scholarly journals Renal Denervation in Hypertension

2021 ◽  
pp. 73-74
Author(s):  
Usman S Ansari ◽  
Benjamin J Lee
Keyword(s):  
Blood Pressure ◽  
Renal Denervation ◽  
Pressure Control ◽  
Renal Nerves ◽  
Radiofrequency Energy ◽  
Potential Treatment ◽  
Lifestyle Modifications ◽  
Potential Strategy ◽  
Maximal Medical Therapy ◽  
Renal Sympathetic

Hypertension is a significant cause of morbidity and mortality worldwide. However, many individuals fail to achieve proper blood pressure control despite lifestyle modifications and maximal medical therapy. Renal sympathetic overactivity has been proposed as a significant driver in such cases. One potential treatment is renal denervation (RDN), a minimally invasive catheter-based technology that uses radiofrequency energy to obliterate the renal nerves adjacent to the afferent and efferent renal arteries. While RDN was initially developed as a potential strategy to treat resistant hypertension, several studies have investigated its use as an adjunctive therapy for hypertension. The following are 10 points to remember about the use of RDN in hypertension.

Renal denervation alters cardiovascular and endocrine responses to hemorrhage in conscious newborn lambs

1998 ◽  
Vol 275 (1) ◽  
pp. H285-H291 ◽  
Author(s):  
Francine G. Smith ◽  
Isam Abu-Amarah
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Renal Denervation ◽  
Plasma Renin ◽  
Sympathetic Nerves ◽  
Renal Nerves ◽  
Elevated Plasma ◽  
Baseline Levels ◽  
Renal Sympathetic

To investigate the role of renal sympathetic nerves in modulating cardiovascular and endocrine responses to hemorrhage early in life, we carried out three experiments in conscious, chronically instrumented lambs with intact renal nerves (intact; n = 8) and with bilateral renal denervation (denervated; n = 5). Measurements were made 1 h before and 1 h after 0, 10, and 20% hemorrhage. Blood pressure decreased transiently after 20% hemorrhage in intact lambs and returned to control levels. In denervated lambs, however, blood pressure remained decreased after 60 min. After 20% hemorrhage, heart rate increased from 170 ± 16 to 207 ± 18 beats/min in intact lambs but not in denervated lambs, in which basal heart rates were already elevated to 202 ± 21 beats/min. Despite an elevated plasma renin activity (PRA) measured in denervated (12.0 ± 6.4 ng ANG I ⋅ ml−1 ⋅ h−1) compared with intact lambs (4.0 ± 1.1 ng ANG I ⋅ ml−1 ⋅ h−1), the increase in PRA in response to 20% hemorrhage was similar in both groups. Plasma levels of arginine vasopressin increased from 11 ± 8 to 197 ± 246 pg/ml after 20% hemorrhage in intact lambs but remained unaltered in denervated lambs from baseline levels of 15 ± 10 pg/ml. These observations provide evidence that in the newborn, renal sympathetic nerves modulate cardiovascular and endocrine responses to hemorrhage.

Abstract P149: Bilateral Renal Denervation Attenuates Hypertension in Male Rats Deficient of Functional Endothelin B Receptors but Does Not Affect Salt-Sensitivity

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Bryan K Becker ◽  
Amanda C Feagans ◽  
Chunhua Jin ◽  
David M Pollock
Keyword(s):  
Blood Pressure ◽  
Total Protein ◽  
Renal Denervation ◽  
High Salt ◽  
Male Rats ◽  
Renal Nerves ◽  
High Salt Diet ◽  
Salt Diet ◽  
Endothelin B ◽  
Renal Sympathetic

