Macroscopic and microscopic features of surgically explanted transcatheter aortic valve prostheses
Bibliographic record
Abstract
OBJECTIVES: With the extended indications of transcatheter aortic valve (TAV) replacement (TAVR) to lower-risk patients, there is an increasing number of patients requiring surgical explantation of failed TAV. We sought to describe macroscopic and microscopic features of surgically explanted percutaneous aortic valve prostheses. METHODS: Preoperative and surgical characteristic of patients undergoing surgical explantation of TAV were retrospectively analyzed from 2007 to 2020. Surgical and pathologic features of these valves, and outcomes of the surgical valve replacement were described. RESULTS: Out of 1764 patients who underwent a TAVR procedure, 21 were operated for TAV failure. Isolated or combined indications for surgery included: significant paravalvular leak (n = 15), delayed prosthesis migration (n = 5), significant increase of trans-TAV gradients (n = 6), and endocarditis (n = 3). Mean time elapsed between TAVR and explantations was 674.9 ± 803.9 days. Macroscopic lesions found on explanted percutaneous valves were severe adhesions to the aorta (n = 10), calcifications (n = 7), leaflet thrombosis (n = 4), and vegetations (n = 3). Except for patients with endocarditis, one or more pathological lesions were found in 15 patients. Pathology analyses on these valves showed fibro-calcific degenerations (n = 12), pannus formation (n = 9), and chronic inflammation (n = 3). One patient (4.8%) died after surgical explantation, and 13 (61.9%) had concomitant procedures. The survival rate at 1 year was 94.4%. CONCLUSIONS: Microscopic findings of fibro-calcific leaflet degeneration, and pannus formation in addition to macroscopic calcification and thrombosis present early, (within a mean of 2 years) after TAVR. Further investigation with a higher number of patients and echocardiographic follow-up is warranted.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.001 | 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".