The morphologic changes of aneurysms after isolated by covered stent implantation:an experimental study

Objective: To investigate the morphologic changes of experimental aneurysms after isolated by covered stent implantation. Methods: Ten experimental aneurysms were established in bilateral carotid arteries in five canines, which were isolated with covered stent two weeks later. MRI of the aneurysms with a 3-tesla unit was performed before, immediately after, 2 weeks and 4 weeks after the procedure, to observe their morphologic changes. Then the canines were sacrificed for pathologic study. The experiment was focused on the changes of aneurysmal volume after cover stent implantation. Data thus obtained were analyzed by using SAS6.12 statistical software. Results: The 3-tesla magnetic resonance unit could clearly display the aneurysmal morphology on T2 imaging. The aneurysmal volume were (100.17 ± 16.64)mm3, (97.25 ± 17.18)mm3, (44.11 ± 5.96)mm3 and (33.75 ± 5.02)mm3 at the time before, immediately after, 2 weeks and 4 weeks after the procedure respectively. Statistically significant difference in volume changes existed among groups (χ2 = 22.254, P = 0.01). The average aneurysmal volume decreased by 55.6%, 66.2% at 2 weeks and 4 weeks after the procedure respectively when compared with that before procedure. Pathologically, the total aneurysms became fibrous degeneration 4 weeks after procedure. Conclusion: The aneurysm can obviously decrease in volume and become totally fibrosed after isolated with covered stent, which can relieve the space-occupying effect of the aneurysm to the surrounding structures. (authors)