title: Clinical demonstration that catheter-delivered ultrasound energy reverses arterial vasoconstriction.
abstract: OBJECTIVE
  This study was designed to describe the clinical effects of ultrasound energy on guide-wire-induced arterial vasoconstriction.
  
  
  BACKGROUND
  We have previously shown that ultrasound energy (20 kHz) delivered by a wire probe produces dose-dependent, endothelium-independent smooth muscle relaxation capable of reversing both receptor-mediated and voltage-dependent vasoconstriction in vitro.
  
  
  METHODS
  A high intensity, low frequency ultrasound catheter system was used to recanalize total occlusions in the superficial femoral arteries of two patients. After recanalization, the proximal residual stenoses were each less than 15%. However, distal arterial vasospasm was found angiographically in a popliteal artery of one patient and in an anterior tibial artery of another. Subsequently, the ultrasound catheter probe was advanced to the sites of arterial vasospasm (diffuse in one, focal in one).
  
  
  RESULTS
  After 30 and 90 s, respectively, of exposure to ultrasound energy with a frequency of 19.5 kHz, peak tip amplitude of 111 microns and power output at the transducer of 25 W, the vasospasm resolved in each arterial segment.
  
  
  CONCLUSIONS
  Our findings are the first reported clinical cases documenting that catheter-delivered low frequency, high intensity ultrasound induces arterial vasodilation at the site of vasoconstriction. These biologic effects appear to be relatively unique for an angioplasty device and may have potential clinical importance.
authors.affiliation: Division of Cardiology, Cedars-Sinai Medical Center, Los Angeles, California 90048-0750.
authors.forename: R J
authors.initials: RJ
authors.lastname: Siegel
authors.forename: P
authors.initials: P
authors.lastname: Gaines
authors.forename: A
authors.initials: A
authors.lastname: Procter
authors.forename: T A
authors.initials: TA
authors.lastname: Fischell
authors.forename: D C
authors.initials: DC
authors.lastname: Cumberland
mesh_terms: D000368:Aged; D001161:Arteriosclerosis / Q000628:therapy*; D002404:Catheterization; D003251:Constriction, Pathologic / Q000628:therapy; D005260:Female; D005263:Femoral Artery / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D011150:Popliteal Artery / Q000000981:diagnostic imaging; D011859:Radiography; D016909:Tibial Arteries / Q000000981:diagnostic imaging; D014464:Ultrasonic Therapy / Q000379:methods*; D014463:Ultrasonography; D014661:Vasoconstriction