Testing bioresorbable stent feasibility in a rat aneurysm model

Abstract

BackgroundAdvances in stent-assisted coiling have incrementally expanded endovascular treatment options for complex cerebral aneurysms. After successful coil consolidation and aneurysm occlusion, endovascular scaffolds are no longer needed. Thus, bioresorbable stents that disappear after aneurysm healing could avoid future risks of in-stent thrombosis and the need for lifelong antiplatelet therapy.ObjectiveTo assess the applicability and compatibility of a bioresorbable magnesium- alloy stent (brMAS) for assisted coiling.MethodsSaccular sidewall aneurysms were created in 84 male Wistar rats and treated with brMAS alone, brMAS + aspirin, or brMAS + coils + aspirin. Control groups included no treatment (natural course), solely aspirin treatment, or conventional cobalt–chromium stent + coils + aspirin treatment. After 1 and 4 weeks, aneurysm specimens were harvested and macroscopically, histologically, and molecularly examined for healing, parent artery perfusion status, and inflammatory reactions. Stent degradation was monitored for up to 6 months with micro-computed and optical coherence tomography.ResultsAneurysms treated with brMAS showed advanced healing, neointima formation, and subsequent stent degradation. Additional administration of aspirin sustained aneurysm healing while reducing stent-induced intraluminal and periadventitial inflammatory responses. No negative interaction was detected between platinum coils and brMAS. Progressive brMAS degradation was confirmed.ConclusionsbrMAS induced appropriate healing in this sidewall aneurysm model. The concept of using bioresorbable materials to promote complete aneurysm healing and subsequent stent degradation seems promising. These results should encourage further device refinements and clinical evaluation of this treatment strategy for cerebrovascular aneurysms.

Aneurysm wall cellularity affects healing after coil embolization: assessment in a rat saccular aneurysm model

“…Although the model used in our study does not represent a true intracranial aneurysm such as the model described by Hashimoto et al ,29 it permits the assessment of basic concepts of aneurysm wall biology7 11 12 while representing a highly standardized and reproducible aneurysm model 17. Furthermore, the low morbidity/mortality of the model and relatively low costs make it a suitable tool to test and refine embolization devices that will be tested later in other more complicated and expensive models 30–32. Another limitation of the study is the lack of imaging modalities.…”

Current status and outlook of biodegradable metals in neuroscience and their potential applications as cerebral vascular stent materials

“…1 The application of Mg-based alloys in neuroscience. Mg alloys can be fabricated as filaments within: (a) nerve conduits to accelerate nerve regeneration [ 32 , 33 ], (b) nerve electrode and devices for neural recording and monitoring [ [34] , [35] , [36] ], (c) coiling-assisted stents for cerebrovascular aneurysms [ 37 ], and (d) expanded endovascular stents for the occlusion common carotid artery (CCA) [ 38 ]. …”

“…Mg stent was implanted into a rat model for the treatment of saccular aneurysms ( Fig. 4 a) [ 37 ]. In addition, Wang et al evaluated the biological outcomes of polytetrafluoroethylene membrane coated Mg-Nd-Zn-Zr alloy stent for the treatment of occlusion of a lateral aneurysm model in the rabbit common carotid artery (CCA).…”

Aspirin treatment prevents inflammation in experimental bifurcation aneurysms in New Zealand White rabbits

“…Previously, loss of mural cells was shown to have an important role in furthering its progression in a saccular rat sidewall model with untreated aneurysms, 4 after coil embolization, 17 and also after stent treatment. 18 With decreased numbers, there are fewer cells that can migrate into the thrombus and form a neointima. Furthermore, in a sidewall rabbit model, all aneurysms thrombosed spontaneously.…”