Kidney function and markers of renal damage after renal denervation. Does method of measurement matter? The Reshape CV-Risk Study

Abstract

Data suggest that renal denervation (RDN) in treatment-resistant hypertension (TRHT) is safe in terms of renal function. However, most studies report kidney function as creatinine-based estimated glomerular filtration rate (eGFR), which may be biased by non-renal factors. Damage markers other than albuminuria have never been evaluated after RDN. In this non-randomized RDN trial, we studied changes in kidney function, assessed as measured GFR (mGFR) and various GFR estimates, six months and two years after RDN. We also examined changes in albuminuria and a biomarker of tubular dysfunction. Adult non-diabetic patients with TRHT and eGFR ≥45 ml/min/1.73 m² were recruited from hypertension clinics. Before bilateral RDN, mGFR was measured by iohexol clearance. We estimated eGFR from serum creatinine and cystatin C (eGFR_crea , eGFR_cys, and eGFR_creacys ), and albumin-creatinine ratio (ACR) and N-acetyl-β-D-glucosaminidase (NAG)-creatinine ratio (NAG-CR) were measured in spot urines. All measurements were repeated after six and twenty-four months. Twenty patients, mean age 54 (±9) years and baseline mGFR 83 (±20) ml/min/1.73 m² underwent RDN. After six months, mGFR fell, eGFR_crea remained unchanged, whereas eGFR_cys and eGFR_creacys increased. At 2 years' follow-up, eGFR_creacys was significantly lower than at baseline. mGFR was 78 (±28) ml/min/1.73 m² . Change in ambulatory systolic BP predicted change in eGFR_crea . Urinary NAG-CR, but not ACR, increased during follow-up. Different GFR assessments gave diverging results after RDN. Therefore, care should be taken to method when evaluating kidney function after RDN. Increases in a tubular dysfunction biomarker suggest that kidney damage may occur. Long-term renal follow-up is needed after RDN.

Keywords: glomerular filtration rate; renal denervation; urinary biomarkers.

FIGURE 1

Mean glomerular filtration rate (GFR) by exact measurement (mGFR) and three different estimates (eGFR_cre, eGFR_cys, and eGFR_crecys) at baseline, and at six months and two years after renal denervation

FIGURE 2

Two urinary biomarkers, albumin‐creatinine ratio (ACR) and N‐acetyl‐β‐D‐glucosaminidase (NAG)‐creatinine ratio (NAG‐CR), at baseline, and at six months and two years after renal denervation. Values are displayed as median and interquartile range, and significant differences (P <.05) indicated by^*