Abstract 10: Intracranial Hemorrhage Risks among Warfarin Treated Acute Ischemic Stroke Patients Receiving Thrombolytic Therapy
Bibliographic record
Abstract
Background While intravenous thrombolytic therapy (tPA) improves the outcomes of ischemic stroke, treatment of those receiving warfarin raises concerns regarding symptomatic intracranial hemorrhage (ICH). While guidelines suggest excluding patients with an international normalized ratio (INR) >1.7, little is known about the use and safety of tPA in warfarin-treated patients in clinical practice. Methods Data from 23,437 ischemic stroke patients treated with tPA with an INR ≤1.7 in 1,203 Get With The Guidelines-Stroke hospitals between April 2009 and June 2011. Multivariable logistic regression analysis was performed to evaluate the association of preadmission warfarin use on ICH risk while adjusting for potential confounders. Results Overall 1,802 (7.7%) were taking warfarin prior to admission. Warfarin treated patients were older (median 77 vs. 71 years, p<0.001) and had more comorbid illness and greater stroke severity (median National Institutes of Health Stroke Scale 14 vs. 11, p<0.001). Crude rates of ICH were higher in those taking warfarin 5.7% vs. 4.7% (unadjusted OR 1.22, 95% CI 0.99-1.51). However, after risk adjustment, ICH risks were similar (adjusted OR 1.01, 95% CI 0.82-1.25). These findings were consistent across several sensitivity analyses (Table). There were no significant differences between warfarin and non-warfarin users for serious systemic hemorrhage (0.9% vs. 0.9%; adjusted OR 0.78; 95% CI 0.48-1.24), any tPA complications (10.6% vs. 8.4%; adjusted OR 1.09; 95% CI 0.93-1.29), and in-hospital mortality (11.4% vs. 7.9%; adjusted OR 0.94; 95% CI 0.79-1.13). Among those receiving warfarin, a trend toward higher crude ICH rates was observed among those with higher baseline INR levels (Cochran-Mantel-Haenszel trend test, p=0.03). After adjustment for risk factors, higher INR levels had a marginally significant association with ICH risk (adjusted OR 1.10, 95% CI 1.00-1.20, p=0.06 for each 0.1 units increase in INR). Conclusion This represents the largest clinical experience of the safety of thrombolysis in warfarin treated patients who meets clinical guideline eligibility criteria. Use of intravenous tPA among warfarin-treated stroke patients (INR ≤1.7) was not associated with increased ICH risk compared to non-warfarin treated patients in routine clinical practice. These data provide empirical support of current AHA/ASA guideline recommendations.
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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 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".