Post-extraction Bleeding: Predictive Value of INR vs Bleeding History

Objective: Warfarin (Coumadin) is an anticoagulant prescribed to patients to prevent and treat thromboembolic disorders.  Each patient on Warfarin has a target range for coagulability as measured by their INR (international normalized ratio), with 1.0 considered normal while readings above 4.0 provide no additional therapeutic value.  The current standard of care in dentistry when treating a patient on Warfarin is to not discontinue or reduce their dosage for minor dental surgery, but rather to use the patient’s current INR value to determine the risk of excessive bleeding.  However, not all dentists are comfortable treating patients on Warfarin due to the perceived risk of post-operative bleeding.   It is common practice for patients undergoing general surgical procedures to first be asked a series of questions regarding their bleeding history to evaluate bleeding risk.  The purpose of this study was to compare the utility of a patient’s INR value to that of a bleeding history as predictors of bleeding following an extraction.

Method: Adult patients currently taking Warfarin and requiring an extraction were recruited in the oral surgery clinic.  Prior to the extraction, a detailed bleeding history was recorded for each patient and a blood sample obtained to determine the patient’s current INR value.  The amount of post-extraction bleeding was determined by a post-hoc measurement of blood on gauze replaced at 3, 5, 10, and 15 minutes following the extraction.   

Result: No correlation was found between a patient’s INR value and the amount of bleeding following an extraction.   At 5 and 10 minutes following the extraction there was a significant correlation between bleeding history and the amount of blood measured on the gauze.

Conclusion: Within our predetermined limits of INR values, bleeding history is a better predictor of the amount of post-extraction bleeding than the INR value alone.