Independent studies of renal sympathetic nerves and the endothelin (ET) system have demonstrated important contributions of each in the progression of hypertension. Very few studies, however, have investigated the interaction between the ET system and renal nerves in relation to blood pressure control and electrolyte homeostasis. Although endothelin B (ETB) receptors in the renal medulla promote natriuresis, ETB receptors on sympathetic neurons are thought to increase neuronal activity. We hypothesized that renal denervation reduces blood pressure in a salt-sensitive, hypertensive model of ET dysfunction, the ETB-deficient (ETB-def) rat, which lacks functional ETB receptors in all tissues except neurons. After bilateral renal sympathetic denervation (Dnx) or sham operation of ETB-def and transgenic control (TG) rats, baseline blood pressure was recorded via telemetry for 5 days on a normal salt (0.49% NaCl) diet followed by a high salt (4.0%) diet. At baseline, ETB-def Dnx rats had a lower 24-hr systolic blood pressure (SBP) (152.6 ± 3.6 mmHg) relative to ETB-def sham (167.8 ± 2.6 mmHg; p < 0.005; n = 7/group). Denervation did not significantly affect TG rats relative to sham on normal salt (138.8 ± 2.5 vs. 144.7 ± 0.5 mmHg respectively; p = 0.53; n = 6/group). Following 10 days of high salt diet, ETB-def sham rats had an increased 24-hr SBP (+10.59 ± 2.8 mmHg relative to baseline; p < 0.005). There was a similar increase in SBP in ETB-def Dnx rats (+10.03 ± 2.3 mmHg relative to baseline; p < 0.005), although the ETB-def Dnx group remained lower than ETB-def sham. High salt had no effect on TG sham or Dnx animals (-2.2 ± 1.3 and -0.6 ± 2.8 mmHg relative to baseline). Preliminary evidence from a subset of the animals in this experiment indicated a dramatically reduced inner medullary ET-1 content in ETB-def sham rats vs. TG sham (97.9 ± 15.4 vs. 327.0 ± 25.4 ng/mg total protein; p < 0.005; n = 3-4/group) in both ETB-def and TG groups, Dnx tended to increase inner medullary ET-1 content (181.8 ± 75.8 and 402.7 ± 19.6 ng/mg total protein respectively). We conclude that in a model of ET dysfunction, the renal nerves are integral mediators of hypertension during normal salt diet, but do not mediate the increase in pressure following high salt diet in this model of salt-sensitive hypertension.

Renal denervation: current implications and future perspectives

2013 ◽  
Vol 126 (1) ◽  
pp. 41-53 ◽  
Author(s):  
Jianzhong Xu ◽  
Dagmara Hering ◽  
Yusuke Sata ◽  
Antony Walton ◽  
Henry Krum ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Resistant Hypertension ◽  
Renal Denervation ◽  
Interventional Procedure ◽  
Strong Association ◽  
Blood Pressure Reduction ◽  
Pressure Control ◽  
Renal Nerves ◽  
Renal Nerve ◽  
Disease States

SNS (sympathetic nervous system) activation is a common feature of arterial hypertension and has been demonstrated to contribute to the development and progression of the hypertensive state. Persuasive evidence suggests a strong association between SNS overactivity and variety of disease states, including chronic renal failure, insulin resistance, congestive heart failure, sleep apnoea, ventricular arrhythmias and others. Although sympatholytic agents are available to target SNS overactivity pharmacologically, they are not widely used in clinical practice, leaving the SNS unopposed in many patients. The recent introduction of catheter-based renal denervation as an alternative approach to target the SNS therapeutically has been demonstrated to result in a clinically relevant blood pressure reduction in patients with resistant hypertension, presumably through its effects on both efferent and afferent renal nerve traffic. Available data on this interventional procedure demonstrate a favourable vascular and renal safety profile. Preliminary data obtained primarily from small and mostly uncontrolled studies in related disease states often characterized by overactivity of the SNS are promising, but require confirmation in appropriately designed clinical trials. In the present paper, we briefly review the physiology of the renal nerves and their role in hypertension and other relevant disease states, summarize the data currently available from clinical studies pertaining to the safety and efficacy of renal denervation in resistant hypertension, discuss potential future implications and the available data supporting such a role for renal denervation, and describe some of the newer devices currently under investigation to achieve improved blood pressure control via renal denervation.

