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

Changing the paradigm of long-term blood pressure control: a systematic review of novel therapies

Novel drug and device therapies have the potential to achieve long-term control of blood pressure (BP) and thereby overcome the barriers of nonadherence and undertreatment. We propose that ideal BP lowering therapy should meet six key criteria: (i) achieve a clinically relevant BP reduction; (ii) durable BP reduction; (iii) be well tolerated; (iv) have the ability to be safely combined with other BP lowering treatments; (v) have high patient acceptability and (vi) be cost-effective and simple to use to maximize scalability. In this paper, we systematically review emerging solutions for long-term control of BP including antibody-based therapies, sRNA therapies, and DNA-based gene editing which target the renin angiotensin system, and implant therapies, and interventional approaches (renal denervation and baroreceptor activation therapies). These novel therapies may substantially complement and, in some settings, even replace current antihypertensive therapies. Implementation will require significant progress in overcoming technological-, systems-, prescriber- and patient-level barriers.

Neurocardiology: translational advancements and potential

In our original white paper published in the The Journal of Physiology in 2016, we set out our knowledge of the structural and functional organization of cardiac autonomic control, how it remodels during disease, and approaches to exploit such knowledge for autonomic regulation therapy. The aim of this update is to build on this original blueprint, highlighting the significant progress which has been made in the field since and major challenges and opportunities that exist with regard to translation. Imbalances in autonomic responses, while beneficial in the short term, ultimately contribute to the evolution of cardiac pathology. As our understanding emerges of where and how to target in terms of actuators (including the heart and intracardiac nervous system (ICNS), stellate ganglia, dorsal root ganglia (DRG), vagus nerve, brainstem, and even higher centres), there is also a need to develop sensor technology to respond to appropriate biomarkers (electrophysiological, mechanical, and molecular) such that closed-loop autonomic regulation therapies can evolve. The goal is to work with endogenous control systems, rather than in opposition to them, to improve outcomes.

Effects of Sympathetic Denervation in Metabolism Regulation: A Novel Approach for the Treatment of MASLD?

Although metabolic dysfunction-associated steatotic liver disease (MASLD), previously termed nonalcoholic fatty liver disease, has become the most common chronic liver disorder, its complex pathophysiology has not been fully elucidated up to date. A correlation between elevated sympathetic activation and MASLD has been highlighted in recent preclinical and clinical studies. Furthermore, increased sympathetic activity has been associated with the main mechanisms involved in MASLD, such as lipid accumulation in the liver, insulin resistance, and metabolic dysregulation, while it has been also correlated with the progression of MASLD, leading to liver fibrosis. Preclinical studies demonstrated that therapies which ameliorate the activation of the sympathetic nervous system, such as renal and liver sympathetic denervation, reduce hepatic insulin resistance, decrease hepatic glucose production, and reverse hepatic steatosis in high-fat-diet models. However, data from clinical trials regarding the effect of renal denervation on metabolic parameters are conflicting, since several trials reported a favorable effect, while other trials stated no significant difference, with the profound limitation of the lack of originally designed denervation trials in this setting. Thus, a thorough review of the role of the sympathetic nervous system in the pathophysiology of MASLD, as well as the results of recent sympathetic denervation studies and trials regarding metabolic regulation and MASLD treatment would be of great importance.

Baroreflex Function in Cardiovascular Disease

The baroreflex system is involved in modulating several physiological functions of the cardiovascular system and can modulate cardiac output, blood pressure, and cardiac electrophysiology directly and indirectly. In addition, it is involved in regulating neurohormonal pathways involved in the cardiovascular function, such as the renin-angiotensin-aldosterone system 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, and coronary artery disease. Targeting the baroreflex system via invasive (eg, baroreflex activation therapy and endovascular baroreceptor amplification) and noninvasive approaches (eg, 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.

Early experience with baroreflex activation therapy from a vascular surgery perspective

