A 58-year-old man with a 10-day history of immobilization following orthopedic surgery presents with sudden-onset dyspnea, pleuritic chest pain, and syncope. CT pulmonary angiography (CTPA) is performed. The structure marked **A** in the diagram shows a large filling defect at the bifurcation of the main pulmonary artery, extending into both right and left pulmonary arteries. Which of the following management strategies is most appropriate for this patient's condition?
A. Anticoagulation with therapeutic enoxaparin and outpatient follow-up
B. Inferior vena cava filter placement as definitive therapy
C. Systemic thrombolysis with alteplase (tPA) 100 mg IV over 2 hours
D. Anticoagulation alone with unfractionated heparin and observation
Explanation
Why Systemic thrombolysis with alteplase (tPA) 100 mg IV over 2 hours is right
The structure marked A — a saddle thrombus at the pulmonary artery bifurcation extending into both right and left pulmonary arteries — represents a massive pulmonary embolism with acute hemodynamic compromise (syncope, hypotension implied by clinical presentation). According to Harrison's 21e Ch 273 and the 2016 CHEST Guidelines, massive PE with hemodynamic instability (SBP < 90 mmHg or shock) requires urgent reperfusion therapy. Systemic thrombolysis with alteplase 100 mg IV over 2 hours is the first-line reperfusion strategy in patients without contraindications. This patient's presentation of sudden dyspnea, pleuritic chest pain, and syncope in the context of a saddle embolus indicates acute right ventricular failure and obstructive shock, mandating immediate thrombolysis rather than anticoagulation alone.
Why each distractor is wrong
Anticoagulation alone with unfractionated heparin and observation: While anticoagulation is essential for all PE patients, anticoagulation monotherapy is insufficient for massive PE with hemodynamic collapse. Saddle emboli carry mortality up to 30% and require active reperfusion, not observation. This approach would be appropriate only for submassive or stable PE.
Inferior vena cava filter placement as definitive therapy: IVC filters are indicated only when there are absolute contraindications to anticoagulation (e.g., active bleeding, recent neurosurgery). They do not treat the existing massive PE and do not address the acute RV failure. Filters are adjunctive, never definitive therapy for massive PE.
Anticoagulation with therapeutic enoxaparin and outpatient follow-up: Outpatient management is inappropriate for a patient with syncope and hemodynamic compromise from a saddle embolus. This patient requires hospitalization and urgent reperfusion, not outpatient anticoagulation. Enoxaparin alone would not address the acute obstructive shock.
High-YieldNEET PG
Saddle PE = massive PE = hemodynamic instability → systemic thrombolysis (alteplase 100 mg IV over 2 hours) is first-line; anticoagulation alone is insufficient.
