Date and Time
December 5, 2007
1:30 PM - 3:00 PM

Availability
Open to the public
No RSVP required

Speaker
Ram Duriseti - Doctoral Candidate in Decision and Risk Analysis at Stanford University

Introduction: In a typical acute care setting, pulmonary embolism (PE) is usually one of several competing diagnoses in patients presenting with chest pain, shortness of breath or a related complaint. Because treatment significantly reduces mortality from PE, proper diagnosis is essential.

Objective: To evaluate the cost-effectiveness of the ELISA D-dimer assay with common diagnostic strategies in an Emergency Department (ED) for patients presenting with undifferentiated symptoms suggestive of PE.

Methods: Using a probabilistic decision model, we evaluated the costs and effectiveness (quality-adjusted life years gained) of 60 testing strategies (six different strategies for use of D-dimer, combined with ten different imaging strategies) for five patient pretest categories (distinguished by Wells score and by whether deep venous thrombosis (DVT) is clinically suspected). We performed deterministic and probabilistic sensitivity analyses.

Results: When DVT is not clinically suspected, the best diagnostic strategy is to use an initial D-dimer test with a cutoff above the levels commonly in use, followed by compression ultrasound (CUS) of the lower extremities if the D-dimer is above the cutoff. For patients in whom DVT is clinically suspected, the best diagnostic strategy consists of a CUS (with no D-dimer) followed by a computed tomographic perfusion test (CTP) if the CUS is negative for DVT. These results were robust over a wide range of deterministic and stochastic sensitivity analyses.

Conclusion:For patients presenting to an ED with chest pain and shortness of breath, and for whom DVT is not clinically suspected, the quantitative D-dimer assay can be a valuable diagnostic tool. However, our analysis suggests that the current D-dimer cutoff widely in use is not cost-effective. Instead, a higher cutoff should be used, and this should be followed by CUS. For patients in whom DVT is clinically suspected, the D-dimer is not part of a cost-effective strategy; instead, a compound imaging strategy with CUS and CTP (if needed) with no D-dimer is cost effective. The recommendations from this analysis represent a significant departure from current practice.