A 58-year-old man with a 3-day history of acute dyspnea and pleuritic chest pain undergoes CT pulmonary angiography (CTPA) for suspected pulmonary embolism. The scan confirms a filling defect in the right lower lobar pulmonary artery. Additionally, the structure marked **C** in the diagram shows an RV/LV diameter ratio of 1.1 on axial imaging. His blood pressure is 128/82 mmHg, heart rate 98 bpm, and troponin I is elevated at 0.08 ng/mL (normal < 0.04). Based on these findings, which of the following is the most appropriate management strategy?