGROUND

Hypertension is a significant risk factor for cardiovascular and chronic kidney diseases. Its management in young people remains limited. Device-based therapies, such as low-level tragus stimulation (LL-TS), a noninvasive method that reduces sympathetic activity, have recently been explored for resistant hypertension.

METHODS AND RESULTS

This trial involved patients with Grade 1 hypertension with no other medical history. LL-TS (20 Hz, 1 mA, 1 h/day) was applied for 3 months on the tragus (Intervention group [IG]) or earlobe (Control group [CG]). Blood pressure and outcomes were assessed at the first, second, and third months. Among 40 patients, 21 were in IG and 19 in CG. Baseline systolic blood pressure was similar between IG (142.62±8.18 mm Hg) and CG (143.00±8.61 mm Hg), P=0.89. Post-LL-TS, systolic blood pressure showed significant reductions in IG compared with CG at the first (IG: 134.47±5.95 mm Hg, CG: 141.28±6.78 mm Hg, P=0.002), second (IG: 132.50±7.51 mm Hg, CG: 140.62±7.15 mm Hg, P=0.001), and third months (IG: 128.81±7.13 mm Hg, CG: 136.51±7.96 mm Hg, P=0.003). diastolic blood pressure also differed significantly: first month (IG: 85.34±5.81 mm Hg, CG: 89.74±6.32 mm Hg, P=0.03), second month (IG: 82.12±5.22 mm Hg, CG: 88.57±7.11 mm Hg, P=0.002), and third month (IG: 80.71±5.96 mm Hg, CG: 87.55±5.26 mm Hg, P=0.001). Heart rate was unchanged (P>0.05). Only 0.01% of IG subjects reported site irritation, with no serious adverse events.

CONCLUSIONS

LL-TS led to significant blood pressure reductions in young patients with essential hypertension. Further larger trials are needed to confirm the safety and efficacy of LL-TS.

REGISTRATION

URL: https://www.chictr.org.cn/; Unique identifier: ChiCTR2000038448.

Neurocardiac Axis Physiology and Clinical Applications

The neurocardiac axis constitutes the neuronal circuits between the arteries, heart, brain, and immune organs (including thymus, spleen, lymph nodes, and mucosal associated lymphoid tissue) that together form the cardiovascular brain circuit. This network allows the individual to maintain homeostasis in a variety of environmental situations. However, in dysfunctional states, such as exposure to environments with chronic stressors and sympathetic activation, this axis can also contribute to the development of atherosclerotic vascular disease as well as other cardiovascular pathologies and it is increasingly being recognized as an integral part of the pathogenesis of cardiovascular disease. This review article focuses on 1) the normal functioning of the neurocardiac axis; 2) pathophysiology of the neurocardiac axis; 3) clinical implications of this axis in hypertension, atherosclerotic disease, and heart failure with an update on treatments under investigation; and 4) quantification methods in research and clinical practice to measure components of the axis and future research areas.

Baroreflex Function in Cardiovascular Disease

The baroreflex system is involved in modulating several physiological functions of the cardiovascular system and can directly and indirectly modulate cardiac output, blood pressure, and cardiac electrophysiology. In addition, it is involved in regulating neurohormonal pathways involved in the cardiovascular function, such as the renin-angiotensin-aldosterone system (RAAS) and vasopressin release. Baroreflex dysfunction is characterized by sympathetic overactivation and parasympathetic withdrawal and is associated with several cardiovascular diseases, such as hypertension, heart failure (HF), and coronary artery disease (CAD). Targeting the baroreflex system via invasive (e.g., baroreflex activation therapy and endovascular baroreceptor amplification) and non-invasive approaches (e.g., slow breathing exercises and exercise training) has emerged as a novel pathway to manage cardiovascular diseases. Studies examining the long-term safety and efficacy of such interventions in various cardiovascular diseases are needed.

Research status and frontiers of renal denervation for hypertension: a bibliometric analysis from 2004 to 2023

BACKGROUND

Renal Denervation (RDN) is a novel non-pharmacological technique to treat hypertension. This technique lowers blood pressure by blocking the sympathetic nerve fibers around the renal artery, then causing a decrease in system sympathetic nerve excitability. This study aimed to visualize and analyze research hotspots and development trends in the field of RDN for hypertension through bibliometric analysis.

METHODS

In total, 1479 studies were retrieved on the Web of Science Core Collection (WoSCC) database from 2004 to 2023. Using CiteSpace (6.2.R4) and VOSviewer (1.6.18), visualization maps were generated by relevant literature in the field of RDN for hypertension to demonstrate the research status and frontiers.

RESULTS

The number of publications was found to be generally increasing. Europe and the United States were the first countries to carry out research on different techniques and related RDN clinical trials. The efficacy and safety of RDN have been repeatedly verified and gained increasing attention. The study involves multiple disciplines, including the cardiovascular system, peripheral vascular disease, and physiological pathology, among others. Research hotspots focus on elucidating the mechanism of RDN in the treatment of hypertension and the advantages of RDN in appliance therapy. Additionally, the research frontiers include improvement of RDN instruments and techniques, as well as exploration of the therapeutic effects of RDN in diseases with increased sympathetic nerve activity.

CONCLUSION

The research hotspots and frontiers reflect the status and development trend of RDN in hypertension. In the future, it is necessary to strengthen international collaboration and cooperation, conduct long-term clinical studies with a large sample size, and continuously improve RDN technology and devices. These measures will provide new options for more patients with hypertension, thereby improving their quality of life.

Pharmacologic, Surgical, and Device-Based Cardiac Neuromodulation

The cardiac autonomic nervous system plays a key role in maintaining normal cardiac physiology, and once disrupted, it worsens the cardiac disease states. Neuromodulation therapies have been emerging as new treatment options, and various techniques have been introduced to mitigate autonomic nervous imbalances to help cardiac patients with their disease conditions and symptoms. In this review article, we discuss various neuromodulation techniques used in clinical settings to treat cardiac diseases.

Permanent Pacing Reduces Blood Pressure in Older Patients with Drug-resistant Hypertension: A New Pacing Paradigm?

Hypertension (HTN) is a major contributor to cardiovascular mortality. Many patients with drug-resistant hypertension (DRH) also require permanent pacing (PP). This large retrospective study evaluated the effect of PP for conventional PP indications in older patients with DRH. We reviewed the charts of 176 patients with dual-chamber PP and DRH. The effects of PP on systolic and diastolic blood pressure (sBP and dBP), the number of HTN-related medications, and left ventricular ejection fraction (LVEF) were assessed at 6 months post-implantation and compared with pre-implantation values. Patients were followed up with for ≥72 months. Patients with a decline of >5 mmHg in sBP and decrease in at least one anti-HTN medication were defined as responders (126/176; P < .01). The mean decline in sBP was 9 mmHg, while that in dBP was 3 mmHg (P < .001 for both). Among responders, optimal reductions in sBP, dBP, and medications were seen at a stratification of >50% atrial pacing and <40% ventricular pacing (-12, -6.3, and -1.6, respectively). When right ventricular pacing of <50% was used for dichotomizing, the optimal atrial/ventricular pacing stratification was atrial pacing > 50% and ventricular pacing < 40% (-11.3, -6.3, and -1.6, respectively). A relationship between increasing atrial pacing and a decline in sBP was noted but did not reach statistical significance. However, of those responders who had a >10-mmHg decline in sBP, the majority were paced between 60%-100% in the atria. The LVEF did not change post-PP in either group. In conclusion, PP results in significant improvement in BP control. The observed association warrants further investigation.

