Effect of tissue injury on D-Dimer levels: a prospective study in trauma patients

D-Dimer measurement has been used as a simple, non-invasive test to rule out thromboembolic phenomena in patients at risk for deep venous thrombosis (DVT) and / or pulmonary embolism (PE). Elevated D-Dimer level caused by tissue injury is believed to show a trend for gradual decrease to normal within the first three days after trauma.

To study the effect of tissue injury on D-Dimer levels, we conducted a prospective measurement of D-Dimer levels in severely traumatized, high-risk patients for DVT or PE, starting within 24 hours after admission until disposition of the patient or to a total of 14 days of hospitalization. Patients were observed clinically for development of thromboembolic phenomena, and were subjected to weekly surveillance using duplex scan of the lower extremities. Additional testing was done if requested by the attending trauma surgeon.

A total of 21 patients were enrolled in the study. There were 17 males, and 4 females. Patients had a mean age of (42) with a range of (17-79), and a mean ISS score of (20) with a range of (4-50). Seven patients completed 3-9 days of testing. Fourteen patients had more than 10 days of testing. Nine patients completed 14 days of testing. In all patients, tissue injury resulted in increased levels of D-Dimer above a threshold (500 ng/ml), below which DVT or PE can be ruled out. The increased levels failed to normalize even when testing was continued for 14 days.

In our study, the increased D-Dimer levels induced by tissue injury failed to show a trend of gradual return to normal within three days after trauma, as currently believed. This, in our opinion, may eliminate our ability to use D-Dimer testing to rule out DVT or PE in a subset of severely traumatized patients in the early post trauma period.