A 77-year-old woman is seen for a preoperative medical evaluation before resection of the sigmoid colon for recurrent diverticulitis scheduled 5 days from now. She has nonvalvular atrial fibrillation and is receiving long-term warfarin, without a history of bleeding complications. She has no history of stroke, transient ischemic attack, or intracardiac thrombus. History is also significant for hypertension. Medications are warfarin, chlorthalidone, and metoprolol. The physical examination, including vital signs, is normal. The INR measurement is 2.3. Calculated CHADS2 score is 2, and CHA2DS2-VASc score is 4. In addition to withholding warfarin before surgery, What is the most appropriate management of this patient's perioperative anticoagulation?