[Does the result of thrombolysis with recombinant tissue-type plasminogen activator (rt-PA) in rabbits depend on the erythrocyte- and fibrin-content of a thrombus?].
OBJECTIVE
It is known from autopsy studies that thromboembolic stroke can be caused by red, white and mixed clots. We therefore examined whether the efficacy of thrombolysis with recombinant tissue-type plasminogen activator (rt-PA) depends on the proportions of fibrin and erythrocytes within thromboembolic material.


METHODS
In 23 rabbits intraarterial thrombolysis with 3 mg rt-PA/kg body weight was started 30 minutes after middle cerebral artery occlusion with either red or white autologous emboli 20 hours old. 20 rabbits served as control. Cerebral perfusion was monitored by MRI.


RESULTS
rt-PA enhanced lysis of red but not of white emboli and decreased the infarct volume only if vascular occlusion was due to red emboli (p <.01). Cerebral perfusion improved only in the red treatment group where the normalized first moment (NFM) decreased (p <.05) and the relative regional cerebral blood volume (rrCBV) reached normal values (p <.05).


CONCLUSIONS
We suggest that in our animal model the efficacy of thrombolysis increases with the proportion of erythrocytes within thromboembolic material and decreases with its content of fibrin. lf these findings would also be applicable to patients, pretherapeutic estimation of the efficacy of thrombolysis might become feasible because the CT values of red and white thrombi differ.
Kirchhof
K
K
Abteilung Neuroradiologie, Neurologische Klinik, Universitätsklinikum Heidelberg.
Sikinger
M
M
Welzel
T
T
Zoubaa
S
S
Sartor
K
K
D000818:Animals; D002560:Cerebrovascular Circulation; D003627:Data Interpretation, Statistical; D004195:Disease Models, Animal; D004912:Erythrocytes; D005337:Fibrin; D005343:Fibrinolytic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D020244:Infarction, Middle Cerebral Artery / Q000150:complications / Q000473:pathology; D002542:Intracranial Embolism and Thrombosis / Q000473:pathology*; D008297:Male; D010960:Plasminogen Activators / Q000008:administration & dosage / Q000627:therapeutic use*; D011379:Prognosis; D011817:Rabbits; D020521:Stroke / Q000188:drug therapy* / Q000209:etiology; D015912:Thrombolytic Therapy; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage / Q000627:therapeutic use*
D005343:Fibrinolytic Agents; D005337:Fibrin; D010960:Plasminogen Activators; D010959:Tissue Plasminogen Activator