A 73-year-old female develops left ankle swelling and pleuritic chest pain after being diagnosed with deep venous thrombosis. What is the most appropriate next step in her management?

The most appropriate next step in the management of this patient, who has developed symptoms suggestive of a pulmonary embolism (PE) following a diagnosis of deep venous thrombosis (DVT), is the placement of an inferior vena cava (IVC) filter. This choice is appropriate because the patient is at high risk for a PE due to her existing DVT, and her presenting symptoms of pleuritic chest pain indicate that there may be a PE.

By placing an IVC filter, it reduces the risk of blood clots traveling to the lungs, which can be life-threatening. This intervention is particularly considered when there is a contraindication to anticoagulation therapy, or when anticoagulation has failed or is not timely due to the risk of a significant clot burden.

In this clinical scenario, continuation of subcutaneous heparin does not address the immediate risk of embolization, while increasing the warfarin dosage is not pertinent at this stage without ensuring therapeutic anticoagulation has been achieved. Likewise, performing a chest x-ray, while useful in evaluating other causes of pleuritic chest pain, does not directly address the need to manage a suspected PE in a patient already diagnosed with DVT. Thus, the IVC filter is