Correlated expression of D-dimer concentrations with thrombotic burden in acute pulmonary embolism

Thrombotic burden might have an influence upon the concentration of D-dimer in patients with acute pulmonary embolism. Patients with small pulmonary embolisms may thus present with relatively low concentrations of D-dimer. The objective of this study was to assess the correlation of the concentrations of D-dimer with the pulmonary artery occlusion score (PAOS) in a cohort of patients with acute pulmonary embolism. We have presently studied the correlation between the concentrations of D-dimer and the PAOS in a group of 75 patients who presented to the Department of Emergency Medicine with a clinical picture suggestive for acute pulmonary embolism and whose pulmonary computerized tomography (CT) angiography was positive for pulmonary embolism. A significant (P< 0.001) correlation (r = 0.42) was noted between the concentration of D-dimer and the PAOS in this group of 75 patients with acute pulmonary embolism. We further divided the cohort into those patients who had a score below the median of 18 (n = 37) and those who had a score above the median (n = 38), the corresponding mean concentrations of D-dimer being 364 and 814 ng/ml, respectively, in contrast to a mean concentration of 285 ng/ ml that was observed in the group of controls (n = 73). In addition, from the receiver-operated characteristic (ROC) curves that were produced for the purpose of differentiating between the presence or absence of pulmonary embolism, for those who had a low score it was not possible to differentiate between those who had or did not have a pulmonary embolism [area under the curve 0.595 as opposed to 0.835 (P<0.001) for the group with the high score]. Patients with acute small pulmonary embolism might present with relatively low concentrations of D-dimer. These findings might have implications regarding the diagnostic yield of D-dimer in patients who are suspected of having an acute pulmonary embolism.