Renal Nerve Ablation in Chronic Kidney Disease Patients

Study Overview
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Brief Summary
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In patients with treatment resistent hypertension renal nerve ablation emerged as an effective interventional approach of treating hypertensive disease with a progressively increasing fall in blood pressure. Decreased activity of the sympathetic nervous system is one of the major underlying pathogenetic mechanism of the fall in blood pressure but the precise mechanisms that causes the fall in blood pressure in the short-term and, in particular, long-term remains elusive. The objective of the study is to understand the pathogenetic mechanisms of renal denervation beyond the reduced activity of the sympathetic nervous system. In 100 hypertensive patients most advanced technology will be applied, before and repeatedly after renal denervation, throughout the follow-up period of 1 year. Systemic activity of the renin angiotensin aldosterone system, renal perfusion (by MRI spin labelling technique), local activity of the renin angiotensin system in the kidney (urinary angiotensinogen concentrations), sodium excretion and total sodium content (23 Na-MRI technique) and vascular remodelling of small (retinal arterioles 50 - 150 µm) and large arteries (carotid - femoral pulse wave velocity and augmentation index, both measured over 24 hours) will be assessed. Identification of the pathogenetic mechanisms involved in the fall in blood pressure after renal denervation may help to identify those hypertensive patients that profit most from renal nerve ablation in terms of blood pressure reduction. The investigators propose the following hypotheses why a progressive decrease in blood pressure happens, in addition to the decreased activity of the central nervous system, after renal nerve ablation: Short term effects: A)Preservation of renal function and perfusion B)Reduction of local RAS activity in the kidney C)Exaggerated sodium excretion immediately after renal nerve ablation Long term effects: D)Decrease of total sodium content after 6 and 12 months. E)Improvement of vascular wall properties after 6 and 12 months

Detailed Description
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In patients with treatment resistent hypertension renal nerve ablation emerged as an effective interventional approach of treating hypertensive disease with a progressively increasing fall in blood pressure. Decreased activity of the sympathetic nervous system is one of the major underlying pathogenetic mechanism of the fall in blood pressure but the precise mechanisms that causes the fall in blood pressure in the short-term and, in particular, long-term remains elusive. The objective of the study is to understand the pathogenetic mechanisms of renal denervation beyond the reduced activity of the sympathetic nervous system. In 100 hypertensive patients most advanced technology will be applied, before and repeatedly after renal denervation, throughout the follow-up period of 1 year. Systemic activity of the renin angiotensin aldosterone system, renal perfusion (by MRI spin labelling technique), local activity of the renin angiotensin system in the kidney (urinary angiotensinogen concentrations), sodium excretion and total sodium content (23 Na-MRI technique) and vascular remodelling of small (retinal arterioles 50 - 150 µm) and large arteries (carotid - femoral pulse wave velocity and augmentation index, both measured over 24 hours) will be assessed. Identification of the pathogenetic mechanisms involved in the fall in blood pressure after renal denervation may help to identify those hypertensive patients that profit most from renal nerve ablation in terms of blood pressure reduction.

Official Title
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Understanding the Mechanisms of Progressive Decrease in Blood Pressure After Renal Nerve Ablation

Conditions
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Hypertension, Chronic Kidney Disease

Intervention / Treatment
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* Device: Simplicity Catheter


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: treatment resistant hypertension chronic kidney disease 3 - 5 male of female aged over 18 years written informed consent agreement to attend all study visits as planned in the protocol Exclusion Criteria: any contraindications for MRI claustrophobia strabismus severe ocular diseases history of epilepsia

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| treatment resistant hypertensives with CKD 3-5<br> | Device: Simplicity Catheter<br>* percutaneous selective renal sympathetic nerve ablation with the use of the Simplicity Catheter system<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| office BP | Change in office blood pressure from baseline to 6 months post-renal nerve ablation | baseline, 6 months | 
| 24-h ABPM | Change in 24 hour ambulatory blood pressure (ABPM) from baseline to 6 months post-renal nerve ablation | baseline, 6 months | 
| Magnetic resonance imaging (MRI) | change in total sodium content measured by MRI from baseline to 6 months post-renal nerve ablation change in renal perfusion measured by MRI spin labelling technique from baseline to 6 months post-renal nerve ablation | baseline, 6 months | 
| Albuminuria | Change in urinary albumin/creatinine ratio from baseline to 6 months post renal nerve ablation (spot urine) | baseline, 6 months | 
| local RAS activity | Change in urinary angiotensinogen concentration from the morning spot urine from baseline to 6 months post-renal nerve ablation | baseline, 6 months | 
| systemic RAS activity | change in sodium, potassium and creatinine from baseline to 6 months post-renal nerve ablation change in aldosterone excretion from baseline to 6 months post-renal nerve ablation change in sodium / potassium ratio from baseline to 6 months post-renal nerve ablation change in plasma renin activity and angiotensin II concentration at least 30 minutes of rest in a supine position and immediately after standing from baseline to 6 months post-renal nerve ablation | baseline, 6 months | 
| vascular structure and function of large and small arteries | change in flow-mediated vasodilation (FMD) from baseline to 6 months post-renal nerve ablation change in scanning laser Doppler flowmetry (SLDF) from baseline to 6 months post-renal nerve ablation change in pulse wave analysis (PWA) from baseline to 6 months post-renal nerve ablation change in pulse wave velocity from (PWV) baseline to 6 months post-renal nerve ablation change in urinary albumine creatinine ratio (UACR) of the morning spot urine sample from baseline to 6 months post-renal nerve ablation | baseline, 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| BP | change in office blood pressure from baseline to 1 and 12 months post-renal nerve ablation change in 24 hour ambulatory blood pressure from baseline to 1 and 12 months post-renal nerve ablation | 1 and 12 months | 
| local RAS activity | Change in urinary angiotensinogen concentration from the morning spot urine from baseline to 1 day and 1 months post-renal nerve ablation | 1 day and 1 months | 
| systemic RAS activity | change in sodium, potassium and creatinine from baseline to 1 day and 1 months post-renal nerve ablation change in albuminuria from baseline to 1 and 12 months post-renal nerve ablation change in aldosterone excretion from baseline to 1 day and 1 months post-renal nerve ablation change in sodium / potassium ratio from baseline to 1 day and 1 months post-renal nerve ablation change in plasma renin activity and angiotensin II concentration at least 30 minutes of rest in a supine position and immediately after standing from baseline to 1 day and 1 months post-renal nerve ablation | 1 day and 1 months | 
| vascular structure and function of large and small arteries | change in flow-mediated vasodilation (FMD) from baseline to 12 months post-renal nerve ablation change in scanning laser Doppler flowmetry (SLDF) from baseline to 12 months post-renal nerve ablation change in pulse wave analysis (PWA) from baseline to 12 months post-renal nerve ablation change in pulse wave velocity from (PWV) baseline to 12 months post-renal nerve ablation change in urinary albumine creatinine ratio (UACR) of the morning spot urine sample from baseline to 12 months post-renal nerve ablation | 12 months | 
| MRI | change in total sodium content measured by MRI from baseline to 12 months post-renal nerve ablation change in renal perfusion measured by MRI spin labelling technique from baseline to 1 day and 1 months post-renal nerve ablation | 1 day, 1 and 12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Treatment Resistant