The efficacy of endovascular stenting in the treatment of supraclinoid internal carotid artery blister aneurysms using a stent-in-stent technique

Abstract

Background and purpose: Blister aneurysms of the supraclinoid ICA represent a rare but well-documented cause of subarachnoid hemorrhage. These aneurysms are difficult to detect, and their surgical treatment is challenging, with high morbidity and mortality rates. The reports currently in the literature that describe the surgical and endovascular treatment of these aneurysms offer no clear consensus on the optimal treatment. We describe a staged endovascular treatment entailing stenting using a stent-in-stent technique, as well as planned but delayed embolization as the aneurysm increases in size to allow the introduction of coils.

Materials and methods: We performed a retrospective review of all cerebral angiograms performed at our institution over an 8-month period for evaluation of subarachnoid hemorrhage, identifying 6 ICA blister aneurysms.

Results: All 6 blister aneurysms were located in the supraclinoid ICA. The stent-in-stent technique was used for the initial treatment of all patients. Three patients had no residual or recurrent aneurysm following initial treatment. Three patients required retreatment with coils after continued growth of the aneurysm, identified on follow-up angiography. Five patients had good recovery (average mRS score of 1), and 1 patient had poor neurologic recovery (mRS score of 3) due to a large hemorrhagic infarction.

Conclusions: Our case series suggests that staged endovascular treatment entailing the use of a stent-in-stent technique, augmented with subsequent coil embolization as necessary for progressive disease, is a viable endovascular option for treating ruptured supraclinoid blister aneurysms, allowing for parent artery preservation.

Fig 1.

Left supraclinoid ICA blister aneurysm. Preprocedure DSA (A) shows a shallow outpouching (white arrow) arising from a nonbranching site along the medial wall of the supraclinoid segment of the left ICA, consistent with a blister aneurysm. Postprocedural DSA (B) immediately following stent deployment (stent-in-stent technique) again shows the blister aneurysm (white arrow), with diminished contrast opacification of the aneurysm sac. One-month (C) and 5-month (D) follow-up DSA show wide patency of the stents with no residual filling of the aneurysm sac.

Fig 2.

Right supraclinoid ICA blister aneurysm. Preprocedural DSA (A) shows a shallow outpouching (white arrow) arising from a nonbranching site along the anterolateral wall of the supraclinoid segment of the right ICA, consistent with a blister aneurysm. One-week follow-up DSA (B) following endovascular stent placement again shows the blister aneurysm (white arrow), now slightly increased in size. The patient subsequently underwent adjunct coil embolization with a single coil. Six-month follow-up DSA (C) following stent placement and coiling shows wide patency of the stents and no residual filling of the aneurysm sac, with note made of a single coil (black arrow) in the thrombosed aneurysm sac.

Fig 3.

Right supraclinoid ICA blister aneurysm. Preprocedural DSA (A) shows a shallow outpouching (white arrow) arising from a nonbranching site along the lateral wall of the supraclinoid segment of the right ICA, consistent with a blister aneurysm. One-month follow-up DSA (B) following endovascular stent placement again shows the blister aneurysm (white arrow), now increased in size and more round in shape. The patient subsequently underwent adjunct coil embolization with a single coil. Subsequent 3-month follow-up DSA (C) again shows the blister aneurysm, again increased in size and more round in shape. The patient subsequently underwent adjunct coil embolization with multiple coils. Subsequent 6-month follow-up DSA (D) again shows the blister aneurysm (white arrow), with recurrence at the aneurysm base. The patient subsequently underwent adjunct coil embolization with multiple coils. Twelve-month follow-up DSA (E) shows wide patency of the stents and minimal residual filling of the aneurysm sac (white arrow), with no filling of the coil interstices or aneurysm dome.

Fig 4.

Left supraclinoid ICA blister aneurysm. Preprocedural DSA (A) shows a blister aneurysm (white arrow) along the medial wall of the supraclinoid segment of the left ICA. Subsequent DSA (B) shows enlargement of the blister aneurysm (white arrow). Due to the repeat hemorrhage and increase in the size of the aneurysm, the patient was treated with parent vessel occlusion (C) and aneurysm trapping (after passing a temporary balloon occlusion).