Effects of renal denervation on cardiovascular response to furosemide in conscious lambs

1995 ◽  
Vol 269 (1) ◽  
pp. H149-H152 ◽  
Author(s):  
F. G. Smith ◽  
A. M. Strack
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Arterial Pressure ◽  
Renal Denervation ◽  
Cardiovascular Response ◽  
Blood Pressure Response ◽  
Sympathetic Nerves ◽  
Renal Nerves ◽  
Before And After ◽  
Renal Sympathetic

The cardiovascular response to furosemide in the newborn and the role of renal sympathetic nerves in influencing this response have not been investigated. We hypothesized that in conscious lambs, furosemide would decrease blood pressure, the response being accentuated in the absence of renal sympathetic nerves. Pulsatile pressures and heart rates were measured before and after furosemide (2 mg/kg) administration to chronically instrumented lambs with either bilateral renal denervation (denervated, n = 8) or renal nerves intact (intact, n = 6). In intact lambs, mean arterial pressure remained constant after furosemide; in denervated lambs there was an increase in arterial pressure 20 min after furosemide (P < 0.001), and control levels were reached by 100 min. Basal heart rate was higher in denervated than in intact lambs (P = 0.009). In both groups of lambs, heart rate increased 40 min after furosemide and remained elevated. These data provide new information that, in conscious newborn animals, renal sympathetic nerves influence the blood pressure response to furosemide, as well as basal control of heart rate.

scholarly journals What we need to know about renal nerve ablation for treatment of hypertension and other states of sympathetic overactivity

2016 ◽  
Vol 311 (6) ◽  
pp. F1267-F1270 ◽  
Author(s):  
Markus P. Schlaich
Keyword(s):  
Blood Pressure ◽  
Renal Disease ◽  
Pressure Control ◽  
Renal Nerves ◽  
Renal Nerve ◽  
Renal Nerve Ablation ◽  
Key Players ◽  
Treatment Of Hypertension ◽  
Recent Developments ◽  
Renal Sympathetic

Renal nerves are key players in the regulation of kidney function and blood pressure control. Targeting the neurogenic mechanisms underlying hypertension and cardiac and renal disease has been attempted by means of surgical and pharmacologic approaches and most recently by catheter-based interventions aimed at disrupting renal sympathetic nerve traffic. The recent developments in the area and the relevant questions that need to be addressed to advance the field further are briefly reviewed in this article.

scholarly journals Role of the heart in blood pressure lowering during chronic baroreflex activation: insight from an in silico analysis

2018 ◽  
Vol 315 (5) ◽  
pp. H1368-H1382 ◽  
Author(s):  
John S. Clemmer ◽  
W. Andrew Pruett ◽  
Robert L. Hester ◽  
Radu Iliescu ◽  
Thomas E. Lohmeier
Keyword(s):  
Blood Pressure ◽  
Mathematical Model ◽  
Renal Denervation ◽  
Sympathetic Nerve Activity ◽  
Blood Pressure Lowering ◽  
Nerve Activity ◽  
Renal Sympathetic Nerve Activity ◽  
Pressure Lowering ◽  
Renal Sympathetic ◽  
Stimulation Of

Electrical stimulation of the baroreflex chronically suppresses sympathetic activity and arterial pressure and is currently being evaluated for the treatment of resistant hypertension. The antihypertensive effects of baroreflex activation are often attributed to renal sympathoinhibition. However, baroreflex activation also decreases heart rate, and robust blood pressure lowering occurs even after renal denervation. Because controlling renal sympathetic nerve activity (RSNA) and cardiac autonomic activity cannot be achieved experimentally, we used an established mathematical model of human physiology (HumMod) to provide mechanistic insights into their relative and combined contributions to the cardiovascular responses during baroreflex activation. Three-week responses to baroreflex activation closely mimicked experimental observations in dogs including decreases in blood pressure, heart rate, and plasma norepinephrine and increases in plasma atrial natriuretic peptide (ANP), providing validation of the model. Simulations showed that baroreflex-induced alterations in cardiac sympathetic and parasympathetic activity lead to a sustained depression of cardiac function and increased secretion of ANP. Increased ANP and suppression of RSNA both enhanced renal excretory function and accounted for most of the chronic blood pressure lowering during baroreflex activation. However, when suppression of RSNA was blocked, the blood pressure response to baroreflex activation was not appreciably impaired due to inordinate fluid accumulation and further increases in atrial pressure and ANP secretion. These simulations provide a mechanistic understanding of experimental and clinical observations showing that baroreflex activation effectively lowers blood pressure in subjects with previous renal denervation. NEW & NOTEWORTHY Both experimental and clinical studies have shown that the presence of renal nerves is not an obligate requirement for sustained reductions in blood pressure during chronic electrical stimulation of the carotid baroreflex. Simulations using HumMod, a mathematical model of integrative human physiology, indicated that both increased secretion of atrial natriuretic peptide and suppressed renal sympathetic nerve activity play key roles in mediating long-term reductions in blood pressure during chronic baroreflex activation.

