The correct answer: D. Acute on chronic PE; start anticoagulation and assess for pulmonary thromboendarterectomy after 3 months

*Answers A, B, and C are incorrect:

·Although the patient does have an acute PE, her mean PA pressure is very high (out of proportion to transient rise in PA pressure typically seen in acute PE). In addition to an acute PE, her CTA demonstrated pulmonary web formation in the left and right lower lobe branches. Although her RA mass could represent a clot in transit, it was actually a highly organized thrombus (Figure 3, with the RA mass placed in the middle).


Figure 3

· Intracardiac thrombus is a relative contraindication to thrombolytic therapy (answer C).

· Answer B (aspiration thrombectomy) is also not ideal because it carries significant risk of distal and proximal embolization. Though the need to quickly intervene on a massive RA thrombus is instinctively tempting, this patient was hemodynamically stable on presentation, requiring only minimal supplemental oxygen, without tachycardia or hypotension. As such, there is no indication for the aforementioned therapies. Further diagnostic studies, including right heart catheterization, pulmonary angiography, and ventilation perfusion (V/Q) scintigraphy should be deferred. Instrumentation is largely contraindicated in the setting of large RA clot, and V/Q would not add any diagnostic value or change management at this time.

Answer E is incorrect:

· Chronic thromboembolic pulmonary hypertension is defined as elevated PA pressures with persistent perfusion defects after at least 3 months of anticoagulation. This patient needs outpatient anticoagulation (for acute PE) followed by V/Q scanning and operability assessment for pulmonary thromboendarterectomy at an experienced center for her underlying chronic disease burden.