title: Evidence for Extending the Duration of Chemoprophylaxis following Free Flap Harvest from the Lower Extremity: Prospective Screening for Deep Venous Thrombosis.
abstract: BACKGROUND
  The purpose of this study was to investigate the incidence of symptomatic and asymptomatic deep venous thrombosis in patients undergoing harvest of a free flap from the lower extremity who were receiving standard chemoprophylaxis while hospitalized.
  
  
  METHODS
  A retrospective review of 65 consecutive patients undergoing surgery between 2011 and 2013 was performed to determine the incidence of symptomatic deep venous thrombosis. These patients were screened for deep venous thrombosis based on development of symptoms. Prospective evaluation of a similar consecutive population of 37 patients between 2014 and 2015 was then performed to determine the incidence of asymptomatic deep venous thrombosis. These patients underwent routine duplex ultrasonography of both legs at postoperative weeks 1 and 4.
  
  
  RESULTS
  Symptomatic deep venous thrombosis occurred in 2.9 percent of all patients. In the prospective cohort, 8.1 percent of the patients were found to have an acute deep venous thrombosis by postoperative week 1. At postoperative week 4, 16.7 percent of the patients developed a new, acute deep venous thrombosis. The estimated costs of screening and treating deep venous thrombosis in the retrospective group and the prospective group were $222 and $2259, respectively. The cost of routine chemoprophylaxis without duplex screening for an additional 14 days after discharge was $125 per patient.
  
  
  CONCLUSIONS
  The rate of asymptomatic deep venous thrombosis may be much higher than previously appreciated in this population of very high-risk patients, especially during the 2 weeks after discharge. Extending the duration of chemoprophylaxis to 4 weeks after surgery may be warranted.
  
  
  METHODS
  Therapeutic, IV.
authors.affiliation: Aurora, Colo.|From the Division of Plastic Surgery, Department of Surgery, and the Department of Otolaryngology, University of Colorado.
authors.forename: Aline S
authors.initials: AS
authors.lastname: Rau
authors.affiliation: Aurora, Colo.|From the Division of Plastic Surgery, Department of Surgery, and the Department of Otolaryngology, University of Colorado.
authors.forename: Brian L
authors.initials: BL
authors.lastname: Harry
authors.affiliation: Aurora, Colo.|From the Division of Plastic Surgery, Department of Surgery, and the Department of Otolaryngology, University of Colorado.
authors.forename: Ted H
authors.initials: TH
authors.lastname: Leem
authors.affiliation: Aurora, Colo.|From the Division of Plastic Surgery, Department of Surgery, and the Department of Otolaryngology, University of Colorado.
authors.forename: John I
authors.initials: JI
authors.lastname: Song
authors.affiliation: Aurora, Colo.|From the Division of Plastic Surgery, Department of Surgery, and the Department of Otolaryngology, University of Colorado.
authors.forename: Frederic W-B
authors.initials: FW
authors.lastname: Deleyiannis
mesh_terms: D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use; D018890:Chemoprevention / Q000379:methods*; D003120:Colorado / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D058752:Free Tissue Flaps; D006493:Heparin / Q000627:therapeutic use*; D006801:Humans; D015994:Incidence; D035002:Lower Extremity / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D011446:Prospective Studies; D013848:Thigh / Q000601:surgery; D013997:Time Factors; D020858:Tissue and Organ Harvesting / Q000009:adverse effects*; D018616:Ultrasonography, Doppler, Duplex; D020246:Venous Thrombosis / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants; D006493:Heparin