[Zurück]

B. Devcic-Kuhar, S. Pfaffenberger, L. Gherardini, M. Gröschl, E. Benes, J. Wojta, M. Gottsauner-Wolf:
"Ultrasound Promotes Penetration of Thrombolytic Agent into Blood Clots and Enhances Thrombolysis";
in: "Proc. 18th Int. Congress on Acoustics (ICA 2004)", Acoustical Society of Japan, Kyoto/Japan, 2004, ISBN: 4-9901915-6-0, 4 S.

Today, enzymatic thrombolysis employing the fibrinselective
recombinant tissue plasminogen activator (rt-
PA) is widely used in the clinical setting for treatment
of myocardial infarction, cerebral insult and limb
ischemia. However, penetration of rt-PA from the
surrounding blood into the thrombus is a very slow
process and a rate-limiting step in the reestablishment of
blood flow and the maintenance of viability of the
affected region, but it can be accelerated when taking
place in an ultrasound field (sonothrombolysis). In our
research on sonothrombolysis we have studied the
effects of therapeutic ultrasound on thrombolysis
enhancement in vitro. Clot weight loss measurements
and measurements of concentration of the fibrin
degradation product D-dimer in the supernatant showed
that ultrasound of 2 MHz frequency and 1.2 W/cm2
acoustic intensity enforced thrombolysis significantly.
By using gel immobilization technique and immunohistochemistry,
we were able to localize plasminogen
and rt-PA within the clot. The spatial distributions of
these fibrinolytic components showed clearly that
ultrasound promoted the penetration of rt-PA into
thrombi significantly and broadened the zone of lysis
from 9 µm to 21 µm on average. We have shown for the
first time that ultrasound facilitates the access of rt-PA
to the deeper layers of the clot, thus leading to
significantly faster clot dissolution.

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