Biological Valves in Younger Patients Undergoing Aortic Valve Replacement
Bibliographic record
Abstract
ortic stenosis is becoming more prevalent as populations age, and surgically implanting a replacement valve can restore a patient's expected life span.There is much discussion about the relative merits of a mechanical or biological valve design.A mechanical valve is expected to outlast the patient but requires anticoagulation with a vitamin K antagonist, whereas a biological valve does not require anticoagulation but is subject to structural valve degeneration after 10 years.After taking patient preferences into consideration, the 2014 American Heart Association/American College of Cardiology guidelines 1 recommend that a mechanical valve should be implanted in patients <60 years of age and a biological one in those >65 years of age.However, biological valves are increasingly being used in patients <60 years of age in both the United States and Europe.In the United Kingdom, successive registry returns from cardiac surgical centers show that the percentage of biological valves implanted in patients <60 years of age is increasing rapidly.Drivers of this trend include the perceived longer durability of newer biological valves, the ability to intervene for structural valve degeneration with a valve-in-valve transcatheter aortic valve replacement (TAVR), and the inconvenience and bleeding risks from anticoagulant therapy.We argue that there is insufficient evidence to justify this downward shift in the age at which biological valves are used. Biological Valves in Younger Patients Undergoing Aortic Valve ReplacementA Word of Caution
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 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".