Permanent arterial blood filtration for embolic stroke prevention - the hemodynamics of a new concept

A new permanent filtering device (the Diverter) was designed for prevention of embolic stroke from proximal sources such as atrial fibrillation, by implantation at the carotid bifurcation. It diverts emboli away from the internal into the external carotid artery (ICA, ECA). The aim was to study hemodynamic parameters governing blood filtration in-vitro, and then test the hemodynamically optimized arterial filtering device in-vivo. An in-vitro Continuous Digital Particle Image Velocimetry (CDPIV) system was used to investigate the filter's flow field in a compliant transparent model of the carotid bifurcation. The results were used to assess the hymodynamic parameters that govern the activation of the coagulation cascade and the design was optimized. An in vivo swine model was applied to assess the validity of the in-vitro results, by testing the patency of 30 harvested filtering devices implanted in arterial bifurcations. A thin filament based design was found to be hemodynamically optimal in-vitro, by invoking the minimally possible flow disturbances and values of Activation Parameter (AP). An arterial filter designed based on these considerations remained patent in a swine model and did not invoke occlusive thrombi. These findings serve as the basis for a novel vascular interventional approach for treatment of embolic disease.