Ex vivo hemodynamic assessment of mechanical aortic valve gradients using a high‐fidelity pressure wire
Bibliographic record
Abstract
OBJECTIVES: Accurate assessment of prosthetic mechanical valve malfunction is challenging for non-invasive and invasive techniques. We evaluated a 0.014-inch pressure-sensing coronary guidewire to assess mechanical valve dysfunction. BACKGROUND: Several case reports have shown that transaortic pressure gradients can be recorded using a 0.014-inch guidewire during cardiac catheterization. METHODS: We performed an ex vivo study measuring the effects of sequentially crossing the center of each valve with a 6 French coronary angiographic catheter, a 0.035-inch guidewire, and a 0.014-inch pressure-sensing guidewire on valve dysfunction using the following 23 mm bileaflet and tilting-disc aortic valves: St. Jude Regent™, CarboMedics, Medtronic Hall™, and Björk-Shiley Monostut. A left heart model pulse duplicator recorded 10 consecutive cycles. RESULTS: For all valves, the greatest increase in valve regurgitation occurred with the 6 French catheter, causing a reduction in aortic valve back pressure and cardiac output, with an increase in leakage rate, regurgitant fraction, and energy loss. In comparison to the 0.035-inch guidewire, the 0.014-inch guidewire had greater regurgitation for St. Jude, lower for Medtronic Hall, and equivalent for CarboMedics and Björk-Shiley valves. For the CarboMedics valve, the 0.035-inch guidewire caused a significant increase in regurgitant fraction and energy loss, while the pressure wire had no change compared to baseline. CONCLUSIONS: The degree of regurgitation caused by the 0.014-inch guidewire varies with the type of mechanical aortic valve. While prior case reports have shown that valve hemodynamics may be measured using a pressure-sensing guidewire, valve regurgitation occurs when crossing a St. Jude, Medtronic Hall, or Björk-Shiley aortic valve.
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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 | 0.000 | 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".