Abstract 16300: Efficacy and Safety of Anticoagulation Following Bioprosthetic Aortic Valve Replacement: A Meta-analysis
Bibliographic record
Abstract
Background: The American College of Cardiology (ACC) guidelines recommend three months of anticoagulation (AC) after replacement of the aortic valve with a bioprosthesis (BP). However, there remains great variability in the current clinical practice and conflicting results from clinical studies. To assist clinical decision making, we pooled the existing evidence to assess whether AC in the setting of a new BP was associated with improved outcomes and/or greater risk of bleeding. Methods: We searched the PubMed database from the inception of these databases until April 2015 to identify original studies (observational studies or clinical trials) that assessed AC with warfarin in comparison with either aspirin or no antiplatelet or anticoagulant therapy. We included the studies if their outcomes included thromboembolism or stroke/transient ischemic attacks (TIA) and bleeding events. Quality assessment was performed in accordance with the Newland Ottawa scale and random effects was used to pool the data from the available studies. I2 testing was done to assess the heterogeneity of the included studies. Results: After screening through 170 papers, a total of 13 studies (cases=6431, controls=18210) were included in the final analyses. Use of warfarin use was associated with a significantly increased risk of overall bleeding (OR= 1.96, 95% CI 1.25-3.08, P<0.0001) or bleeding risk at 3 months (OR= 1.92, 95% CI 1.10-3.34), P<0.0001) compared with aspirin or placebo. With regard to composite primary outcome variables (risk of venous thromboembolism, stroke or TIA) at 3 months, no significant difference was seen with warfarin (OR= 1.13, 95% CI 0.82-1.56, P=0.67). Moreover AC was also not shown to improve outcomes at time interval >3 months (OR= 1.12, 95% CI 0.80-1.58, P=0.79). Conclusion: Contrary to the current guidelines, a meta-analysis of prior studies suggests that AC in the setting of an aortic bioprosthesis significantly increases bleeding risk without a favorable impact on thromboembolic events. Larger, randomized controlled studies should be performed to further guide this clinical 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 | 0.017 | 0.029 |
| Meta-epidemiology (narrow) | 0.003 | 0.001 |
| Meta-epidemiology (broad) | 0.015 | 0.061 |
| Bibliometrics | 0.005 | 0.006 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.004 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.003 | 0.003 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
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".