Impact of renal denervation on tissue Na + content in treatment-resistant hypertension

Clin Res Cardiol. 2018 Jan;107(1):42-48. doi: 10.1007/s00392-017-1156-4. Epub 2017 Aug 28.

Abstract

Objectives: Renal denervation (RDN) has been introduced for reducing blood pressure (BP) in treatment-resistant hypertension (TRH). The precise mechanism how RDN exerts its BP-lowering effects are not yet fully understood. It is widely accepted that sodium (Na+) plays a crucial role in the pathogenesis of hypertensive disease. However, there is increasing evidence of osmotically inactive Na+ storage. We investigated the impact of RDN on Na+ homeostasis using estimation of salt intake, and measurement of tissue Na+ content.

Methods: In a study 41 patients with TRH (office BP ≥140/90 mmHg and diagnosis confirmed by 24-h ambulatory BP monitoring) underwent RDN. Tissue Na+ content was assessed non-invasively with 3.0 T magnetic resonance imaging before and 6 months after RDN. In addition, 24-h urinary Na+ excretion as an estimate of salt intake and spot urine Na+/K+ excretion were assessed. The study was registered at http://www.clinicaltrials.gov (ID: NCT01687725).

Results: There was a significant fall in BP (office: -17 ± 20/-10 ± 12 mmHg; 24-h: -11 ± 13/-6 ± 9 mmHg, all p < 0.001) 6 months after RDN. In contrast, tissue Na+ content of the muscle (20.1 ± 3.9 vs. 20.7 ± 4.0 mmol/L, p = 0.229) and skin (24.4 ± 6.5 vs. 24.8 ± 6.6 mmol/L, p = 0.695) did not change after RDN. Moreover, there was also no change in salt intake after RDN, whereas Na+/K+ ratio only acutely increased.

Conclusions: Although RDN resulted in a substantial reduction of BP, tissue Na+ content of the muscle and skin was not mobilized and reduced. These data indicate that the BP reduction after RDN is unrelated to Na+ homeostasis.

Keywords: Hypertension; Magnetic resonance imaging; Nervous system; Renal denervation; Sodium; Sympathetic.

Publication types

  • Observational Study

MeSH terms

  • Aged
  • Antihypertensive Agents / therapeutic use
  • Blood Pressure* / drug effects
  • Catheter Ablation* / adverse effects
  • Drug Resistance
  • Female
  • Humans
  • Hypertension / diagnosis
  • Hypertension / metabolism
  • Hypertension / physiopathology
  • Hypertension / surgery*
  • Kidney / blood supply*
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Muscle, Skeletal / metabolism*
  • Pilot Projects
  • Prospective Studies
  • Renal Artery / innervation*
  • Renal Elimination
  • Skin / metabolism*
  • Sodium / metabolism*
  • Sodium / urine
  • Sympathectomy / adverse effects
  • Sympathectomy / methods*
  • Time Factors
  • Treatment Outcome
  • Urinalysis

Substances

  • Antihypertensive Agents
  • Sodium

Associated data

  • ClinicalTrials.gov/NCT01687725