Hydrodynamic Assessment of Explanted Degenerated Transcatheter Aortic Valves
Bibliographic record
Abstract
The etiology of transcatheter aortic valve (TAV) degeneration is poorly understood, particularly noncalcific mechanisms. The authors sought to investigate noncalcific and calcific mechanisms of TAV degeneration and evaluate their impact on leaflet function by bench testing, imaging, and histology. TAV explants were obtained from the EXPLANT THV registry and clinical institutions. Hydrodynamic assessment was performed using a heart valve pulse duplicator system under physiological conditions. Micro-computed tomography, high-resolution photography, high speed video, and hematoxylin and eosin staining were used to evaluate the morphological appearance, leaflet kinematics, and calcium burden of TAVs. A total of 14 explants were evaluated: 10 self-expanding CoreValve/Evolut TAVs (Medtronic), 3 balloon-expandable SAPIEN 3 TAVs (Edwards Lifesciences), and 1 mechanically expandable Lotus TAV (Boston Scientific). The median patient age at explantation was 73.0 years (Q1-Q3: 64.5-80.0 years), with a time to explantation of 4 years 1 month (1 year 5 months to 4 years 11 months). Six TAV explants were found to have leaflet calcification (162.4 mm3; 58.8-603.0 mm3), and 8 had no calcification detectable by micro-computed tomography and histology. All samples had impaired leaflet kinematics. There was no significant difference in the hydrodynamic mean gradient between calcified (47.2 mm Hg; 26.6-74.1 mm Hg) and noncalcified (27.6 mm Hg; 15.2-36.7 mm Hg; P = 0.28) TAVs. Leaflet calcification had a weak but nonsignificant association with the hydrodynamic mean gradient (r = 0.42; P = 0.14). TAV function can be severely impacted by noncalcific and calcific mechanisms of tissue degeneration. Importantly, functional stenosis can occur in TAVs in the absence of obvious and significant calcification.
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How this classification was reachedexpand
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 | 0.027 |
| 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, 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".