The effect of pre-operative aspirin on bleeding, transfusion, myocardial infarction, and mortality in coronary artery bypass surgery: a systematic review of randomized and observational studies
Bibliographic record
Abstract
AIMS: To obtain estimates of the efficacy and safety of pre-operative aspirin in patients undergoing coronary artery bypass grafting (CABG). METHODS AND RESULTS: Eligible studies included randomized controlled trials (RCTs) and observational studies of patients undergoing CABG, comparing pre-operative aspirin with no aspirin/placebo, and reporting at least one of our primary outcomes. In eight RCTs (n = 805), pre-operative aspirin increased post-operative bleeding [Mean difference (MD), 104.9 mL; 95% confidence interval (CI), 19.2-190.6; P = 0.016] and reoperation [odds ratio (OR), 2.52; 95% CI, 1.18-5.38; P = 0.017), but not transfusion requirements (MD, 0.62 units; 95% CI, -0.06-1.30; P = 0.072). Subgroup analysis suggested that bleeding was increased with aspirin doses > or =325 mg/day, but not with lower doses. In 14 observational studies (n = 4485), pre-operative aspirin increased post-operative bleeding (MD, 113.6 mL; 95% CI, 45.2-182.0; P = 0.001) and transfusion requirements (MD, 0.34; 95% CI, 0.12-0.56 units; P = 0.002), but not reoperation (OR, 1.12; 95% CI, 0.69-1.83; P = 0.647). Neither analysis detected a significant effect on myocardial infarction or death. CONCLUSION: Pre-operative aspirin increases post-operative bleeding, but this may be avoided by the use of aspirin doses <325 mg/day. Most of the RCTs are old and the meta-analysis was underpowered for efficacy outcomes. A large randomized trial is necessary to determine the safety and efficacy of pre-operative aspirin in the setting of contemporary cardiac surgical practice.
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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 | 0.014 | 0.060 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.012 | 0.011 |
| Bibliometrics | 0.007 | 0.007 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| 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".