Histopathological Characteristics of IV Recombinant Tissue Plasminogen -Resistant Thrombi in Patients with Acute Ischemic Stroke

Abstract

Rates of angiographic recanalization following IV
recombinant tissue plasminogen activator (rt-PA) vary
from 23% to 56% depending upon the location of occlusion and time interval between administration of rt-PA
and ascertainment of recanalization [1–3]. It remains
unclear whether certain thrombus characteristics result
in resistance to lysis with IV rt-PA. In animal models of
embolic stroke and femoral artery thrombosis, white
thrombi composed of platelets and fibrin displayed a relative resistance against thrombolysis, whereas erythrocytes-rich (red) thrombi were more vulnerable to lysis
[4]. Platelet-rich thrombi were relatively resistant to rtPA compared with in a rabbit model of femoral artery
thrombosis [5]. Furthermore, thrombolytics exposure
results in platelet activation, which increases the platelet
content in thrombus and thus render thrombus resistant
to additional thrombolytic activity [6].
We performed this study to evaluate and compare the
histopathological characteristics of persistent in vivo
thrombi retrieved from acute ischemic stroke patients
who had received IV rt-PA prior to endovascular treatment.