title: Maintenance of warfarin anticoagulation for patients undergoing vitreoretinal surgery.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the risk of hemorrhagic complications associated with vitreoretinal surgery in patients in whom warfarin therapy was continued throughout the surgical period.
  
  
  METHODS
  A review of 1,737 consecutive charts of patients undergoing pars plana vitrectomy was conducted. Inclusion criteria included patients on warfarin therapy whose international normalized ratio (INR) was elevated above normal on the day of vitreoretinal surgery. The occurrence of intraoperative and postoperative hemorrhagic complications was documented.
  
  
  RESULTS
  The retrospective review detected 54 patients who underwent 57 vitreoretinal surgical procedures while on warfarin therapy. Group S consisted of patients whose INR ranged from 1.2 to 1.49, values that were considered to be subtherapeutic. Group B had INR values ranging from 1.5 to 1.99, values that were considered to be borderline therapeutic. Group T had INRs ranging from 2.0 to 2.49, values that were considered therapeutic. Group HT had INRs of 2.5 or greater, values that were considered highly therapeutic. No patients experienced anesthesia-related or intraoperative hemorrhagic complications. Four procedures (7.0%) were complicated by postoperative hemorrhage. Two of 26 eyes (7.7%) in group S and two of 12 eyes (16.7%) in group HT experienced postoperative hemorrhages. All hemorrhagic complications cleared without additional therapy.
  
  
  CONCLUSIONS
  Our findings suggest that many patients may safely undergo vitreoretinal surgery while maintaining therapeutic levels of warfarin anticoagulation. We found no intraoperative hemorrhagic complications. Those hemorrhagic complications that occurred postoperatively resolved spontaneously without persistent visual sequelae or the need for supplemental surgery.
authors.affiliation: Washington University School of Medicine, St Louis, Missouri, USA.
authors.forename: Pouya N
authors.initials: PN
authors.lastname: Dayani
authors.forename: M Gilbert
authors.initials: MG
authors.lastname: Grand
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000009:adverse effects; D001281:Atrial Fibrillation / Q000188:drug therapy; D005260:Female; D006801:Humans; D019934:International Normalized Ratio; D007431:Intraoperative Complications; D008297:Male; D008875:Middle Aged; D010314:Partial Thromboplastin Time; D011183:Postoperative Complications; D011517:Prothrombin Time; D012164:Retinal Diseases / Q000601:surgery*; D012189:Retrospective Studies; D012307:Risk Factors; D014821:Vitrectomy; D014823:Vitreous Hemorrhage / Q000139:chemically induced; D014859:Warfarin / Q000009:adverse effects / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D014859:Warfarin