Noninvasive transcutaneous ultrasound augments thrombolysis in the left circumflex coronary artery--an in vivo canine study.
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.
Jeon
Doo-Soo
DS
Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.
Luo
Huai
H
Fishbein
Michael C
MC
Miyamoto
Takashi
T
Horzewski
Michael
M
Iwami
Takahiro
T
Mirocha
James M
JM
Ikeno
Fumiaki
F
Honda
Yasuhiro
Y
Siegel
Robert J
RJ
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
D005343:Fibrinolytic Agents; D010959:Tissue Plasminogen Activator