title: Impact of age on incidence and prevalence of moderate-to-severe cellular rejection detected by routine surveillance biopsy in pediatric heart transplantation.
abstract: BACKGROUND
  The effect of age at transplant on rejection detected by routine surveillance biopsy (RSB) in pediatric heart transplant (HT) recipients is unknown. We hypothesized there would be low diagnostic yield and decreased prevalence of rejection detected on RSB in infants (age <1 year) when compared with children (age 1 to 9 years) and adolescents (age 10 to 18 years).
  
  
  METHODS
  We utilized Pediatric Heart Transplant Study (PHTS) data from 2010 to 2013 to analyze moderate-to-severe (ISHLT Grade 2R/3R) cellular rejection (MSR) detected only on RSB (RSBMSR).
  
  
  RESULTS
  RSB detected 280 of 343 (81.6%) episodes of MSR. RSBMSR was detected in all age groups even >5 years after HT. Infant RSBMSR had a greater proportion (p = 0.0025) occurring >5 years after HT (39.2 vs 18.4 vs 10.8%) and a lower proportion (p = 0.0009) occurring in the first year after HT (25.5 vs 60.6 vs 51.7%) compared with children and adolescents, respectively. Freedom from RSBMSR was 87 ± 7% in infants, 76 ± 6% in children and 73 ± 7% in adolescents 4 years after HT. In 1-year survivors who had RSBMSR in the first year after HT, the risk of RSBMSR occurring in Years 2 to 4 was significantly (p < 0.0001) greater than patients without RSBMSR in the first year (hazard ratio 21.28, 95% confidence interval 10.87 to 41.66), regardless of recipient age.
  
  
  CONCLUSIONS
  RSBMSR exists in all age groups after pediatric HT with long-term follow-up. The prevalence in infant recipients is highest >5 years after HT. Those with RSBMSR in the first year after HT are at a high risk for recurrent rejection regardless of age at HT.
authors.affiliation: Department of Pediatrics, Division of Cardiology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA; Department of Pediatric Cardiology, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA. Electronic address: matthew.zinn@chp.edu.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Zinn
authors.affiliation: Division of Biostatistics, Washington University School of Medicine, St. Louis, Missouri, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Wallendorf
authors.affiliation: Department of Pediatrics, Division of Cardiology, Washington University School of Medicine, St. Louis, Missouri, USA; Department of Pediatric Cardiology, Saint Louis Children's Hospital, St. Louis, Missouri, USA.
authors.forename: Kathleen E
authors.initials: KE
authors.lastname: Simpson
authors.affiliation: Department of Pediatrics, Division of Cardiology, Washington University School of Medicine, St. Louis, Missouri, USA.
authors.forename: Ashley D
authors.initials: AD
authors.lastname: Osborne
authors.affiliation: Department of Surgery, Division of Cardiothoracic Surgery, University of Alabama at Birmingham, Birmingham, Alabama, USA.
authors.forename: James K
authors.initials: JK
authors.lastname: Kirklin
authors.affiliation: Department of Pediatrics, Division of Cardiology, Washington University School of Medicine, St. Louis, Missouri, USA; Department of Pediatric Cardiology, Saint Louis Children's Hospital, St. Louis, Missouri, USA.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Canter
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D005260:Female; D006084:Graft Rejection / Q000453:epidemiology* / Q000473:pathology*; D006333:Heart Failure / Q000209:etiology / Q000473:pathology / Q000601:surgery*; D016027:Heart Transplantation / Q000009:adverse effects*; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D018579:Patient Selection; D011159:Population Surveillance; D015995:Prevalence; D012189:Retrospective Studies; D013997:Time Factors
keywords: biopsy; pediatric heart transplantation; rejection