Abstract 13110: Pediatric Heart Transplantation in Pre-Sensitized Recipients: A Current Perspective
Bibliographic record
Abstract
Introduction: Anti-HLA antibodies (Ab) are increasingly prevalent in pediatric patients (pts) awaiting heart transplant (HT) and may result in a significant delay in time to HT because of the need to wait for a negative prospective donor HLA crossmatch (XM). Methods: Data from pts in the Pediatric HT Study transplanted between 2010-2014 were analyzed to determine the association of pre-HT percent reactive anti-HLA Ab (PRA) detected by flow cytometry with retrospective donor XM results and outcomes after HT. Sensitization was defined as a PRA >20%. Results: HT was performed in 1,596 pts, 1,459 had a PRA calculated and 1,419 had XM results available. Sensitization was present in 32% of pts; 25% were sensitized against Class I and 20% were sensitized against Class II Ab (p<0.01). Sensitization was more common in pts with congenital heart disease (CHD) compared to cardiomyopathy (CM), 28% vs. 15%, respectively, p<0.01). Sensitization was similar between pts with and without ventricular assist device support, 20% vs. 25%, respectively, p=0.07. The level of sensitization was significantly associated with a +XM (p<0.01, Table). Sensitized pts who had a +XM were at higher risk for rejection than those who had a - XM and those who were not sensitized (p<0.01, Figure). There was no difference in post-HT survival between sensitized and nonsensitized pts, p=0.11, or those with and without a +XM, p=0.06. Conclusions: In the current era, 32% of pediatric HT pts are sensitized, with a higher incidence seen in pts with CHD compared to those with CM. Although, increasing PRA levels were associated with a higher likelihood of a positive retrospective XM, 68% of pts with a pre-HT PRA >50% had a negative XM. XM was positive in 9% of pts with a PRA between 1-20%. Sensitized pts with a positive XM had a higher incidence of rejection than all other pts. Better methods of identifying pts at risk for a positive XM are needed to refine the indications for a prospective XM in pediatric pts listed for HT.
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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 | 0.003 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.003 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.003 |
| 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".