Abstract 2467: Stentless Aortic Valve Replacement Increased the Requirement for Permanent Pacemaker
Bibliographic record
Abstract
BACKGROUND: Stentless aortic valve prosthesis are thought to provide a superior hemodynamic profile compared to mechanical or other tissue valve replacements. Unlike other aortic valve prostheses, stentless valves are most commonly implanted in the subcoronary position, potentially resulting in the placement of sutures in the atrio-ventricular node of the heart’s conduction system. We assessed the incidence of permanent pacemaker insertion following aortic valve replacement. METHODS: We performed a retrospective cohort analysis of all patients who underwent aortic valve replacement at the University of Alberta Hospital between January 1996 and December 2004. The primary outcome was heart block requiring permanent pacemaker insertion. Binary logistic regression analysis was performed to assess the influence of a number of factors on the requirement for permanent pacemaker insertion. RESULTS: In total, 1,451 patients underwent aortic valve replacement (69% male, age 17–92). Permanent pacemaker insertion was required in 32 (5.0%) of 644 patients receiving mechanical valves and in 24 (4.4%) of 543 patients who had a stented tissue aortic valve replacement. In contrast, 27 (10.2%) of 264 patients who had a stentless bioprosthetic valves implanted developed heart block necessitating permanent pacemaker insertion (P = 0.02). Logistic regression demonstrated that implantation of a stentless tissue valve and postoperative inotropic support were the only two significant predictors of the development of heart block following aortic valve replacement. CONCLUSIONS: Aortic valve replacement with a stentless valve prosthesis increases the risk of heart block and the requirement for permanent cardiac pacing. Multivariate predictors of requirement for permanent pacemaker
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 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".