Review Question - QID 211070

A 47-year-old woman presents to the emergency department with calf pain and swelling that has persisted for the past 24 hours. She recently had an elective cholecystectomy 4 days ago that was complicated intraoperatively by bleeding requiring a transfusion of 1 unit of packed red blood cells. The patient is otherwise healthy and does not take any medications at baseline. Her temperature is 98.7°F (37°C), blood pressure is 112/71 mmHg, pulse is 81/min, respirations are 12/min, and oxygen saturation is 98% on room air. A physical exam is notable for an enlarged and tender right calf. Ultrasound with Doppler reveals non-compressible veins of the affected leg. Which of the following is the most appropriate initial management of this patient?