Markedly elevated plasma D-dimer and the prevalence of acute pulmonary embolus

Objective. To evaluate if increasingly elevated levels of plasma Ddimerare associated with higher prevalence of acute pulmonaryembolus (PE). Patients and Methods. A retrospective study wasconducted evaluating all PE protocol CT examinations performed inlow-to-intermediate risk emergency department and hospitalized patientsduring 2007. All PE protocol CT reports were reviewed for thepresence or absence of acute PE. Th e charts of all of these subjectswere then reviewed for quantitative plasma D-dimer values, measuredin mg/ml Fibrinogen Equivalent Units, drawn within one day prior tothe CT exam. Th e prevalence of acute PE at diff erent D-dimer thresholdresults was then evaluated using D-dimer groups as follows: < 1.0mg/ml, ≥ 1.0 but < 2.0 mg/ml, ≥ 2.0 but < 4.0 mg/ml, and ≥ 4.0 mg/ml. Results. 943 PE protocol CT exams were reviewed. 410 subjectshad D-dimer values drawn before their CT exams; 30 (7.3%) of thesewere positive for acute PE. As D-dimer values became increasingly elevated,the prevalence of acute PE increased accordingly. In particular,D-dimer elevation ≥4.0 mg/ml was almost 94% specifi c for acute PEby CT criteria. Conclusion. Increased elevation of plasma D-dimer isassociated with increased prevalence of acute PE in low-to-intermediaterisk patients.