Additional Rescue Stent Placement for Stabilization of a Prolapsed Coil during Stent-assisted Coil Embolization of a Wide-Neck Intracranial Aneurysm

Abstract

We report a case of a 55-year-old man carrying two unruptured internal carotid artery (ICA) wide-neck aneurysms. In the same session, the smaller aneurysm was treated by coils using the remodeling technique and the large aneurysm was treated by stent-assisted coil embolization. During the stent-assisted procedure for the large aneurysm, the microcatheter tip moved from the aneurysm into the parent artery causing a prolapse of some coil loops into the vessel lumen. The distal part of the coil was tangled within the stent's struts, therefore, in order to introduce the entire coil, an attempt was made to withdraw the prolapsed loops of the coil within the microcatheter and concomitantly repositioning the microcatheter into the residual aneurysm neck through the stent struts. However this maneuver was unsuccessful. An attempt to retrieve gently the coil also failed and the coil prematurely detached. For maintaining the patency of the arterial lumen and to reduce the embolic risk, a second stent was used to pin the free coil loops. The rescue stent was positioned within the coil loops and its deployment allowed a circumferential expansion of some loops around the stent perimeter while other loops were flattened against the wall of the artery. The parent artery remained patent at one-year follow-up angiographic study. No clinical complications were observed.

Figure 1

Additional stent placement for stabilization of a floating coil during endovascular treatment of a wide-neck intracranial aneurysm in a 55-year-old patient. A) Non-subtracted and subtracted left Internal Carotid Artery (ICA) angiograms in Antero-Posterior (AP) view show an intermediate step of a Stent-assisted Coil Embolization of a large unruptured aneurysm of the carotid siphon. The image also shows a small anterior choroidal aneurysm formerly treated by coiling with balloon remodeling technique in the same session. During placement of another coil, the microcatheter kicked back in the arterial lumen (not shown) and the maneuvers for repositioning the microcatheter caused coil premature detachment. B) Same views as in (A), some distal coil loops are entangled within the stent mesh and proximal loops freely float in the artery lumen at the proximal extremity of the stent. C) Before the deployment of the rescue stent, working non-subtracted and non injected oblique views show the positioning of the tip of Vasco 21 microcatheter within the center of the prolapsed coil mass.

Figure 1

D) Same views as in (C), after the deployment of the rescue stent, circumferential spread of some free coil loops around the stent is observed (arrows). There is a slight overlapping of the two stents. E) Non-subtracted and subtracted left ICA angiograms in AP view show the patency of the artery lumen. Some pinned up coil loops look like a ring around the rescue stent which has now a diameter adapted to the arterial lumen and the rest of the free loops are flattened against the arterial wall. F) Same views as in (E), one year follow-up angiogram during re-treatment of aneurismal recurrence shows persistent patency of the ICA with no post-stenting stenosis. The patient remained asymptomatic.