ABSTRACT NUMBER: ESOC2026A2482 IN VITRO ASSESSMENT OF INTRA-ARTERIAL TIROFIBAN VERSUS R-TPA FOR THROMBOLYSIS ON MECHANICAL RETRIEVED THROMBI AND CLINICAL PREDICTORS OF RESPONSE

Abstract Background and aims When Mechanical thrombectomy (MT) fails to achieve recanalization intra-Arterial (IA) administration of lytic agents represents a potential alternative therapeutic strategy. We aimed to assess the thrombolytic efficacy of 2 different drugs, on MT-retrieved thrombi and evaluate whether its effect is associated with clinical variables. Methods MT-retrieved thrombi were embolized in an in-vitro 3D-printed model simulating M2-M3 branches of Middle Cerebral Artery integrated into a closed flow-loop. A total of 128 thrombi were divided into 287 fragments. Each fragment was randomized to five minutes of circulating plasma alone (control), +r-tPA, or +tirofiban. Lytic effect was quantified by clot weight reduction (WR). Interactions between treatment arms and clinical variables were analyzed. Results At baseline, the mean fragment weight was similar in the 3 experimental groups (p=0.84). Clot WR was higher with alteplase (22%) and tirofiban (23%) than with control (10%;p<0.001). In mixed-effects analyses restricted to drugs, age≥80 years significantly modified treatment effect (interaction p=0.007), with significant age×treatment interaction also observed by etiology. Among patients≥80 years with non-cardioembolic thrombi, tirofiban achieved greater mean percent clot WR than r-tPA by an absolute 12.3% (p<0.001) (Figure 1). No other treatment differences were observed. Conclusions In this experimental model, IA r-tPA and tirofiban both reduced clot weight versus control, confirming comparable thrombolytic activity. Although overall efficacy was similar, subgroup analyses revealed significant age–etiology interactions, with tirofiban showing greater efficacy in non-cardioembolic thrombi from older patients, suggesting that this characteristics may guide more tailored use of pharmacological adjuncts during endovascular stroke therapy. Conflict of interest Cristina Marquez: nothing to disclose Figure 1 - belongs to Results