In acute thrombus retrieval therapy, a catheter device is used to recover blood flow by entangling the thrombus in the blood vessel and pulling it out. 　We are fabricating a thrombus model with controlled mechanical properties from porcine blood and using a silicone cerebrovascular model to evaluate the risk of vascular injury and thrombus detachment during the pulling out of the device in vitro. Using our experimental system, we will provide evidence of the effectiveness of physicians' procedures performed in clinical practice.

The flow diverter is a cylindrical device with a mesh structure used to treat large and giant cerebral aneurysms and is expected to shrink the aneurysm after placement. 　For evaluating the device's effectiveness, it is important to elucidate the effect of flow diverter implantation on the flow field in the aneurysm. Therefore, we analyze the velocity distribution in the mass using particle image velocimetry (PIV) and measure the change in the flow in the aneurysm before and after the implantation of the flow diverter. 　The preliminary results suggest that the flow field in the aneurysm after implantation of the flow diverter is formed by combining the impinging flow on the flow diverter and the seeping flow from the mother vessel.

Implantable VAD is a therapeutic device that assists the heart's pumping function in patients with severe heart failure, and demand for this device is increasing as a solution to the shortage of organ donors. However, there has been a problem that thrombus forms around the inflow cannula insertion site in the left ventricle and spreads through the bloodstream. 　We developed an in vitro thrombogenicity testing method to quantify the amount of thrombus that spread from the inflow cannula and compared the conventional cannula with a newly developed titanium mesh cannula. Based on the results, the improved cannula was approved without clinical trials and is currently used for patients.

Animal blood is sometimes used to evaluate the hemocompatibility of medical devices. Still, the properties of animal blood are different from those of human blood, and there are few assay kits for platelets and coagulation factors in animal blood. If we can use human blood, we can evaluate the coagulation activity and inhibition mechanism of medical materials and drugs. Therefore, we have been developing a small pulsatile circuit for comparative evaluation of blood compatibility using human blood and investigating platelet activity and coagulation activity change over time using this testing system. In addition, we are analyzing the effect of blood flow conditions on the changes in blood coagulation factors over time using human blood.