Abstract 19528: Biomechanical Properties of Patient-specific Aortas and Pulmonary Arteries According to Aortic Valve Phenotype: Relevance to the Ross Procedure
Bibliographic record
Abstract
Background: Long-term outcomes of the Ross procedure can be limited by late autograft dilatation requiring reoperation. It has been suggested that bicuspid aortic valve is a risk factor for autograft dilatation. The aim of this study is to compare the biomechanical properties of pulmonary arteries according to aortic valve phenotype. Methods: At the time of surgery, segments of aortic and pulmonary artery wall were harvested according to aortic valve phenotype (n=29 patients). The segments were subjected to displacement-controlled biaxial stretch testing within 8 hours of surgery, in a physiological solution (37 C). Tissue stiffness at an engineering strain of 60% was evaluated, using engineering stress. Histological analyses were performed on the specimens to assess the number of elastic lamellae. Aortic valve phenotype was bicuspid in 18 patients (62%), unicuspid in 7 patients (24%) and tricuspid in 4 patients (14%). Results: Pulmonary artery circumferential and longitudinal elastic moduli were similar among the 3 populations (Unicuspid: 0.11±0.05 and 0.09±0.03 MPa, bicuspid: 0.10±0.05 and 0.11±0.05 MPa, tricuspid:0.14±0.07 and 0.09±0.05 MPa, p=0.462 and p=0.621 respectively). Aortic circumferential and longitudinal elastic moduli were also similar among the 3 populations (Unicuspid: 0.13±0.01 and 0.12±0.05 MPa , bicuspid: 0.17±0.06 MPa and 0.14±0.06 MPa, tricuspid: 0.09 MPa and 0.11 MPa , p=0.188 and p=0.720 respectively). Aortic and pulmonary artery thickness were also similar among the 3 populations (Unicuspid: 1.53±0.16 mm and 1.22±0.29 mm, bicuspid: 1.65±0.33 mm and 1.20±0.32 mm, tricuspid: 2.12 and 1.38±0.15, p=0.248 and p=0.566, respectively). Pulmonary artery lamellae unit count was also similar among the 3 populations (tricuspid: 30 units, bicuspid: 43±9 units and unicuspid: 30 units, p=0.10). The number of elastic lamellae was also similar in aortic specimens (tricuspid: 52 units, bicuspid: 60±11 units, unicuspid: 52 units, p=0.640). Conclusion: Current findings suggest that the biomechanical properties of pulmonary arteries obtained from patients undergoing the Ross procedure are independent of aortic valve phenotype. These results may have significant impact on the long-term clinical outcomes following this procedure.
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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 | 0.000 | 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) | 0.002 | 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".