Introduction In the treatment of acute ischemic stroke, localising the clot and identifying its mechanical characteristics are two of the main highlighted challenges for the choice of the extraction technique.

Aim of Study This study aims to: 1) explore the interaction forces between a guidewire and a synthetic clot for different occlusion conditions in a simplified arterial model; 2) develop algorithms to identify the beginning and the end of the clot and therefore deduce its length.

Methods Clot analogues of different stiffnesses and sizes were injected with a controlled pressure in a silicone conical arterial phantom. A robotic device instrumented with a force sensor controlled the movement of a guidewire at 1 mm/s both in crossing the lesion and in retracting the guidewire after clot penetration.

Results For a given pressure and clot volume, a rigid clot produces higher forces than a soft clot. However, at the same location, we can have a softer clot inserted at a high pressure or a stiffer clot inserted at a low pressure, resulting in similar forces. Based on the slope of the measured force during penetration, the beginning of the clot can be successfully detected. The clot’s end can be identified through the force measurement while retracting the guidewire.

Conclusion This in vitro study shows that multiple factors influence the lodgement of the clot and the corresponding forces that the guidewire encounters. Through a proximal force measurement, the extremities of the clot can be detected.

Disclosure of Interest Nothing to disclose.