Baseline characteristics
| Early window patients with EVT <6.5 hours after onset or LSW (n=3158) | Late window patients with EVT ≥6.5 hours after onset or LSW (n=106) | P value* | |
| Age (years); mean (SD) | 70.0 (14.1) | 67.1 (14.6) | 0.04 |
| Sex (male) | 1642/3158 (52.0%) | 47/106 (44.3%) | 0.12 |
| Prestroke mRS 0–1 | 2498/3087 (80.9%) | 86/106 (81.1%) | 0.96 |
| Prestroke mRS 0–2 | 2729/3087 (88.4%) | 96/106 (90.6%) | 0.49 |
| NIHSS at presentation; median (IQR) | 16 (11–20) (n=3108) | 16 (11–20) (n=103) | 0.84 |
| ASPECTS at presentation; median (IQR) | 9 (7–10) (n=3055) | 8 (6–10) (n=102) | <0.01 |
| Location of occlusion | 0.96 | ||
| ICA | 790/3004 (26.3%) | 29/102 (28.4%) | |
| MCA M1-segment | 1750/3004 (58.3%) | 57/102 (55.9%) | |
| MCA M2-segment | 440/3004 (14.6%) | 15/102 (14.7%) | |
| Other (M3, ACA) | 24/3004 (0.8%) | 1/102 (1.0%) | |
| Collateral status | 0.01 | ||
| Absent collaterals | 184/2959 (6.2%) | 2/101 (2.0%) | |
| Filling ≤50% of occluded area | 1067/2959 (36.1%) | 30/101 (29.7%) | |
| Filling 51%–100% of occluded area | 1146/2959 (38.7%) | 38/101 (37.6%) | |
| Filling 100% of occluded area | 562/2959 (19.0%) | 31/101 (30.7%) | |
| CT perfusion performed | Treated 2014–2016: unknown | Treated 2014–2016: 6/41 (14.6%) | n/a |
| Treated 2016–2017: 319/1673 (19.1%) | Treated 2016–2017: 15/65 (23.1%) | 0.42 | |
| Transfer from primary hospital to intervention centre | 1743/3158 (55.2%) | 34/106 (32.1%) | <0.01 |
| Treated with IVT | 2420/3149 (76.8%) | 24/105 (22.9%) | <0.01 |
| Unknown time of onset | 842/3158 (26.7%) | 93/106 (87.7%) | <0.01 |
| Time between onset/LSW and groin puncture in minutes; mean (SD); median (IQR) | 203 (73) (n=3158) 195 (150–250) | 559 (174) (n=106) 508 (415–637) | <0.01 |
| Time between onset/LSW and end of procedure in minutes; mean (SD); median (IQR) | 259 (78) (n=2925) 250 (200–312) | 616 (185) (n=95) 564 (467–697) | <0.01 |
| Performed procedure | 0.07 | ||
| Attempt for thrombectomy | 2683/3149 (85.2%) | 97/106 (91.5%) | |
| Catheterisation/DSA only | 466/3149 (14.8%) | 9/106 (8.5%) |
P-values <0.05 were considered significant and are provided in bold.
*χ2 tests for categorical variables and independent t-tests or Mann-Whitney U tests for continuous variables with complete data.
ACA, anterior cerebral artery; ASPECTS, Alberta Stroke Programme Early CT Score; DSA, digital subtraction angiography; EVT, endovascular treatment; ICA, internal carotid artery; IVT, intravenous thrombolysis; LSW, last seen well; MCA, middle cerebral artery; mRS, modified Rankin Scale; NIHSS, National Institutes of Health Stroke Scale.