Effects of acute carotid baroreceptor stimulation on sympathetic nerve traffic in resistant and uncontrolled hypertension: a systematic review and meta-analysis

In resistant hypertensive patients acute carotid baroreflex stimulation is associated with a blood pressure (BP) reduction, believed to be mediated by a central sympathoinhbition.The evidence for this sympathomodulatory effect is limited, however. This meta-analysis is the first to examine the sympathomodulatory effects of acute carotid baroreflex stimulation in drug-resistant and uncontrolled hypertension, based on the results of microneurographic studies. The analysis included 3 studies assessing muscle sympathetic nerve activity (MSNA) and examining 41 resistant uncontrolled hypertensives. The evaluation included assessment of the relationships between MSNA and clinic heart rate and BP changes associated with the procedure. Carotid baroreflex stimulation induced an acute reduction in clinic systolic and diastolic BP which achieved statistical significance for the former variable only [systolic BP: -19.98 mmHg (90% CI, -30.52, -9.43), P < 0.002], [diastolic BP: -5.49 mmHg (90% CI, -11.38, 0.39), P = NS]. These BP changes were accompanied by a significant MSNA reduction [-4.28 bursts/min (90% CI, -8.62, 0.06), P < 0.07], and by a significant heart rate decrease [-3.65 beats/min (90% CI, -5.49, -1.81), P < 0.001]. No significant relationship was detected beween the MSNA, systolic and diastolic BP changes induced by the procedure, this being the case also for heart rate. Our data show that the acute BP lowering responses to carotid baroreflex stimulation, although associated with a significant MSNA reduction, are not quantitatively related to the sympathomoderating effects of the procedure. This may suggest that these BP effects depend only in part on central sympathoinhibition, at least in the acute phase following the intervention.

Real-time closed-loop brainstem stimulation modality for enhancing temporal blood pressure reduction

BACKGROUND

Traditional pharmacological interventions are well tolerated in the management of elevated blood pressure (BP) for individuals with resistant hypertension. Although neuromodulation has been investigated as an alternative solution, its open-loop (OL) modality cannot follow the patient's physiological state. In fact, neuromodulation for controlling highly fluctuating BP necessitates a closed-loop (CL) stimulation modality based on biomarkers to monitor the patient's continuously varying physiological state.

OBJECTIVE

By leveraging its intuitive linkage with BP responses in ongoing efforts aimed at developing a CL system to enhance temporal BP reduction effect, this study proposes a CL neuromodulation modality that controls nucleus tractus solitarius (NTS) activity to effectively reduce BP, thus reflecting continuously varying physiological states.

METHOD

While performing neurostimulation targeting the NTS in the rat model, the arterial BP response and neural activity of the NTS were simultaneously measured. To evaluate the temporal BP response effect of CL neurostimulation, OL (constant parameter; 20 Hz, 200 μA) and CL (Initial parameter; 11 Hz, 112 μA) stimulation protocols were performed with stimulation 180 s and rest 600 s, respectively, and examined NTS activity and BP response to the protocols.

RESULTS

In-vivo experiments for OL versus CL protocol for direct NTS stimulation in rats demonstrated an enhancement in temporal BP reduction via the CL modulation of NTS activity.

CONCLUSION

This study proposes a CL stimulation modality that enhances the effectiveness of BP control using a feedback control algorithm based on neural signals, thereby suggesting a new approach to antihypertensive neuromodulation.

Diagnosis and management of resistant hypertension

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

Unraveling the complex pathophysiology of heart failure: insights into the role of renin-angiotensin-aldosterone system (RAAS) and sympathetic nervous system (SNS)

Heart failure (HF) is a widespread disease with significantly elevated mortality, morbidity, and hospitalization rates. Dysregulation of the sympathetic nervous system (SNS) and renin-angiotensin-aldosterone system (RAAS) are both postulated to be significant regulators of cardiovascular function, thereby playing a pivotal role in its pathophysiology. The RAAS is a sophisticated hormonal system that controls electrolyte homeostasis, fluid balance, and blood pressure. Angiotensin II, which operates to constrict blood vessels and raise blood pressure, is its principal effector molecule. The RAAS is frequently hyperactive in HF, which increases fluid retention and worsens cardiac function. The SNS is frequently hyperactive in heart failure, which increases the workload on the heart and worsens symptoms. This review will discuss what is currently known about the pathophysiology of heart failure, specifically in the context of RAAS and the SNS, in-depth to emphasize the knowledge gap that necessitates more research.

Device's design and clinical perspectives for resistant hypertension therapy

Introduction

Hypertension is the leading cause of death in the cardiovascular system. Indeed, untreated hypertension can affect one's general health, but medicine can help hypertensive people reduce their chance of developing high blood pressure. However, secondary hypertension remains an unresolved illness.

Areas covered

This review will go through the typical and unusual device-based therapies for resistant hypertension that have arisen in recent years. Further to that, the innovations developed in device-based RH treatment will be covered, as well as the research and studies assessing these novel technologies.

Expert opinion

The innovative device-based techniques that target resistant hypertension provide a potential therapy that has been backed by a number of studies and clinical trials, whereas pharmacological non-adherence and increased sympathetic activity are recognized to be the primary causes of resistant hypertension. Nevertheless, some limitations will be critical for the future of these RH systems, with the device's design and larger RCTs playing a significant role in determining whether a position in routine treatment could be warranted.

Efficacy of pharmacological and interventional treatment for resistant hypertension: a network meta-analysis

AIMS

Resistant hypertension is associated with a high risk of cardiovascular disease, chronic kidney disease, and mortality. Yet, its management is challenging. This study aims to establish the comparative effectiveness of pharmacologic and interventional treatments by conducting a network meta-analysis.

METHODS AND RESULTS

MEDLINE, Cochrane Register of Controlled Trials, and Web of Science Core Collection were systematically searched in March 2022. Randomized controlled trials comparing treatment options for management of resistant hypertension were included. Outcomes were blood pressure (BP) changes, measured in the office and in 24 h ambulatory BP measurement. We applied a frequentist random effects model to perform a network meta-analysis combining placebo medication and sham procedure as the reference comparator. From 4771 records, 24 studies met the inclusion criteria with 3458 included patients in total. Twelve active treatment alternatives [spironolactone, doxazosin, β-blocker, clonidine, darusentan, guanfacine, various types of renal sympathetic denervation, lifestyle intervention, continuous positive airway pressure, and baroreflex activation therapy (BAT)] were analysed. Among all comparators, spironolactone had the highest ranking probability and was considered the most effective treatment to reduce office systolic blood pressure (sBP) [-13.30 mmHg (-17.89; -8.72); P < 0.0001] and 24 h sBP [-8.46 mmHg (-12.54; -4.38); P < 0.0001] in patients with resistant hypertension. Lifestyle interventions were the most effective non-pharmacological treatment, lowering office sBP by -7.26 mmHg (-13.73; -0.8), whereas BAT lowered office sBP by -7.0 (-18.59; 4.59). Renal denervation lowered office sBP by -5.64 mmHg (-12.95; 1.66) and -3.79 mmHg (-11.39; 3.8) depending on the type of the procedure.

CONCLUSION

Among all pharmacologic and interventional treatments, spironolactone is the most effective treatment in reducing BP in patients with resistant hypertension. More comparative trials and especially trials with long-term follow-up are needed. In the meanwhile, we have to conclude that a combination of spironolactone and lifestyle modification are the most effective treatments in resistant hypertension.

Key challenges in exploring the rat as a preclinical neurostimulation model for aortic baroreflex modulation in hypertension

Electrode-based electrophysiological interfaces with peripheral nerves have come a long way since the 1960s, with several neurostimulation applications witnessing widespread clinical implementation since then. In resistant hypertension, previous clinical trials have shown that "carotid" baroreflex stimulation using device-based baroreflex activation therapy (BAT) can effectively lower blood pressure (BP). However, device-based "aortic" baroreflex stimulation remains untouched for clinical translation. The rat is a remarkable animal model that facilitates exploration of mechanisms pertaining to the baroreceptor reflex and preclinical development of novel therapeutic strategies for BP modulation and hypertension treatment. Specifically, the aortic depressor nerve (ADN) in rats carries a relatively pure population of barosensitive afferent neurons, which enable selective investigation of the aortic baroreflex function. In a rat model of essential hypertension, the spontaneously hypertensive rat (SHR), we have recently investigated the aortic baroreceptor afferents as an alternate target for BP modulation, and showed that "low intensity" stimulation is able to evoke clinically meaningful reductions in BP. Deriving high quality short-term and long-term data on aortic baroreflex modulation in rats is currently hampered by a number of unresolved experimental challenges, including anatomical variations across rats which complicates identification of the ADN, the use of unrefined neurostimulation tools or paradigms, and issues arising from anesthetized and conscious surgical preparations. With the goal of refining existing experimental protocols designed for preclinical investigation of the baroreflex, this review seeks to outline current challenges hindering further progress in aortic baroreflex modulation studies in rats and present some practical considerations and recently emerging ideas to overcome them. Aortic baroreflex modulation.

