Refractory and Challenging Thrombectomy.

Despite continued advancement in thrombectomy devices and techniques, a small proportion, approximately 10%, of thrombectomy attempts result in failed reperfusion due to technical difficulties with reaching the clot or recanalizing the occluded vessel. Technically challenging thrombectomy cases are often longer, with more thrombectomy passes, resulting in poorer clinical outcomes and higher rates of complications. Factors causing difficulty during thrombectomy include tortuous vasculature preventing access, challenging clot location (tandem or distal occlusions), underlying vessel abnormality, and hard-to-retrieve clots. Anticipating potentially challenging or refractory thrombectomy cases allows one to plan appropriate procedural strategies with the goal of maximizing technical success and favorable clinical outcome. We review these challenging situations and discuss specific procedural techniques that can be employed in each scenario to overcome the barriers and achieve fast and successful reperfusion.