Catheter-based renal sympathetic denervation exerts acute and chronic effects on renal hemodynamics in swine

Objectives: We investigated the acute and chronic effects of catheter-based renal sympathetic denervation (RSD) on renal hemodynamics assessed by average peak velocity (APV), renal blood flow (RBF), renal flow reserve (RFR) and resistive index (RI). Background: Sympathetic overdrive is accompanied by impaired RBF, whereas there is no data on the effects of transcatheter RSD on renal hemodynamic balance. Methods: Before and post-RSD (acutely and after 1 month), in 9 farm swines we measured APV by a 0.014-inch Doppler flow wire placed in the stem of the renal artery under baseline and hyperemic conditions, induced by intrarenal dopamine (50 mu g/kg). RFR was calculated as the ratio of hyperemic to basal peak velocity, and RI was estimated as (peak systolic velocity-end-diastolic velocity)/peak systolic velocity. RSD was achieved via the lumen of the main renal artery with a specifically designed catheter connected to a radiofrequency generator according to prespecified algorithm. Results: APV and RBF increased acutely post ablation in all animals, compared to APV and RBF before ablation (61.44 +/- 32.6 vs 20.44 +/- 6.38 cm/s, p<0.001 and 407.4 +/- 335.1 vs 161.1 +/- 76.6 ml/min, p=0.003; respectively), whereas RFR and RI were reduced (1.51 +/- 0.59 vs 2.85 +/- 1.33, p<0.001 and 0.67 +/- 0.07 vs 0.74 +/- 0.07, p=0.005; respectively). One month post ablation APV and RBF compared to APV and RBF before ablation remained significantly higher whereas RFR and RI remained lower as compared to baseline. Conclusions: Catheter-based RSD exerts acute and chronic effects on renal hemodynamics in a large animal model. If confirmed in humans RBF parameters may be used as direct markers of successful RSD. (C) 2012 Elsevier Ireland Ltd. All rights reserved.