Non-pharmacologic autonomic neuromodulation for treatment of heart failure: A systematic review and meta-analysis of randomized controlled trials

Treatment strategies that modulate autonomic tone through interventional and device-based therapies have been studied as an adjunct to pharmacological treatment of heart failure with reduced ejection fraction (HFrEF). The main objective of this study was to perform a meta-analysis of randomized controlled trials which evaluated the efficacy of device-based autonomic modulation for treatment of HFrEF. All randomized-controlled trials testing autonomic neuromodulation device therapy in HFrEF were included in this trial-level analysis. Autonomic neuromodulation techniques included vagal nerve stimulation (VNS), baroreflex activation (BRA), spinal cord stimulator (SCS), and renal denervation (RD). The prespecified primary endpoints included mean change and 95% confidence intervals (CI) of left ventricular ejection fraction (LVEF), NT pro-B-type natriuretic peptide (NT-proBNP), and quality of life (QOL) measures including 6-minute hall walk distance (6-MHWD), and Minnesota Living with Heart Failure Questionnaire (MLHFQ). New York Heart Association (NYHA) functional class improvement was reported as odds ratios and 95% CI of improvement by at least 1 functional class. Eight studies were identified that included 1037 participants (2 VNS, 2 BRA, 1 SCS, and 3 RD trials). This included 6 open-label, 1 single-blind, and 1 sham-controlled, double-blind study. The mean age (±SD) was 61 (±9.3) years. The mean follow-up time was 7.9 months. Twenty percent of the total patients were female, and the mean BMI (±SD) was 29.86 (±4.12). Autonomic neuromodulation device therapy showed a statistically significant improvement in LVEF (4.02%; 95% CI 0.24,7.79), NT-proBNP (-219.80 pg/ml; 95% CI -386.56, -53.03), NYHA functional class (OR 2.32; 95% CI 1.76, 3.07), 6-MHWD (48.39 m; 95% CI 35.49, 61.30), and MLHFQ (-12.20; 95% CI -19.24, -5.16) compared to control. In patients with HFrEF, the use of autonomic neuromodulation device therapy is associated with improvement in LVEF, reduction in NT-proBNP, and improvement in patient-centered QOL outcomes in mostly small open-label trials. Large, double-blind, sham-controlled trials designed to detect differences in hard cardiovascular outcomes are needed before widespread use and adoption of autonomic neuromodulation device therapies in HFrEF.

Baroreflex Activation Therapy in Patients with Heart Failure with a Reduced Ejection Fraction

A randomized, controlled trial of baroreflex activation therapy (BAT) in patients with heart failure and reduced ejection fraction demonstrated that BAT was safe and significantly improved patient-centered symptomatic outcomes, increasing exercise capacity, improving quality of life, decreasing n-terminal pro B-type natriuretic peptide (NT-proBNP), and improving functional class. BAT was approved by the FDA for improvement of symptoms of heart failure for patients who remain symptomatic despite treatment with guideline-directed management, are New York Heart Association Class III or Class II (with a recent history of Class III), have a left ventricular ejection fraction ≤ 35%, an NT-proBNP < 1600 pg/mL and excluding patients indicated for cardiac resynchronization therapy.

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.

Recent Advancements in Bioelectronic Medicine: A Review

Bioelectronic medicine is a multidisciplinary field that combines molecular medicine, neurology, engineering, and computer science to design devices for diagnosing and treating diseases. The advancements in bioelectronic medicine can improve the precision and personalization of illness treatment. Bioelectronic medicine can produce, suppress, and measure electrical activity in excitable tissue. Bioelectronic devices modify specific neural circuits using electrons rather than pharmaceuticals and uses of bioelectronic processes to regulate the biological processes underlining various diseases. This promotes the potential to address the underlying causes of illnesses, reduce adverse effects, and lower costs compared to conventional medication. The current review presents different important aspects of bioelectronic medicines with recent advancements. The area of bioelectronic medicine has a lot of potential for treating diseases, enabling non-invasive therapeutic intervention by regulating brain impulses. Bioelectronic medicine uses electricity to control biological processes, treat illnesses, or regain lost capability. These new classes of medicines are designed by the technological developments in the detection and regulation of electrical signaling methods in the nervous system. Peripheral nervous system regulates a wide range of processes in chronic diseases; it involves implanting small devices onto specific peripheral nerves, which read and regulate the brain signaling patterns to achieve therapeutic effects specific to the signal capacity of a particular organ. The potential for bioelectronic medicine field is vast, as it investigates for treatment of various diseases, including rheumatoid arthritis, diabetes, hypertension, paralysis, chronic illnesses, blindness, etc.

Electrical carotid sinus nerve stimulation attenuates experimental colitis induced by acetic acid in rats

AIMS

The carotid bodies are sensors that detect physiological signals and convey them to the central nervous system, where the stimuli are processed inducing reflexes through efferent pathways. Recent studies have demonstrated that electrical stimulation of the carotid sinus nerve (CSN) triggers the anti-inflammatory reflex under different conditions. However, whether this electrical stimulation attenuates colitis was never examined. This study aimed to evaluate if the electrical CSN stimulation attenuates the experimental colitis induced by intrarectal administration of acetic acid in rats.

METHODS

Electrodes were implanted around the CSN to stimulate the CSN, and a catheter was inserted into the left femoral artery to record the arterial pressure. The observation of hypotensive responses confirmed the effectiveness of the electrical CNS stimulation. This maneuver was followed by a 4 % acetic acid or saline administered intrarectally. After 24 h, colons were segmented into distal and proximal parts for macroscopy, histological and biochemical assessment.

KEY FINDINGS

As expected, the electrical CSN stimulation was effective in decreasing arterial pressure in saline and colitis rats. Moreover, electrical CSN stimulation effectively reduced colonic tissue lesions, colitis scores, and histopathologic parameters associated with colitis. In addition, the CSN stimulation also reduced the colonic mucosa pro-inflammatory cytokine interleukin-1 beta, and increased the anti-inflammatory interleukin-10, in rats submitted to colitis.

SIGNIFICANCE

These findings indicated that electrical CSN stimulation breaks the vicious cycle of local colon inflammation in colitis, which might contribute to its better outcome.

Novel approaches: targeting sympathetic outflow in the carotid sinus

Uncontrolled hypertension drives the global burden of increased cardiovascular disease (CVD) morbidity and mortality. Although high blood pressure (BP) is treatable and preventable, only half of the patients with hypertension undergoing treatment have their BP controlled. The failure of polypharmacy to attain adequate BP control may be due to a lack of physiological response, however, medication non-adherence and clinician inertia to increase treatment intensity are critical factors associated with poor hypertension management. The long-time medication titration, lifelong drug therapy, and often multi-drug treatment strategy are frustrating when the BP goal is not achieved, leading to increased CVD risk and a substantial burden on the healthcare system. Growing evidence indicates that neurohumoral activation is critical in initiating and maintaining elevated BP and its adverse consequences. Over the past decades, device-based therapies targeting the mechanisms underlying hypertension pathophysiology have been extensively studied. Among these, robust clinical experience for hypertension management exists for renal denervation (RDN) and baroreflex activation therapy (BAT), carotid body denervation (CBD), central arteriovenous anastomosis, and to a lesser extent, deep brain stimulation. Future studies are warranted to define the role of device-based approaches as an alternative or adjunctive treatment option to treat hypertension.

