The thromboembolic clot in patients with stroke was previously reported to be a complex of fibrin, red-cells, and nucleated cells rather than simple red clot.

In this study, two experimental types of clot were created: group A, erythrocyte-rich clot and group B, fibrin-rich clot. Each type of clot was injected into eight extracranial arteries of swine. Mechanical thrombectomy was then performed using Merci clot retriever device. The average number of attempts to achieve recanalization was significantly less in group A (p <0.001). Less mean operative time was also observed in group A (15.5 min vs. 81.5 min, p <0.01). Failure in recanalization was observed in 5/8 arteries in group B.

This study demonstrates the stiffness of fibrin-rich clot in the animal vessels. This will help for the improvement of mechanical thrombectomy devices and the techniques for capture of clot. However, this might not be totally applied in human ischemic stroke. Experimental clot configuration does not completely mimic human clot. The clotting system of swine is different to human setting.