Introduction: Blood blister-type aneurysms (BBA) and iatrogenic pseudoaneurysms create unique treatment challenges. Flow-diverting stents (FDS) have recently been used for BBA treatment. Dual antiplatelet therapy for FDS after acute subarachnoid hemorrhage (SAH) and intracranial tumor surgery warrants careful consideration. This abstract reports on the use of the Pipeline Embolization Device (PED) as primary treatment of these complex aneurysm subtypes.

Methods: Four patients were treated with PED after diagnosis of BBA or pseudoaneurysm (Table). Dual antiplatelet therapy was started > 24 hours prior to placement. Intraprocedural stent-view flat-detector CT (XperCT) was used to detect stent position and endoleak.

Results: PED placement was technically successful in all 4 patients. In patients 2 (Figure 1) and 4 (Figure 2), endoleak (type III and I, respectively) was detected and treated with balloon angioplasty. Radiological outcome demonstrated complete aneurysm occlusion in three of four patients between 2-4 weeks after treatment. Patient 1 with a BBA died as a result of aneurysmal re-rupture (Figure 3). Patients 2 and 3 had normal neurological exams at follow-up. Patient 4 had a good neurological outcome, but died of unrelated causes 3 months after procedure (Figure 4).

Conclusions: FDS can be used as primary treatment for BBA and iatrogenic pseudoaneurysms. Intraoperative contrast stasis within the aneurysm may suggest flow diversion; however, the extent to which this predicts aneurysm occlusion is yet to be determined. The placement of additional telescoping stents could lead to intraoperative contrast stasis, but it may also place the patient at additional risk of procedural complications. FDS should be used judiciously in the setting of acute SAH due to the need for dual antiplatelet therapy and the lack of immediate aneurysm occlusion compared to other endovascular or surgical treatments. Optimization of outcome requires consideration of all treatment options.

Patient Care: This abstract describes cases and scenarios which are relatively uncommon in the literature, but address current controversies in aneurysm treatment. The challenges of dual antiplatelet therapy in the setting of acute subarachnoid hemorrhage and subtotal tumor resection are highlighted. From a technical standpoint, intraoperative findings such as stent endoleak and intraaneurysmal contrast stasis and their implications for stent placement are also discussed.

Learning Objectives: By the conclusion of this session, participants should be able to (1) describe the pathophysiology and treatment options for blood blister-type aneurysms and pseudoaneurysms, (2) discuss the management of intraoperative and immediate postoperative complications associated with PED placement, (3) identify risk factors for PED placement in this subset of patients.

References: Literature references available upon request.