Update on advanced interventional neuromodulatory approaches to lower blood pressure

Herein, we review interventional peripheral neuromodulatory approaches to reduce blood pressure (BP), specifically focusing on catheter-based renal denervation (RDN), as well as the latest data from recent clinical trials underpinning its clinical use. Given the apparent failure of established lifestyle measures and pharmacologic BP-lowering approaches to improve hypertension (HTN) control rates, the past decade has seen remarkable scientific efforts to explore the utility of interventional strategies for BP management. Experimental studies and human clinical trials have demonstrated the crucial role of the sympathetic nervous system in the development and mainenance of HTN - consequently, most recent interventional technologies aimed primarily at modulating neural pathways. Advanced approaches that were rigorously tested in human studies include RDN, endovascular baroreflex amplification, baroreflex activation therapy and cardiac neuromodulation stimulation.Amongst these, RDN is by far the most established technology. With recent robust evidence from clinical trials and real-world data showing the safety and efficacy of both ultrasound and radiofrequency-based approaches, a recent clinical consensus statement of the European Society of Cardiology Council on Hypertension and the European Association of Percutaneous Cardiovascular Interventions concludes that RDN represents an ancillary therapeutic option in patients with uncontrolled resistant HTN confirmed by ambulatory blood pressure measurement and in spite of attention to lifestyle changes and optimised pharmacological treatment. Furthermore, RDN could alos be considered for patienst unlikley to adhere to or tolerate long-term antihypertensive drug treatment. Very recent data indicate long-term safety and efficacy up to 10 years. Appropriate implementation of RDN into clinical practice is now warranted.For all other interventions additional data from adequately designed human studies are required to establish their safety and clinical utility for potential future use in routine practice.

Resistant hypertension: consensus document from the Korean society of hypertension

Although reports vary, the prevalence of true resistant hypertension and apparent treatment-resistant hypertension (aTRH) has been reported to be 10.3% and 14.7%, respectively. As there is a rapid increase in the prevalence of obesity, chronic kidney disease, and diabetes mellitus, factors that are associated with resistant hypertension, the prevalence of resistant hypertension is expected to rise as well. Frequently, patients with aTRH have pseudoresistant hypertension [aTRH due to white-coat uncontrolled hypertension (WUCH), drug underdosing, poor adherence, and inaccurate office blood pressure (BP) measurements]. As the prevalence of WUCH is high among patients with aTRH, the use of out-of-office BP measurements, both ambulatory blood pressure monitoring (ABPM) and home blood pressure monitoring (HBPM), is essential to exclude WUCH. Non-adherence is especially problematic, and methods to assess adherence remain limited and often not clinically feasible. Therefore, the use of HBPM and higher utilization of single-pill fixed-dose combination treatments should be emphasized to improve drug adherence. In addition, primary aldosteronism and symptomatic obstructive sleep apnea are quite common in patients with hypertension and more so in patients with resistant hypertension. Screening for these diseases is essential, as the treatment of these secondary causes may help control BP in patients who are otherwise difficult to treat. Finally, a proper drug regimen combined with lifestyle modifications is essential to control BP in these patients.

Neuromodulation Therapies in Heart Failure: A State-of-the-Art Review

Heart failure (HF) continues to impact the population globally with increasing prevalence. While the pathophysiology of HF is quite complex, the dysregulation of the autonomic nervous system, as evident in heightened sympathetic activity, serves as an attractive pathophysiological target for newer therapies and HF. The degree of neurohormonal activation has been found to correlate to the severity of symptoms, decline in functional capacity, and mortality. Neuromodulation of the autonomic nervous system aims to restore the balance between sympathetic nervous system and the parasympathetic nervous system. Given that autonomic dysregulation plays a major role in the development and progression of HF, restoring this balance may potentially have an impact on the core pathophysiological mechanisms and various HF syndromes. Autonomic modulation has been proposed as a potential therapeutic strategy aimed at reduction of systemic inflammation. Such therapies, complementary to drug and device-based therapies may lead to improved patient outcomes and reduce disease burden. Most professional societies currently do not provide a clear recommendation on the use of neuromodulation techniques in HF. These include direct and indirect vagal nerve stimulation, spinal cord stimulation, baroreflex activation therapy, carotid sinus stimulation, aortic arch stimulation, splanchnic nerve modulation, cardiopulmonary nerve stimulation, and renal sympathetic nerve denervation. In this review, we provide a comprehensive overview of neuromodulation in HF.

Advances in the Pathogenesis and Treatment of Resistant Hypertension

Hypertension is a prevalent chronic disease associated with an increased risk of cardiovascular (CV) premature death, and its severe form manifests as resistant hypertension (RH). The accurate prevalence of resistant hypertension is difficult to determine due to the discrepancy in data from various populations, but according to recent publications, it ranges from 6% to 18% in hypertensive patients. However, a comprehensive understanding of the pathogenesis and treatment of RH is essential. This review emphasizes the importance of identifying the causes of treatment resistance in antihypertensive therapy and highlights the utilization of appropriate diagnostic methods. We discussed innovative therapies such as autonomic neuromodulation techniques like renal denervation (RDN) and carotid baroreceptor stimulation, along with invasive interventions such as arteriovenous anastomosis as potential approaches to support patients with inadequate medical treatment and enhance outcomes in RH.

Autonomic control of ventricular function in health and disease: current state of the art

PURPOSE

Cardiac autonomic dysfunction is one of the main pillars of cardiovascular pathophysiology. The purpose of this review is to provide an overview of the current state of the art on the pathological remodeling that occurs within the autonomic nervous system with cardiac injury and available neuromodulatory therapies for autonomic dysfunction in heart failure.

METHODS

Data from peer-reviewed publications on autonomic function in health and after cardiac injury are reviewed. The role of and evidence behind various neuromodulatory therapies both in preclinical investigation and in-use in clinical practice are summarized.

RESULTS

A harmonic interplay between the heart and the autonomic nervous system exists at multiple levels of the neuraxis. This interplay becomes disrupted in the setting of cardiovascular disease, resulting in pathological changes at multiple levels, from subcellular cardiac signaling of neurotransmitters to extra-cardiac, extra-thoracic remodeling. The subsequent detrimental cycle of sympathovagal imbalance, characterized by sympathoexcitation and parasympathetic withdrawal, predisposes to ventricular arrhythmias, progression of heart failure, and cardiac mortality. Knowledge on the etiology and pathophysiology of this condition has increased exponentially over the past few decades, resulting in a number of different neuromodulatory approaches. However, significant knowledge gaps in both sympathetic and parasympathetic interactions and causal factors that mediate progressive sympathoexcitation and parasympathetic dysfunction remain.

CONCLUSIONS

Although our understanding of autonomic imbalance in cardiovascular diseases has significantly increased, specific, pivotal mediators of this imbalance and the recognition and implementation of available autonomic parameters and neuromodulatory therapies are still lagging.

A systematic review and meta-analysis of all sham and placebo controlled trials for resistant hypertension

INTRODUCTION

There is a lack of consensus regarding the best add on therapy for treatment of resistant hypertension (RH). This is likely secondary to a paucity of data on the comparative effectiveness of proposed therapies for RH.

METHODS

Placebo-controlled and sham-controlled randomized clinical trials testing therapies for the treatment of RH were included in this meta-analysis. Therapies with two or more studies were included as subgroups in this meta-analysis. The primary outcomes being tested were 24-hr systolic blood pressure (SBP) and office SBP.

RESULTS

Eight studies were identified that tested mineralocorticoid receptor antagonist (MRA) including 1,414 participants. The raw mean difference (RMD) between MRA and placebo control was statistically significant for 24-hour SBP (-10.56 mmHg; 95% confidence interval (CI) -12.82 to -8.30), 24-hour diastolic (DBP) (-5.48 mmHg; 95% CI -8.48 to -2.58), office SBP (-11.97 mmHg; 95% CI -16.41 to -7.54), and office DBP (-4.14 mmHg; 95% CI -5.62 to -2.65). Six studies were identified that tested renal denervation (RD) including 989 participants. The RMD between RD and sham control was not statistically significant for 24-hour SBP (-1.84 mmHg; 95% CI -3.92 to 0.24), 24-hour DBP (-0.66 mmHg; 95% CI -1.85 to 0.54), office SBP (-1.57 mmHg; 95% CI -6.04 to 2.89), and office DBP (-1.49 mmHg; 95% CI -3.52 to 0.55). Four studies were identified that tested endothelin receptor antagonists (ERA) including 1,193 participants. The raw mean difference (RMD) between ERA and placebo control was statistically significant for 24-hr systolic (SBP) (-7.02 mmHg; 95% CI -9.15 to -4.90, 24-hr diastolic (DBP) (-6.22 mmHg; 95% CI -7.61 to -4.82), office SBP (-5.84 mmHg; 95% CI -10.08 to -1.60), and office DBP (-3.73 mmHg; 95% CI -5.87 to -1.59).

