Objectives:
To compare the blood pressure lowering efficacy and safety of renal denervation vs. usual medical therapy. The primary endpoints for efficacy and safety are the baseline-adjusted between-group differences in 24-h systolic blood pressure and in glomerular filtration rate as estimated by Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Secondary endpoints for efficacy and safety include other indexes of blood pressure control and renal function, metabolic variables and morbidity and mortality. These endpoints will be assessed 6 months after randomization.
Trial design:
Randomized controlled trial with blinded assessment of the primary and secondary endpoints. The study consists of 6 stages. Supervised and nonsupervised follow-up refer to assessment of outcome at or outside the participating center, respectively.
* Screening involves checking eligibility and ruling out secondary hypertension.
* Run-in period of 3 months to optimize medical treatment and to assess adherence to treatment.
* Stratification and randomization Eligible patients will be stratified by center and age group (adults vs. elderly, 20-49 vs. 50-69 years) and randomized centrally in a one-to-one proportion to control or intervention.
* Renal sympathetic denervation in the intervention group, patients of the control group will be offered renal denervation after 6 months.
* Supervised follow-up at 1, 3 and 6 months after randomization.
* Long-term supervised or non-supervised follow-up of morbidity and mortality beyond 6 months and up to 3 years.
Sample size:
To detect a 10-mm Hg difference (SD 20 mm Hg) in systolic blood pressure between the randomized groups with a 2-sided P-value of 0.01 and 90% power in total 240 patients need to be randomized. Allowing 50% screening failures, 480 patients would have to be screened.
Assessment of adherence:
Adherence to treatment will be assessed by measurement of drugs or drug metabolites in biological fluids. Jung and coworkers developed a liquid chromatography-mass spectrometric method that allows detecting all antihypertensive drugs or their metabolites in a single urine sample. This obligatory approach will be implemented.
Assessment of quality of life Assessment of quality of life is compulsory at baseline and at each visit during the supervised follow-up, using the EuroQol 5D.
Assessment of sympathetic modulation:
heart rate variability (HRV) will be assessed at baseline and at the 6-month follow-up visit, based on 15 minutes ECG recordings. A software program, developed in LabVIEW by the group of Aubert et al. will be used.
Relevance:
INSPiRED differs from previous and ongoing studies in several aspects: (1) a stringent selection of patients; (2) drug optimization with assessment of adherence throughout the study; (3) out-of-the-office blood pressure for patient selection and follow-up; (4) state-of-the-art renal artery imaging by computerized tomographic angiography; (5) validation of urinary proteomic biomarkers to predict blood pressure responses and changes in renal function; (6) follow-up will be beyond 6 months up to 3 years; (7) use of heart rate variability and renal nerve stimulation to assess the completeness of renal denervation.
