Rapid D-dimer test combined a clinical model for deep vein thrombosis Validation with ultrasonography and clinical follow-up in 383 patients
Nuria Ruiz-Giménez (1), Alfonsa Friera (2), Pilar Artieda (3), Paloma Caballero (2), Pilar Sanchez Moliní (1), Marta Morales (3), Carmen Suárez (1), Thromboembolic Disease Group (4)
(1) Internal Medicine Service, (2) Radiology Department and (3) Clinical Analysis Department, (4) Hospital Universitario La Princesa, Universidad Autónoma de Madrid, Spain
An optimal approach to the diagnosis of deep vein thrombosis
(DVT) in lower limbs in the emergency department is still
unknown. In this prospective cohort study, we aimed to evaluate
the accuracy of the widely available plasma D-dimer test
(VIDAS) and establish the usefulness of combining D-dimer
testing with a clinical model to reduce the need for serial ultra-sonographies
and improve the diagnostic strategy of DVT.
We performed a cohort study in 383 consecutive outpatients
referred to the emergency department of Hospital La Princesa,
with clinical suspicion of DVT. The patients were stratified into
three pre-test probability categories using an explicit clinical
model (Wells score), and underwent a quantitative automated
ELISA D-dimer assay (VIDAS D-Dimer® bioMérieux). Patients
were managed according to the diagnostic strategy based on
clinical probability and compression ultrasonography (CU).
Patients for whom DVT was considered a high pre-test probability
with negative ultrasonographic findings in the initial CU,
returned the following week for repeat ultrasonography. All
patients with DVT excluded did not receive anticoagulant therapy, and were followed up for three months to monitor the
development of venous thromboembolic complications. DVT
was confirmed in 102 patients (26.6%): 95 in the initial test, four
in the second test, and three who developed venous throm-boembolic
complications in the three-month follow-up period.
The calculated D-dimer cut-off level was 1 µg/ml. One hundred
patients (98%) with DVT had positive D-dimer. D-dimer had a
sensitivity of 98% and a negative predictive value of 98.6%.
Among the high-probability patients with positive D-dimer
tests and initial negative CU, 9.75% had DVT on repeat CU at
one week.The study results suggest that the addition of VIDAS
D-dimer to this diagnostic algorithm could improve the management
of patients with suspected DVT in daily practice.
A diagnostic approach of DVT based on D-dimer (cut-off
/ge;1 µg/ml) as the first diagnostic tool for the exclusion of DVT,
and the clinical probability model as the tool that identifies
those patients requiring a second ultrasonography is useful and
suitable for daily medical practice.