DISCUSSION

MRA lowers BP in patients with RH more than RD, which seems to have little to no effect in RH. ERAs lead to a statistically significant reduction in BP but the confidence in efficacy is limited due to the low number of studies and differences in trial population. Individual factors and their impact on treatment response in RH should be investigated in future research.

When blood pressure refuses to budge: exploring the complexity of resistant hypertension

Resistant hypertension, defined as blood pressure that remains above goal despite using three or more antihypertensive medications, including a diuretic, affects a significant proportion of the hypertensive population and is associated with increased cardiovascular morbidity and mortality. Despite the availability of a wide range of pharmacological therapies, achieving optimal blood pressure control in patients with resistant hypertension remains a significant challenge. However, recent advances in the field have identified several promising treatment options, including spironolactone, mineralocorticoid receptor antagonists, and renal denervation. In addition, personalized management approaches based on genetic and other biomarkers may offer new opportunities to tailor therapy and improve outcomes. This review aims to provide an overview of the current state of knowledge regarding managing resistant hypertension, including the epidemiology, pathophysiology, and clinical implications of the condition, as well as the latest developments in therapeutic strategies and future prospects.

A new use of transcutaneous electrical nerve stimulation: Role of bioelectric technology in resistant hypertension (Review)

Hypertension is an important risk factor for cardiovascular and cerebrovascular disease-associated death. Hypertension and its complications are the main problems that have an impact on public health at present. A portion of adults with hypertension fail to meet the recommended blood pressure (BP) treatment goals, despite strict clinical management. Those individuals requiring at least three types of antihypertensive drugs to achieve their BP goal may be classified as patients with resistant hypertension (RH). Bioelectric technology is an emerging method that functions with the help of the human body's own bioelectric system. It is widely used in auxiliary examination, pain relief and organ function rehabilitation. Bioelectrical technology, as an effective treatment for RH, has developed rapidly in recent years and mainly includes renal sympathetic denervation, carotid baroreflex activation therapy, Traditional Chinese Medicine electroacupuncture and transcutaneous electrical nerve stimulation (TENS). The present review describes the pathogenesis of hypertension and provides an understanding of bioelectrical technology as a treatment. In particular, the development of the application of TENS in RH is introduced. The aim is to provide a basis for the clinical treatment of RH and a new idea for further clinical trials in this field.

Hypotensive Effect of Electric Stimulation of Caudal Ventrolateral Medulla in Freely Moving Rats

Background and Objectives: An altered sympathetic function is established in primary arterial hypertension (PAH) development. Therefore, PAH could be targeted by applying an electric current to the medulla where reflex centers for blood pressure control reside. This study aims to evaluate the electric caudal ventrolateral medulla (CVLM) stimulation effect on blood pressure and animal survivability in a freely moving rat model. Materials and Methods: A total of 20 Wistar rats aged 12-16 weeks were randomly assigned to either: the experimental group (n = 10; electrode tip implanted in CVLM region) or the control group (n = 10; tip implanted 4 mm above the CVLM in the cerebellum). After a period of recovery (4 days), an experimental phase ensued, divided into an "OFF stimulation" period (5-7 days post-surgery) and an "ON stimulation" period (8-14 days post-surgery). Results: Three animals (15%, one in the control, two in the experimental group) dropped out due to postoperative complications. Arterial pressure in the experimental group rats during the "OFF stimulation" period decreased by 8.23 mm Hg (p = 0.001) and heart rate by 26.93 beats/min (p = 0.008). Conclusions: From a physiological perspective, CVLM could be an effective deep brain stimulation (DBS) target for drug-resistant hypertension: able to influence the baroreflex arc directly, having no known direct integrative or neuroendocrine function. Targeting the baroreflex regulatory center, but not its sensory or effector parts, could lead to a more predictable effect and stability of the control system. Although targeting neural centers in the medullary region is considered dangerous and prone to complications, it could open a new vista for deep brain stimulation therapy. A possible change in electrode design would be required to apply CVLM DBS in clinical trials in the future.

Autonomic Regulation of Inflammation in Conscious Animals

Bioelectronic medicine is a novel field in modern medicine based on the specific neuronal stimulation to control organ function, cardiovascular, and immune homeostasis. However, most studies addressing neuromodulation of the immune system have been conducted on anesthetized animals, which can affect the nervous system and neuromodulation. Here, we review recent studies involving conscious experimental rodents (rats and mice) to better understand the functional organization of neural control of immune homeostasis. We highlight typical experimental models of cardiovascular regulation, such as electrical activation of the aortic depressor nerve or the carotid sinus nerve, bilateral carotid occlusion, the Bezold-Jarisch reflex, and intravenous administration of the bacterial endotoxin lipopolysaccharide. These models have been used to investigate the relationship between neuromodulation of the cardiovascular and immune systems in conscious rodents (rats and mice). These studies provide critical information about the neuromodulation of the immune system, particularly the role of the autonomic nervous system, i.e., the sympathetic and parasympathetic branches acting both centrally (hypothalamus, nucleus ambiguus, nucleus tractus solitarius, caudal ventrolateral medulla, and rostral ventrolateral medulla), and peripherally (particularly spleen and adrenal medulla). Overall, the studies in conscious experimental models have certainly highlighted to the reader how the methodological approaches used to investigate cardiovascular reflexes in conscious rodents (rats and mice) can also be valuable for investigating the neural mechanisms involved in inflammatory responses. The reviewed studies have clinical implications for future therapeutic approaches of bioelectronic modulation of the nervous system to control organ function and physiological homeostasis in conscious physiology.

Pathophysiology of the Nondipping Blood Pressure Pattern

The nondipping blood pressure (BP) pattern corresponds to a disruption in the circadian BP rhythm with an insufficient decrease in BP levels during nighttime sleep as observed using 24-hour ambulatory BP monitoring. Patients with nondipping BP pattern have poorer renal and cardiovascular outcomes, independent of their average 24-hour BP levels. The pathophysiology of nondipping BP is complex and involves numerous mechanisms: perturbations of (1) the circadian rhythm, (2) the autonomic nervous system, and (3) water and sodium regulation. This review provides an outline of the pathways potentially involved in the nondipping BP profile in different conditions. A recent hypothesis is also discussed involving the role of gut microbiota in the dipping/nondipping patterns, via the fecal diet-derived short chain fatty acids.

Emerging topics on basic research in hypertension: interorgan communication and the need for interresearcher collaboration

The pathogenesis of hypertension is multifactorial and highly complex. Basic research plays critical roles in elucidating the complex pathogenesis of hypertension and developing its treatment. This review covers recent topics in basic research related to hypertension in the following six parts: brain/autonomic nervous system, kidney, vascular system, potential treatments, extracellular vesicles, and gut microbiota. The brain receives afferent nerve inputs from peripheral organs, including the heart, kidneys, and adipose tissue, and humoral inputs from circulating factors such as proinflammatory cytokines and leptin, which are involved in the regulation of central sympathetic outflow. In the kidneys, changes in Wnt/β-catenin signaling have been reported in several hypertensive models. New findings on the renin-angiotensin-aldosterone system in the kidneys have also been reported. Sirtuin 6, which participates in various cellular functions, including DNA repair, has been shown to have protective effects on the vascular system. Skin water conservation, mediated by skin vasoconstriction and the accumulation of osmolytes such as sodium, has been found to contribute to hypertension. Studies of rivaroxaban and sodium-glucose cotransporter-2 inhibitors as drug repositioning candidates have been performed. Extracellular vesicles have been shown to be involved in novel diagnostic approaches and treatments for hypertension as well as other diseases. In gut microbiota studies, interactions between microbiota and antihypertensive drugs and potential pathophysiology linking microbiota and COVID-19 have been reported. It can be seen that inter-organ communication has received particular attention from these recent research topics. To truly understand the pathogenesis of hypertension and to develop treatments for conquering hypertension, interresearcher communication and collaboration should be further facilitated. This mini-review focuses on recent topics on basic research in hypertension from the several points of view. The recent topics indicate that inter-organ communication has received particular attention. Interresearcher communication and collaboration should also be further facilitated to truly understand the complex pathogenesis of hypertension and to develop the treatments.

