Abstract 12430: Vicious Circle Between Progressive Right Ventricular Dilatation and Pulmonary Regurgitation in Patients After Tetralogy of Fallot Repair? Right Heart Enlargement Promotes Flow Reversal in the Left Pulmonary Artery
Bibliographic record
Abstract
Introduction: The left pulmonary artery (LPA) contributes more than the right (RPA) to total pulmonary regurgitation (PR) in patients after tetralogy of Fallot (TOF) repair, but the mechanism of this difference is not well known. We hypothesized that unilaterally increased pulmonary vascular resistance (PVR), resulting from lung compression by the enlarged and levorotated heart leads to greater PR in the LPA. This study aimed to analyze the interplay between heart and lung size, mediastinal geometry, and differential PR. Methods: This is a single-center retrospective analysis of 50 magnetic resonance studies in patients after TOF repair. Patients with more than mild discrete branch pulmonary artery stenosis were excluded. Blood flow was measured by phase-contrast velocity encoding within the branch pulmonary arteries. On the axial image with the largest total cardiac surface area, cardiac angle (α) between the thoracic anterior-posterior line and the interventricular septum, right and left lung areas as well as right and left hemithorax areas were measured (Figure). Results: There was no difference in LPA and RPA diameters. The LPA showed significantly less total forward flow (p=0.04), smaller net forward flow (p=<0.001), and greater RF (p=0.001) than the RPA. Left lung area was smaller than the right (p<0.001). RVEDVi correlated with LPA RF (R=0.48, p<0.001), but not with RPA RF. Larger RVEDVi correlated with a larger α angle (R=0.46, p<0.001), i.e. a more leftward cardiac axis and with smaller left lung area (R=-0.58, p<0.001). LPA RF, but not RPA RF, correlated inversely with left lung area indexed to the left hemithorax area (R=-0.34, p=0.02). Conclusions: An enlarged and levorotated heart - as a result of PR - is associated with smaller left lung size, and augments diastolic flow reversal in the LPA, presumably via increased left PVR. By imposing a further volume load on the RV, LPA regurgitation may thus close a positive feed-back loop of PR and RV dilatation.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".