The effect of stopping phenprocoumon 5 days preoperatively: A retrospective study

Background: Clinicians lack substantiated guidance on when vitamin K antagonist (VKA) treatment should be interrupted preoperatively, especially with regard to phenprocoumon, with its long half-life of 5.5 days. Objective: To evaluate the efficacy of discontinuing phenprocoumon 5 days preoperatively and determine whether a safe international normalized ratio (INR) was reached. Methods: This was a retrospective review of 118 patients using phenprocoumon prior to elective surgery. Preoperative INRs and factors that could potentially influence these values were identified and described. A safe preoperative INR was defined as <1.8. Results: Of the 118 included patients, 42 patients (35.6%) had an off-target INR. The male sex was significantly and independently associated with an off-target INR (odds ratio [OR] 2.4, 95% confidence interval [CI] 1.022-5.445). A high American Society of Anesthesiologists (ASA) classification was also significantly and independently associated with an off-target INR (OR 2.3, 95% CI: 1.029-5.173). Conclusion: Discontinuation of phenprocoumon 5 days preoperatively resulted in an INR < 1.8 in more than one-third of patients. Individualizing or extending the period of phenprocoumon discontinuation may be a necessary treatment option.