title: Arterial applanation tonometry: feasibility and reproducibility in children and adolescents.
abstract: BACKGROUND
  Aortic pulse wave velocity (PWV) and augmentation index (AIx) are markers of vascular health and have recently been used in pediatric clinical trials. However, there are limited data on standardization of these measurements in pediatrics. The objective of this study was to prospectively test the feasibility and reproducibility of PWV and AIx in children and adolescents.
  
  
  METHODS
  We performed arterial tonometry on 2 different days within 2 weeks in 40 healthy subjects aged 10-19 years. PWV and AIx were measured in triplicate on each visit.
  
  
  RESULTS
  The visits were separated by a mean of 3.08±3.7 days. We obtained PWV in 77 of 80 (96%) visits and AIx in 76 of 80 (95%) visits in triplicate. Intraclass correlation coefficients (ICCs) for PWV were 0.61 (95% confidence interval (CI) = 0-0.86) when at least 2 measurements and 0.92 (95% CI = 0-1) when 3 measurements were obtained at each visit that met the quality criteria established for adults by the manufacturer (n = 17 and 3 paired visits, respectively). For AIx, ICCs were 0.78 (95% CI = 0.58-0.88) and 0.81 (95% CI = 0.63-0.90) when measurements with an operator index ≥80, a measure of the quality of the waveform, were included (n = 39 and 36 paired visits, respectively).
  
  
  CONCLUSIONS
  Arterial applanation tonometry is feasible and reproducible in healthy children and adolescents. AIx has excellent intervisit reproducibility, whereas the intervisit reproducibility of PWV relies on acquisition of multiple measurements that meet quality criteria established for adults. These results have implications for the methodology of future pediatric clinical trials in a population at increasingly higher risk for premature atherosclerosis.
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics, Stanford University, Lucile Packard Children's Hospital, Palo Alto, California;
authors.forename: Alexander
authors.initials: A
authors.lastname: Lowenthal
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics, Stanford University, Lucile Packard Children's Hospital, Palo Alto, California;
authors.forename: Jasmine M A
authors.initials: JM
authors.lastname: Evans
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics, Stanford University, Lucile Packard Children's Hospital, Palo Alto, California;
authors.forename: Rajesh
authors.initials: R
authors.lastname: Punn
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics, Stanford University, Lucile Packard Children's Hospital, Palo Alto, California;
authors.forename: Susan E
authors.initials: SE
authors.lastname: Nourse
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics, Stanford University, Lucile Packard Children's Hospital, Palo Alto, California;
authors.forename: Chau N
authors.initials: CN
authors.lastname: Vu
authors.affiliation: Division of Epidemiology, Stanford University, Palo Alto, California.
authors.forename: Rita A
authors.initials: RA
authors.lastname: Popat
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics, Stanford University, Lucile Packard Children's Hospital, Palo Alto, California; tierneys@stanford.edu.
authors.forename: Elif Seda
authors.initials: ES
authors.lastname: Selamet Tierney
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001158:Arteries / Q000502:physiology*; D002648:Child; D005240:Feasibility Studies; D005260:Female; D064368:Healthy Volunteers; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008365:Manometry / Q000379:methods*; D015588:Observer Variation; D011237:Predictive Value of Tests; D011446:Prospective Studies; D063177:Pulse Wave Analysis / Q000379:methods*; D015203:Reproducibility of Results; D013997:Time Factors; D055815:Young Adult
keywords: adolescents; augmentation index; blood pressure; children; hypertension; pulse wave analysis; pulse wave velocity; reproducibility.