Augmented experimental pulse-spray thrombolysis with tissue plasminogen activator, enabling dose reduction by one or more orders of magnitude.
OBJECTIVE
To critically evaluate and optimize methodologic details of pulse-spray thrombolysis with tissue plasminogen activator (tPA) in a subacute rabbit inferior vena cava thrombosis model.


METHODS
Occlusive inferior vena cava thrombi were produced in 104 rabbits and 2 days later were treated for 1 hour with pulse-spray thrombolysis using tPA. Methodologic variables included pulse frequency, concentration and amount of tPA, infusion versus pulse therapy, and admixture of heparin. After the rabbits were killed, residual thrombus was weighed.


RESULTS
The authors' earlier standard regimen (3 mg of tPA in 6 mL of heparinized saline, 0.2-mL hand pulses, frequency 1 pulse per 2 minutes) produced 60% mean lysis. Optimization involved increasing the pulse frequency to two per minute and decreasing tPA concentration by 98% to 0.01 mg/mL, modifications that produced 22% more thrombolysis, despite 92% reduction in amount of tPA to 0.25 mg.


CONCLUSIONS
Consistent with the in vitro work of other investigators, a roughly bell-shaped dose-response curve was elicited in vivo for pulse-spray with tPA. By diluting tPA to an optimal level, and increasing pulse frequency to two per minute, thrombolysis was markedly augmented. These results suggest that the conventional dose of tPA used for clinical pulse-spray thrombolysis can be reduced by one to two orders of magnitude, possibly markedly reducing procedural risk.
Bookstein
J J
JJ
Division of Research, VA Hospital, La Jolla, CA, USA. jbookstein@ucsd.edu
Bookstein
F L
FL
D000818:Animals; D002405:Catheterization, Central Venous; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D007262:Infusions, Intravenous; D008297:Male; D010960:Plasminogen Activators / Q000008:administration & dosage*; D011817:Rabbits; D015912:Thrombolytic Therapy / Q000379:methods*; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage*; D016896:Treatment Outcome; D014682:Vena Cava, Inferior; D020246:Venous Thrombosis / Q000188:drug therapy* / Q000473:pathology
D010960:Plasminogen Activators; D010959:Tissue Plasminogen Activator