The Use of a Rapid D-dimer Blood Test in the Diagnostic Work-up for Pulmonary Embolism: A Management Study
Marco R. de Groot (1, 2) , Marinus van Marwijk Kooy (2) , Jos G. J. Pouwels (3) , Anneke H. Engelage (4) , Bart F. Kuipers (5) , Harry R. Büller (1)
From the (1) Department of Vascular Medicine, Academic Medical Centre, Amsterdam, and the (2) Departments of Internal Medicine, (3) Clinical Chemistry, (4) Nuclear Medicine and (5) Pulmonology, Sophia Hospital, Zwolle, The Netherlands
Summary Background. D-dimer assays have a potential to rule out pulmonaryembolism in case of a normal test result. We studied the clinical utilityof incorporating the SimpliRED D-dimer test result and clinical probabilityin the routine diagnostic work-up of patients with suspectedacute pulmonary embolism. Methods. In a prospective managementstudy 245 consecutive patients, hospitalised as well as outpatients,were included. A SimpliRED D-dimer test and perfusion/(ventilation)scintigraphy were obtained in all patients, whereas clinical probabilitywas determined in the subgroup of patients with a non-diagnostic scanand normal D-dimer result. A diagnostic algorithm determined thenecessity for further testing and decisions about treatment. All patientswere followed up for 3 months. Results. In 54 patients (22%) with anormal lung scan and 50 patients (21%) with a high probability lungscan, antithrombotic therapy was withheld or started respectively, irrespectiveof the D-dimer result. A non-diagnostic lung scan was found in137 (56%) patients, of whom 70 patients had an abnormal D-dimer test,in whom further testing was ordered. Of the remaining 67 patients witha non-diagnostic lung scan and normal D-dimer test 8 patients hada high clinical probability, and the subsequent ultrasonography andpulmonary angiography yielded pulmonary emboli in 1 patient. In theremaining 66 patients, pulmonary embolism was considered to beabsent and antithrombotic treatment was stopped/withheld. Duringfollow-up of these patients only one patient experienced a possiblevenous thromboembolic event (failure rate 1,5% ; 95% CI 0-8%). TheSimpliRED D-dimer was normal in 6 of 61 patients with proven pulmonaryembolism (sensitivity 90% ; 95% CI 80-96%). Conclusion. Ourfindings suggest that it is safe to withhold anticoagulant therapy inthose patients with a non-diagnostic lung scan, a normal SimpliREDD-dimer test result, and without a high clinical probability. This resultsin a substantial decreased need for ultrasonography and pulmonaryangiography. The SimpliRED should not be used in isolation to excludepulmonary embolism.