EP12.17: Decreased left heart flow is sufficient to produce hypoplasia in mid‐gestation fetal lambs
Bibliographic record
Abstract
A decrease in fetal left heart flow has been proposed as the cause of hypoplastic left heart syndrome (HLHS). Supravalvar aortic banding in fetal lambs led to conflicting results as to whether left ventricular (LV) hypoplasia or hypertrophy occurred. LV inflow obsturction was poorly tolerated in 90-120 day fetal lambs who died within 7 days from hydrops. We attempted a more gradual onset of LV inflow obstruction in 75 day old fetal lambs. Coils were implanted in the left atrium guided by ultrasound, using a 22G needle under aseptic technique in 75 day fetal lambs. Survivors underwent echocardiography 50 days later and were harvested. 15 of 34 coiled fetuses reached 125 days, 5 had no inflow obstruction (sham controls), 1 had anasarca due to coil-induced severe maitral regurgitation and 9 had sufficiently decreased LV inflow/preload so that antegrade aortic valve flow was so reduced that there was compensatory retrograde flow in the ascending aorta from the duct. Four of five with retrograde aortic flow had no antegrade aortic valve flow (no_aov_flow), and these had the most severe left heart hypoplasia. LV free-wall/RV free-wall weight: no_aov_flow 0.63 + 0.19, controls 0.99 + 0.17, p = 0.008. Aortic valve/Pulmonary valve diameter: no_aov_flow 0.48 + 0.03, controls 0.82 + 0.15, p = 0.0004. Ascending aorta/Pulmonary artery diameter: no_aov_flow 0.56 + 0.09, controls 0.83 + 0.11, p = 0.0004. LV end-diastolic/RV end-diastolic diameter: no_aov_flow 0.48 + 0.23, controls 1.0 + 0.12, p = 0.0021. LV end-diastolic/RV end-diastolic length: no_aov_flow 0.67 + 0.21, 1.13 + 0.17, p = 0.0036. Long after cardiogenesis has been completed, a severe prolonged decrease in left heart flow is sufficient to produce LV and ascending aortic hypoplasia. In the most severe cases, there was no antegrade aortic valve flow and perfusion of the brain and coroanries was wholly retrograde from the duct. This recapitulates much of human HLHS fetal physiology.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".