Abstract Body: Background and Purpose— In the current era, where mechanical thrombectomy (MT) has become the gold standard for treating large vessel occlusions in acute ischemic stroke, the role of intravenous tissue plasminogen activator (tPA) remains pivotal. It is well-established that pre-thrombectomy administration of tPA can enhance recanalization rates and excellent outcomes, leading to an increased adoption of this combined treatment approach. Understanding how tPA alters clots occluding large vessels is of crucial clinical importance for improving outcomes in thrombectomy when tPA is combined. This study seeks to elucidate the temporal changes in clots characteristics post-tPA administration, providing insights that could optimize the timing and strategy of subsequent mechanical intervention.
Methods— We utilized a modified Chandler loop technique to generate RBC-rich clots from ovine blood for simulating clot analogs. The clots were treated with 10 μg/ml concentration of Alteplase to evaluate clot dissolution. An in-vitro MCA occlusion model, replicating human neurovascular anatomy, was used to assess the impact of clot treatment under dynamic flow conditions. Clots were analyzed for weight changes before and after treatment, and detailed pathological analyses were conducted using advanced imaging techniques. Statistical significance was determined using Student t test and 2-way repeated-measures ANOVA, with p-values <0.05 considered significant. All analyses were performed using SPSS software.
Results: In the tPA group, clot weight decreased over time, with an average reduction to 46.7% of the initial value after 1 hour of solution exposure. In contrast, the control group showed relatively stable clot weight, remaining around 80% throughout the 1-hour exposure (P<0.001). Figure showing fhe fibrin content of the clot in the tPA group decreased significantly from 10.3% to 4.5% over time (P=0.038), whereas in the control group, it remained relatively unchanged, going from 7.3% to 8.1% (P=0.868).
Conclusion: This study confirmed that tPA effectively reduces clot weight and decreases the fibrin content within clots. Our results suggest that tPA administration not only reduces clot mass but also modifies its structural integrity, thereby potentially increasing the success rate of subsequent mechanical thrombectomy procedures.