A comparative study of bovine and porcine pericardium to highlight their potential advantages to manufacture percutaneous cardiovascular implants
Bibliographic record
Abstract
RATIONALE: Prosthetic heart valves designed to be implanted percutaneously must be loaded within delivery catheters whose diameter can be as low as 18 F (6 mm). This mandatory crimping of the devices may result in deleterious damages to the tissues used for valve manufacturing. As bovine and porcine pericardial tissue are currently given preference because of their excellent availability and traceability, a preliminary comparative study was undertaken to highlight their potential advantages. MATERIALS AND METHODS: Bovine and pericardium patches were compared morphologically (light microscopy, scanning electron microscopy and transmission electron microscopy). The acute thrombogenicity of both materials was measured in term of platelet uptake and observed by scanning electron microscopy, porcine intact and injured arteries being used as controls. The pericardium specimens were also subjected to uniaxial tensile tests to compare their respective mechanical characteristics. RESULTS: Both pericardiums showed a layered architecture of collagen bundles presenting some interstitial cells. They displayed wavy crimps typical of an unloaded collagenous tissue. The collagen bundles were not bound together and the fibrils were parallel with characteristic periodicity patterns of cross striations. The mesothelial cells found in vivo on the serous surface were no longer present due to tissue processing, but the adjacent structure was far more compacted when compared to the fibrous side. The fibrinocollagenous surfaces were found to be more thrombogenic for both bovine and porcine tissues and the serous side of the porcine pericardium retained more platelets when compared to the bovine samples, making the acute thrombogenicity more important in the porcine pericardium. CONCLUSION: Both bovine and porcine pericardium used in cardiovascular implantology can be selected to manufacture percutaneous heart valves. The selection of one pericardium preferably to the other should deserve additional testing regarding the innocuousness of crimping when loaded in delivery catheters and the long-term durability after percutaneous deployment.
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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 | 0.001 | 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".