Abstract 403: Renal Denervation Reveals Renal Sympathetic Activation in Adult Rats Exposed to Early Life Stress

Hypertension ◽  
2012 ◽  
Vol 60 (suppl_1) ◽  
Author(s):  
Analia S Loria ◽  
Michael W Brands ◽  
David M Pollock ◽  
Jennifer S Pollock
Keyword(s):  
Life Stress ◽  
Early Life ◽  
Renal Denervation ◽  
Early Life Stress ◽  
Male Rats ◽  
Renal Nerves ◽  
Adult Rats ◽  
Baseline Conditions ◽  
Control Sham ◽  
Renal Sympathetic

We previously reported that maternal separation (MS), a model of early life stress, does not modify baseline blood pressure in adult rats, but increases sensitivity to hypertensive stimuli. Under baseline conditions, adult male rats exposed to MS have significantly reduced glomerular filtration rate (GFR). Acute phenylephrine-induced reductions in renal blood flow is significantly attenuated in rats exposed to MS compared to control rats. Furthermore, norephinephrine (NE) content was increased in renal cortex of MS rats compared to control rats (p<0.05). These data indicate that MS induces increased renal sympathetic outflow. Thus, we hypothesized that renal denervation will normalize GFR in rats exposed to MS. Male WKY rat pups were separated from their mothers for 3 hrs/day during the morning hours from day 2 to 14 of life. Male non-separated littermates served as control rats. Experiments were performed in 300-320 g adult rats. Denervation (DnX) was performed mechanically stripping all visible renal nerves followed by topical phenol (10%) on the renal artery. Control-sham, MS-sham, control-DnX, and MS-DnX rats were instrumented with catheters in the femoral vein and abdominal aorta. Rats were placed in metabolic cages, connected to swivels, and allowed to recover for 4-5 days. Sodium intake was clamped at 2.8 mEq/day in both groups by combining sodium deficient diet and 24 hr/day 0.9% iv saline infusion (20 ml/day). GFR was determined by plasma clearance of [125I]iothalamate in the conscious state. During baseline conditions, MAP was not different between control-sham and MS-sham rats (99±4 vs 97±2 mmHg, respectively). MAP was reduced in both control-DnX and MS-DnX rats (91±2 mmHg and 83±3 mmHg, p<0.05, respectively) compared with the respective sham group. The reduction in MAP tended to be greater in MS than in control rats (-9±1 and -14±2 mmHg, p=0.074). DnX did not modify GFR in control rats (sham: 3.1±0.1 ml/min vs DnX: 3.5±0.4 ml/min). However, DnX significantly increased GFR in rats exposed to MS (sham: 2.4±0.2 ml/min vs DnX: 3.8±0.4 ml/min, p<0.05). These data support our hypothesis that MS induces increased renal sympathetic tone to reduce GFR in MS male rats, and may contribute to the exacerbated response to hypertensive stimuli observed in MS rats.

