Central Blood Pressure and Pulse Wave Velocity Changes Post Renal Denervation in Patients With Stages 3 and 4 Chronic Kidney Disease: The Regina RDN Study

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 (CBP), 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-/post-RDN follow-up.

Setting: Patients were recruited from the multidisciplinary CKD clinic, Regina General Hospital, Canada.

Patients: About 25 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 were CBP, pulse wave velocity, ambulatory 24-hour blood pressure, office blood pressures on BP Tru, GFR, 24-hour urine protein and sodium, dose and number of blood pressure medication and doses.

Methods: The primary outcome measure was the change in CBP from baseline to 6 months post-RDN. Secondary outcome measures included changes in CBP, office blood pressure, 24-hour ambulatory pressures, pulse wave velocity, kidney function (eGFR and 24-hour protein excretion), and the change in the number and dose of medications during the 2-year follow-up period. The primary outcome and the secondary outcomes were evaluated using a Friedman's analysis of variance (ANOVA) and Wilcoxon signed-rank test for changes from post RDN procedure. Bonferroni correction was used to adjust P values for multiple testing. A two-sided alpha of .05 was used.

Results: Median central blood pressures (mm Hg) were 127/75 at baseline versus 118/70 at 6 months and 118/67 at 24 months (P = .13). Median office blood pressures (mm Hg) were 148/76 at baseline versus 135/75 at 6 months and 133/75 at 24 months (P ≤ .001). Median ambulatory 24-hour day (mm Hg) was 148/64 at baseline and 146/68 at 6 months and 152/67 at 24 months (P = .60). Median pulse wave velocity (m/s) at baseline was 13.8 at baseline versus 13.3 m/s at 6 months and 12.3 at 12 months' time (P = .62). Estimated glomerular filtration rate (mL/min/1.73m2) at baseline was 37, at 6 months was 36 and 34 at 24 months (P = .33).

Limitations: Single-center study, with no sham arm.

Conclusions: Our study demonstrates that there was a significant improvement in office blood pressures from baseline to 6 months, maintained to 24 months. There was a numerical improvement in central pressures, and pulse wave velocity at 6 and 24 months, with no sustained changes noted in 24-hour blood pressure. Kidney function remained at or near baseline throughout the 24 months of observation.

Trial registration: ClinicalTrials.gov (NCT01832233).

Keywords: central blood pressure; chronic kidney disease; chronic renal failure; renal denervation; resistant hypertension.

Conflict of interest statement

Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Dr. Raymond Townsend is a Consultant for Medtronic. No other authors have any conflict of interest.

Figures

Figure 1.

Study flowchart. Note. CKD = chronic kidney disease; BP = blood pressures; CT= computerized tomography; TSH= thyroid stimulating hormone; ECHO= echocardiogram; ABPM = ambulatory blood pressure monitoring.

Figure 2.

Mean Office BP Tru Blood pressures at baseline, 3, 6, 12, 18 and 24 months. (b) Mean Central blood pressures at baseline, 3, 6,12,18, and 24 months. (c) Mean day time ambulatory blood pressures at baseline, 3, 6, 12, 18, and 24 months. (d) Mean night-time ambulatory pressure at baseline, 3, 6, 12, and 24 months.

Figure 3.

Pulse wave velocity at baseline, 3, 6, 12, 18 and 24 months.