Thrombolysis at 3–4.5 Hours after Acute Ischemic Stroke Onset – Evidence from the Canadian Alteplase for Stroke Effectiveness Study (CASES) Registry
Bibliographic record
Abstract
BACKGROUND: Extending the therapeutic window for thrombolysis is an important strategy in maximizing the proportion of patients treated. ECASS III examined a 3-4.5-hour window and showed a benefit to treated patients. We examined the experience in Canadian centres using intravenous tPA treatment in the 3-4.5-hour time window. METHODS: The data were obtained from the CASES (Canadian Alteplase for Stroke Effectiveness Study)--a prospective, multicentric cohort study with patient enrollment from 60 centres across Canada over 2.5 years. The 90-day outcome, mortality and symptomatic intracranial hemorrhage of patients thrombolysed between 3 and 4.5 h and within 3 h of symptom onset were compared. A mRS 0-1 (no symptoms at all or no significant disability despite symptoms, able to carry out all usual duties and activities) at 90 days was defined as a favorable outcome. RESULTS: A total of 1,112 patients with complete data were included. 129 (11.6%) patients received tPA between 3 and 4.5 h of symptom onset and 983 (88.4%) patients received tPA within 3 h. At 90 days, 39.4% of the patients in the 3-4.5-hour treatment group and 36.5% of patients in the under 3-hour treatment group attained a mRS ≤1. There were no differences between the two groups regarding their functional status at 3 months. There was a trend towards higher rate of sICH in the 3-4.5-hour group compared to the 0-3-hour group (7.8 vs. 3.8%, p = 0.06). Similarly there was a trend towards higher rate of deaths in the 3-4.5-hour group compared to the 0-3-hour group (28.4 vs. 21.4%, p = 0.09). A χ(2) test for trend demonstrated a rising proportion of symptomatic ICH in later time windows (p = 0.013). A similar trend (non-significant) was observed for mortality. CONCLUSION: Our study suggests that patients with acute ischemic stroke may be successfully treated with intravenous tPA in the 3-4.5-hour treatment window, but cautions that later time window treatment may result in greater adverse events.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".