Objective : Since the outbreak of the coronavirus disease 2019 (COVID-19) pandemic, neurointerventionists have been increasingly concerned regarding the prevention of infection and time delay in performing emergency thrombectomy procedures in patients with acute stroke. This study aimed to analyze the effects of changes in mechanical thrombectomy protocol before and after the COVID-19 pandemic on procedure time and patient outcomes and to identify factors that significantly impact procedure time.Methods : The last-normal-to-door, first-abnormal-to-door, door-to-imaging, door-to-puncture, and puncture-to-recanalization times of 88 patients (45 treated with conventional pre-COVID-19 protocol and 43 with COVID-19 protection protocol) were retrospectively analyzed. The recanalization time, success rate of mechanical thrombectomy, and modified Rankin score of patients at discharge were assessed. A multivariate analysis was conducted to identify variables that significantly influenced the time delay in the door-to-puncture time and total procedure time.Results : The door-to-imaging time significantly increased under the COVID-19 protection protocol (p=0.0257) compared to that with the conventional pre-COVID-19 protocol. This increase was even more pronounced in patients who were suspected to be COVID-19-positive than in those who were negative. The door-to-puncture time showed no statistical difference between the conventional and COVID-19 protocol groups (p=0.5042). However, in the multivariate analysis, the last-normal-to-door time and door-to-imaging time were shown to affect the door-to-puncture time (p=0.0068 and 0.0097). The total procedure time was affected by the occlusion site, last-normal-to-door time, door-to-imaging time, and type of anesthesia (p=0.0001, 0.0231, 0.0103, and 0.0207, respectively).Conclusion : The COVID-19 protection protocol significantly impacted the door-to-imaging time. Shortening the door-to-imaging time and performing the procedure under local anesthesia, if possible, may be required to reduce the door-to-puncture and doorto- recanalization times. The effect of various aspects of the protection protocol on emergency thrombectomy should be further studied.