title: Prevention of thrombosis in hypercoagulable patients undergoing microsurgery: A novel anticoagulation protocol.
abstract: BACKGROUND
  Hypercoagulable conditions are often considered relative contraindications to free flap reconstruction. This paper presents and critically examines a novel anticoagulation regimen developed to address this disease state.
  
  
  METHODS
  Hypercoagulable patients who underwent free tissue transfer between 2007 and 2015 were identified. From 2011, all such patients were subjected to a novel anticoagulation protocol involving an intravenous bolus of 2000 U of unfractionated heparin prior to microvascular pedicle anastomosis, followed by a heparin infusion at 500 U/h, which was postoperatively increased to therapeutic levels. Patients were discharged on full anticoagulation for 1 month. Patients prior to 2011 received only subcutaneous heparin. Outcomes in patients receiving this novel anticoagulation protocol were compared to those of patients receiving standard therapy (postoperative subcutaneous heparin).
  
  
  RESULTS
  Twenty-three hypercoagulable patients underwent reconstruction with 32 flaps. Eleven patients were administered the novel protocol. No thromboses were noted in the novel protocol cohort, while three thrombotic events occurred in the control cohort (0% vs. 17.6%, p = 0.23). No flaps were salvaged after thrombosis. All losses occurred in the control cohort (0% vs. 17.6%, p = 0.23). The novel protocol cohort was more likely to have postoperative red blood cell transfusions (72.6% vs. 16.7%, p = 0.007), hematomas (26.7% vs. 0%, p = 0.04), and lower mean hemoglobin nadirs [6.9 (1.0) vs. 8.9 ± 1.8 g/dL, p = 0.01].
  
  
  CONCLUSIONS
  The key approach to hypercoagulable patients is likely prevention over treatment. Patients who received prophylactic heparin infusions had clinically lower rates of thrombotic events and flap loss. However, this encouraging finding must be balanced with the increased risk for postoperative bleeding complications.
authors.affiliation: Section of Plastic and Reconstructive Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, United States. Electronic address: jonas.nelson@gmail.com.
authors.forename: Jonas A
authors.initials: JA
authors.lastname: Nelson
authors.affiliation: Division of Plastic and Reconstructive Surgery, University of California San Francisco, San Francisco, CA, United States.
authors.forename: Cyndi U
authors.initials: CU
authors.lastname: Chung
authors.affiliation: Division of Plastic Surgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Bauder
authors.affiliation: Division of Plastic Surgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States.
authors.forename: Liza C
authors.initials: LC
authors.lastname: Wu
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D005260:Female; D058752:Free Tissue Flaps; D006493:Heparin / Q000008:administration & dosage*; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008866:Microsurgery / Q000379:methods*; D008875:Middle Aged; D011183:Postoperative Complications / Q000517:prevention & control; D012189:Retrospective Studies; D019851:Thrombophilia / Q000150:complications*; D013927:Thrombosis / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants; D006493:Heparin
keywords: Complications; Free flap; Hypercoagulable; Thrombophilia