Lit Matters 2: D-Dimer focused PE testing in ED

Pulmonary embolism workup in the ED often hinges on balancing missed PE against unnecessary CT pulmonary angiography. A simplified d-dimer-focused pathway appears safe for selected low- to moderate-risk patients, but it may trade some imaging efficiency for easier bedside implementation.

D-Dimer Focused PE Testing

• Core pathway finding: For PERC-positive patients at low or moderate pretest risk, a negative age-adjusted d-dimer supported stopping the PE workup without further imaging.
• Safety signal: Missed PE was rare: only 2 of 5,153 patients who tested negative on the pathway were diagnosed with PE within 30 days, a reassuring result clinicians will want to contextualize in the episode.
• Imaging tradeoff: The simplified pathway did not produce a clinically meaningful overall drop in CT or VQ imaging, suggesting convenience may come at the cost of maximal scan reduction.
• Implementation advantage: Protocol adherence improved from 91.3% to 97.6%, supporting the idea that a simpler d-dimer-first strategy is easier to use consistently in real ED workflows.
• Diagnostic yield effect: PE diagnoses and positive imaging yield both increased after implementation, raising the possibility that more disciplined front-end testing improved who actually reached the scanner. We get into the interpretation caveats in the episode.