In-vitro study on the relationship between progressive sinotubular junction dilatation and aortic regurgitation for several stentless aortic valve substitutes
Bibliographic record
Abstract
OBJECTIVE: Stentless aortic valves are widely used due to their excellent hemodynamic properties. However, if the subcoronary implantation technique is used later dilatation of the sinotubular junction (STJ) can cause regurgitation. The aim of the study was to determine the dilatation tolerance of two commercially available stentless xenografts and fresh aortic and pulmonary roots against such dilatation. METHODS: Four groups each comprising five specimens of fresh porcine aortic roots, pulmonary roots, Medtronic freestyle or Toronto SPV Xenografts were tested in a mock circulation using a special device for gradually increasing the diameter of the sinotubular junction. The smallest diameter D(r) where regurgitation occurs was measured and correlated with the starting diameter D(a) and expressed as per cent values. Opening and closing patterns were obtained by a high speed camera and flow characteristics were determined. RESULTS: The highest dilatation tolerance of STJ was found in the fresh porcine aortic roots (165%+/-10) followed by fresh pulmonary roots (146%+/-12), the Freestyle (143%+/-4) and the SPV (132%+/-5) bioprostheses. All differences were significant with P< or =0.05 except that between the fresh pulmonary roots and the two commercial available bioprostheses. CONCLUSIONS: Our results indicate that aortic homografts provide higher resistance against regurgitation induced by dilatation of the STJ than an autograft or the stentless xenografts, Freestyle xenograft followed by the Toronto SPV. The use of the full-root technique should be considered if aortic dilatation seems to be likely.
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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 | 0.000 |
| 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) | 0.001 | 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".