Introduction: Flow diversion is an effective and increasingly accepted method for endovascular treatment of cerebral aneurysms. Acute in-situ thrombosis during Pipeline embolization device (PED) deployment has potential for devastating morbidity. There is limited experience in the flow diversion literature on the usage of Abciximab (ReoPro) to address this issue.

Methods: Data were collected retrospectively on patients who encountered in-situ thrombosis during Pipeline flow diversion of anterior and/or posterior circulation intracranial aneurysms. Data collected include aneurysms characteristics, Abciximab dosing and administration regimen, post-procedural antiplatelet therapy, and clinical/radiographical follow up.

Results: Twenty-five patients (mean age 56 years; range 36-75 years) with 26 unruptured aneurysms (mean size 8.7 mm; range 2-25 mm) were identified to have in-situ thrombosis during PED deployment. Intraarterial (IA) ReoPro was administered in all cases, with 15 patients receiving increments of 5mg boluses and 10 patients receiving 0.125mg/kg bolus. Immediate or partial resolution of in-situ thrombosis was observed in 100% of the patients. Intravenous (IV) ReoPro infusion was administered post-procedurally in 18 patients. 19 patients were transitioned to Prasugrel (Effient) from Clopidogrel (Plavix) post procedurally. Average length of stay was 4.5 days (range 1-30 days), with 21/26 (81%) patients discharged to home. Intracranial hemorrhage was noted in 2 patients (8%). At six-months clinical follow up, 20/25 (80%) patients had mRS of 0. Angiographic follow up was available for 18 patients at a mean duration of 9.6 months, at which time aneurysm occlusion rate was 94% (16/17 patients).

Conclusions: IA and IV ReoPro administration is a effective and safe strategy for the management of acute in-situ thrombosis during PED, with high rates of immediate thrombosis resolution and relatively low rates of hemorrhagic complications and long term morbidity.

Patient Care: Acute in-situ or in-stent thrombosis during and/or immediately following PED deployment remain a significant challenge, with the potential for devastating ischemic neurological sequelae secondary to side branch occlusion, distal emboli, or device closure. This phenomenon is postulated to be due to platelet aggregation as a result of the high metal density of the device in conjunction with a patient’s metabolic hypo-responsivity to pre-procedural dual antiplatelet therapy. Studies attempting to quantify and predict the risk for peri-procedural thromboembolic events using the P2Y12 receptor inhibition assay have been inconclusive. Furthermore, there is no clear consensus or evidence based protocol for the management of PED associated acute in-situ thrombosis. The current research will improve patient care by examining the role of Abciximab for the management of this complication. Specifically, this research explores the the delivery method, indication, dosing algorithm, and clinical/radiographical outcomes, which have not been previously reported in the flow diversion literature.

Learning Objectives: To discuss the use of Abciximab for in-situ thrombosis during flow diversion

References: 1 Kallmes, D. F. et al. International retrospective study of the pipeline embolization device: a multicenter aneurysm treatment study. AJNR Am J Neuroradiol 36, 108-115, doi:10.3174/ajnr.A4111 (2015). 2 Lylyk, P. et al. Curative endovascular reconstruction of cerebral aneurysms with the pipeline embolization device: the Buenos Aires experience. Neurosurgery 64, 632-642; discussion 642-633; quiz N636, doi:10.1227/01.NEU.0000339109.98070.65 (2009). 3 Patel, A., Miller, T. R., Shivashankar, R., Jindal, G. & Gandhi, D. Early angiographic signs of acute thrombus formation following cerebral aneurysm treatment with the Pipeline embolization device. J Neurointerv Surg, doi:10.1136/neurintsurg-2016-012701 (2016). 4 Skukalek, S. L. et al. Effect of antiplatelet therapy and platelet function testing on hemorrhagic and thrombotic complications in patients with cerebral aneurysms treated with the pipeline embolization device: a review and meta-analysis. J Neurointerv Surg 8, 58-65, doi:10.1136/neurintsurg-2014-011145 (2016). 5 Bender, M. T. et al. P2Y12 hyporesponse (PRU>200) is not associated with increased thromboembolic complications in anterior circulation Pipeline. J Neurointerv Surg, doi:10.1136/neurintsurg-2016-012618 (2016). 6 Park, J. H. et al. Intraarterial abciximab for treatment of thromboembolism during coil embolization of intracranial aneurysms: outcome and fatal hemorrhagic complications. J Neurosurg 108, 450-457, doi:10.3171/JNS/2008/108/3/0450 (2008). 7 Ries, T., Siemonsen, S., Grzyska, U., Zeumer, H. & Fiehler, J. Abciximab is a safe rescue therapy in thromboembolic events complicating cerebral aneurysm coil embolization: single center experience in 42 cases and review of the literature. Stroke 40, 1750-1757, doi:10.1161/STROKEAHA.108.539197 (2009). 8 Velat, G. J. et al. The use of abciximab in the treatment of acute cerebral thromboembolic events during neuroendovascular procedures. Surg Neurol 65, 352-358, discussion 358-359, doi:10.1016/j.surneu.2005.08.024 (2006). 9 Lall, R. R., Crobeddu, E., Lanzino, G., Cloft, H. J. & Kallmes, D. F. Acute branch occlusion after Pipeline embolization of intracranial aneurysms. J Clin Neurosci 21, 668-672, doi:10.1016/j.jocn.2013.07.011 (2014).