Safety and Efficacy of Ultrasound Renal Denervation in Kidney Transplantation Patients With Uncontrolled Hypertension

This prospective, single-arm, interventional study is designed to assess the short-term and long-term safety and efficacy of bilateral ultrasound renal sympathetic denervation (RDN) of the native kidneys in renal transplant patients with uncontrolled hypertension.

Objectives:

* To assess the short-term and long-term changes in ambulatory and office blood pressure (BP) following native kidney RDN in renal transplant patients
* To assess the long-term safety of native kidney RDN in renal transplant patients
* To assess the short-term and long-term change in antihypertensive drug prescriptions following native kidney RDN in renal transplant patients
* To assess the short-term and long-term change in adherence to antihypertensive drugs following native kidney RDN in renal transplant patients

The RESTART study is an investigator-initiated, prospective, single-center, single-arm interventional study investigating the safety and efficacy of bilateral native kidney RDN in 40 renal transplant patients with uncontrolled hypertension despite antihypertensive medication (or with a documented intolerance to antihypertensive drugs).

Previously, RDN demonstrated to safely reduce BP as compared to sham-control in multiple randomized clinical trials, both in patients with and without concomitant antihypertensive medication. Up until now, patients with a history of renal failure or kidney transplantation have been excluded from these studies. As the pathophysiology of hypertension is considered different in hypertensive renal transplant patients as compared to the previously studied populations (without kidney transplantation), the effect of native kidney RDN in hypertensive patients with a history of kidney transplantation remains unknown. The current study aims to provide novel insights on the safety and efficacy of RDN in this particular population. Adjustment for routine therapy adherence will also be performed as this proved to be an important confounding factor in previous research.

Eligibility Criteria:
Inclusion Criteria:

* Age ≥ 18 years
* Kidney transplantation ≥ 12 months ago with stable immunosuppressive drug treatment
* Estimated Glomerular Filtration Rate (eGFR) ≥ 40 ml/min/1.73m2
* Office systolic BP ≥ 140 mmHg and a mean 24-hour ambulatory systolic BP ≥ 130 mmHg at screening
* Antihypertensive medication regimen:

  * Stable regimen of at least two antihypertensive drugs of different classes, including a diuretic (defined a thiazide diuretic, loop diuretic or mineralocorticoid receptor antagonist), for at least three months, or
  * Documented intolerance to three classes of antihypertensive drugs, and
  * A change in antihypertensive drug regimen is not anticipated within the oncoming three months.
* Patient is willing and able to provide written informed consent

Exclusion Criteria:

* Native renal artery anatomy not eligible for RDN, defined as at least one of the following conditions:

  * History of renal artery stenting or angioplasty
  * History of renal denervation
  * History of kidney tumors
  * Renal artery diameter \< 3 mm or \> 8 mm
  * Renal artery length \< 20 mm
  * Fibromuscular disease (FMD) of the native renal arteries
  * Renal artery aneurysm
  * Renal artery stenosis \> 30%
* Presence of a remnant transplant kidney after re-transplantation or absence of native kidneys
* Solitary native kidney
* History of intravenous contrast dye allergy or nephropathy
* Iliac/femoral artery stenosis precluding insertion of the Paradise catheter
* Uncorrected, treatable secondary cause of hypertension
* Pregnancy
* Life expectancy \< one year at the discretion of the investigator