Effects of bileaflet mechanical heart valve orientation on fluid stresses and coronary flow
Bibliographic record
Abstract
The effects of the orientation of a bileaflet mechanical heart valve on the viscous and turbulent stresses in the flow past it and on the flow rate in the right coronary artery were investigated in vitro in a mock circulation loop, using a fluid that matched the kinematic viscosity of blood and the refractive index of the aorta model. Measurements were made past the valve mounted in three orientations at the base of an anatomical aorta model, within physiological aortic flow conditions. At peak flow, the turbulent stresses were on average 21 % higher and viscous stresses exceeding 10 Pa (namely of a level that has been associated with blood cell damage) were 30 % more frequent when the valve was oriented with its plane of symmetry normal to the aorta’s plane of curvature than when it was parallel to it. This was attributed to the impingement of a lateral jet on the concave wall of the aorta and to steeper velocity gradients resulting from the geometrical imbalance of the sinuses relative to the valve’s central jet when the valve was in the ‘normal’ orientation. Very high levels of turbulent stresses were found to occur distal to the corners of the valve’s lateral orifices. The bulk flow rate in the right coronary artery was highest when the valve was positioned with its central orifice aligned with the artery’s opening. The coronary flow rate was directly affected by the size, orientation and time evolution of the vortex in the sinus, all of which were sensitive to the valve’s orientation.
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How this classification was reachedexpand
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 | 0.001 |
| 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)
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 teacher head, 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".