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Updated: Oct 5, 2025
Optimized Management of Endovascular Treatment for Acute Ischemic Stroke
Published on: January 18, 2018
Stroke imaging prior to thrombectomy in the late window: results from a pooled multicentre analysis
Mohammed A Almekhlafi1, John Thornton2, Ilaria Casetta3
1Departments of Clinical Neurosciences, Radiology, and Community Health Sciences. Hotchkiss Brain Institute and O'Brien Institute for Public Health, Cumming School of Medicine at the University of Calgary, Calgary, Alberta, Canada mohammed.almekhlafi1@ucalgary.ca.
Insights
CT angiography collateral assessment for late window endovascular thrombectomy (EVT) shows similar outcomes to perfusion imaging. This study compared patient selection methods for EVT, finding comparable functional outcomes regardless of imaging technique used.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- CT angiography is a promising tool for selecting patients for endovascular thrombectomy (EVT) in the late window (6-24 hours).
- The comparative outcomes of patients selected using collateral imaging versus perfusion imaging are not well-defined.
Purpose of the Study:
- To compare the functional outcomes of patients selected for late window EVT using collateral imaging alone versus those selected using both perfusion and collateral imaging.
Main Methods:
- Pooled data from seven trials and registries of EVT-treated patients in the late time window.
- Classified patients into collateral imaging alone (collateral cohort) and perfusion plus collateral imaging (perfusion cohort).
- Utilized propensity score weighting to balance predictors between cohorts and analyzed 90-day functional outcomes (modified Rankin Scale 0-2).
Main Results:
- In 608 patients, 43.1% achieved independent 90-day functional outcome.
- Perfusion cohort: 45.5% achieved mRS 0-2; Collateral cohort: 43.9% achieved mRS 0-2 (p=0.71).
- Logistic regression showed no significant difference in 90-day mRS 0-2 (aOR 1.05) or favorable mRS shift (aOR 1.01) between cohorts.
Conclusions:
- Pooled analysis of late window EVT indicates comparable functional outcomes between patients selected with collateral imaging alone and those selected with perfusion plus collateral imaging.
Background And Purpose:
Collateral assessment using CT angiography is a promising modality for selecting patients for endovascular thrombectomy (EVT) in the late window (6-24 hours). The outcome of these patients compared with those selected using perfusion imaging is not clear.
Methods:
We pooled data from seven trials and registries of EVT-treated patients in the late-time window. Patients were classified according to the baseline imaging into collateral imaging alone (collateral cohort) and perfusion plus collateral imaging (perfusion cohort). The primary outcome was the proportion of patients achieving independent 90-day functional outcome (modified Rankin Scale 'mRS' 0-2). We used the propensity score-weighting method to balance important predictors between the cohorts.
Results:
In 608 patients, the median onset/last-known-well to emergency arrival time was 8.8 hours and 53.2% had wake-up strokes. Both cohorts had collateral imaging and 379 (62.3%) had perfusion imaging. Independent functional outcome was achieved in 43.1% overall: 168/379 patients (45.5%) in the perfusion cohort versus 94/214 (43.9%) in the collateral cohort (p=0.71). A logistic regression model adjusting for inverse-probability-weighting showed no difference in 90-day mRS score of 0-2 among the perfusion versus collateral cohorts (adjusted OR 1.05, 95% CI 0.69 to 1.59, p=0.83) or in a favourable shift in 90-day mRS (common adjusted OR 1.01, 95% CI 0.69 to 1.47, p=0.97).
Conclusion:
This pooled analysis of late window EVT showed comparable functional outcomes in patients selected for EVT using collateral imaging alone compared with patients selected using perfusion and collateral imaging.
Prospero Registration Number:
CRD42020222003.
