Risk factors affecting postoperative hemorrhage after tooth extraction in patients receiving oral antithrombotic therapy.

PURPOSE We investigated risk factors affecting the onset of postoperative hemorrhage after tooth extraction in patients receiving oral antithrombotic therapy. PATIENTS AND METHODS A total of 443 tooth extractions were performed in 382 patients. All extractions were performed while continuing conventional antithrombotic therapy, and local hemostatic measures were performed. RESULTS Among the 17 patients with postoperative hemorrhage, 9 received warfarin monotherapy, 6 received warfarin and antiplatelet combination therapy, and 2 received antiplatelet monotherapy. Postoperative hemorrhage occurred within 6 days in 16 patients (94.1%), with a median of 3 days. The international normalized ratio at the time of extraction was less than 3.0 for all 15 patients receiving warfarin therapy but was prolonged, at 3.0 or greater, in 7 of 12 patients in whom this value was measured at the time of postoperative hemorrhage. As for local hemostatic measures at the time of postoperative hemorrhage, thorough local hemostatic measures were required in 12 (80.0%) of the 15 patients receiving warfarin therapy. Conversely, in the 2 patients receiving antiplatelet therapy, hemostasis was achieved by use of compression alone. Concerning factors affecting postoperative hemorrhage, significant differences were seen in relation to surgical tooth extraction (P = .008) and acute inflammation findings (P = .007). CONCLUSIONS In patients receiving antithrombotic therapy, surgical tooth extraction and acute inflammatory findings were associated with a significantly increased incidence of postoperative hemorrhage. In more than 90% of cases, postoperative hemorrhage occurred within 6 days of extraction. Thorough local hemostatic measures are therefore required in patients receiving warfarin therapy.