title: Prolongation of the prothrombin time and activated partial thromboplastin time in children with sickle cell disease.
abstract: BACKGROUND
  Patients with sickle cell disease (SCD) have high rates of perioperative complications, including bleeding 1,2.
  
  
  METHODS
  We conducted a retrospective review of pre-operative coagulation studies in pediatric patients with SCD followed by a prospective study of 100 well children with SCD to determine the prevalence of abnormal coagulation screening tests, and to evaluate potential etiologies.
  
  
  RESULTS
  In the retrospective study, 32/84 (38.1%) had a prolonged prothrombin time (PT), compared to 8/100 in the prospective study. Prolongations of the activated partial thromboplastin time (aPTT) were less common. Children in the prospective study with prolonged PTs had significantly lower levels of Factor V and VII compared to those with normal PTs. Factor VII levels were <50% in 4/8 with long PTs, compared to 3/92 with normal PTs, P=0.001. Though retrospectively, several patients had normalization of their PT with vitamin K, there was no laboratory evidence of vitamin K deficiency in the prospective study. In the retrospective analysis, six of seven children who had pre-operative coagulation studies and significant intraoperative blood loss had prolonged PTs (P=0.04).
  
  
  CONCLUSIONS
  Children with SCD admitted for surgical procedures were more likely to have prolonged PTs than those tested at a well visit. There was intra-patient variability in coagulation studies that may be related to clinical status, hepatocellular dysfunction, and/or increased clotting factor consumption. Future well-designed prospective studies to determine whether abnormal coagulation studies are associated with an increased risk of perioperative bleeding in children with SCD are necessary.
authors.affiliation: Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104-4399, and Duke University School of Medicine, Durham, NC, USA. raffini@email.chop.edu
authors.forename: Leslie J
authors.initials: LJ
authors.lastname: Raffini
authors.forename: Alison E
authors.initials: AE
authors.lastname: Niebanck
authors.forename: Joanne
authors.initials: J
authors.lastname: Hrusovsky
authors.forename: Amanda
authors.initials: A
authors.lastname: Stevens
authors.forename: Anne
authors.initials: A
authors.lastname: Blackwood-Chirchir
authors.forename: Kwaku
authors.initials: K
authors.lastname: Ohene-Frempong
authors.forename: Janet L
authors.initials: JL
authors.lastname: Kwiatkowski
mesh_terms: D000293:Adolescent; D000328:Adult; D000755:Anemia, Sickle Cell / Q000097:blood* / Q000150:complications; D001778:Blood Coagulation Disorders / Q000150:complications / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D019992:Databases as Topic; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D010314:Partial Thromboplastin Time; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011517:Prothrombin Time; D012189:Retrospective Studies; D013997:Time Factors