Etiological Diagnosis and Personalized Therapy for Hypertension: A Hypothesis of the REASOH Classification

With the epidemic of risk factors such as unhealthy lifestyle, obesity and mental stress, the prevalence of hypertension continues to rise across the world. Although standardized treatment protocols simplify the selection of antihypertensive drugs and ensure therapeutic efficacy, the pathophysiological state of some patients remains, which may also lead to the development of other cardiovascular diseases. Thus, there is an urgent need to consider the pathogenesis and selection of antihypertensive drug for different type of hypertensive patients in the era of precision medicine. We proposed the REASOH classification, based on the etiology of hypertension, including renin-dependent hypertension, elderly-arteriosclerosis-based hypertension, sympathetic-active hypertension, secondary hypertension, salt-sensitive hypertension and hyperhomocysteinemia hypertension. The aim of this paper is to propose a hypothesis and provide a brief reference for the personalized treatment of hypertensive patients.

Novel Invasive Methods as the Third Pillar for the Treatment of Essential Uncontrolled Hypertension

Pharmacologic therapies remain the treatment of choice for patients with essential hypertension, as endorsed by international guidelines. However, several cases warrant additional modalities, such as invasive antihypertensive therapeutics. The major target of these interventions is the modulation of the sympathetic nervous system, which is a common pathophysiologic mechanism in essential hypertension. In this narrative review, we elaborate on the role of invasive antihypertensive treatments with a focus on renal denervation, stressing their potential as well as the drawbacks that prevent their widespread implementation in everyday clinical practice. In the field of renal denervation, several trials have shown significant and sustained reductions in the level of office and ambulatory blood pressure, regardless of the type of energy that was used (radiofrequency or ultrasound). Critically, renal denervation is considered a safe intervention, as evidenced by follow-up data from large clinical trials. Baroreflex activation therapy may result in enhanced parasympathetic nervous system activation, thus lowering blood pressure levels. Along the same lines, carotid body ablation could also produce a significant antihypertensive effect, which has not been tested in appropriately designed randomized trials. Moreover, cardiac neuromodulation therapy could prove efficacious by altering the duration of the atrioventricular interval in order to regulate the preload of the left ventricle and, therefore, lower blood pressure.

Effect of baroreflex activation therapy on dipping pattern in patients with resistant hypertension

A relevant number of patients with resistant hypertension do not achieve blood pressure (BP) dipping during nighttime. This inadequate nocturnal BP reduction is associated with elevated cardiovascular risks. The aim of this study was to evaluate whether a nighttime intensification of BAT might improve nocturnal BP dipping. In this prospective observational study, non-dippers treated with BAT for at least 6 months were included. BAT programming was modified in a two-step intensification of nighttime stimulation at baseline and week 6. Twenty-four hours ambulatory BP (ABP) was measured at inclusion and after 3 months. A number of 24 patients with non- or inverted dipping pattern, treated with BAT for a median of 44 months (IQR 25-52) were included. At baseline of the study, patients were 66 ± 9 years old, had a BMI of 33 ± 6 kg/m² , showed an office BP of 135 ± 22/72 ± 10 mmHg, and took a median number of antihypertensives of 6 (IQR 4-9). Nighttime stimulation of BAT was adapted by an intensification of pulse width from 237 ± 161 to 267 ± 170 μs (p = .003) while frequency (p = .10) and amplitude (p = .95) remained unchanged. Uptitration of BAT programming resulted in an increase of systolic dipping from 2 ± 6 to 6 ± 8% (p = .03) accompanied with a significant improvement of dipping pattern (p = .02). Twenty four hours ABP, day- and nighttime ABP remained unchanged. Programming of an intensified nighttime BAT interval improved dipping profile in patients treated with BAT, while the overall 24 h ABP did not change. Whether the improved dipping response contributes to a reduction of cardiovascular risk beyond the BP-lowering effects of BAT, however, remains to be shown.

Emerging drugs for the treatment of diabetic nephropathy

INTRODUCTION

Diabetic nephropathy remains a significant economic and social burden on both the individual patient and health-care systems as the prevalence of diabetes increases in the general population. The complex pathophysiology of diabetic kidney disease poses a challenge in the development of effective medical treatments for the disease. However, the multiple facets of diabetic nephropathy also offer a variety of potential strategies to manage this condition.

AREAS COVERED

We retrieved PubMed, Cochrane Library, Scopus, Google Scholar, and ClinicalTrials.gov records to identify studies and articles focused on new pharmacologic advances to treat diabetic nephropathy.

EXPERT OPINION

RAAS blockers have remained the mainstay of therapy for DM nephropathy for many years, with only recent advancements with SGLT2 inhibitors and nonsteroidal MRAs. Better understanding of the long-term renal effects of ambient hyperglycemia, ranging from hemodynamic changes to increased production of oxidative and pro-inflammatory substances, has evolved our approach to the treatment of diabetic nephropathy. With continuing research for new therapeutics as well as combination therapy, the medical community may be able to better ease the burden of diabetic kidney disease.

Screening for Obstructive Sleep Apnea in Adults: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Obstructive sleep apnea (OSA) is associated with adverse health outcomes.

OBJECTIVE

To review the evidence on screening for OSA in asymptomatic adults or those with unrecognized OSA symptoms to inform the US Preventive Services Task Force.

DATA SOURCES

PubMed/MEDLINE, Cochrane Library, Embase, and trial registries through August 23, 2021; surveillance through September 23, 2022.

STUDY SELECTION

English-language studies of screening test accuracy, randomized clinical trials (RCTs) of screening or treatment of OSA reporting health outcomes or harms, and systematic reviews of treatment reporting changes in blood pressure and apnea-hypopnea index (AHI) scores.

DATA EXTRACTION AND SYNTHESIS

Dual review of abstracts, full-text articles, and study quality. Meta-analysis of intervention trials.

MAIN OUTCOMES AND MEASURES

Test accuracy, excessive daytime sleepiness, sleep-related and general health-related quality of life (QOL), and harms.

RESULTS

Eighty-six studies were included (N = 11 051). No study directly compared screening with no screening. Screening accuracy of the Multivariable Apnea Prediction score followed by unattended home sleep testing for detecting severe OSA syndrome (AHI ≥30 and Epworth Sleepiness Scale [ESS] score &gt;10) measured as the area under the curve in 2 studies (n = 702) was 0.80 (95% CI, 0.78 to 0.82) and 0.83 (95% CI, 0.77 to 0.90). Five studies assessing the accuracy of other screening tools were heterogeneous and results were inconsistent. Compared with inactive control, positive airway pressure was associated with a significant improvement in ESS score from baseline (pooled mean difference, -2.33 [95% CI, -2.75 to -1.90]; 47 trials; n = 7024), sleep-related QOL (standardized mean difference, 0.30 [95% CI, 0.19 to 0.42]; 17 trials; n = 3083), and general health-related QOL measured by the 36-Item Short Form Health Survey (SF-36) mental health component summary score change (pooled mean difference, 2.20 [95% CI, 0.95 to 3.44]; 15 trials; n = 2345) and SF-36 physical health component summary score change (pooled mean difference, 1.53 [95% CI, 0.29 to 2.77]; 13 trials; n = 2031). Use of mandibular advancement devices was also associated with a significantly larger ESS score change compared with controls (pooled mean difference, -1.67 [95% CI, 2.09 to -1.25]; 10 trials; n = 1540). Reporting of other health outcomes was sparse; no included trial found significant benefit associated with treatment on mortality, cardiovascular events, or motor vehicle crashes. In 3 systematic reviews, positive airway pressure was significantly associated with reduced blood pressure; however, the difference was relatively small (2-3 mm Hg).

CONCLUSIONS AND RELEVANCE

The accuracy and clinical utility of OSA screening tools that could be used in primary care settings were uncertain. Positive airway pressure and mandibular advancement devices reduced ESS score. Trials of positive airway pressure found modest improvement in sleep-related and general health-related QOL but have not established whether treatment reduces mortality or improves most other health outcomes.

