Repeatability of Reactive Hyperemia Flow‐Mediated Dilation in the Superficial Femoral Artery
Bibliographic record
Abstract
Reactive hyperemia (RH) is induced via the release of a temporary limb occlusion and causes a transient increase in artery shear stress. Flow‐mediated dilation stimulated by RH (RH‐FMD) is a standard index of endothelial function in the brachial artery however, relatively few studies have assessed RH‐FMD in the superficial femoral artery (SFA). The purpose of this study was to determine the repeatability of RH‐FMD in the SFA. SFA RH‐FMD was measured in 19 subjects (10 males and 9 females; age: 24 ± 2 years). Subjects performed four 5‐minute occlusion RH trials in a seated position with the cuff placed above the knee. Six minutes of recovery followed cuff release. SFA diameter and blood velocity were assessed using echo and Doppler ultrasound, respectively. Shear stress was estimated using shear rate (SR = mean blood velocity/SFA diameter). RH‐FMD was calculated as the % increase from baseline diameter to the peak 3 second diameter measurement post occlusion release. Results are expressed as mean ± SD. The RH SR area under the curve (AUC) for the 30 seconds following cuff release was higher in trial 1 versus trial 2 and 3 (p < 0.001 and p = 0.021). There were no differences in %RH‐FMD across trials (RH trial 1: 5.2 ± 2.6%, trial 2: 5.0 ± 2.3%, trial 3: 4.5 ± 2.2%, and trial 4: 5.0 ± 2.9%, p = 0.465). FMD normalized to the SR AUC also did not differ between trials (p = 0.879). In conclusion, despite some variability in the SR stimulus, there was no systematic change in %RH‐FMD over four repeated trials. Funded by NSERC and 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 | 0.002 | 0.004 |
| 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".