Abstract 12022: Transcatheter Aortic Valve Implantation Wait-Time Management: Derivation and Validation of the Canadian TAVI Triage Tool (CAN3T)

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.