THE ASSOCIATION BETWEEN D-DIMER AND DEEP VEIN THROMBOSIS LOCATION AND ITS ABILITY TO PREDICT PULMONARY EMBOLISM, a retrospective pilot study

Abstract Background In lower limb deep vein thrombosis; it is important to identify proximal from distal deep vein thrombosis as it carries the highest risk of pulmonary embolism. It is known that D-dimer has a great role in deep vein thrombosis diagnosis. Yet, the use of D-dimer to predict the location of deep vein thrombosis and the risk of pulmonary embolism in deep vein thrombosis patients has not been investigated before. Objective To address the correlation between D-dimer and the location of deep vein thrombosis and to study the efficacy of D-dimer to predict risk of PE in patients with proximal or extensive deep vein thrombosis. Method We included 110 consecutive patients who were hospitalized with the diagnosis of deep vein thrombosis, with or without a concomitant diagnosis of PE, and with D-dimer measured at initial presentation. We categorized the location of deep vein thrombosis as: distal, proximal, and extensive. In the analysis, patients were grouped into high-risk (patients with Proximal or Extensive deep vein thrombosis and pulmonary embolism) and low risk group (patients without pulmonary embolism). Results There was no significant association between D-dimer level and the location of deep vein thrombosis (p=0.519). However, D-dimer level was greater among patients with pulmonary embolism (9.6mg/L) than among patients without pulmonary embolism (7.4mg/L), (p=0.027). D-dimer was a significant predictor of pulmonary embolism as patients with proximal or extensive deep vein thrombosis had 8-folds increased risk of pulmonary embolism than patients with D-dimer less than 4.75mg/L (OR=7.9, p=0.013). Conclusion Though D-dimer was not significantly associated with the location of deep vein thrombosis, it was a significant predictor of pulmonary embolism in patients hospitalized with proximal or extensive deep vein thrombosis.