Comparison of the clinical usefulness of two quantitative D-Dimer tests in patients with a low clinical probability of pulmonary embolism.

BACKGROUND: Quantitative D-Dimer tests are established methods in the non-invasive diagnostic management to rule out venous thromboembolism (VTE). The diagnostic performance and the clinical efficiency different D-Dimer assays in the exclusion of pulmonary embolism (PE) have not yet been compared in a clinical outcome study. OBJECTIVE: Evaluation of the efficiency and safety of excluding the diagnosis of PE with two different quantitative D-Dimer assays in consecutive patients with clinically suspected PE. PATIENTS AND METHODS: We studied the VTE-failure rate of 2206 consecutive patients with an unlikely clinical probability in whom VIDAS or Tinaquant D-Dimer tests were performed. RESULTS: The prevalence of PE in 1238 patients whose D-Dimer level was analyzed with Tinaquant assay was 11%. The VIDAS assay group consisted of 968 patients with a PE prevalence of 13%. The VIDAS assay had a sensitivity of 99.2% (95%CI; 96- >99.9%), the Tinaquant assay of 97.3% (95%CI; 93 -99%). The negative predictive value (NPV) in the Tinaquant assay group was 99.4% (95%CI 98-99.8%) in comparison to 99.7% (95%CI 99->99.9%) in the VIDAS assay group. During 3 month of follow-up, there were no fatal cases of PE among patients with normal D-Dimer and unlikely clinical probability in both D-Dimer assay groups. In addition, the test efficiency of Tinaquant assay was significantly higher in comparison to VIDAS assay (52% vs 42%, p<0.001). CONCLUSION: Both Tinaquant and VIDAS D-Dimer tests perform equally well in combination with an unlikely clinical probability in excluding PE. The Tinaquant test was shown to be more efficient.

High D-dimer level is associated with increased 15-d and 3 months mortality through a more central localization of pulmonary emboli and serious comorbidity.

High D-dimer levels are predictors of death in patients with pulmonary embolism (PE), as are more proximally located, larger emboli. The direct link between these three has not yet been described. A cohort of 674 consecutive patients with confirmed PE was studied. Patients were followed up for 3 months. D-dimer levels were measured only in patients with an unlikely clinical probability (n = 262). The odds ratio (OR) for death of all variables was calculated. Multivariate analysis was performed to identify independent risk factors for mortality. The best predictive D-dimer cut-off point for mortality was a concentration >3000 ng/ml FEU (OR 7.29). High D-dimer levels were correlated with active malignancy and age over 65 years, both being indicators of 3-month mortality. High D-dimer levels were also correlated with centrally located pulmonary emboli and 15-d mortality. The combination of high D-dimer levels and central emboli increased early mortality risk by 2.2. High D-dimer levels in patients with an unlikely clinical probability were associated with fatal outcome after PE. Centrally located pulmonary emboli were associated with higher D-dimer levels and worse 15-d mortality. Active malignancy, being an inpatient at time of diagnosis and age over 65 years were associated with higher D-dimer levels and worse 3-month survival.