Abstract 8: The Pipeline Embolization Device: Midterm Results and Predictors of Outcomes in 335 Consecutive Patients

Introduction: Flow diversion has emerged as a promising treatment for intracranial aneurysms. The safety and efficacy of this new technology is under investigation. We present the largest single-center experience to date with the pipeline embolization device (PED) and identify several predictors of outcomes. Methods: The study includes 335 consecutive patients who underwent PED treatment at our institution between 2011-2015. Safety data was prospectively recorded both peri-operatively and through follow-up. Angiographic images were independently reviewed and aneurysm occlusion classified as complete (100%), near-complete (95-99%), or incomplete (<95%). Results: Mean Aneurysm size was 9.4 mm. Aneurysms were saccular in 84% and fusiform/dissecting in 16%. Seventeen patients (5%) were treated in the setting of subarachnoid hemorrhage (SAH). The mean number of PEDs used was 1.2, and this number significantly decreased from 1.9 early in the study to 1.1 in the last year (p<0.05). Complications occurred in 5% which included a 3.0% hemorrhagic complication rate, 1.5% thromboembolic complication rate, and 0.5% rate of PED migration. Predictors of complications were increasing aneurysm size, early discontinuation of dual antiplatelet therapy, and treatment in the setting of SAH. At follow-up (mean, 14 months), aneurysm occlusion was complete in 77.6%, near-complete in 9.1%, and incomplete in 13.3%. No patient had aneurysm recurrence. Predictors of incomplete occlusion were older patients, previously coiled/stented aneurysms, and MCA and posterior circulation aneurysms. At the latest follow-up, favorable outcomes (mRS 0-2) were noted in 95.7%. Neurologic mortality was 1.7% and neurologic morbidity was 1.2%. Multivariate predictors of poor outcome were early discontinuation of antiplatelet therapy, increasing aneurysm size, and increasing number of PEDs deployed. Conclusion: Treatment with the PED has an excellent safety-efficacy profile at large cerebrovascular centers. Several key factors associated with outcomes are discussed. Prolonged dual antiplatelet therapy is crucial for avoidance of complications. Off label locations are associated with lower occlusion rates. A single PED should be used whenever possible.