In suspected pulmonary embolism evaluated in the ED, which sequence of steps is appropriate?

• A. Use Wells or PESI score, obtain D-dimer if low probability, CT pulmonary angiography if moderate/high probability, start anticoagulation if confirmed or highly suspected; consider thrombolysis or embolectomy for massive PE
• B. CT pulmonary angiography first
• C. Start anticoagulation immediately without imaging
• D. Rely on symptoms alone

Answer: (A)

Managing suspected pulmonary embolism in the ED depends on risk stratification and a stepwise diagnostic plan. Start by estimating pretest probability with clinical rules like Wells or PESI. If the probability is low, a D-dimer is used because a negative result effectively rules out PE in this group; if the D-dimer is positive or if the patient has moderate to high probability, proceed to CT pulmonary angiography to confirm the diagnosis. CT angiography is the preferred imaging test because it directly visualizes clots and helps rule out other causes of symptoms. Once PE is confirmed or if the suspicion is so high that treatment can’t wait, begin anticoagulation promptly to prevent clot propagation. For a massive PE with hemodynamic instability, consider reperfusion therapy, such as thrombolysis or surgical/catheter-directed embolectomy, as rapid restoration of blood flow improves survival. Relying on symptoms alone or imaging first without considering pretest probability can lead to misdiagnosis or unnecessary testing.