Abstract 16042: Selective Renal Sympathetic Denervation With Arterial Sparing?: An in vivo Proof of Principle Study Using Ultrasound Energy
Introduction: Renal artery sympathetic denervation using radiofrequency (RF) energy has recently been shown to reduce blood pressure in patients with hypertension. However, RF energy causes transmural arterial damage before achieving denervation of the adventitial sympathetic fibers. We assessed the ability of ultrasound to ablate the nerve fibers while sparing the arterial wall.
Methods: Percutaneous femoral arterial access was obtained in adult swine and renal angiography was performed to assess for stenosis before and after the procedure. A cylindrical ultrasound transducer mounted on the tip of the intravascular catheter was used to deliver bilateral renal artery sonications. All animals were then recovered and survived for up to 30 hours before sacrifice.
Results: No post- ablation renal artery stenosis was noted. The renal sympathetic nerves were located at a distance of 1.42±0.58 mm from the renal artery intima. Acutely, 59% of all nerves seen in the histological sections demonstrated moderate to complete injury and 27% demonstrated mild injury from ultrasound ablation. With circumferential cooling of the transducer, 71% of sections located in treatment areas demonstrated no intervening arterial injury; 100% of sections showed moderate or greater degree of nerve ablation.
Conclusions: Circumferential ultrasonic ablation can achieve renal sympathetic nerve ablation with only minimal injury to the arterial wall in the sub-acute setting. Chronic in vivo studies are needed to further evaluate these findings.
- © 2011 by American Heart Association, Inc.