Device-Based Therapy for Resistant Hypertension: An Up-to-Date Review

Hypertension is the major risk factor for cardiovascular morbidity and mortality. Matter of fact, untreated hypertension can worsen the overall health, whereas pharmacotherapy can play an important role in lowering the risk of high blood pressure in hypertensive patients. However, persistent uncontrolled hypertension remains an unsolved condition characterized by non-adherence to medication and increased sympathetic activity. This paper will review the non-pharmacological treatments for resistant hypertension (RH) that have emerged in recent years. In addition, the technologies developed in device-based RH therapy, as well as the clinical trials that support their use, will be discussed. Indeed, the novel device-based approaches that target RH present a promising therapy which has been supported by several studies and clinical trials, whereas drug non-adherence and high sympathetic activity are known to be the main causes of RH. Nevertheless, some additional aspects of these RH systems need to be tested in the near future, with a particular focus on the device's design and availability of randomized controlled trials.

Hypertension in chronic kidney disease: What lies behind the scene

Hypertension is a frequent condition encountered during kidney disease development and a leading cause in its progression. Hallmark factors contributing to hypertension constitute a complexity of events that progress chronic kidney disease (CKD) into end-stage renal disease (ESRD). Multiple crosstalk mechanisms are involved in sustaining the inevitable high blood pressure (BP) state in CKD, and these play an important role in the pathogenesis of increased cardiovascular (CV) events associated with CKD. The present review discusses relevant contributory mechanisms underpinning the promotion of hypertension and their consequent eventuation to renal damage and CV disease. In particular, salt and volume expansion, sympathetic nervous system (SNS) hyperactivity, upregulated renin–angiotensin–aldosterone system (RAAS), oxidative stress, vascular remodeling, endothelial dysfunction, and a range of mediators and signaling molecules which are thought to play a role in this concert of events are emphasized. As the control of high BP via therapeutic interventions can represent the key strategy to not only reduce BP but also the CV burden in kidney disease, evidence for major strategic pathways that can alleviate the progression of hypertensive kidney disease are highlighted. This review provides a particular focus on the impact of RAAS antagonists, renal nerve denervation, baroreflex stimulation, and other modalities affecting BP in the context of CKD, to provide interesting perspectives on the management of hypertensive nephropathy and associated CV comorbidities.

Current and future use of neuromodulation in heart failure. Eur Heart J Suppl 2022;24:E28-E34. [PMID: 35991620 PMCID: PMC9385118 DOI: 10.1093/eurheartjsupp/suac031]

Autonomic imbalance is a common finding in heart failure (HF) with reduced ejection fraction (HFrEF). Addressing different targets within the autonomic nervous systems has been evaluated in patients with HF, including renal sympathetic denervation, vagal nerve stimulation, and baroreceptor activation therapy (BAT). Although all are pathophysiologically plausible and promising, only BAT shows sufficient evidence for implementation into clinical practice in randomized controlled trials. Baroreceptor activation therapy can be used in patients with symptomatic HFrEF despite optimal guideline-directed medication and device therapy. This article reviews the current and future use of neuromodulation in HF and provides an overview on current guideline recommendations and clinical practice.

Neuromodulation devices for heart failure

Autonomic imbalance with a sympathetic dominance is acknowledged to be a critical determinant of the pathophysiology of chronic heart failure with reduced ejection fraction (HFrEF), regardless of the etiology. Consequently, therapeutic interventions directly targeting the cardiac autonomic nervous system, generally referred to as neuromodulation strategies, have gained increasing interest and have been intensively studied at both the pre-clinical level and the clinical level. This review will focus on device-based neuromodulation in the setting of HFrEF. It will first provide some general principles about electrical neuromodulation and discuss specifically the complex issue of dose-response with this therapeutic approach. The paper will thereafter summarize the rationale, the pre-clinical and the clinical data, as well as the future prospectives of the three most studied form of device-based neuromodulation in HFrEF. These include cervical vagal nerve stimulation (cVNS), baroreflex activation therapy (BAT), and spinal cord stimulation (SCS). BAT has been approved by the Food and Drug Administration for use in patients with HfrEF, while the other two approaches are still considered investigational; VNS is currently being investigated in a large phase III Study.

Impact of medication adherence on the efficacy of Baroreflex activation therapy

Therapy adherence significantly determines the success of antihypertensive therapy, especially in patients with resistant hypertension. Our study investigates the impact of drug adherence on the efficacy of Baroreflex‐activation‐therapy (BAT). In this retrospective analysis, the authors measured blood pressure (BP) and antihypertensive medication adherence (by gas chromatography‐mass spectrometry [GC‐MS] urine analysis) before and 6 months after BAT initiation. Adherence was defined as detection of ≥80% intake of prescribed medication at the time of follow‐up. Response to BAT was defined as BP drop ≥5 mmHg in systolic 24 h‐ambulatory BP (ABP) after 6 months. Overall patients (n = 38) median medication adherence was low, but rose from 60% (IQR 25%–100%) to 75% (IQR 38%–100%; p = .0194). After 6 months of BAT, mean systolic and diastolic office BP (‐21 ± 25 mmHg and ‐9 ± 15 mmHg; p < .0001 and .0004) as well as 24 h‐ABP dropped significantly (‐9 ± 17 mmHg and ‐5 ± 12 mmHg; p = .0049 and .0280). After 6 months of BAT, 21 patients (60%) could be classified as responders. There was neither significant difference in mean office systolic (‐21 ± 23 mmHg vs. ‐21 ± 28 mmHg; p = .9581) nor in 24 h‐systolic ABP decrease (‐11 ± 19 mmHg vs. ‐7 ± 15 mmHg; p = .4450) comparing adherent and non‐adherent patients. Whereas Antihypertensive Therapeutic Index (ATI) was unchanged in non‐responders, it significantly decreased in responders (from 50 ± 16 to 46 ± 16; p = .0477). These data are the first to show that BAT‐initiation leads to a clear BP reduction independently of patients´ medication adherence. Response to BAT is associated with a significant lowering of ATI, which might contribute to an underestimation of BAT efficacy.

Low intensity stimulation of aortic baroreceptor afferent fibers as a potential therapeutic alternative for hypertension treatment

Carotid baroreceptor stimulation has been clinically explored for antihypertensive benefits, but neuromodulation of aortic baroreceptor afferents remains unexplored for potential translation into the clinic. Published studies have used supramaximal stimulations, which are unphysiological and energy inefficient. The objective of the present study was to identify optimal low-charge nerve stimulation parameters that would provide a clinically-relevant (20–30 mmHg) decrease in mean arterial pressure (MAP) in anesthetized spontaneously hypertensive rats. Stimulations of 20 s were delivered to the left aortic depressor nerve (ADN) of these rats using low ranges of pulse amplitudes (≤ 0.6 mA), widths (≤ 0.5 ms) and frequencies (≤ 5 Hz). We also assessed the effects of continuous (20 s) versus intermittent (5 s ON/3 s OFF and 5 s ON/3 s OFF for 20 s) stimulation on MAP, heart rate (HR), mesenteric (MVR) and femoral (FVR) vascular resistance using low (5 Hz) and high (15 Hz) frequencies. Lower pulse amplitudes (0.2 mA) produced 9 ± 2 to 18 ± 2 mmHg decreases in MAP. Higher pulse amplitudes (0.4 mA) produced a median MAP reduction of 28 ± 4 mmHg at 0.2 ms and 5 Hz, with no added benefit seen above 0.4 mA. Continuous and intermittent low frequency stimulation at 0.4 mA and 0.2 ms produced similar sustained decreases in MAP, HR, MVR and FVR. Continuous high frequency stimulation at 0.4 mA and 0.2 ms produced larger reductions in MAP, HR, MVR and FVR compared with all low frequency and/or intermittent high frequency stimulations. We conclude from these findings that “low intensity intermittent” electrical stimulation is an effective alternate way for neuromodulation of the aortic baroreceptor afferents and to evoke a required restoration of MAP levels in spontaneously hypertensive rats. This approach enables low energy consumption and markedly lowers the excessive decreases in MAP and hemodynamic disturbances elicited by continuous high-charge injection protocols.

An Update on Refractory Hypertension

Purpose of Review

To update on definition, diagnosis, prevalence, patient characteristics, pathophysiology, and treatment of refractory hypertension (RfHTN).

