title: Use of Enoxaparin in Obese Adolescents During Bariatric Surgery--a Pilot Study.
abstract: BACKGROUND
  Obese patients have a higher risk of venous thromboembolism when immobilized due to surgery. The objective of this study was to assess anti-factor Xa activity in adolescent bariatric surgical patients receiving prophylactic enoxaparin.
  
  
  METHODS
  Four morbidly obese adolescents undergoing laparoscopic sleeve gastrectomy were enrolled. Enoxaparin was administered (40 mg subcutaneous (SC) if BMI ≤50 kg/m(2) or 60 mg SC if BMI >50 kg/m(2)) for prevention of venous thromboembolism every 12 h starting after induction of anesthesia until discharge. Plasma anti-factor Xa activity was assessed over 12 h after the first dose and used as a surrogate marker for enoxaparin levels. Non-compartmental analysis of anti-factor Xa activity levels was performed and compared with previously published studies.
  
  
  RESULTS
  Patients recruited were 16 to 18 years of age with a mean BMI of 52.6 ± 5.8 kg/m(2) (>99th BMI percentile). Peak anti-factor Xa activity ranged from 0.20 to 0.23 IU/mL in our study population, compared to 0.38 to 0.53 IU/mL in the cited lean comparator groups.
  
  
  CONCLUSIONS
  Our current dosing practice of 40 mg SC for individuals with a BMI ≤50 kg/m(2) and 60 mg for individuals with a BMI ≥50 kg/m(2) resulted in anti-factor Xa activity that was sufficient for adequate thromboprophylaxis in adolescent bariatric surgical patients. Our data also demonstrates lower drug exposures in the obese when compared to lean patients. Therefore, randomized controlled efficacy and safety studies are urgently needed to guide the use of low-molecular-weight heparins in the pediatric and adolescent obese population.
authors.affiliation: Clinical Pharmacology, Clinical and Translational Science Institute, Children's National Medical Center, Washington, DC, USA, raisenal@hotmail.com.
authors.forename: Alvina
authors.initials: A
authors.lastname: Mushtaq
authors.forename: Janelle D
authors.initials: JD
authors.lastname: Vaughns
authors.forename: Victoria C
authors.initials: VC
authors.lastname: Ziesenitz
authors.forename: Evan P
authors.initials: EP
authors.lastname: Nadler
authors.forename: John N
authors.initials: JN
authors.lastname: van den Anker
mesh_terms: D000293:Adolescent; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D050110:Bariatric Surgery / Q000009:adverse effects / Q000379:methods*; D018890:Chemoprevention; D004334:Drug Administration Schedule; D017984:Enoxaparin / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D006495:Heparin, Low-Molecular-Weight / Q000008:administration & dosage / Q000009:adverse effects; D006801:Humans; D007430:Intraoperative Care / Q000379:methods; D008297:Male; D009767:Obesity, Morbid / Q000453:epidemiology / Q000601:surgery*; D010351:Patient Discharge; D063766:Pediatric Obesity / Q000453:epidemiology / Q000601:surgery*; D010865:Pilot Projects; D011183:Postoperative Complications / Q000453:epidemiology / Q000517:prevention & control; D054556:Venous Thromboembolism / Q000453:epidemiology / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants; D017984:Enoxaparin; D006495:Heparin, Low-Molecular-Weight