Can a commercial diagnostic ultrasound device accelerate thrombolysis? An in vitro skull model.
OBJECTIVE
Recently, 3 clinical trials revealed encouraging results in recanalization and clinical outcome in acute stroke patients when 2-MHz transcranial Doppler monitoring was applied. This study investigated whether a 1.8-MHz commercial diagnostic ultrasound device has the potential to facilitate thrombolysis using an in vitro stroke model.


METHODS
Duplex-Doppler, continuous wave-Doppler, and pulsed wave (PW)-Doppler were compared on their impact on recombinant tissue plasminogen activator (rtPA)-mediated thrombolysis. Blood clots were transtemporally sonicated in a human stroke model. Furthermore, ultrasound attenuation of 5 temporal bones of different thickness was determined.


RESULTS
In comparison, only PW-Doppler accelerated rtPA-mediated thrombolysis significantly. Without temporal bone, PW-Doppler plus rtPA showed a significant enhancement in relative clot weight loss of 23.7% when compared with clots treated with rtPA only (33.9+/-5.5% versus 27.4+/-5.2%; P<0.0005). Ultrasound attenuation measurements revealed decreases of the output intensity of 86.8% (8.8 dB) up to 99.2% (21.2 dB), depending on temporal bone thickness (1.91 to 5.01 mm).


CONCLUSIONS
Without temporal bone, PW-Doppler significantly enhanced thrombolysis. However, because of a high attenuation of ultrasound by temporal bone, no thrombolytic effect was observed in our in vitro model, although Doppler imaging through the same temporal bone was still possible.
Pfaffenberger
Stefan
S
Department of Internal Medicine II, University of Vienna, Austria.
Devcic-Kuhar
Branka
B
Kollmann
Christian
C
Kastl
Stefan P
SP
Kaun
Christoph
C
Speidl
Walter S
WS
Weiss
Thomas W
TW
Demyanets
Svitlana
S
Ullrich
Robert
R
Sochor
Heinz
H
Wöber
Christian
C
Zeitlhofer
Josef
J
Huber
Kurt
K
Gröschl
Martin
M
Benes
Ewald
E
Maurer
Gerald
G
Wojta
Johann
J
Gottsauner-Wolf
Michael
M
D001777:Blood Coagulation; D005343:Fibrinolytic Agents / Q000494:pharmacology / Q000627:therapeutic use; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D012886:Skull / Q000000981:diagnostic imaging*; D020521:Stroke / Q000097:blood / Q000000981:diagnostic imaging / Q000188:drug therapy*; D013701:Temporal Bone / Q000000981:diagnostic imaging; D015912:Thrombolytic Therapy / Q000295:instrumentation*; D010959:Tissue Plasminogen Activator / Q000494:pharmacology / Q000627:therapeutic use; D018616:Ultrasonography, Doppler, Duplex; D018617:Ultrasonography, Doppler, Pulsed; D017585:Ultrasonography, Doppler, Transcranial
D005343:Fibrinolytic Agents; D010959:Tissue Plasminogen Activator