Arteriovenous Fistulas for Hemodialysis: Application of High-Frequency US to Assess Vein Wall Morphology for Cannulation Readiness
Bibliographic record
Abstract
PURPOSE: To determine whether venous wall thickness and hoop (circumferential) stress, as determined with high-frequency ultrasonography (US), can predict cannulation readiness in arteriovenous fistulas (AVFs). MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained for this prospective study. To determine the US appearance of the venous wall, an AVF specimen was excised and scanned in a bath of degassed lactated Ringer solution with a 55-MHz probe. The appearance of the wall at high-frequency US was correlated with histologic findings. High-frequency (40-55-MHz) US was used to image the near-field AVF venous wall of 14 men (mean age, 59 years ± 11 [standard deviation]) and six women (mean age, 55 years ± 14) with newly created AVFs within 1 week of cannulation between January 2008 and December 2009. Measurements of the intima-media thickness (IMT) were generated by three independent observers who were blinded to outcomes. Intraclass correlation analysis was performed. Cannulation readiness was defined as no extravasation during the first dialysis treatment. RESULTS: By using high-frequency US, the IMT was defined as the sum of a thin echogenic blood-intima interface and a uniform hypoechoic media. The mean IMT of the no extravasation group (0.16 mm ± 0.03) was greater than that of the extravasation group (0.10 mm ± 0.02) (P < .001). A minimum threshold IMT of 0.13 mm (P < .001) was associated with successful cannulation. The mean hoop stress of the no extravasation group (246 kPa ± 57) was lower than that of the extravasation group (530 kPa ± 199) (P < .001). A maximum hoop stress threshold of 248 kPa was associated with successful cannulation (P = .009). CONCLUSION: Venous IMT and hoop stress assessed with high-frequency US can predict cannulation readiness in AVFs that are clinically deemed mature.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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 teacher head, 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".