Abstract 16098: Mechanism of Branch Pulmonary Artery Stenosis After the Arterial Switch Operation
Bibliographic record
Abstract
Background: Branch pulmonary artery (PA) stenosis, most commonly on the left, is a recognized postoperative complication of the arterial switch operation (ASO) for transposition of the great arteries. We hypothesized that greater rightward rotation of the neopulmonary root and dilation of the ascending aorta are associated with stenosis of the left PA (LPA). Methods: This study represents a retrospective analysis of cardiac magnetic resonance imaging (CMR) studies performed in patients after ASO. Neo-pulmonary root position in relation to the aorta was expressed as an angle, with a negative angle implying a rightward neo-pulmonary root. For the purpose of this study, perfusion imbalance was defined as <40% of pulmonary blood flow to the affected lung. The offset between the LPA and right PA (RPA) as a result of cranial displacement of the LPA by asymmetric aortic root dilation was measured in the coronal plane. Results: 74 patients / studies were included for analysis. 73% had no branch PA stenosis, 24% had LPA stenosis and 3% had RPA stenosis. LPA area indexed to BSA was smaller than RPA area (287 ± 185mm2 vs 151 ± 114mm2, p=0.001). Smaller LPA area correlated with reduced LPA flow (r=0.213, p=0.0001) and a greater rightward positioning of the neopulmonary to aortic root (r=0.361, p=0.002). There was no correlation between LPA size or flow and offset of the LPA take-off due to an enlarged aortic root. Patients with reduced relative LPA flow were more likely to have required pulmonary arterioplasty with the primary repair (17% vs 2%, p=0.04), had a smaller LPA area [102±102mm2 vs 160±108mm2, p=0.04) and a smaller anterior-posterior thoracic diameter (101±53mm vs 131±55mm, p=0.04). There was no significant difference in patient demographics, cardiac diagnosis, age at operation, aortic root dimension, ventricular volumetrics or ventricular function between patients with normal LPA flow vs. reduced LPA flow. Patients with reduced LPA flow did not have greater peak gradients on echo. Conclusions: Greater rightward rotation of the neopulmonary root is associated with reduced LPA size and likely contributes to the development of LPA stenosis after ASO.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.005 | 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".