title: Noninvasive transcutaneous ultrasound augments thrombolysis in the left circumflex coronary artery--an in vivo canine study.
abstract: BACKGROUND
  Ultrasound has the potential to augment chemical thrombolysis.
  
  
  RESULTS
  Thrombotic occlusions in the left circumflex artery (LCx) were induced in 27 dogs. Sixty minutes later, tissue-type plasminogen activator (t-PA) was given intravenously over 90 min. Thrombotic occlusions (n = 20) were treated with concomitant transcutaneous low frequency (27 kHz), continuous wave (CW) (n = 10) or pulsed wave (PW) (n = 10) ultrasound. Tissue-type plasminogen activator plus ultrasound (n = 20) vs. tissue-type plasminogen activator alone (n=7) resulted in more frequent Thrombolysis in Myocardial Infarction (TIMI) 3 flow (90% vs. 43%, P = 0.024) and less reocclusion (11% vs. 67%, P = 0.080). At 60 min, median TIMI grade flow for tissue-type plasminogen activator alone was 2 (mean: 1.43 +/- 1.40) compared to 3 (mean: 2.70 +/- 0.95) for tissue-type plasminogen activator plus continuous as well as pulsed wave ultrasound (P = 0.035). Continuous wave and pulsed wave ultrasound were equally effective in augmenting thrombolysis. Histologically, no ultrasound-mediated injury to the myocardium or coronary arteries occurred.
  
  
  CONCLUSIONS
  Both transcutaneous low frequency continuous wave ultrasound and pulsed wave ultrasound enhance tissue-type plasminogen activator-mediated thrombolysis of the posterior circulation with higher TIMI 3 flow rates and less reocclusion than with tissue-type plasminogen activator alone. In addition, at the energy levels used, low frequency ultrasound appears safe.
authors.affiliation: Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.
authors.forename: Doo-Soo
authors.initials: DS
authors.lastname: Jeon
authors.forename: Huai
authors.initials: H
authors.lastname: Luo
authors.forename: Michael C
authors.initials: MC
authors.lastname: Fishbein
authors.forename: Takashi
authors.initials: T
authors.lastname: Miyamoto
authors.forename: Michael
authors.initials: M
authors.lastname: Horzewski
authors.forename: Takahiro
authors.initials: T
authors.lastname: Iwami
authors.forename: James M
authors.initials: JM
authors.lastname: Mirocha
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Ikeno
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Honda
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Siegel
mesh_terms: D000818:Animals; D002304:Cardiac Pacing, Artificial; D017023:Coronary Angiography; D003331:Coronary Vessels / Q000187:drug effects* / Q000528:radiation effects*; D004285:Dogs; D005343:Fibrinolytic Agents / Q000494:pharmacology*; D006339:Heart Rate; D009206:Myocardium / Q000473:pathology; D012881:Skin Temperature; D010959:Tissue Plasminogen Activator / Q000494:pharmacology*; D014465:Ultrasonics
chemical_list: D005343:Fibrinolytic Agents; D010959:Tissue Plasminogen Activator