A New Strategy For Renal Sympathetic Denervation Using Double Ultrasonic Beam Catheter

Objective：Recently,the study found that excessive activation of thesympathetic ervous system （SNS) is a most important factor to thedevelopment of pertension.Transcatheter renal sympathetic denervation isone of the important methods in the treatment of resistant hypertension.Thisstudy investigated the feasibility and safety of renal sympatheticndenervation using a new double ultrasonic beam catheter in animals,whichsought to explore a new method to sympathectomy with catheter treatment.Methods::A double ultrasonic beam catheter integrated with twoultrasonic transducer which clearance of8mm,the catheter could delivertwo parallel ultrasonic beam.Sixteen healthy adult mongrel dogs,randomlydivided into2groups,ablation group(n=12) and control group(n=4).Theultrasound catheter was delivered into renal artery through the guidingcatheter sheath which was inserted to engage each main RA sequentially bytransabdominal ultrasound uidance,then ablation was performed innon-circumferential of0°-270°rotation.Meanwhile, the sham group animalswere underwent a similar catheterization procedure but without acoustics energy emission.The animals were sacrificed,the renal and surroundingtissue sent to pathological examination,and blood pressure and plasmanoradrenaline index were compared.Results：1.Access to both renal arteries and ablation was successful in12canines.During the course of the experiment,there was no complicationoccurs.2.Both blood pressure and noradrenaline concentration in ablationgroup were significantly decreased than that of the sham group.3.Renalartery and the surrounding tissue,there was no macroscopic injury such asintimal dissection, thrombogenesis or pathologic stenosis within the renalartery.The nerve fibers ablation target area appeared vacuolardegneration,pyknosis,dark stained and shrunken.The nerve fibers ofmidpiece segment which had no regeneration occurred.Conclusions: It was safety and effective for RDN using a new doubleultrasonic beam catheter,which could prevent nerve regenerationprocess.This catheter may provide a more persistent,more effective methodfor renal sympathetic denervation.