Maintenance of warfarin anticoagulation for patients undergoing vitreoretinal surgery

Objective: To evaluate the risk of hemorrhagic complications associated with vitreoretinal surgery in patients whose warfarin sodium therapy was continued throughout the surgical period. Methods: A review of 1737 records of patients undergoing pars plana vitrectomy was conducted. Inclusion criteria included patients receiving warfarin therapy whose international normalized ratios (INRs) were elevated above normal values on the day of surgery. Intraoperative and postoperative hemorrhagic complications were documented. Results: Fifty-four patients underwent 57 vitreoretinal surgical procedures with warfarin therapy and were divided into groups as follows: group S with INRs of 1.20 to 1.49, values considered subtherapeutic; group B with INRs of 1.50 to 1.99, values considered borderline therapeutic; group T with INRs of 2.00 to 2.49, values considered therapeutic; and group HT with INRs of 2.50 or greater, values considered highly therapeutic. No patients experienced anesthesia-related or intraoperative hemorrhagic complications. Two (7.7%) of 26 eyes in group S and 2 (16.7%) of 12 eyes in group HT experienced postoperative hemorrhages. All of the patients with vitreous hemorrhages had spontaneous clearing without additional treatment. Conclusions: Many patients may safely undergo vitreoretinal surgery while maintaining therapeutic levels of warfarin anticoagulation. We experienced no intraoperative hemorrhagic complications; the 4 postoperative complications resolved spontaneously without persistent visual sequelae or the need for supplemental surgery.