Augmentation of in-stent clot dissolution by low frequency ultrasound combined with aspirin and heparin. An ex-vivo canine shunt study.
BACKGROUND
Ultrasound can accelerate clot dissolution in vitro and in vivo. We used an ex vivo canine shunt to investigate low frequency ultrasound effects on platelet-rich stent thrombosis.


RESULTS
Nitinol stents were expanded to 2 mm in diameter in two perfusion chambers in a parallel shunt and exposed to flowing arterial blood at 2100 s(-1) to generate stent thrombi (n=224 perfusion runs). Dethrombotic effects were assessed during treatment with saline and combined treatment with aspirin and heparin. One stent was exposed to ultrasound (27 kHz, 1.4 W/cm2), while the other was not. Stent thrombi were weighed before and after treatment. There was no significant effect of ultrasound during saline infusion. Treatment with aspirin+heparin alone reduced thrombus weight by 37+/-25% (18.9+/-6.1 to 11.8+/-7.7 mg, p<0.0001). Combined treatment with aspirin+heparin+ultrasound produced a 49+/-23% reduction in thrombus weight (19.0+/-6.3 to 9.6+/-7.8 mg, p<0.0001). The reduction in thrombus weight was significantly greater in aspirin+heparin+ultrasound compared with aspirin+heparin alone (p=0.04).


CONCLUSIONS
Transcutaneous ultrasound significantly enhances dethrombotic effect of aspirin plus heparin on preformed stent thrombi. These findings suggest the potential of ultrasound as an adjunct to antithrombotic therapy to improve effectiveness without increasing the risk of bleeding complications during treatment of vascular thrombosis.
Neuman
Yoram
Y
Vascular Physiology and Thrombosis Research Laboratory of the Atherosclerosis Research Center, Cedars-Sinai Medical Center, Division of Cardiology, Room 5314, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA.
Rukshin
Vladimir
V
Tsang
Vivian
V
Atar
Shaul
S
Miyamoto
Takashi
T
Luo
Huai
H
Kobal
Sergio
S
Thompson
Todd
T
Birnbaum
Yochai
Y
Horzewski
Mike
M
Siegel
Robert J
RJ
Kaul
Sanjay
S
D000818:Animals; D001241:Aspirin / Q000627:therapeutic use*; D001807:Blood Vessel Prosthesis / Q000009:adverse effects*; D003131:Combined Modality Therapy / Q000379:methods; D004285:Dogs; D005260:Female; D006493:Heparin / Q000627:therapeutic use*; D015607:Stents / Q000009:adverse effects*; D016896:Treatment Outcome; D014464:Ultrasonic Therapy / Q000379:methods*; D020246:Venous Thrombosis / Q000188:drug therapy / Q000209:etiology* / Q000628:therapy*
D006493:Heparin; D001241:Aspirin