Abstract 171: A Hole In One: Using A Balloon Microcatheter To Delineate Rupture Point For High‐Flow Direct Carotid‐Cavernous Fistula, Followed By Scaffolding With Flow Diversion

Introduction Direct Carotid‐Cavernous fistulas (CC‐fistula) are a result of high flow arteriovenous shunt, typically sequelae of aneurysmal rupture, trauma or other etiologies. Numerous first line endovascular options exist, including vessel sacrifice and flow diversion. However, rupture/rent points in extremely high‐flow shunts may be difficult to characterize for treatment. We describe a case of a Barrow Type‐A Direct CC‐Fistula that arose secondary to ruptured ICA aneurysm and successfully treated with dual overlapping flow diverters as a scaffold for arterial access. Balloon microcatheter inflation was utilized to “roadmap” the point of rupture, allowing direct access to the cavernous sinus (CS) through this arterial defect. Case Report A 68‐year‐old woman with history of hereditary hemorrhagic telangiectasia and 7mm left cavernous ICA aneurysm presented with decreased alertness, inability to follow commands and left‐sided proptosis/chemosis. CTA revealed enlargement and intense enhancement of the left CS with prominence of adjacent venous structures concerning for CC‐fistula. Cerebral angiogram demonstrated brisk opacification of left greater than right CS with apparent wall defect of dorsal aspect of the genu at proximal left cavernous ICA in a blowout configuration. There was marked opacification of petrosal sinuses, internal jugular veins and reflux antegrade into cortical cyst/dilated superior ophthalmic veins with faint opacification of left MCA territory and even less opacification of left ACA‐A1 segment. 3‐D rotational angiography was performed with suboptimal visualization related to degree of arteriovenous shunting. To better accurately assess the source of extravasation, a balloon microcatheter was advanced and inflated under continuous fluoroscopy until adequate antegrade obstruction was noted followed by gentle hand‐injection through the proximal guide catheter. This revealed a carotid rent in the proximal carotid siphon at the site of known aneurysm. Using the roadmap imaging from the guide catheter, transvenous access was obtained through the rent/defect and transvenous coil embolization was performed until subsequent runs demonstrated increased intracranial arterial contrast transit. Persistent shunting warranted telescoping flow diversion over the defect after removal of the coiling catheter with 2x Pipeline Shield TM flow diverters (Medtronic). Subsequent angiogram revealed wide patency of overlapping pipeline embolization devices with significantly decreased CC‐fistula flow and preservation of intracranial artery circulation. The patient was eventually discharged to rehab and during follow‐up appointments noted no lasting neurologic symptoms. Follow up angiograms demonstrated successive occlusion and decreased shunting. Discussion Direct CC‐fistulas are often a consequence of traumatic tear in the carotid artery from skull base fracture, acceleration‐deceleration forces, iatrogenic injury from endovascular/trans‐sphenoidal interventions or cavernous carotid artery aneurysm rupture. This unique case illustrates a combination of techniques available to the practicing neurointerventionalist including the following: balloon microcatheter occlusion for angioarchitecture characterization, transarterial to venous access for cavernous sinus embolization, and final occlusion with scaffolding flow diverters.