Urinary 11-dehydrothromboxane B2 aspirin efficacy testing is sensitive to perioperative inflammation in pediatric solid-organ transplant patients

Alexander A. Boucher, Brenton J. Francisco, Amanda Pfeiffer, Matthew Martin, Janine Martin, Amy Shova, Jaimie D. Nathan, Gregory M. Tiao, Lori Luchtman-Jones

Research output: Contribution to journalArticlepeer-review


Background: Evidence for aspirin efficacy testing in pediatrics is limited, especially outside of cardiology, yet thrombotic events have high morbidity in other areas such as pediatric transplant surgery. Debates about whether thromboembolic events while on aspirin represent “aspirin resistance” or “high on-treatment platelet reactivity” persist, given the poor intertest agreement between testing platforms. Procedure: This prospective observational study involved measuring aspirin efficacy using ex vivo testing of platelet aggregation (VerifyNow-Aspirin, VN) and urine 11-dehydrothromboxane B2 (AsprinWorks, UTxB2) contemporaneously at up to three time points after major noncardiac organ transplant surgery. The collection days (CD) were the second and seventh days after stable aspirin dosing and then a convalescent time point 2-9 months later. Results: Fifty-five participants (age range, 0-21 years) were enrolled, having undergone total pancreatectomy with islet autotransplantation (N = 36), orthotopic liver transplantation (N = 18), and combined liver-kidney transplantation (N = 1). Platelet reactivity measured by VN remained unchanged, whereas UTxB2, which was elevated postoperatively, decreased significantly from CD1 to CD2 and CD3. Discordance in therapeutic efficacy was noted per manufacturer cutoffs, with therapeutic VN results in 86% of tests, whereas 12% of UTxB2 were therapeutic. Age-based stratification of UTxB2 results using previously published pediatric median levels increased overall UTxB2 therapeutic rates (80%) and intertest concordance (67% vs 27% if using adult range). No thrombotic events were observed. Conclusions: Our data suggest that urine thromboxane production may be an underappreciated reflection of postoperative inflammation. Validation of pediatric normal ranges for UTxB2 is a critical next step.

Original languageEnglish (US)
Article numbere29413
JournalPediatric Blood and Cancer
Issue number2
Early online dateOct 22 2021
StatePublished - Feb 2022

Bibliographical note

Funding Information:
We appreciate the willingness of patients and families to participate in this study, the test kit support from Corgenix and Werfen, and the collaboration by the surgical and gastroenterology teams at Cincinnati Children's Hospital Medical Center.

Publisher Copyright:
© 2021 Wiley Periodicals LLC

PubMed: MeSH publication types

  • Journal Article
  • Observational Study


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