Validation of an in vitro testing platform for intra-arterial thrombolytics on human thrombectomy retrieved clots

Endovascular thrombectomy (EVT) is the standard treatment for acute ischemic stroke (AIS) due to large vessel occlusion. However, many patients fail to achieve good outcomes, especially without first pass reperfusion. Intra-arterial thrombolytics such as recombinant tissue plasminogen activator (rtPA) and tirofiban have shown potential as adjunctive therapies. The aim of this study was to compare the in vitro effects of rtPA, tirofiban, and their sequential combination on EVT retrieved clots.

Human clot obtained during EVT was tested in an in vitro model of cerebral circulation. A three-dimensional printed arterial flow loop was used to replicate middle cerebral artery circulation. Clots were exposed to four treatment arms: plasma (control), rtPA, tirofiban, or both rtPA and tirofiban sequentially. Thrombolytic efficacy was quantified by clot weight reduction with multivariable statistical analyses adjusted by clinical variables.

70 clots were collected and used to perform 172 thrombolytic experiments. Both rtPA and tirofiban significantly reduced clot weight (tirofiban 20.6%, rtPA 20.7%, P<0.001), with a greater reduction when administered sequentially (37.9%, P<0.001). The treatment arm was the only significant predictor of thrombolytic effect. Clinical variables showed no statistically significant associations, although occlusion location and diabetes showed trends toward an association with clot weight reduction.

This study supports the use of clot based in vitro models with autologous plasma for standardized drug testing for patients with AIS. Sequential administration of rtPA and tirofiban resulted in greater clot degradation than either agent alone. Further studies are needed to confirm clinical applicability and optimize dual thrombolytic strategies.