Baroreflex activation therapy (BAT) is an emerging device-based treatment for patients with heart failure with a reduced ejection fraction refractory to maximally tolerated goal-directed medical therapy. Currently, there is sparse literature on the critical role that vascular surgeons serve in the delivery of this novel therapy. This single-institution series describes the creation of a BAT program and elaborates on the function of vascular surgeons in the multidisciplinary heart failure team. The preoperative evaluation, perioperative care, and postoperative course of patients receiving BAT from March 2022 to August 2023 were retrospectively analyzed. Eleven patients were evaluated by a dedicated heart failure cardiologist for medical eligibility and assessed by a vascular surgeon for technical feasibility. Of the 11 patients, 7 were men (63.6%). The median age was 60.5 years (range, 44-73 years). No patient (0.00%) had existing carotid artery disease, and one patient (9.1%) had undergone previous neck radiation therapy. All 11 patients (100%) had an existing cardiac implantable electronic device, and BAT implantation was performed on the same side as the cardiac implantable electronic device in two patients (18.1%). Four patients (36.4%) required preoperative hospital admission for medical optimization before surgery. The median length of surgery was 82 minutes (range, 58-113 minutes), and the median length of stay in the hospital after surgery was 1 day (range, 0-6 days). No major adverse neurologic or cardiovascular events, cranial nerve injuries, device complications requiring reintervention, or heart failure-related mortality at 6 months occurred. Three patients (27.3%) experienced extraneous stimulations, which affected BAT tolerability. Within 6 months after BAT implantation, no significant improvements were observed for several heart failure disease burden markers compared with 6 months before BAT implantation. Our early results demonstrate that BAT implantation is a safe procedure with rare complications. Vascular surgeons play an important role in the multidisciplinary delivery of this novel device-based therapy. More data are needed to understand whether BAT is beneficial in the treatment of heart failure with a reduced ejection fraction refractory to maximally tolerated goal-directed medical therapy.

Renal Denervation in Heart Failure Treatment: Data for a Self-Fulfilling Prophecy

Renal denervation (RDN), a transcatheter renal sympathetic nerve ablation procedure, is a relatively novel established procedure for the treatment of hypertension, with it being recognized as a third option for hypertension management in the most recent European guidelines, together with pharmacotherapy, for achieving blood pressure targets. Given the relationship between both hypertension and sympathetic overdrive and the development of heart failure (HF), even studies at the dawn of research on RDN explored it as a treatment to overcome diuretic resistance in those patients. As it is now recognized that RDN does not only have organ-specific but also systemic effects, several investigators have aimed to delineate whether renal sympathetic denervation could alter the prognosis, symptoms, and adverse events of HF patients. Data are available in both HF patients with reduced and preserved ejection fraction. As the significance of neuromodulation is gaining grounds in the HF therapeutic arsenal, in this review, we aim to provide a rationale for using RDN in HF and an up-to-date overview of available data in both HF phenotypes, as well as discuss the future of neuromodulatory therapy in HF management.

Options for patients with out-of-control blood pressure: after all avenues have been exhausted

INTRODUCTION

Uncontrolled hypertension is the leading risk factor for global mortality. Most hypertensive patients can be controlled with standard medication combinations, but some may not respond adequately to ≥3 or even to ≥5 antihypertensive agents.

AREAS COVERED

In this review, we summarize the recent literature on difficult-to-treat hypertension identified by a Medline search, and we discuss the options for fourth line and subsequent therapy.

EXPERT OPINION

It is essential to confirm resistant hypertension with out-of-office blood pressure measurements and to consider lifestyle factors, adherence to medication and secondary causes of hypertension. When true resistant hypertension is confirmed and blood pressure is not controlled with an optimal triple combination, preferably as a fixed dose combination tablet, spironolactone is usually recommended as the fourth medication. Comorbid conditions should be treated as appropriate with sodium-glucose-cotransporter 2 inhibitors, glucagon-like peptide-1 receptor agonists, sacubitril-valsartan or finerenone. Renal denervation appears to be a useful addition to overcome some of the problems of medication adherence. The endothelin antagonist aprocitentan may be a final option in some countries. Of the drugs in development, the RNA based therapeutics that inhibit angiotensinogen synthesis appear to be some of the most promising.

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.

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.

Baroreflex activation therapy for heart failure with reduced ejection fraction: A comprehensive systematic review and meta-analysis

Background

In recent years, baroreflex activation therapy (BAT) has been utilized to treat heart failure with reduced ejection fraction (HFrEF). However, the supporting literature on its efficacy and safety is still limited. This investigation elucidates the effects of BAT in HFrEF patients to provide a reference for future clinical applications.

Methods

This investigation follows Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) 2020 guidelines. Relevant investigations on the use of BAT in HFrEF patients were searched and selected from 5 databases, including Web of Science, MEDLINE, PubMed, Embase, and Cochrane Library, from inception to December 2022. The methodological quality of eligible articles was assessed via the Cochrane risk of bias tool, and for meta-analysis, RevMan (5.3) was used.

Results

Randomized controlled trials comprising 343 participants were selected for the meta-analysis, which revealed that in HFrEF patients, BAT enhanced the levels of LVEF (MD: 2.97, 95 % CI: 0.53 to 5.41), MLHFQ (MD: -14.81, 95 % CI: -19.57 to -10.06) and 6MWT (MD: 68.18, 95 % CI: 51.62 to 84.74), whereas reduced the levels of LVEDV (MD: -15.79, 95 % CI: -32.96 to 1.37) and DBP (MD: -2.43, 95 % CI: -4.18 to -0.68).

