gms | German Medical Science

While Guglielmi detachable coil (GDC) systems have been widely accepted for treatment of intracranial aneurysms, primary stenting of aneurysms using porous stents, stentgrafts, or implantation of coils after stent placement constitute emerging techniques in endovascular treatment. The aim of the present study was to use an animal model to investigate these different approaches to treat cerebral aneurysms concerning the rate of closure, the histopathological changes within the aneurysm cavity and the parent vessel after stent placement.

We created aneurysms in 30 rabbits by distal ligation and intraluminal incubation of the right common carotid artery with elastase. 10 animals were treated with porous stents alone, 10 animals with stentgrafts (covered stents) and ten animals were treated with stents and additional coiling via the interstices of the stent that enabled dense packing of the coils. Five animals in each group were observed for 1 month, the other animals were observed for 3 months. Histological analyses were performed including immunohistochemical investigations for estimating the proliferation of the intima and possible inflammatory infiltration.

Covered stents led to a complete and stable aneurysm occlusion with only minimal proliferative carrier vessel wall changes. One covered stent was completely occluded with old thrombus, the other remained patent. Porous stents occluded 2 of 5 aneurysms in the one-month follow-up group and 4 of 5 after three months. However, progressive sprouting of neointima inside the carrier vessel which resulted in a stenosis of up to 40% was present. In the Stent+Coil group, one aneurysm showed recanalization after one month and 3 of 5 aneurysms were recanalized after three months following coil compaction. Moreover, in-stent stenosis of up to 30% was present.

The study demonstrates the possible shortcomings and problems of emerging “Stent-techniques” to treat intracerebral aneurysms, shows where technical advances have to be made and describes in which cases of aneurysm morphology caution has to be taken when considering an endovascular approach employing stents.