Value of quantitative D-dimer assays in identifying pulmonary embolism: implications from a sequential decision model

Area of Science:

• Emergency Medicine
• Diagnostic Imaging
• Health Economics

Background:

• Pulmonary embolism (PE) diagnosis in emergency departments (EDs) requires efficient and cost-effective strategies.
• Evaluating diagnostic accuracy and cost-effectiveness of D-dimer assays alongside imaging is crucial.

Purpose of the Study:

• To assess the cost-effectiveness of quantitative D-dimer assays for diagnosing PE in urban ED settings.
• To compare various diagnostic strategies based on pretest probability (Wells criteria).

Main Methods:

• Analysis of diagnostic strategies using D-dimer assay performance (ELISA) and imaging techniques (CUS, VQ scan, CTA).
• Inclusion of five D-dimer cutoff values and multiple imaging combinations.
• Outcome measures included incremental costs and quality-adjusted life-years (QALYs).

Main Results:

• CT angiography (CTA) without D-dimer was the preferred strategy when available.
• D-dimer combined with compression ultrasound (CUS) and ventilation-perfusion (VQ) scan was dominant when CTA was infeasible for moderate-to-high risk patients.
• D-dimer with CUS was preferred for low-risk patients when CTA was infeasible.
• D-dimer testing became valuable if CT pulmonary angiography (CTP) specificity dropped below 80%.

Conclusions:

• Quantitative D-dimer assays are unlikely to be cost-effective for suspected PE when CTA is available.
• D-dimer assays are valuable adjuncts with CUS and pulmonary imaging when CTA is unavailable or performance is compromised.
• Findings may differ for broader patient populations presenting with undifferentiated chest pain or dyspnea.