International Journal of Nephrology and Renovascular Disease (Aug 2017)

Renal sympathetic denervation increases renal blood volume per cardiac cycle: a serial magnetic resonance imaging study in resistant hypertension

  • Delacroix S,
  • Chokka RG,
  • Nelson AJ,
  • Wong DT,
  • Sidharta S,
  • Pederson SM,
  • Rajwani A,
  • Nimmo J,
  • Teo KS,
  • Worthley SG

Journal volume & issue
Vol. Volume 10
pp. 243 – 249

Abstract

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Sinny Delacroix,1,2 Ramesh G Chokka,1,3 Adam J Nelson,1,2 Dennis T Wong,4 Samuel Sidharta,1,2 Stephen M Pederson,5 Adil Rajwani,1,2 Joanne Nimmo,1,2 Karen S Teo,1,2 Stephen G Worthley1,2 1Cardiovascular Research Centre, Royal Adelaide Hospital, 2Department of Medicine, University of Adelaide, Adelaide, SA, 3South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, SA, 4Monash Medical Centre, Clayton, VIC, 5Bioinformatics Hub, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia Aim: Preclinical studies have demonstrated improvements in renal blood flow after renal sympathetic denervation (RSDN); however, such effects are yet to be confirmed in patients with resistant hypertension. Herein, we assessed the effects of RSDN on renal artery blood flow and diameter at multiple time points post-RSDN. Methods and results: Patients (n=11) with systolic blood pressures ≥160 mmHg despite taking three or more antihypertensive medications at maximum tolerated dose were recruited into this single-center, prospective, non-blinded study. Magnetic resonance imaging indices included renal blood flow and renal artery diameters at baseline, 1 month and 6 months. In addition to significant decreases in blood pressures (p<0.0001), total volume of blood flow per cardiac cycle increased by 20% from 6.9±2 mL at baseline to 8.4±2 mL (p=0.003) at 1 month and to 8.0±2 mL (p=0.04) 6 months post-procedure, with no changes in the renal blood flow. There was a significant decrease in renal artery diameters from 7±2 mm at baseline to 6±1 mm (p=0.03) at 1 month post-procedure. This decrease was associated with increases in maximum velocity of blood flow from 73±20 cm/s at baseline to 78±19 cm/s at 1 month post-procedure. Notably, both parameters reverted to 7±2 mm and 72±18 cm/s, respectively, 6 months after procedure.Conclusion: RSDN improves renal physiology as evidenced by significant improvements in total volume of blood flow per cardiac cycle. Additionally, for the first time, we identified a transient decrease in renal artery diameters immediately after procedure potentially caused by edema and inflammation that reverted to baseline values 6 months post-procedure. Keywords: renal denervation, resistant hypertension, magnetic resonance imaging, renal blood flow, renal physiology 

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