Review Question - QID 210513

A 27-year-old man presents to the emergency department with severe leg pain since yesterday, which has been steadily worsening. The patient plays intramural football and rugby and is currently a senior in college. He has no known medical history. His temperature is 98.0°F (36.7°C), blood pressure is 124/63 mmHg, pulse is 90/min, respirations are 13/min, and oxygen saturation is 98% on room air. Physical exam reveals the finding in Figure A with tenderness on palpation of the lower extremity indicated by the arrow in the image. No bruising is noted on either lower extremity. The patient is started on a therapeutic heparin bolus and drip with standard weight-based dosing. Laboratory studies are ordered 3 hours later and shown below.

Hemoglobin: 14 g/dL
Hematocrit: 42%
Leukocyte count: 6,500/mm^3 with normal differential
Platelet count: 197,000/mm^3
PT: 20 seconds
PTT: 10 seconds

Which of the following is the most appropriate management of this patient?