This document discusses the challenges of managing anticoagulation in patients undergoing surgical procedures. It provides guidance on estimating thromboembolic and bleeding risk, deciding whether to interrupt anticoagulation, and timing interruptions. For patients at very high thromboembolic risk, the goal is to limit time off anticoagulation. Bleeding risk depends on procedure type and duration. Warfarin should be stopped 5 days before elective surgery to allow the INR to decrease safely.