Device Therapy of Hypertension

2021 ◽  
Vol 128 (7) ◽  
pp. 1080-1099
Author(s):  
Felix Mahfoud ◽  
Markus P. Schlaich ◽  
Melvin D. Lobo
Keyword(s):  
Blood Pressure ◽  
Nervous System ◽  
Blood Pressure Control ◽  
Carotid Body ◽  
Renal Denervation ◽  
Pressure Control ◽  
Hypertension Control ◽  
Baroreflex Activation Therapy ◽  
Improve Blood Pressure Control ◽  
Activation Therapy

In the past decade, efforts to improve blood pressure control have looked beyond conventional approaches of lifestyle modification and drug therapy to embrace interventional therapies. Based upon animal and human studies clearly demonstrating a key role for the sympathetic nervous system in the etiology of hypertension, the newer technologies that have emerged are predominantly aimed at neuromodulation of peripheral nervous system targets. These include renal denervation, baroreflex activation therapy, endovascular baroreflex amplification therapy, carotid body ablation, and pacemaker-mediated programmable hypertension control. Of these, renal denervation is the most mature, and with a recent series of proof-of-concept trials demonstrating the safety and efficacy of radiofrequency and more recently ultrasound-based renal denervation, this technology is poised to become available as a viable treatment option for hypertension in the foreseeable future. With regard to baroreflex activation therapy, endovascular baroreflex amplification, carotid body ablation, and programmable hypertension control, these are developing technologies for which more human data are required. Importantly, central nervous system control of the circulation remains a poorly understood yet vital component of the hypertension pathway and mandates further investigation. Technology to improve blood pressure control through deep brain stimulation of key cardiovascular control territories is, therefore, of interest. Furthermore, alternative nonsympathomodulatory intervention targeting the hemodynamics of the circulation may also be worth exploring for patients in whom sympathetic drive is less relevant to hypertension perpetuation. Herein, we review the aforementioned technologies with an emphasis on the preclinical data that underpin their rationale and the human evidence that supports their use.

scholarly journals Treatment adherence and blood pressure outcome among hypertensive out-patients in two tertiary hospitals in Sokoto, Northwestern Nigeria

2018 ◽  
Vol 18 (1) ◽  
Author(s):  
Rasaq Adisa ◽  
Olumide Ayodeji Ilesanmi ◽  
Titilayo Oyelola Fakeye
Keyword(s):  
Blood Pressure ◽  
Cigarette Smoking ◽  
Treatment Adherence ◽  
Pressure Control ◽  
Patient Specific ◽  
Lifestyle Modifications ◽  
Antihypertensive Medications ◽  
Chi Square ◽  
Cross Sectional ◽  
Adherence To Medication

Abstract Background Treatment adherence play important roles in blood pressure control leading to reduction in morbidity and mortality. This study therefore assessed adherence to pharmacological and non-pharmacological therapies among ambulatory hypertensive patients. Reasons for treatment non-adherence, and association between adherence and blood pressure were also investigated. Methods Cross-sectional questionnaire-guided interview and retrospective review of medical records of 605-patients from two-tertiary healthcare institutions in Sokoto, Northwestern Nigeria. Nine-item modified Morisky adherence scale was used to assess medication adherence. Overall adherence score to lifestyle modifications was obtained from the total scores from 4-domains of non-pharmacological measures including cigarette smoking and alcohol cessation, salt-restriction and exercise. Patient-specific adherence education was provided at contact to resolve the knowledge gap(s). Clinical-parameters were retrieved at contact and subsequent 2-months appointment. Descriptive statistics, Chi-square and Student’s t-test were used for analysis at p < 0.05. Results Fifty-four (8.9%) patients were adherent to medications. Forgetfulness (404; 35.2%) was the most common reason for medication non-adherence. Use of buddy/companion reminder (605, 30.2%) top the list of adherence education. Overall adherence to lifestyle modifications was 36(6.0%). Mean systolic blood pressure (SBP) at contact was 149.6 ± 22.5 versus 134.2 ± 15.8 mmHg at 2-months with a 10% reduction. There were significant associations in baseline SBP for patients with or without adherence to medication, cigarette smoking cessation, and exercise (p < 0.05). Conclusions Overall adherence to antihypertensive medications and lifestyle modifications is suboptimal, underscoring the need for continuous patient-specific adherence education to ensure better therapeutic outcomes.

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