Pulmonary Embolism USMLE Step 1 Practice Question
A 50-year-old woman with acute pulmonary embolism (confirmed on CT pulmonary angiography) presents with dyspnea, tachycardia (HR 108/min), and tachypnea (RR 22/min). She is initiated on warfarin and bridged with enoxaparin. On hospital day 3, her INR is 1.8, hemoglobin is 13.2 g/dL, and platelet count is normal. She denies chest pain or hemoptysis. When can enoxaparin be safely discontinued?
Answer choices
- AEnoxaparin can be stopped as soon as warfarin is initiated
- BINR must be 2.0 to 3.0 for at least 24 hours on two consecutive measurements
- CFive days of overlap therapy must be completed AND INR must be 2.0 to 3.0 for at least 24 hoursCorrect answer
- DINR must exceed 3.0 to ensure adequate anticoagulation
- EINR must reach 2.0 on any single measurement
- FEnoxaparin can be discontinued after 3 days of overlap when INR is therapeutic on 2 consecutive measurements
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