Objectives: Recent studies have shown that strategies for pulmonary embolism diagnosis which have included D-dimer testing have been most cost effective. The objective of this study is to evaluate the impact of a new strategy for pulmonary embolism diagnosis based on D-dimer results.
Methods: A prospective survey was conducted in the emergency ward and three medical departments of a university teaching hospital. Guidelines for diagnosis of PE were established and implemented through an educational intervention and a specific order form. D-dimer (ELISA) was required for all patients suspected of having PE. A result above 500 ng/ml was to be followed by an a pulmonary imaging procedure. Appropriateness of prescription of D-dimer and non-compliance with guidelines (absence of diagnostic imaging procedure following D-dimer results above 500 ng/ml) were evaluated.
Results: One-hundred sixty patients were studied. D-dimer test was performed in 154 patients (96.3%) suspected of PE during a two-month period. Test results were above 500 ng/ml in 111 cases. PE was confirmed in 20 cases. Twenty percent (31/154) of the D-dimer prescriptions were inappropriate. Among those with D-dimer results above 500 ng/ml, 45% (50/111) of the patients experienced no imaging procedure.
Conclusions: Despite implementation of clinical guidelines for its use, D-dimer was excessively prescribed. A large proportion of results was not taken in consideration by prescribers. Often new technologies have good experimental results, but behave differently when used routinely in ordinary care settings. It is important that field studies be developed to evaluate the effectiveness of new technologies.