Introduction: Circumferential aneurysms, which incorporate >180 degrees of the circumference of the parent vessel, present a unique therapeutic challenge, particularly in circumstances in which a deconstructive treatment strategy is not feasible. We detail a novel technique for endovascular parent vessel reconstruction with aneurysm embolization.
Methods: We performed a retrospective review of the prospectively maintained databases of our two institutions to identify cases in which a balloon-in-stent technique had been used to treat circumferential aneurysms. During the first stage of this technique, a stent (Neuroform [Boston Scientific, Natick, MA], Multilink Vision [Guidant, Indianapolis, IN], or Bx Velocity [Cordis, New Brunswick, NJ]) is placed across the neck of the aneurysm to achieve parent vessel reconstruction. During the second stage, aneurysm coil embolization is performed with a compliant temporary occlusion balloon (Sentry [Boston Scientific, Natick, MA] or Hyperglide [Microtherapeutics, Irvine, CA]) placed within the stent to unambiguously demarcate and protect the parent vessel. In some cases, during the course of the embolization, coils project over and obscure the parent vessel in both working views. Before each coil detachment, the protection balloon is deflated under blank fluoroscopic roadmap visualization. The absence of shifting of any portion of the coil mass during balloon deflation indicates that the introduced coil is external to the stent-reconstructed parent vessel (i.e., within the aneurysm) and can be detached. This process is repeated until satisfactory aneurysm embolization is achieved. After embolization, the balloon catheter may be exchanged for a stent delivery system to facilitate the placement of a second stent.
Results: Seven patients underwent balloon-in-stent-assisted embolization over a 15-month period. Three were performed for internal carotid aneurysms, three for basilar trunk or basilar apex aneurysms, and one for a dissecting/fusiform V4 segment vertebral artery aneurysm. In three cases, the presence of the inflated balloon facilitated the manipulation of the image intensifier into a position which produced a "down-the-barrel" view of the parent vessel. In the four additional cases, for anatomic reasons, this view could not be achieved and coil mass projected over the reconstructed parent vessel in both views. Partial aneurysm occlusion (75-90%), was achieved in five cases, and near complete (>95%) occlusion was achieved in two cases. Complications included two significant retroperitoneal hematomas and two brainstem infarcts, both of which resulted in hemisensory symptoms.
Conclusion: The balloon-in-stent technique provides a practical and safe treatment strategy for the management of circumferential aneurysms that are not amenable to deconstructive embolization.