The benefit of mechanical thrombectomy (MT) in acute ischemic stroke (AIS) due to large vessel intracranial occlusions is directly related to the technical success of the procedures in achieving fast and complete reperfusion. While a precise definition of refractoriness is lacking in the literature, it may be considered when there is reperfusion failure, long procedural times, or high number of passes with the MT devices. Detailed knowledge about the causes for refractory MT in AIS is limited; however, it is most likely a multifaceted problem including factors related to the vascular anatomy and the underlying nature of the occlusive lesion amongst other factors. We aim to review the impact of several key unfavorable anatomical factors that may be encountered during endovascular AIS treatment and discuss potential bail-out strategies to these challenging situations.

Mechanical thrombectomy (MT) has become the gold-standard for patients with acute large vessel occlusion strokes (LVOS). MT is highly effective in the treatment of embolic occlusions; however, underlying intracranial atherosclerotic disease (ICAD) represents a therapeutic challenge, often requiring pharmacological and/or mechanical rescue treatment. Glycoprotein IIb/IIIa inhibitors have been suggested as the best initial approach, if reperfusion can be achieved after thrombectomy, with angioplasty and/or stenting being reserved for the more refractory cases. In this review, we focus on the therapeutic considerations surrounding the endovascular treatment of ICAD-related acute LVOS.