gms | German Medical Science

Objective: Thromboembolic complications are serious adverse events associated with stenting of intracranial aneurysms. However, current experimental models for the testing of new devices do not include the analysis of distal embolic events.

Methods: To test the thrombogenicity of the Enterprise vascular reconstruction devise (Enterprise) versus pipeline embolization device (PED), six Yorkshire pigs underwent implantation of size-matched devices across the carotid bifurcation. Every animal received one Enterprise to one side and one PED contra-laterally. After 2 weeks, follow up angiography was performed and the animals were sacrificed.

Results: Two animals in each group had similar thromboembolic events (33.3%). Neo-endothelialization was slightly more pronounced with PED. The porcine rete mirabile, a small vessel conglomerate between the extra and intracranial circulation, acted as a filter catching embolic debris. If no event was present at 2 weeks, the rete height measured 17.0 ± 0.6 mm, the width 8.8 ± 0.4 mm, the rete area 134.4 ± 6.9 mm2 (n=8). With thromboembolic events (n=4), the perfused rete was reduced to a height of 9.5 ± 0.9 mm, a width of 4.6 ± 0.1 mm, covering 37.1 ± 8.6 mm2 (p<0.01). Size reduction of the rete indicated presence of distal thromboembolic events. There was no difference between the two devices.

Conclusion: The porcine carotid bifurcation is well suited to test stents for thrombogenicity and distal embolic events in-vivo. Thrombogenicity and embolic events are characterized by stent/branch occlusions, the endothelial response and compromise of the rete mirabile. Both Enterprise and PED were associated with similar thrombogenicity.