Repeatability of Superficial Femoral Artery Flow Mediated Dilation as induced by Calf Exercise
Bibliographic record
Abstract
In the brachial artery, a sustained (via handgrip exercise) shear stress stimulus elicits flow mediated dilation (FMD) which is stable and may relate to vascular health. The legs experience different patterns of shear stress than the arms, and are prone to different manifestations of cardiovascular disease, however a protocol to assess leg FMD as stimulated by exercise has yet to be established. The study purpose was to determine the repeatability of superficial femoral artery (SFA) FMD created using a sustained shear stress stimulus via calf exercise (LEX). 19 subjects (9 females) (age: 24 ± 2) performed 4 trials of dynamic LEX for 6 minutes to reach an individually determined shear rate (SR=blood velocity/artery diameter) target in a specially designed machine. SFA blood velocity and diameter were assessed via echo and Doppler ultrasound. FMD was quantified as the % change from baseline to peak 1 min mean diameter during LEX. Values are mean ± SD. There were no differences between trials in mean SR produced during the last 5 min of LEX (p = 0.17) or during the minute with the highest SR during LEX (p = 0.73). Trial 1 (T1) LEX FMD was significantly lower than T3, but not T2 or T4 (T1: 3.6 ± 2.7 %, T2: 3.9 ± 3.0 %, T3: 4.9 ± 3.4 %, T4: 4.5 ± 2.6 % FMD, p = 0.023). There was a trend for declining baseline diameter from T1 to T4 (impact of Trial p = 0.049), but no trials were significantly different (pairwise posthoc testing all p > 0.10), and there was no difference in peak 1 min diameter between trials (p=0.74). The interpretation of %FMD is complicated by changing baseline diameter, however these results suggest that when shear stress is controlled, the artery may dilate to a consistent peak diameter. Further research is required to determine the reasons for the instability in baseline SFA diameter and the utility of SFA LEX FMD. NSERC CFI
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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 | 0.002 |
| 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".