Pulmonary Embolism
USMLE/ABIM Question #1
Last Updated: 2/5/2025
Vignette
A 45-year-old woman presents to the emergency department with acute onset dyspnea and pleuritic chest pain. CT pulmonary angiogram confirms bilateral pulmonary emboli. Her vital signs show: BP 115/75 mmHg, HR 88/min, RR 20/min, O2 saturation 94% on room air. She has a history of well-controlled hypertension and takes hydrochlorothiazide. Physical exam shows no signs of DVT or right heart strain. Laboratory studies reveal normal complete blood count, basic metabolic panel, and liver function tests. Her simplified Pulmonary Embolism Severity Index (sPESI) score is 0.
Question
Which of the following is the most appropriate initial anticoagulation strategy for this patient?
A) Initiate intravenous unfractionated heparin and admit to the hospital
B) Start low molecular weight heparin and transition to warfarin as an inpatient
C) Begin direct oral anticoagulant therapy and discharge home with close follow-up
D) Administer thrombolytic therapy followed by anticoagulation
E) Start low molecular weight heparin and discharge home with bridge to warfarin
Audio
Video
Correct Answer:
C) Begin direct oral anticoagulant therapy and discharge home with close follow-up
Explanation of Correct Answer:
This patient is an excellent candidate for outpatient management with a direct oral anticoagulant (DOAC) because:
- She is hemodynamically stable with normal vital signs
- Has an sPESI score of 0, indicating low risk
- No significant comorbidities or contraindications to DOACs
- Normal renal and hepatic function
- No signs of right heart strain or DVT
Explanation of Incorrect Answers:
A) Intravenous unfractionated heparin and admission - This level of monitoring is not necessary for a hemodynamically stable, low-risk patient. Hospital admission would not provide additional benefit.
B) Low molecular weight heparin with transition to warfarin as inpatient - Hospital admission is not necessary for this low-risk patient, and DOACs are preferred over vitamin K antagonists for most patients with PE.
D) Thrombolytic therapy - This is reserved for patients with high-risk PE characterized by hemodynamic instability (systolic BP <90 mmHg). This patient is hemodynamically stable.
E) Low molecular weight heparin bridge to warfarin - While this is a valid treatment strategy, DOACs are preferred over vitamin K antagonists for most patients with PE due to their safety profile and convenience.
Alternative Scenarios:
- If the patient had active cancer, LMWH would be preferred over a DOAC
- If the patient had antiphospholipid antibody syndrome, warfarin would be the anticoagulant of choice
- If the patient was hemodynamically unstable with systolic BP <90 mmHg, thrombolytic therapy would be indicated
Additional Facts:
- DOACs have been shown to be non-inferior to traditional therapy for PE treatment with lower bleeding risk
- Outpatient management is appropriate for PE patients with sPESI score of 0
- The 30-day mortality rate for patients with sPESI score of 0 is approximately 1%
- Factors favoring hospitalization include severe symptoms, significant comorbidities, or limited home support
- DOACs don't require routine monitoring of anticoagulation levels unlike warfarin
Main Takeaway:
Low-risk PE patients (sPESI=0) who are hemodynamically stable can be safely treated as outpatients with DOACs, avoiding unnecessary hospitalization.
