title: Deficits in bone density and structure in children and young adults following Fontan palliation.
abstract: BACKGROUND
  Survival of patients with congenital heart disease has improved such that there are now more adults than children living with these conditions. Complex single ventricle congenital heart disease requiring Fontan palliation is associated with multiple risk factors for impaired bone accrual. Bone density and structure have not been characterized in these patients.
  
  
  METHODS
  Tibia peripheral quantitative computed tomography (pQCT) was used to assess trabecular and cortical volumetric bone mineral density (vBMD), cortical dimensions, and calf muscle area in 43 Fontan participants (5-33 years old), a median of 10 years following Fontan palliation. pQCT outcomes were converted to sex- and race-specific Z-scores relative to age based on >700 healthy reference participants. Cortical dimensions and muscle area were further adjusted for tibia length.
  
  
  RESULTS
  Height Z-scores were lower in Fontan compared to reference participants (mean ± SD: -0.29 ± 1.00 vs. 0.25 ± 0.93, p < 0.001); BMI Z-scores were similar (0.16 ± 0.88 vs. 0.35 ± 1.02, p = 0.1). Fontan participants had lower trabecular vBMD Z-scores (-0.85 ± 0.96 vs. 0.01 ± 1.02, p < 0.001); cortical vBMD Z-scores were similar (-0.17 ± 0.98 vs. 0.00 ± 1.00, p = 0.27). Cortical dimensions were reduced with lower cortical area (-0.59 ± 0.84 vs. 0.00 ± 0.88, p<0.001) and periosteal circumference (-0.50 ± 0.82 vs. 0.00 ± 0.84, p < 0.001) Z-scores, compared to reference participants. Calf muscle area Z-scores were lower in the Fontan participants (-0.45 ± 0.98 vs. 0.00 ± 0.96, p = 0.003) and lower calf muscle area Z-scores were associated with smaller periosteal circumference Z-scores (R = 0.62, p < 0.001). Musculoskeletal deficits were not associated with age, Fontan characteristics, parathyroid hormone or vitamin D levels.
  
  
  CONCLUSIONS
  Children and young adults demonstrate low trabecular vBMD, cortical structure and muscle area following Fontan. Muscle deficits were associated with smaller periosteal dimensions. Future studies should determine the fracture implications of these deficits and identify interventions to promote musculoskeletal development.
authors.affiliation: Division of Cardiology, Children's Hospital of Philadelphia, 34(th) and Civic Center Boulevard, Philadelphia, PA 19104, USA. Electronic address: Catherine.avitabile@tenethealth.com.
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Avitabile
authors.affiliation: Division of Cardiology, Children's Hospital of Philadelphia, 34(th) and Civic Center Boulevard, Philadelphia, PA 19104, USA; Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, 415 Curie Boulevard, Philadelphia, PA 19104, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Goldberg
authors.affiliation: Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, 415 Curie Boulevard, Philadelphia, PA 19104, USA; Division of Gastroenterology, Hepatology and Nutrition, Children's Hospital of Philadelphia, 34(th) and Civic Center Boulevard, Philadelphia, PA 19104, USA.
authors.forename: Babette S
authors.initials: BS
authors.lastname: Zemel
authors.affiliation: Mid-Hudson Medical Group, 30 Columbia Street, Poughkeepsie, NY 12601, USA.
authors.forename: Jill L
authors.initials: JL
authors.lastname: Brodsky
authors.affiliation: Division of Cardiology, Children's Hospital of Philadelphia, 34(th) and Civic Center Boulevard, Philadelphia, PA 19104, USA.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Dodds
authors.affiliation: Division of Cardiology, Children's Hospital of Philadelphia, 34(th) and Civic Center Boulevard, Philadelphia, PA 19104, USA.
authors.forename: Christina
authors.initials: C
authors.lastname: Hayden-Rush
authors.affiliation: Division of Cardiology, Children's Hospital of Philadelphia, 34(th) and Civic Center Boulevard, Philadelphia, PA 19104, USA; Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, 415 Curie Boulevard, Philadelphia, PA 19104, USA.
authors.forename: Kevin K
authors.initials: KK
authors.lastname: Whitehead
authors.affiliation: Division of Cardiology, Children's Hospital of Philadelphia, 34(th) and Civic Center Boulevard, Philadelphia, PA 19104, USA; Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, 415 Curie Boulevard, Philadelphia, PA 19104, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Goldmuntz
authors.affiliation: Division of Cardiology, Children's Hospital of Philadelphia, 34(th) and Civic Center Boulevard, Philadelphia, PA 19104, USA; Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, 415 Curie Boulevard, Philadelphia, PA 19104, USA.
authors.forename: Jack
authors.initials: J
authors.lastname: Rychik
authors.affiliation: Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, 415 Curie Boulevard, Philadelphia, PA 19104, USA; Division of Nephrology, Children's Hospital of Philadelphia, 34(th) and Civic Center Boulevard, Philadelphia, PA 19104, USA; Department of Biostatistics and Epidemiology, Perelman School of Medicine at the University of Pennsylvania, 415 Curie Boulevard, Philadelphia, PA 19104, USA.
authors.forename: Mary B
authors.initials: MB
authors.lastname: Leonard
mesh_terms: D000293:Adolescent; D000328:Adult; D015519:Bone Density; D002648:Child; D002675:Child, Preschool; D005260:Female; D018729:Fontan Procedure; D006330:Heart Defects, Congenital / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Bone mineral density; Congenital heart disease; Fontan; Muscle; Peripheral quantitative computed tomography