Prophylaxis for Recurrent DVT or PE
A 78-year old man with a history of mild dementia is hospitalized due to severe shortness of breath, pleuritic chest pain and mild fever for five hours. Today, in the morning, he woke up and could not breathe normally. He is afebrile, his heart rate is 105 bpm and his respiratory rate is 19 breaths per minute. His blood pressure is 140/93 mm Hg. Two days ago, he stopped going for his daily morning walk due to right leg pain. He also complains that his right leg has been burning for a couple of days. Four weeks ago, he underwent right hemicolectomy for a tumor in the ascending colon. His laboratory studies after surgery showed no abnormalities and he was discharged with appropriate instructions. He has no family history of cardiac or pulmonary disease. He quit smoking ten years ago and drinks two glasses of wine every Sunday, when his younger brother visits him. His BMI is 24. He has no other medical problems and takes no medications except from over the counter vitamins that "protect his neurons."
Which of the following drug would be the most appropriate, chronic therapeutic approach to prevent any recurrence of the current condition?