Stent and leaflet stresses across generations of balloon-expandable transcatheter aortic valves
Why this work is in the frame
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Bibliographic record
Abstract
OBJECTIVES: Transcatheter aortic valve replacement (TAVR) is established therapy for severe aortic stenosis patients with intermediate-, high- and prohibitive-risk for surgery. A significant challenge when expanding TAVR to low-risk and younger patients is the unknown long-term durability. High leaflet stresses have been associated with surgical bioprosthetic valve degeneration. In this study, we examined the impact of changes in valve design across 3 generations of same-sized TAVR devices on stent and leaflet stresses. METHODS: The 26-mm Edwards SAPIEN, 23, 26 and 29 mm SAPIEN XT (XT) and 26 mm SAPIEN 3 (S3) (n = 1 each) underwent micro-computed tomography (micro-CT) scanning. Dynamic finite element computational simulations of 23-26 mm SAPIEN, 23-29 mm XT and 23-29 mm S3 were performed with physiological loading and micro-CT or scaled geometries. RESULTS: Peak stresses were concentrated in the commissure area and along the bottom of the suture, representing areas most likely to develop structural valve degeneration across TAVR generations. Latest-generation S3 showed greatest 99th percentile principal stress on commissural leaflets for 26 and 29 mm, and increased stresses over XT for 23 mm. Percentage of higher stress areas within the leaflets steadily increased across generations, 3.8%, 3.9% and 5.7%, respectively, for 26 mm SAPIEN, XT and S3 with similar trend for 29-mm valves. CONCLUSIONS: Using computational simulations based on high-fidelity modelling of balloon-expandable TAVRs, our study demonstrated that maximum stress areas existed in similar leaflet locations across SAPIEN generations, while the latest model S3 had the highest magnitude for both 26- and 29-mm valves. S3 also had the largest area of higher stresses than other generations, which would be prone to degeneration. Our study coupled with future long-term clinical outcomes >10 years will provide insight on biomechanics of TAVR degeneration.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.003 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 it