Systemic Sirolimus Monitoring in Pediatric Pulmonary Vein Stenosis

Heather Meluskey, Bridget Blowey, Anna B. O’Brien, Michael L. O’Byrne, Jonathan J. Rome, David B. Frank, Catherine M. Avitabile, Mudit Gupta, Jessica Tang, Kimberly L. Butler, Constantine D. Mavroudis, Stephanie Fuller, Ryan Callahan

Children’s Hospital of Philadelphia and Perelman School of Medicine at the University of Pennsylvania. Dell School of Medicine at the University of Texas.
United States

Pediatric Cardiology
Pediatr Cardiol 2025;
DOI: 10.1007/s00246-025-04038-6

Abstract
Systemic sirolimus (SS) is an mTOR inhibitor used in the management of pediatric intraluminal pulmonary vein stenosis (PVS). SS initiation, monitoring, including patient compliance with toxicity surveillance, and potential adverse events (AE) in PVS patients are under reported. A single-center retrospective cohort study of consecutive patients who were initiated on SS for PVS from January 1, 2020 to December 31, 2024 was performed. Fifty patients with a median age of 7 months (range 2-165) received SS for PVS (median number of stenotic veins; n = 3 (1-4)) for a median duration of 18 months (1-60). The median time to therapeutic level was 9 days [IQR 3, 20] with two never achieving therapeutic values. In patients who received SS for at least 6 months (n = 39), the median number of blood draws and number of dose adjustments in the first 6 months were 14 [IQR 5, 27] and 3 [1, 7], respectively. Most levels among patients (75%; [IQR 64, 84]) did not require a dose adjustment. Toxicity surveillance compliance increased from 58% [IQR 42, 83] to 79% [IQR 62.5, 92] (p = 0.22) following transitioning ownership of SS management to a dedicated PVS team. Eighteen percent (9/50) of patients had an AE potentially related to SS; SS was discontinued in three. PVS patients receiving SS have high, but variable rates of therapeutic levels and SS discontinuation due to AEs is uncommon. Compliance with safety labs may improve with ownership by a dedicated monitoring team.

Category
Stenosis or Obstruction of Normal Pulmonary Venous Connections
Stenosis or Obstruction of Pulmonary Veins Following Surgical Repair of Anomalous Pulmonary Venous Connections
Medical Therapy. Adverse Effects or Lack of Adverse Effects
Medical Therapy. Pharmacokinetics or Pharmacology
Multidisciplinary Care

Year of Publication: 2025

Age Focus: Pediatric

Article Type: Retrospective Observational Cohort Studies (>10 patients)

Article Access: Free PDF File or Full Text Article Available Through PubMed or DOI: Yes