A novel hyper-elastic thin film nitinol covered stent significantly decreases intra-aneurysmal flow in vitro

A novel hyper-elastic thin film nitinol (HE-TFN) covered stent has been developed to promote aneurysm quiescence by diminishing flow across the aneurysm's neck. Laboratory aneurysm models were used to assess the flow changes produced by stents covered with different patterns of HE-TFN. The flow diverters were constructed by covering Wingspan stents (Boston Scientific) with HE-TFNs (i.e., 82 and 77% porosity) and deployed in both in vitro wide-neck and fusiform glass aneurysm models. In wide-neck aneurysms, the 82% porous HE-TFN stent reduced mean flow velocity in the middle of the sac by 86.42±0.5%, while a 77% porous stent reduced the velocity by 93.44±4.99% (n=3). Local wall shear rates were also significantly reduced by about 98% in this model after device placement. Tests conducted on the fusiform aneurysm revealed smaller intra-aneurysmal flow velocity reduction to 48.96±2.9% for 82% porous and to 59.2±6.9% for 77% porous stent, respectively. The wall shear was reduced by approximately 50% by HE-TFN stents in fusiform models. These results suggest that HE-TFN covered stents have potential to promote thrombosis in both wide-necked and fusiform aneurysm sacs.