Establishing the interchangeability of arterial stiffness but not endothelial function parameters in healthy individuals
Bibliographic record
Abstract
BACKGROUND: Development of instruments capable of detecting early stage vascular disease has increased interest in employing arterial stiffness (e.g. pulse wave velocity (PWV), augmentation index (AIx)) and endothelial dysfunction (e.g. reactive hyperemia index (RHI)) to diagnose atherosclerotic disease before occurrence of a cardiovascular event. However, amongst the equipment designed for this purpose, there is insufficient information regarding each of these parameters to establish appropriate cutoffs to distinguish between healthy and unhealthy blood vessels. To address these limitations, the study was designed to establish the upper arterial stiffness and endothelial function thresholds in a healthy population, by comparing the outputs from different instruments capable of measuring PWV, AIx and RHI. METHODS: A systematic comparison of PWV, AIx and RHI was conducted to determine the inter-relationships between these parameters of vascular functionality. Outputs were obtained non-invasively using three instruments, the VP-1000 (VP), SphygmoCor (SC), and EndoPAT (EP), in 40 apparently healthy males and females. RESULTS: Correlations were found between the brachial-ankle PWV and radial-ankle PWV (by VP and SC), and PWV (VP) with AIx (SC). The interchangeability of these outputs was demonstrated by the Bland Altman test, making it feasible to extrapolate cut-offs for radial-ankle PWV and AIx equivalent to brachial-ankle PWV that signify healthy vessels. In contrast, RHI showed no association with AIx, suggesting these endothelial and arterial parameters are functionally distinct. CONCLUSIONS: It was concluded that it is possible to compare the vascular function outputs of different instruments and identify healthy from unhealthy vessels, even though the approaches for quantifying the underlying physiological processes may differ. In this way, non-invasive determination of arterial function could be a new paradigm for detecting existing early stage asymptomatic atherosclerotic disease in individuals using techniques that are amenable to the clinical setting.
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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 | 0.009 | 0.018 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 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".