Failed mechanical thrombectomy: prevalence, etiology, and predictors

Despite advances in endovascular techniques, mechanical thrombectomy (MT) fails to achieve successful reperfusion in approximately 20% of patients. This study aimed to identify common etiologies and predictors of failed thrombectomy in a contemporary series.A prospectively maintained database of MT patients between January 2013 and August 2021 was interrogated. Failed MT was defined as a final modified Thrombolysis in Cerebral Infarction score < 2b. Demographic data, procedural details, stroke etiology, and anatomical data in patients who underwent MT with subsequent failed reperfusion were collected.Of a total 1010 MT procedures, 120 (11.9%) were unsuccessful. The mean patient age was 66.8 years; 51.5% of patients were male, and 61.1% were White. The most common failure location was intracranial (93.3%) followed by failure at the arch (3.3%) and neck (3.3%). Among patients with intracranial failure, underlying intracranial atherosclerosis (ICAS) was the cause of failure in 84 patients (70%). Compared with patients with successful MT, patients with failed MT had a longer onset to puncture time (p = 0.012) and onset to groin time (p = 0.04). Rescue stenting was performed in 45 cases: 39 patients (4.4%) with successful MT and 6 (5.0%) with MT failure (p = 0.765). Multivariate analysis demonstrated that diabetes mellitus (p = 0.009) was independently associated with unsuccessful reperfusion.Failed MT was encountered in approximately 12% of MT procedures. The most common cause of failed MT was underlying ICAS. Further studies to evaluate better ways of early identification and treatment of ICAS-related large-vessel occlusion are warranted.