Abstract 12022: Transcatheter Aortic Valve Implantation Wait-Time Management: Derivation and Validation of the Canadian TAVI Triage Tool (CAN3T)
Bibliographic record
Abstract
Introduction: Transcatheter aortic valve implantation (TAVI) for patients with aortic stenosis has seen indication expansion and exponential growth in demand over the last decade. In many jurisdictions the growing demand outpaced capacity, increasing wait-times and pre-procedural adverse events. Objective: To derive prediction models that estimate the risk of adverse events on the waitlist that would inform the development of a triage tool for use by clinicians to identify patients who should be prioritized for TAVI. Methods: We conducted an observational retrospective cohort study using population-based administrative data from Ontario, Canada. Adult patients referred for TAVI from April 1 st , 2012 to March 31 st , 2020 were included and followed-up to the first of: death, TAVI procedure, removal from waitlist, or end of the observation period. We used competing risk subdistributions hazards models to find significant predictors for each of the following outcomes: (1) all-cause death while on the waitlist, (2) all-cause hospitalization while on the waitlist, (3) receipt of urgent TAVI, and (4) a composite of outcomes 1-3. The median predicted risk in our population at 12 weeks was chosen as a threshold for a maximum acceptable risk while on the waitlist, and was incorporated in the triage tool to recommend individualized wait-times. Results: We included 13,128 patients in the analyses. 586 (4.46%) patients died on the waitlist, and 4,343 (33.08%) had at least one all-cause hospitalization. 6,854 TAVIs were completed, of which 1,135 (16.56%) were urgent procedures. We were able to create parsimonious models for each outcome that included clinically relevant predictors. Optimism-corrected C-statistics varied from 0.63 to 0.75, optimism-corrected Brier scores from 0.03 to 0.19, and the calibration slopes from 0.79 to 0.99. Conclusions: We developed the Canadian TAVI Triage Tool (CAN3T), a triage tool to assist clinicians in the prioritization of patients who should have timely access to TAVI. We anticipate that the CAN3T will be a valuable support tool for patients and clinicians, with the potential of bringing meaningful changes to the health system as it may improve equity in access to care, reduce preventable adverse events and improve system efficiency.
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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 | 0.007 | 0.020 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| 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".