The Real-World Boards: Question #10
A 47-year-old woman has a PE. How long should she take anticoagulation?
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A 47-year-old woman has experienced a pulmonary embolism. She spent one night in the ICU because of concerning radiographic features (large, central clot), but had no hemodynamic compromise, hypoxemia, or right ventricular strain on echocardiogram. She was treated with heparin and is being transitioned to apixaban with continued care on the medical unit.
She has a BMI of 35 and was taking oral contraceptives with estrogen, which have been discontinued. She had a deep venous thrombosis four years ago, which occurred one month after surgical repair of a proximal tibial fracture sustained in a motor vehicle collision. Her mother once had a DVT. She and her mother had full hematologic workups showing no inherited thrombophilia.
She has no major risk factors for hemorrhage, but is very worried about bleeding due to her traumatic experience in the car crash. She asks how long she will have to take blood thinners. She is medically literate and points out that this was a “provoked” PE (by estrogen), as was her prior DVT, for which she took 3 months of anticoagulation.
All patients with venous thromboembolism (deep venous thrombosis and pulmonary embolism) are recommended to take anticoagulation for at least three months if their risk of bleeding is acceptable.
VTE recurs at a variable rate after anticoagulation is discontinued. Predicting which patients whose risk for recurrence (especially for clinically significant PEs) exceeds their risk for serious hemorrhage, and who should therefore take extended courses of anticoagulation, can be complex and difficult.
VTEs have been traditionally classified as “provoked” (by a transient risk factor) or “unprovoked” (associated with a presumed persistent risk factor). Transient risk factors have been classified as “major” or “minor”.
Major: surgery under general anesthesia > 30 minutes; C-section; hospitalization for acute medical illness lasting ≥3 days; major trauma; immobilization for ≥3 days
Minor: estrogen therapy, including contraception; pregnancy and postpartum period; leg injury with casting or nonsurgical fracture; minor surgery; long-haul travel (8+ hour flights).