MRCP2-2214
A 42-year-old man presents to the Emergency Department with a 4-week history of left lower leg pain and swelling. On examination, his left calf is enlarged and tender to touch. He denies chest pain or shortness of breath.
There is no past medical history of note and he takes no regular medication after recently switching from the combined oral contraceptive pill to the intrauterine coil one month ago.
Further investigations were ordered:
Haemoglobin 142 g/l 135–175 g/l
Platelets 320 × 109/l 150–450 × 109/l
D-dimer 1200 ng/ml < 400 ng/ml
Fibrinogen 2.3 g/l 2–4 g/l
Prothrombin time 11 seconds 10–14 seconds
Factor V Leiden Positive
What is the next step in the management of this patient?