J Korean Med Sci.  2022 Dec;37(50):e358. 10.3346/jkms.2022.37.e358.

Improving the Prognosis of Patients With Acute Ischemic Stroke Treated in the Late Time Window After the Introduction of Advanced Imaging Software: Benefits From Thrombectomy in the Extended Time Window

  • 1Department of Neurology, National Health Insurance Service Ilsan Hospital, Goyang, Korea
  • 2Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
  • 3Department of Radiology, National Health Insurance Service Ilsan Hospital, Goyang, Korea
  • 4Department of Neurology, Graduate School of Medicine, Kangwon National University, Chuncheon, Korea


Mechanical thrombectomy (MT) of ischemic stroke was recommended as a clinical guideline in 2015, and the indication for time was expanded in 2018 based on two clinical studies. We aimed to compare and analyze the prognosis of patients treated under the extended time indication before and after the introduction of advanced software.
We obtained data from medical records between 2016 to 2020. From 2016 to 2017, patients who did not receive MT who visited the hospital within 24 hours from the last normal time (LNT) were classified as standard medical treatment (SMT) group. Among patients who underwent MT between 2019 and 2020, patients who visited the hospital between 6-24 hours from the LNT were classified into the extended MT (EMT) group. Good outcome was defined as 3-months modified rankin scale (mRS) ≤ 2, and a poor outcome as mRS ≥ 4.
From 2016 to 2017, 1,058 patients were hospitalized for ischemic stroke, of which 60 (5.7%) received MT, and 27 patients were classified into the SMT group. Among 1,019 patients between 2019 and 2020, 85 (8.3%) received MT, and 24 patients were in the EMT group. Among the SMT group, only 3 had a good prognosis, and 24 (88.9%) had a poor prognosis. However, in the EMT group, 10 (41.7%) had a good prognosis, and 9 (37.5%) had a poor prognosis. The SMT group had a 49.1 times higher risk of poor prognosis compared to the EMT group (P = 0.008).
The number of patients with ischemic stroke who receive MT has increased by using advanced imaging software. It was confirmed that patients treated based on the extended time indication also had a good prognosis.


Thrombectomy; Endovascular Therapy; Hyperacute Stroke; Perfusion Imaging; Prognosis


  • Fig. 1 The process of selecting subjects for the study among all patients with ischemic stroke.CT = computerized tomography, NIHSS = National Institutes of Health Stroke Scale, Pre-mRS = pre-modified rankin scale, ASPECTS = Alberta Stroke Program Early CT Score, tPA = tissue plasminogen activator.


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