Complex Cerebral Aneurysms

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Treatment of Complex Cerebral Aneurysms:
The Use of Flow-diverting Devices


by Alois Zauner, MD

Medical Director, Stroke and Neurovascular Center of Central California



The emergence of intracranial flow-diverting stents has sparked interest in a potential alternative for treating complex cerebral aneurysms.


Despite the tremendous evolution in endovascular therapy, some important limitations remain, particularly in the treatment of wide-necked, large and giant, or "nonsaccular" fusiform aneurysms.



To date, endovascular therapy has been almost exclusively focused on filling the aneurysm sac with embolic material, i.e., "endosaccular" treatment. This strategy is very effective for the treatment of smaller, narrow-necked aneurysms. However, these larger, more complex lesions can frequently be difficult to treat with coils, even when they are used with the commercially available self-expanding intracranial stents. Endovascular treatments of such lesions frequently fail to produce complete aneurysm occlusion. Even when complete or near-complete occlusion has been achieved after the initial embolization, these aneurysms remain prone to coil compaction and recanalization, and they frequently recur, requiring retreatment.


The Pipeline Embolization DeviceTM (PED) represents the first U.S. Food and Drug Administration-approved endovascular construct specifically engineered to function as a stand-alone device for the endovascular reconstruction of a segmentally diseased parent vessel. The PED is a self- expanding, micro-catheter-delivered, cylindrical mesh device composed of 48 individual cobalt chromium (75 percent) and platinum tungsten (25 percent) strands. The device has approximately 30 percent to 35 percent metal surface area coverage when fully deployed.


During the procedure, the PED is delivered through a micro catheter and deployed across the aneurysm neck. This device redirects the blood flow to its natural course and slows the flow of blood into the aneurysm, which allows for the diseased vessel to heal and the aneurysm to eventually thrombose.


The PED was FDA-approved and launched in April 2011 and is indicated for the endovascular treatment of adults (22 years of age or older) with large or giant wide-necked intracranial aneurysms (lAs) in the internal carotid artery from the petrous to the superior hypophyseal segments.


Santa Barbara Cottage Hospital began using the device in November of 2011 and to date has performed more than 20 of these procedures.


Case Presentation


After a high-speed motor vehicle rollover accident, a 21-year-old female developed an arterial dissection and subsequent fusiform aneurysm and pseudo-aneurysm involving the cavernous segment of the left internal carotid artery (ICA).


The diagnostic cerebral angiogram demonstrated a 15 x 12 x 11mm lobulated and fusiform aneurysm arising from the dissected segment of the cavernous segment of the left ICA. A decision was made to place a flow-diverting stent after loading doses of clopidogrel (300mg) and aspirin (325mg) followed by maintenance doses of 75mg and 81mg. A 3.75 x 20mm flow-diverting stent was then placed across the distal left ICA proximal to the ophthalmic artery. A second flow-diverting stent measuring 4 x 18mm was telescoped into the first flow-diverting stent, reconstructing the cavernous segment of the distal left ICA. Post stent deployment angiogram demonstrated stagnant flow within the aneurysm.


Approximately 12 months after intervention, the patient returned for a follow-up diagnostic angiogram. Cerebral injection of the left ICA demonstrated normal contour of the reconstructed cavernous segment of the ICA and normal antegrade flow into the ipsilateral anterior and middle cerebral arteries.



The advent of flow-diverting stents, such as the PED, has generated much consideration and excitement in the neurointerventional community. These devices offer a treatment option for complex cases in which coil embolization is challenging or not feasible. The PED allows for reconstruction of the cerebrovasculature and has documented use in unfavorable aneurysm features, including wide neck, large size, fusiform morphology and post-treatment recanalization.


The PED allowed reconstruction of the cavernous segment of the ICA, and the telescoping of two devices supplemented cover- age across the vascular defect, eliminating intra-aneurysmal flow. Follow-up angiogram performed 12 months later demonstrated normal flow dynamics and a completely thrombosed aneurysm.


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