Unfractionated and Low-Molecular-Weight Heparin as Adjuncts to Thrombolysis in Aspirin-Treated Patients With ST-Elevation Acute Myocardial Infarction
Bibliographic record
Abstract
BACKGROUND: There is uncertainty about the role of intravenous unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) in patients with ST-elevation myocardial infarction (STEMI) treated with aspirin and thrombolysis. METHODS AND RESULTS: We performed a meta-analysis of the randomized trials to assess the effect of UFH and LMWH on reinfarction, death, stroke, and bleeding. Fourteen trials involving a total of 25,280 patients were included (1239 comparing intravenous UFH versus placebo or no heparin; 16,943 comparing LMWH versus placebo; and 7098 comparing LMWH versus intravenous UFH). Intravenous UFH during hospitalization did not reduce reinfarction (3.5% versus 3.3%; odds ratio [OR], 1.08; 95% CI, 0.58 to 1.99) or death (4.8% versus 4.6%; OR, 1.04; 95% CI, 0.62 to 1.78) and did not increase major bleeding (4.2% versus 3.4%; OR, 1.21; 95% CI, 0.67 to 2.18) but increased minor bleeding (19.6% versus 12.5%; OR, 1.72; 95% CI, 1.22 to 2.43). During hospitalization/at 7 days, LMWH compared with placebo reduced the risk of reinfarction by approximately one quarter (1.6% versus 2.2%; OR, 0.72; 95% CI, 0.58 to 0.90; number needed to treat [NNT]=167) and death by &10% (7.8% versus 8.7%; OR, 0.90; 95% CI, 0.80 to 0.99; NNT=111) but increased major bleeding (1.1% versus 0.4%; OR, 2.70; 95% CI, 1.83 to 3.99; number needed to harm [NNH]=143) and intracranial bleeding (0.3% versus 0.1%; OR, 2.18; 95% CI, 1.07 to 4.52; NNH=500). The reduction in death with LMWH remained evident at 30 days. LMWH compared with UFH during hospitalization/at 7 days reduced reinfarction by &45% (3.0% versus 5.2%; OR, 0.57; 95% CI, 0.45 to 0.73; NNT=45), did not reduce death (4.8% versus 5.3%; OR, 0.92; 95% CI, 0.74 to 1.13) or increase major bleeding (3.3% versus 2.5%; OR, 1.30; 95% CI, 0.98 to 1.72), but increased minor bleeding (22.8% vs 19.4%; OR, 1.26; 95% CI, 1.12 to 1.43). The reduction in reinfarction remained evident at 30 days. CONCLUSIONS: In aspirin-treated patients with STEMI who are treated with thrombolysis, intravenous UFH has not been shown to prevent reinfarction or death. LMWH given for 4 to 8 days compared with placebo reduces reinfarction by approximately one quarter and death by &10% and when directly compared with UFH reduces reinfarction by almost one half. These data suggest that LMWH should be the preferred antithrombin in this setting.
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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 | 0.009 | 0.018 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.007 | 0.011 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.002 | 0.002 |
| 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".