Enterprise stent-within-stent embolization of a basilar artery perforator aneurysm

Objective and Importance—Vertebrobasilar artery aneurysms can be very challenging to treat and are preferentially dealt with using endovascular techniques, since they are associated with lower risk than surgical clipping. Small aneurysms located on perforating arteries can pose problems though, as their dimensions may not be favorable for coiling and leave the endovascular surgeon without many options. We present a basilar perforating artery aneurysm that was successfully embolized using a stent-within-stent technique. Clinical Presentation—A 47 year old female presented with a Hunt-Hess 3, Fisher Grade-3 subarachnoid hemorrhage with blood in the pre-pontine cistern. Initial imaging (CT angiogram and digital subtraction angiography) did not reveal an aneurysm. Follow-up angiography on post-bleed day eight demonstrated a three-millimeter basilar perforating artery aneurysm. After an unsuccessful coiling attempt a closed-cell stent-within-stent technique was used to divert flow away from the aneurysm neck to induce aneurysm thrombosis. Intervention (or Technique)—Multiple attempts were made to access and stabilize a microcatheter in the small basilar perforator artery aneurysm in order to deliver coils for endovascular embolization; this could not be done safely. Therefore a closed-cell 4.5 × 22 mm Enterprise stent (Cordis Neurovascular, Inc., Miami Lakes, Florida) was deployed in the basilar artery across the origin of the perforator aneurysm in order for the stent tines to divert flow away from the aneurysm neck and induce thrombosis. Persistant brisk flow within the aneurysm continued however, and a second closedcell 4.5 × 22 mm Enterprise stent was placed within the first one to increase the stent metal surface area across the aneurysm neck to further reduce flow into the aneurysm. Subsequently, angiography demonstrated stagnant blood flow in the aneurysm dome and the aneurysm spontaneously thrombosed, sparing all associated vessels. Conclusion—Stent-within-stent technique should be considered as a possible endovascular treatment option for small side-wall and perforator artery aneurysms that can’t be safely treated with coils or embolic agents.