Abstract 10294: Percutaneous Renal Sympathetic Denervation Exerts a Chronic Effect on Renal Hemodynamics Using a Novel Catheter for Radiofrequency Ablation: Data From an Animal Study
Introduction: Sympathetic overdrive impairs renal blood flow, whereas the effect of renal denervation on chronic autoregulation of renal hemodynamics has yet to be adequately explored.
Hypothesis: Renal sympathetic denervation, performed using a novel radiofrequency ablation catheter, should have a chronic (1 month post ablation) effect on renal hemodynamics: average peak velocity (APV), renal flow reserve (RFR) and resistive index (RI).
Methods: We studied renal haemodynamics in 9 anaesthetized female juvenile farm swines (mean age 6 months, mean weight 34.5 kg). The renal angiogram, percutaneously performed through femoral artery, found no renal artery stenosis in all subjects. A 0.014 inch Doppler flow wire was introduced in the renal artery for the measurement of the APV under baseline and hyperemic condition that was induced by the bolus intrarenal administration of dopamine (50μ g/kg). RFR was calculated as the ratio of hyperemic to basal peak velocity. RI was estimated as (peak systolic velocity - end-diastolic velocity)/peak systolic velocity. APV, RFR and RI were measured before and 1 month after renal sympathetic denervation. The sympathetic denervation was achieved via the lumen of the main renal artery with the novel catheter connected to a radiofrequency generator from St. Jude Medical according to pre-specified algorithm.
Results: In all animals, APV 1 month after ablation compared to APV before ablation was significantly higher (30.21±13.14 vs 21.79±8.53 cm/sec, p=0.035). Moreover, radiofrequency ablation resulted in reduced RFR (1.36±0.25 vs 2.96±1.33, p<0.0001) and RI (0.48±0.15 vs 0.74±0.07, p=0.003), while no significant changes in the diameter of the renal artery was observed after dopamine administration (p=NS).
Conclusions: Catheter-based renal sympathetic denervation augmented APV and decreased RFR and RI, persistently and significantly at 1 month post ablation in healthy swines. These results support the chronic effect of renal artery denervation by the radiofrequency ablation catheters on renal hemodynamic function even in a healthy animal setting.
- © 2011 by American Heart Association, Inc.