SYMPATHY: Renal sympathetic denervation as a new treatment for therapy resistant hypertension.

Hypertension is a global public health concern. The first results of renal
denervation (RD), the deliberate disruption of the nerves connecting the
kidneys with the central nervous system, show that RD is feasible, effective
and safe in the short-term. However, RD is a costly and invasive procedure, of
which the long-term efficacy in terms of blood pressure (BP) control and safety
has not yet been proven compared to usual care.
Secondly, in the previous studies patients with an impaired renal function
(eGFR < 45 mL/min per 1.73m2) were excluded. It is likely that especially
patients with more advanced kidney failure will show a BP drop after the
procedure.
Moreover literature data and our first own results show a large variability of
the BP-lowering potential of the procedure. So far no predictors for effect of
treatment have been identified.
This current study will address these issues.

The primary objective is to assess whether RD added to usual care compared to
usual care alone reduces BP (24-h or average day-time SBP as determined with
the use of ambulatory BP monitoring (ABPM)) in subjects with an average mean
day-time SBP of at least 135 mmHg or mean 24h SBP of at least 130 mmHg as
determined with the use of ABPM, despite the use of three or more BP
lowering-agents or with documented intolerance to 2 or more antihypertensive
drugs, six months after treatment.

Key secondary objectives are evaluated at 6 months and at regular intervals
during continued follow- up, and include:
1.To assess the effect of RD on the use of BP-lowering agents (defined as daily
defined dose of all prescribed drugs).
2.To explore the effect of RD in different subgroups: across strata of eGFR
(eGFR 20-60 mL/min per 1.73m2 and eGFR>60 mL/min per 1.73m2) and across strata
of baseline BP.
3.To assess the effect of RD on office based BP

Multi-center randomized controlled trial. Randomization will be stratified by
hospital and eGFR and will be at a 2:1 ratio to addition of catheter-based RD
treatment to usual care or to continued usual care

Bilateral renal denervation, using radiofrequency energy delivered to the renal
arterial walls via an intra-arterial catheter.

Published studies have reported an excellent safety profile of RD. Procedure
related complications have been few in number and of the type expected for an
endovascular procedure utilizing femoral arterial access. Most of the
complications consisted of groin complications and a single renal artery
dissection that occurred prior to the delivery of radiofrequency energy by the
RD catheter. These events were treated with standard measures and all resolved
without sequelae. Long term vascular safety has been demonstrated by follow-up
imaging studies which showed no lesion formation at any of the RF energy
treatment sites examined. The safety profile of RD is expected to be the same
for patients with a lower BP (SBP> 140 mmHg)