Abstract Body: Introduction: The choice of initial imaging modality significantly impacts door-to-puncture time (DPT) in acute ischemic stroke (AIS) patients undergoing endovascular thrombectomy (EVT). Studies have shown that using CT as the first imaging modality can reduce DPT compared to MRI. In July 2023, we revised critical pathway (CP) protocols including first image modalities from MRI to CT regardless of last known normal time (LNT). Therefore, we evaluated the impact of process modification including first image modalities could reduce the DPT for the EVT candidates.

Methods: Prior to July 2023, EVT candidate AIS patients who visited Seoul National University Bundang Hospital, comprehensive stroke center, received CT as the first imaging modality if they arrived within 6 hours after onset, while others underwent MRI. From July 2023, all patients with disabling symptoms or an NIHSS score of 6 or higher received CT as the initial imaging, irrespective of LNT. We retrospectively analyzed the single center quality indicators, including DPT, door-to-image time, door-to-reperfusion time, and proportion of symptomatic intracerebral hemorrhage (sICH) comparing outcomes before and after the protocol change.

Results: The total number of AIS patients undergoing EVT increased from 396 in the first half of 2022 to 442 in the second half of 2023. Median DPT decreased from 71 minutes in early 2022 to 60 minutes after the protocol change, with a corresponding increase in the proportion of patients achieving DPT within 60 minutes from 37.5% to 52.2%. The median door-to-image time for patients receiving CT decreased from 27 minutes to 22.5 minutes, with 94% achieving imaging within 30 minutes post-change compared to 70% pre-change. MRI, on the other hand, showed a median door-to-image time reduction from 30 minutes to 28.5 minutes, but only 50% achieved imaging within 30 minutes. Overall, the median door-to-reperfusion time decreased from 130 minutes to 105 minutes, with the proportion of patients achieving reperfusion within 120 minutes increasing from 37.9% to 62.5%. There was no significant change in proportion of sICH.

Conclusions: The protocol change to a CT-first approach significantly improved key EVT quality indicators, particularly in reducing door-to-puncture time. These findings underscore the importance of optimizing imaging strategies to enhance outcomes in AIS patients undergoing EVT.