Intradialytic changes in reflective properties of the arterial system during a single hemodialysis session
Bibliographic record
Abstract
Increased aortic stiffness-measured as aortic augmentation index (AIx), a global stiffness marker-has emerged as a powerful predictor of survival in hemodialysis (HD). A single HD session is known to produce considerable improvement in aortic stiffness. We set out, for the first time, to examine the relative contributions to the post-HD drastic improvement in aortic stiffness of ultrafiltration rate and volume, or blood pressure (BP) changes. Aortic AIx (difference between the first and the second systolic peak of the aortic pressure waveform divided by pulse wave height) was determined hourly and recorded by applanation tonometry using a SphygmoCor device in 20 chronic HD patients (9 males, age 55.1 years). The other parameters recorded were: weight pre- and post-HD, ultrafiltration volume (UFV), hemoglobin, albumin, creatinine, urea reduction rate (URR), calcium and PTH, and BP. The dialysis significantly decreased AIx from 24.2+/-11.27% to 15.57+/-12.58% (p<0.05). In a univariate analysis, the intradialytic decrease in AIx (AIx 0-4) did not correlate with UFV, URR or with any of the biochemical markers. Significant correlations for AIx 0-4 were age (p=0.018), systolic blood pressure (SBP) at the beginning of HD (p=0.049), the intradialytic decrease in the SBP (p=0.001), and in pulse pressure (PP) (p=0.009). Multivariate stepwise regression showed that the decrease in SBP, PP, and intradialytic percentage reduction in weight explained 64.9% of the total variation in AIx 0-4. The decrease in SBP was the most important factor influencing the AIx variation (b=1.54, p=0.007). The most significant reduction in AIx was from the beginning of HD to the third hour (p=0.039), and correlated with the reduction in SBP (p=0.006) and PP (p=0.025) between the same moments. A single HD session produces a drastic improvement in aortic stiffness. The effect is not explained by the UFV depletion but is highly correlated with the decrease in SBP and PP. Further work is now needed to explore a potential role for endothelin and nitric oxide metabolism.
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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 | 0.001 |
| 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) | 0.000 | 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".