MSFinals-2095

A 75-year-old woman comes in with a swollen and hot right calf. She had undergone a right knee arthroscopy and had been immobile for a while. She only takes paracetamol and codeine for osteoarthritis as needed. An above-knee deep vein thrombosis (DVT) is detected on ultrasound, which is her first DVT. What is the recommended treatment?