Acute Pulmonary Embolism

A 62- year- old man presented with a 5- day history of progressively worsening dyspnea and orthopnea after returning from a 3- day business trip to the Far East. On physical examination, the heart rate was 102 beats per minute, and the blood pressure 110/ 60 mm Hg. The arterial oxygen saturation was 86% while the patient was breathing ambient air. The neck veins were distended. There was no heart murmur. The lungs were clear, and the extremities appeared normal. The D- dimer level was 5.13 mg per liter ( normal level, less than 0.5), and the troponin T level was less than 0.01 g per liter. A computed tomographic ( CT) scan showed multiple thrombi in the pulmonary arteries and a dilated right ventricle. How should this case be managed?