Intracranial clot lysis with intravenous microbubbles and transcranial ultrasound in swine.
OBJECTIVE
Destruction of microbubbles by transcutaneous low-frequency ultrasound (LFUS) has been used to lyse adjacent clot and recanalize acutely thrombosed vessels. LFUS with intraarterial microbubbles has been shown to lyse cerebral clot rapidly in pigs without thrombolytic drugs. We hypothesized that intravenous platelet-targeted microbubbles with LFUS may be a rapid noninvasive technique to recanalize thrombosed intracerebral vessels.


METHODS
After angiography, 0.5 cc of autogenous thrombus was injected into 1 ascending pharyngeal artery of a pig, occluding it and the rete mirabile. These vessels connect the carotid to the internal carotid and are the main cerebral blood supply. Saline control or intravenous decafluorobutane-sonicated dextrose albumin microbubbles tagged with a subtherapeutic quantity of glycoprotein 2b/3a receptor inhibitor eptifibatide (75 U/kg plus 12 cc of microbubbles administered over 21 minutes), or eptifibatide control, was given with transcutaneous temporal LFUS (1 MHz at 2.0 W/cm2) for 24 minutes. Angiography followed with scoring of declotting and flow. The same protocol was repeated on the contralateral side with the other test fluid so each animal received a saline control and either tagged microbubble or eptifibatide alone.


RESULTS
Fifteen pigs completed the protocol with a mean clot age of 4.6 hours. Using tagged microbubbles, 6 of 8 achieved success compared with 0 of 7 receiving eptifibatide alone (P=0.007) and 1 of 15 receiving saline alone (P=0.02).


CONCLUSIONS
Intravenous platelet-targeted microbubbles combined with transcranial LFUS can rapidly open acute intracranial thrombotic occlusions. Further development for ischemic stroke therapy is justified.
Department of Radiology, University of Arkansas for Medical Sciences, 4301 W Markham St, Slot 556, Little Rock, AR 72205-7199, USA. culpwilliamc@uams.edu
William C
WC
Culp
Thomas R
TR
Porter
John
J
Lowery
Feng
F
Xie
Paula K
PK
Roberson
Louis
L
Marky
D000818:Animals; D005947:Glucose / Q000008:administration & dosage; D007275:Injections, Intravenous; D020767:Intracranial Thrombosis / Q000628:therapy*; D045423:Microbubbles; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000037:antagonists & inhibitors; D012709:Serum Albumin / Q000008:administration & dosage; D000075462:Serum Albumin, Human; D013552:Swine; D017585:Ultrasonography, Doppler, Transcranial
D010975:Platelet Aggregation Inhibitors; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D012709:Serum Albumin; C094311:dextrose albumin solution; D005947:Glucose; D000075462:Serum Albumin, Human