Postoperative bleeding after tooth extractions in patients controlled with warfarin--a clinico-statistical study on the factors influencing postoperative bleeding

There are many reports about tooth extractions of patients taking warfarin, however PT-INR level is used to examine the postoperative bleeding in patients. To investigate other factors, postoperative bleeding, age, gender, PT-INR level, combined use of anti-platelet drugs, conditions of extracted tooth, a number of tooth extractions at a treatment, methods of management for warfarin therapy, degree of the alveolar bone loss and size of radiolucency of apical region were examined in this study. To apply Mann-Whitney U-test and chi2-test, ninety-three patients (38 male and 55 female) who took warfarin and visited our clinic for tooth extractions from April 1994 to November 2002 were classified into 2 groups: One group showed hemostasis by the next day (77 patients), the other showed the continuous bleeding after the next day (16 patients). These analyses indicated that PT-INR level, a number of tooth extractions at a treatment, methods of management for warfarin therapy, and size of radiolucency of apical region influenced postoperative bleeding. In addition, stepwise logistic regression analysis was applied to all of the factors, obtained from 77 patients out of 93 patients. This data showed that PT-INR level, a number of tooth extractions at a treatment and methods of management for warfarin therapy influenced postoperative bleeding. These results suggest that before the tooth extractions not only PT-INR level but methods of management for warfarin therapy and size of wound could be important to control the postoperative bleeding in warfarin taking patients.