Why Does Mechanical Thrombectomy in Large Vessel Occlusion Sometimes Fail? : A Review of the Literature

Thrombectomy is a technique that has completely changed the management of acute stroke and current devices have shown that they can achieve upwards of 90% successful recanalization in selected cohorts. However, despite the effectiveness of these devices, there are a proportion of patients who still fail to achieve reperfusion of the affected vascular territory and an even larger portion of patients who have poor functional outcomes in spite of successful recanalization. There are no guidelines on how to treat these patients when such failures occur. In an effort to understand the underpinnings of how failed thrombectomy occurs, we extensively reviewed the current literature in clot properties, vascular access problems, stroke pathogenic mechanisms, embolic complications, failed procedures and pre-procedural imaging. A short summary of each of these contentious areas are provided and the current state of the art. Together these elements give a cohesive overview of the mechanisms of failed thrombectomy as well as the controversies facing the field. New techniques and devices can then be developed to minimize such factors during stroke thrombectomy.