Abstract T P48: Intravenous Thrombolysis Using Low-Dose Alteplase for Nonagenarians with Acute Ischemic Stroke: The SAMURAI rtPA Registry
Bibliographic record
Abstract
Objective: Although intravenous thrombolysis (IVT) using alteplase for octogenarians with acute ischemic stroke becomes relatively familiar, it is unclear whether IVT for nonagenarians is a futile intervention. The purpose of this study is to clarify the efficacy and safety of IVT using low-dose alteplase (0.6 mg/kg) for nonagenarians compared with octogenarians. Methods: Stroke Acute Management with Urgent Risk-factor Assessment and Improvement (SAMURAI) rtPA registry retrospectively collected 600 consecutive acute stroke patients receiving IVT from 10 Japanese stroke centers between October 2005 and July 2008. We extracted all octogenarians (O group) and nonagenarians (N group) from the registry. We compared baseline characteristics, symptomatic intracranial hemorrhage (SICH), and 3-month outcomes between the groups. 3-month outcomes include; functional independence (FI) defined as a mRS score 0-2, good outcome (GO) as a mRS score 0-2 or same as the premorbid mRS, poor outcome (PO) defined as a mRS score 5-6, and death. Results: Twenty-five nonagenarians (mean age, 93 years) and 124 octogenarians (mean age, 84 years) were included. N group was more female-predominant (76% versus 56%, p=0.06) and premorbidly dependent (44% versus 14%, p<0.001) than O group. There were no significant differences of median baseline NIHSS score (16 versus 14, p=0.95) and Alberta Stroke Program Early CT Score (9 versus 9, p=0.36) between the groups. The rate of FI tended to be lower in N group than O group (16% versus 36%, p=0.06), otherwise, the differences of the rates of GO (28% versus 37%, p=0.39), PO (40% versus 36%, p=0.73), death (20% versus 11%, p=0.23) and SICH (0% versus 2.4%, p=1.00) were not significant between the groups. In comparison with O group, N group was not associated with 3-month clinical outcomes (FI; OR 0.61; 95% CI, 0.15-2.42, GO; 0.98; 0.31-3.07, PO; 0.63; 0.15-2.70, death; 3.18; 0.62-16.3) and SICH (0.68; 0.17-2.69) after multivariate adjustment. Conclusions: IVT using low-dose alteplase for N group resulted in less frequent achievement of FI mainly because of more premorbid dependency than O group, however, showed at least a similar safety and a potential efficacy.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".