CHANGING ARTERIAL STIFFNESS GRADIENT BY NITROGLYCERIN AND ITS RELATION TO CENTRAL PRESSURE WAVE ANALYSIS
Bibliographic record
Abstract
Objective: We have previously shown that administration of nitroglycerin (NTG) reduced femoral pulse wave velocity without affecting aortic stiffness, which results in an increase in aortic-femoral (AF) PWV ratio (a measure of arterial stiffness gradient). In this study, we examined the impact of post-NTG changes of AF-PWV ratio on wave reflection using wave separation analysis. Design and method: In 20 treated hypertensive subjects with or without kidney disease, carotid-femoral (CFPWV) (aortic) and femoral-distal (FDPWV) were determined as respective measures of aortic and femoral stiffness. Aortic-femoral PWV ratio (AF PWV ratio) was used as a measure of arterial stiffness gradient. Aortic pressure waveform was obtained through generalized transfer function applied to the radial artery pressure waveform after calibration with systolic and diastolic blood pressures (SBP and DBP). Using GEE, we examined the extent of association between changes in aortic-femoral (AF) PWV ratio, and augmentation index (Aix), pressure forward (Pf), pressure backward (Pb) and reflection magnitude (RM). Results: After administration of NTG, SBP and mean BP (area under the curve) decreased (114 ± 19 vs 107 ± 15 and 89 ± 11 vs 85 ± 9 mm Hg, p < 0.01) without changes in DBP. The CFPWV remained unchanged (12.2 ± 2.2 vs 12.3 ± 2.9 m/s), whereas FDPWV decreased (8.7 ± 1.5 vs 7.2 ± 1.1 m/s, p < 0.001). Accordingly, AF PWV ratio increased (1.42 ± 0.25 vs 1.73 ± 0.41). Aix declined as expected (20.1 ± 11.9 vs 7.7 ± 12.8 %, p < 0.001). There was a slight but not statistically significant reduction in Pf (27.7 ± 10.7 vs 25.4 ± 7.9 mmHg, p = 0.068), while Pb decreased (17.2 ± 8.1 vs 13.4 ± 6.6 mmHg), resulting in a reduction in RM from 0.61 ± 0.10 to 0.51 ± 0.13 (p < 0.001). There was a significant association between the extent of changes in AF PWV ratio and changes in Aix (β = −15, p < 0.001), Pb (β = −9.5, p < 0.001) and RM (β = −0.21, p < 0.001). Conclusions: This study shows that alteration of arterial stiffness gradient with nitroglycerin is associated with changes in arterial wave reflection indices.
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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 | 0.002 |
| 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".