Table 1.
Baseline characteristics
| Characteristics* | Repeated imaging (n=165) | No repeated imaging (n=386) | p value |
| Age, years – mean±SD | 71±15.3 | 70±13.3 | 0.40 |
| Male sex – no./total (%) | 79/165 (48%) | 200/386 (52%) | 0.40 |
| Hypertension – no./total (%) | 68/164 (41%) | 150/382 (39%) | 0.63 |
| Diabetes mellitus – no./total (%) | 21/164 (13%) | 56/382 (15%) | 0.57 |
| Atrial fibrillation – no./total (%) | 34/164 (21%) | 95/382 (25%) | 0.30 |
| Coronary artery disease – no./total (%) | 14/164 (9%) | 80/382 (21%) | <0.01 |
| Previous stroke – no./total (%) | 30/164 (18%) | 66/382 (17%) | 0.78 |
| Pre-stroke mRS score† – median (IQR) | 1 (0–1) | 1 (0–1) | 0.72 |
| Systolic blood pressure (mm Hg) – mean±SD | 150±28.1 | 148±23.9 | 0.37 |
| Diastolic blood pressure (mm Hg) – mean±SD | 83±17.0 | 82±16.5 | 0.65 |
| NIHSS score at PSC arrival‡ – median (IQR) | 11 (7–15) | 13 (9–17) | <0.01 |
| NIHSS score at CSC arrival§ – median (IQR) | 9 (4–17) | 16 (10–20) | <0.01 |
| Intracranial occlusion site (on PSC imaging) – no./total (%) | 0.07 | ||
| ICA | 26/164 (16%) | 76/386 (20%) | |
| M1 | 90/164 (55%) | 228/386 (59%) | |
| Proximal M2 | 31/164 (19%) | 38/386 (10%) | |
| Anterior cerebral artery | 0/164 (0%) | 1/386 (0%) | |
| Basilar artery | 13/164 (8%) | 31/386 (8%) | |
| No LVO (misread by radiologist at PSC) | 4/164 (2%) | 12/386 (3%) | |
| Reason for repeating imaging – no./total (%) | |||
| Clinical improvement | 86/165 (52%) | NA | – |
| Clinical deterioration | 40/165 (24%) | NA | – |
| Additional imaging characteristics for assessing indication for EVT** | 11/165 (7%) | NA | – |
| Other | 6/165 (4%) | NA | – |
| Reason not recorded | 22/165 (13%) | NA | – |
| Presentation outside office hours – no./total (%) | 74/150 (49%) | 233/365 (64%) | <0.01 |
| Time from stroke onset to arrival at PSC (min)¶ – median (IQR) | 50 (30–81) | 58 (32–95) | 0.14 |
| Treatment with IVT – no./total (%) | 135/165 (82%) | 276/386 (72%) | 0.01 |
*All baseline characteristics were measured on arrival at the CSC, unless reported otherwise.
†Number of missing values: 350.
‡28.
§4.
¶178.
**For example, ASPECTS, collaterals, core/penumbra ratio <6 hours.
ASPECTS, Alberta Stroke Program Early CT Score; CSC, comprehensive stroke center; EVT, endovascular treatment; ICA, intracranial part of internal carotid artery; IVT, intravenous thrombolysis; LVO, large vessel occlusion; M1, first segment of the middle cerebral artery; M2, proximal part of the second segment (after first bifurcation) of the middle cerebral artery; mRS, modified Rankin Scale; NA, not applicable; NIHSS, National Institutes of Health Stroke Scale; no., number; PSC, primary stroke center.