Stent and Leaflet Stresses of 29mm, First-generation, Self-expandable Transcatheter Aortic Valve Deployed in Patient Aortic Root
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Bibliographic record
Abstract
Objective: Transcatheter aortic valve replacement (TAVR) is approved for low-, intermediate-, high-, and prohibitive-risk patients with severe aortic stenosis, but questions remain regarding long-term durability. We previously determined leaflet stresses for nominal ex-vivo TAVRs. Our goal here was to quantify TAVR stent and leaflet stresses when deployed in native patient anatomy to determine biomechanical interactions in patients. Methods: Commercial CoreValve underwent high-resolution micro-computed tomography (micro-CT) to develop precise geometries. Stent material properties were based on Nitinol, whereas leaflet materials were based on published literature of fixed porcine pericardium. Three patients’ pre-TAVR CT angiography (CTA) images were contoured with MeVisLab and imported into LS-DYNA. TAVR models underwent simulated deployment in patient-specific anatomy and loading at systemic pressurization; geometries were validated with post-TAVR CT geometries. Short- and long-term endpoints were collected from clinical follow-up and echocardiography. Results: At 80mmHg, 1st and 2nd principal stresses on the TAVR stent for patient-specific deployment were 377.7±101.8 MPa and 85.7±61.4 MPa, respectively, and 488.7±16.2 kPa and 236.8±8.9 kPa, respectively, on the leaflet (Figure). All three TAVR patients were alive without complications at 30-day and 1-year echocardiography follow-up. Conclusions: Patient-specific deployment demonstrated constraint of CoreValve stent shape based upon patient-specific anatomy, which in turn impacted leaflet geometry. Leaflet pinwheeling was demonstrated, but leaflet stresses in self-expanding TAVR were still less than that previously reported for balloon-expandable TAVR. TAVR leaflet stress distribution varied among the individual patient-specific models. Finite-element analysis of native aortic root morphologies is essential for analyzing the impact of stent distortion and leaflet function on long-term durability. KEYWORD: e-P-24 The authors do not declare any conflict of interest.
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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) | 0.000 | 0.000 |
| 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)
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Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
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