Recent Findings

Refractory hypertension (RfHTN) is defined as blood pressure (BP) that is uncontrolled despite using ≥ 5 antihypertensive medications of different classes, including a long-acting thiazide diuretic and a mineralocorticoid receptor antagonist (MRA) at maximal or maximally tolerated doses. This new phenotype is different from resistant hypertension (RHTN), defined as BP that is uncontrolled despite using ≥ 3 medications, commonly a long-acting calcium channel blocker (CCB), a blocker of the renin-angiotensin system (angiotensin-converting enzyme [ACE] inhibitor or angiotensin receptor blocker [ARB]), and a diuretic. The RHTN phenotype includes controlled RHTN, BP that is controlled on 4 or more medications. RfHTN is largely attributable to increased sympathetic activity, unlike RHTN, which is mainly due to increased intravascular fluid volume frequently caused by hyperaldosteronism and chronic excessive sodium ingestion. Compared to those with controlled RHTN, patients with RfHTN have a higher prevalence of target organ damage and do not have elevated aldosterone levels. Ongoing clinical trials are assessing the safety and efficacy of using devices to aid with BP control in patients with RfHTN.

Summary

RfHTN is a separate entity from RHTN and is generally attributable to increased sympathetic activity.

New Insights Into Cerebrovascular Pathophysiology and Hypertension

Despite advances in acute management and prevention of cerebrovascular disease, stroke and vascular cognitive impairment together remain the world's leading cause of death and neurological disability. Hypertension and its consequences are associated with over 50% of ischemic and 70% of hemorrhagic strokes but despite good control of blood pressure (BP), there remains a 10% risk of recurrent cerebrovascular events, and there is no proven strategy to prevent vascular cognitive impairment. Hypertension evolves over the lifespan, from predominant sympathetically driven hypertension with elevated mean BP in early and mid-life to a late-life phenotype of increasing systolic and falling diastolic pressures, associated with increased arterial stiffness and aortic pulsatility. This pattern may partially explain both the increasing incidence of stroke in younger adults as well as late-onset, chronic cerebrovascular injury associated with concurrent systolic hypertension and historic mid-life diastolic hypertension. With increasing arterial stiffness and autonomic dysfunction, BP variability increases, independently predicting the risk of ischemic and intracerebral hemorrhage, and is potentially modifiable beyond control of mean BP. However, the interaction between hypertension and control of cerebral blood flow remains poorly understood. Cerebral small vessel disease is associated with increased pulsatility in large cerebral vessels and reduced reactivity to carbon dioxide, both of which are being targeted in early phase clinical trials. Cerebral arterial pulsatility is mainly dependent upon increased transmission of aortic pulsatility via stiff vessels to the brain, while cerebrovascular reactivity reflects endothelial dysfunction. In contrast, although cerebral autoregulation is critical to adapt cerebral tone to BP fluctuations to maintain cerebral blood flow, its role as a modifiable risk factor for cerebrovascular disease is uncertain. New insights into hypertension-associated cerebrovascular pathophysiology may provide key targets to prevent chronic cerebrovascular disease, acute events, and vascular cognitive impairment.

Rethinking Resistant Hypertension

Resistant hypertension is common and known to be a risk factor for cardiovascular events, including stroke, myocardial infarction, heart failure, and cardiovascular mortality, as well as adverse renal events, including chronic kidney disease and end-stage kidney disease. This review will discuss the definition of resistant hypertension as well as the most recent evidence regarding its diagnosis, evaluation, and management. The issue of medication non-adherence and its association with apparent treatment-resistant hypertension will be addressed. Non-pharmacological interventions for the treatment of resistant hypertension will be reviewed. Particular emphasis will be placed on pharmacological interventions, highlighting the role of mineralocorticoid receptor antagonists and sodium-glucose cotransporter-2 inhibitors and device therapy, including renal denervation, baroreceptor activation or modulation, and central arteriovenous fistula creation.

Treatment of Resistant Hypertension With Endovascular Baroreflex Amplification: 3-Year Results From the CALM-FIM Study

OBJECTIVES

The aim of this study was to evaluate the long-term (3-year) safety and effectiveness of endovascular baroreflex amplification (EVBA) from both the European and American CALM-FIM cohorts.

BACKGROUND

The CALM-FIM study demonstrated that EVBA in patients with resistant hypertension significantly lowered blood pressure (BP) with an acceptable safety profile during 6-month follow-up.

METHODS

The CALM-FIM studies were prospective, nonrandomized, first-in-human studies that enrolled patients with resistant hypertension (office systolic BP ≥160 mm Hg and mean 24-hour ambulatory BP ≥130/80 mm Hg despite a stable regimen of ≥3 antihypertensive medications, including a diuretic agent). The incidence of (serious) adverse events and changes in BP, heart rate, and prescribed antihypertensive medication up to 3 years after implantation were determined.

RESULTS

The Mobius device was implanted in 47 patients (30 in Europe, 17 in the United States; mean age 54 years, 23 women). Five serious adverse events (hypotension, n = 2; hypertension, n = 1; vascular access complications, n = 2) and 2 transient ischemic attacks occurred within 30 days postprocedure. Two strokes and 1 transient ischemic attack occurred more than 2 years postimplantation. Mean office BP at baseline was 181 ± 17/107 ± 16 mm Hg and decreased by 25/12 mm Hg (95% CI: 17-33/8-17 mm Hg) at 6 months and 30/12 mm Hg (95% CI: 21-38/8-17 mm Hg) at 3 years. Mean 24-hour ambulatory BP at baseline was 166 ± 16/98 ± 15 mm Hg and decreased by 20/11 mm Hg (95% CI: 14-25/8-15 mm Hg) at 6 months.

CONCLUSIONS

EVBA with the MobiusHD was effective in reducing BP at 3-year follow-up and appears to have an acceptable safety profile in patients with uncomplicated implantation, although data from randomized sham-controlled trials are needed to further evaluate the risk-benefit profile. (Controlling and Lowering Blood Pressure With the MobiusHD™ [CALM-FIM_EUR], NCT01911897; Controlling and Lowering Blood Pressure With the MobiusHD™ [CALM-FIM_US], NCT01831895).

Relationship Between Baroreflex and Cerebral Autoregulation in Patients With Cerebral Vasospasm After Aneurysmal Subarachnoid Hemorrhage

Introduction: Common consequences following aneurysmal subarachnoid hemorrhage (aSAH) are cerebral vasospasm (CV), impaired cerebral autoregulation (CA), and disturbance in the autonomic nervous system, as indicated by lower baroreflex sensitivity (BRS). The compensatory interaction between BRS and CA has been shown in healthy volunteers and stable pathological conditions such as carotid atherosclerosis. The aim of this study was to investigate whether the inverse correlation between BRS and CA would be lost in patients after aSAH during vasospasm. A secondary objective was to analyze the time-trend of BRS after aSAH.

Materials and Methods: Retrospective analysis of prospectively collected data was performed at the Neuro-Critical Care Unit of Addenbrooke's Hospital (Cambridge, UK) between June 2010 and January 2012. The cerebral blood flow velocity (CBFV) was measured in the middle cerebral artery using transcranial Doppler ultrasonography (TCD). The arterial blood pressure (ABP) was monitored invasively through an arterial line. CA was quantified by the correlation coefficient (Mxa) between slow oscillations in ABP and CBFV. BRS was calculated using the sequential cross-correlation method using the ABP signal.

Results: A total of 73 patients with aSAH were included. The age [median (lower-upper quartile)] was 58 (50–67). WFNS scale was 2 (1–4) and the modified Fisher scale was 3 (1–3). In the total group, 31 patients (42%) had a CV and 42 (58%) had no CV. ABP and CBFV were higher in patients with CV during vasospasm compared to patients without CV (p = 0.001 and p < 0.001). There was no significant correlation between Mxa and BRS in patients with CV, neither during nor before vasospasm. In patients without CV, a significant, although moderate correlation was found between BRS and Mxa (r_S = 0.31; p = 0.040), with higher BRS being associated with worse CA. Multiple linear regression analysis showed a significant worsening of BRS after aSAH in patients with CV (R_p = −0.42; p < 0.001).

Conclusions: Inverse compensatory correlation between BRS and CA was lost in patients who developed CV after aSAH, both before and during vasospasm. The impact of these findings on the prognosis of aSAH should be investigated in larger studies.