311 © Springer Nature Switzerland AG 2021 F. K. Hui et al. (eds.), 12 Strokes, https://doi.org/10.1007/978-3-030-56857-3_23 Chapter 23 Challenges in Thrombectomy: Impossible Aortic Arches and Tortuous Vessels Jaims Lim, Muhammad Waqas, Kunal Vakharia, and Adnan H. Siddiqui Abbreviations ADAPT A direct aspiration frst-pass technique AIS Acute ischemic stroke BCA Brachiocephalic artery CCA Common carotid artery CT Computed tomography DI Divergence index ICA Internal carotid artery MR Magnetic resonance rtPA Recombinant tissue plasminogen activator TI Tortuosity index Introduction The goal of endovascular treatment of acute ischemic stroke (AIS) is to achieve rapid, safe, and effective arterial recanalization of large intracranial vessel occlu- sions. The likelihood of recanalization with intravenous thrombolysis using J. Lim · M. Waqas · K. Vakharia Department of Neurosurgery, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA Department of Neurosurgery, Gates Vascular Institute at Kaleida Health, Buffalo, NY, USA A. H. Siddiqui (*) Department of Neurosurgery, Gates Vascular Institute at Kaleida Health, Buffalo, NY, USA Departments of Neurosurgery and Radiology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA Jacobs Institute, Buffalo, NY, USA e-mail: asiddiqui@ubns.com