Thrombogenicity assessment of surface-modified flow diverters: the impact of different surface modification strategies on thrombin generation in an acute in vitro test.

Background: New generation flow-diverting stents have benefited from recent technological advances to reduce their thrombogenicity. This in vitro study is the first of its kind to compare multiple surface modified flow diverters with their bare metal counterparts.

Methods: A thrombin generation assay (TGA) was used to compare thrombin generation resulting from different stent types with glass beads (positive control) and plasma (negative control). Ten different stent types were studied, including a next-generation implant, Surpass Elite, with two different surface modifications. A thrombogram was generated from each of the 10 sample types, from which peak thrombin generation and time to peak (TTP) were obtained.

Results: Compared with the positive control and their bare metal counterparts, lower peak thrombin and longer TTP were obtained with most of the surface modified devices tested. Only the stent with an active heparin drug coating demonstrated lower peak thrombin and TTP than the negative control plasma.

Conclusion: Generally, surface modification resulted in lower thrombogenicity, as assessed by peak thrombin concentration and TTP, when compared with the unmodified version of the device. The device with an active heparin drug coating was significantly different from other surface modifications and plasma with respect to peak thrombin and TTP, though the implications of this should be investigated through future in vitro and in vivo studies.