“Impact and effect of aspiration catheters in mechanical thrombectomy – an in vitro study.”
Mechanical thrombectomy as the gold standard therapy for treating acute ischemic stroke either consists of aspiration and stent retrieval of clots used side by side or by using each technique alone. We aimed for understanding how aspiration effects the thrombus configuration in order to understand benefits and disadvantages of this procedure.
We built models of the proximal middle cerebral artery using shrinkage plastic tubing to simulate tapering vessels. Clots built from human whole blood by dynamic and static coagulation methods were injected into these models to obliterate the lumen. Under continuous high-speed camera monitoring clot aspiration was performed with increasing vacuum levels. We analysed how aspiration was effected by catheter size, suction power, time, thrombus size and composition.
Small red clots were aspirated completely by low vacuum levels, while more complex red clots with a higher amount of fibrin were sucked out of erythrocytes. The resulting white clots were difficult to retrieve, as same as the white or mixed clots in general, which were complicated to retrieve by aspiration at all vacuum levels. Furthermore, we observe a typical breaking point, most likely due to internal clot architecture that leads to new clot fragments.
Interaction between clots and aspiration tubing is highly dependent on clot composition. Whereas small red clots can be aspirated effectively and safely at low vacuum levels, more complex clots should be secured by an additional stent retriever placement. Ideally, clot composition should be known in advance according to choose the ideal technique for the case.