Endovascular renal sympathetic denervation versus spironolactone for treatment-resistant hypertension: a randomized, multicentric study

Endovascular, radiofrequency, renal sympathetic denervation (RFSD) is a new
treatment modality for patients with treatment-resistant hypertension. RFSD is
available in various medical centers in The Netherlands. Two studies published
in the Lancet have shown that RFSD is a safe procedure with a large effect on
office blood pressure, but a much smaller effect on 24-hour ambulatory blood
pressure. The elevated blood pressure in patients with therapy-resistant
hypertension responds often surprisingly good to the addition of
mineralocorticoid receptor blocker. It is unknown whether RFSD has advantages
with regard to blood pressure lowering effect, costs and quality of life
compared to addition of spironolactone in patients with therapy-resistant
hypertension. With this proposal we want to compare the additional blood
pressure lowering effect of RFSD with that of the addition of spironolactone in
patients with still an elevated blood pressure despite the use of three
different antihypertensive agents. From our own experience in 14 subjects it
appeared that the blood pressure response to RFSD shows a large
inter-individual variation. The reason for this variation is unclear. Since it
is assumed that the decrease in blood pressure in response to RFSD depends on a
decrease in renal and systemic sympathetic tone it will be explored wheter the
blood pressure response can be predicted by the clonidine-suppression test.

Comparison of the additional blood pressure lowering effect of RFSD with that
of the addition of spironolactone in patients with a persistant increased blood
pressure despite treatment with three different antihypertensive agents.

Randomized multcentric study

RFSD or addition of spironolacton in a maximal dose of 50 mg per day. Per
treatment arm 47 evaluable patients are needed. Follow-up duration after
intervention is 6 months.

At least 2 visits before and 4 visits to the otupatient department after RFSD
or start of spironolactone. These visits take about 1.5 hour and consist of 1
hour blood pressure measurement, blood sampling via an infusion needle and
medical consultation. In addition 24-hour urine collections 3 times. 24-hour
ambulatory blood pressure recordings 3 times and 1 clonidine-suppression test
for patients randomized for RFSD.
Patients who are randomized for RFSD are hospitalized for one night following
the procedure.
Addition of spironolactone or RFSD are accepted and safe treatments for
patients with refractory hypertension. Individual patients may benefit from the
interventions as their blood pressure may become better controlled.