Conclusion

It was concluded that BAT is an efficient treatment option for HFrEF patients. However, to validate this investigation, further randomized clinical trials with multiple centers and large sample sizes are needed.

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.

Novel Therapies on the Horizon of Hypertension Management

BACKGROUND

The rates of uncontrolled hypertension, along with downstream cardiovascular outcomes, has been worsening in this country. Despite the plethora of antihypertensive medications on the market, the prevalence of resistant hypertension (RH) is estimated to be 13.7%. Therefore in addition to increased clinical education and focus on lifestyle management of hypertension and medication compliance, new therapies are needed to address this rise in hypertension.

METHODS

A systematic review of the available medical literature was performed to identify emerging treatment options for RH.

RESULTS

Six different pharmacologic classes and 2 procedural interventions were identified as being appropriate for review in this paper. The pharmacologic classes to be explored are non-steroidal mineralocorticoid receptor antagonists, aminopeptidase A inhibitors, dual endothelin antagonists, aldosterone synthetase inhibitors, atrial natriuretic peptide inhibitors, and attenuators of hepatic angiotensinogen. Discussion of procedural interventions to lower blood pressure will focus on renal denervation and devices that increase carotid baroreceptor activity.

CONCLUSIONS

Promising medication and procedural interventions are being developed and studied to expand our treatment arsenal for patients with uncontrolled essential hypertension and RH.

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.

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.

Endovascular Baroreflex Amplification With the MobiusHD Device in Patients With Heart Failure and Reduced Ejection Fraction: Interim Analysis of the First-in-Human Results

Background

Endovascular baroreflex amplification with the MobiusHD, a self-expanding stent-like device that is implanted in the internal carotid artery, was designed to reduce the sympathetic overactivity that contributes to progressive heart failure with reduced ejection fraction.

Methods

Symptomatic patients (New York Heart Association class III) with heart failure with reduced ejection fraction (left ventricular ejection fraction [LVEF] ≤40%) despite guideline directed medical therapy and n-terminal pro-B type natriuretic peptide (NT-proBNP) levels ≥400 pg/mL in whom carotid ultrasound and computed tomographic angiography demonstrated absence of carotid plaque were enrolled. Baseline and follow-up measures included 6-minute walk distance (6MWD), Kansas City Cardiomyopathy Questionnaire overall summary score (KCCQ OSS), and repeat biomarkers and transthoracic echocardiography.

Results

Twenty-nine patients underwent device implantation. The mean age was 60.6 ± 11.4 years, and all had New York Heart Association class III symptoms. Mean KCCQ OSS was 41.4 ± 12.7, mean 6MWD was 216.0 ± 43.7 m, median NT-proBNP was 1005.9 pg/mL (894, 1294), and mean LVEF was 34.7 ± 2.9%. All device implantations were successful. Two patients died (161 days and 195 days) and one stroke occurred (170 days) during follow-up. For the 17 patients with 12-month follow-up, mean KCCQ OSS improved by 17.4 ± 9.1 points, mean 6MWD increased by 97.6 ± 51.1 meters, a mean 28.4% reduction from the baseline NT-proBNP concentration was found, and mean LVEF improved by 5.6% ± 2.9 (paired data).

Conclusion

Endovascular baroreflex amplification with the MobiusHD device was safe and effected positive changes in quality of life, exercise capacity, and LVEF, consistent with observed reductions in NT-proBNP levels.

Aortic thoracic neuromodulation in heart failure with preserved ejection fraction

The inadequacy of medical therapies for heart failure with preserved ejection fraction (HFpEF) is driving the development of device-based solutions targeting underlying pathophysiologic abnormalities. The maladaptive autonomic imbalance with a reduction in vagal parasympathetic activity and increased sympathetic signalling contributes to the deterioration of cardiac performance, patient fitness, and the increased overall morbidity and mortality. Thoracic aortic vagal afferents mediate parasympathetic signalling, and their stimulation has been postulated to restore autonomic balance. In this first-in-man experience with chronic stimulation of aortic vagal afferents (Harmony™ System, Enopace, Israel), we demonstrate improved left atrial remodelling and function parallel with improved left ventricular performance. The observed favourable structural and functional cardiac changes remained stable throughout the 1 year follow-up and were associated with improved symptoms and physical fitness. The current experience warrants further validation of the endovascular stimulation of aortic thoracic afferents as a new interventional approach for device-based treatment in HFpEF.