Abstract
BACKGROUND: Central aortic blood pressures and arterial stiffness are better indicators of cardiovascular outcomes than brachial blood pressures. However, their response to renal denervation (RDN) in patients with stage 3 and stage 4 chronic kidney disease (CKD) has not yet been examined. OBJECTIVE: To evaluate the impact of RDN on central blood pressures, brachial (office and ambulatory) blood pressures, arterial stiffness, glomerular filtration rate (GFR), 24-hour urine protein, and selective cardiac parameters observed on echocardiograms. DESIGN: Single-center, single-arm with pre-RDN/post-RDN follow-up. SETTING: Patients are being recruited from the multidisciplinary CKD clinic. PATIENTS: Fifty consecutive patients with stage 3 or stage 4 CKD and resistant hypertension, with no radiological or laboratory evidence of secondary causes of hypertension. MEASUREMENTS: The key measurements are central blood pressures, pulse wave velocity, ambulatory 24-hour blood pressure, office blood pressures on BP Tru, GFR, 24-hour urine protein and sodium, blood pressure medication, and doses. METHODS: For our primary outcome, we will compare changes in central blood pressures from baseline to 6 months post RDN using a paired t test or Mann-Whitney U test. Secondary outcomes will examine changes in central blood pressures from baseline to 3, 12, 18, and 24 months post RDN as well as changes in office pressures, GFR, 24-hour urine protein and sodium, and medications at all time points using mixed-model analyses of variance or Friedman test. Multiple regression may be used to control for potential covariates. LIMITATIONS: Single-center study, with no sham arm. CONCLUSIONS: Aortic blood pressure, rather than brachial blood pressure, optimally reflects the load placed on the left ventricle. Aortic blood pressure is also better associated with cardiovascular outcomes. If our study shows a preferential decrease in central blood pressures and improvements in cardiac parameters on echocardiograms post RDN, this may influence the way in which blood pressures are managed in clinics and offices. TRIAL REGISTRATION: ClinicalTrials.gov (NCT01832233).