The Association of D-dimer Levels with Clinical Outcomes in Patients Presenting with Acute Pulmonary Embolism

Abstract

The D-dimer fragment of fibrin degradation has been a useful adjunct in the diagnosis of venous thromboembolism (VTE). In conjunction with predictive algorithms, the high negative predictive value (NPV) of D-dimer measurements has provided this analyte with a prominent position in the diagnosis of pulmonary embolism (PE). The purpose of this study was to determine if D-dimer levels correlate with ventilation/perfusion (V/Q) derangements as assessed by the alveolar-arterial oxygen tension gradient (DeltaA-a) and to ascertain if quantitative measurements of D-dimer on admission have prognostic value in terms of during-admission mortality and recurrence over a 60-week period. The study utilized a retrospective cohort of 108 subjects admitted to a single institution and studied longitudinally. The cohort was divided into 4 groups representing degree of severity assessed by computed tomographic (CT) angiography: mild, moderate, severe, and very severe. Differences in D-dimer levels among these groups were strongly significant (P < .0001). A strong correlation was observed between D-dimer concentration and DeltaA-a (P < .0001). Logistic methods were used to calculate a "cut-off" level that would distinguish mild-moderate from severe-very severe PE. At a concentration of 12.35 mug/mL, this level yielded an odds ratio (OR) of 12.64 (P = .006) for during-admission mortality and a hazard ratio (HR) of 0.13 (P < .0001) for 60-week recurrence. These data suggest that D-dimer levels have utility beyond their NPV and should be considered as potential prognostic markers in subjects presenting with acute PE.