Understanding the mechanism for branch pulmonary artery stenosis after the arterial switch operation for transposition of the great arteries
Bibliographic record
Abstract
The pathophysiology of branch pulmonary artery (PA) stenosis after the arterial switch operation, most commonly on the left, is incompletely understood. This study examines factors associated with left PA (LPA) obstruction. Cardiac magnetic resonance (CMR) imaging studies performed in patients after arterial switch operation (ASO) were retrospectively analysed. Blood flow was measured in both branch PAs and neo-pulmonary root position in relation to the aorta was expressed as an angle, relative to a line connecting the sternum and the spine. Sixty-six patients were included for analysis. Seventy per cent (n = 46) had balanced pulmonary blood flow, 28% (n = 18) had decreased flow to the left, and 2% (n = 2) had decreased flow to the right lung. LPA area indexed to body surface area (BSA) was smaller than RPA area (62 ± 37 vs. 120 ± 64 mm2/m2, P < 0.0001). Patients with reduced LPA flow were more likely to have required pulmonary arterioplasty at the time of ASO (17 vs. 2%, P = 0.04) and had a larger aortic root diameter (25 ± 7 vs. 22 ± 5 mm2/m2, P = 0.01). Greater rightward orientation of the neo-pulmonary root correlated inversely with LPA cross-sectional area (r = −0.39, P = 0.001) but not with LPA flow. Aortic root diameter correlated inversely with LPA flow (r = −0.43, P = 0.0004) but not with LPA cross-sectional area (P = 0.32). Patients with a rightward neo-pulmonary root and/or a dilated aortic root in the upper quartile range had a smaller LPA area (53 vs. 73 mm2/m2, P = 0.04) and less pulmonary blood flow (41 vs. 46%, P = 0.02) compared with patients without those risk factors. Neo-pulmonary to neo-aortic geometry as well as post-operative compression of the LPA by an enlarged aorta impact LPA size and perfusion of the left lung.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".