CLOTT – The Pathogenesis of Post-Traumatic Pulmonary Embolism

What is the CLOTT study?

CLOTT (Coalition of Leaders in Thromboembolism) is a multi-center investigation into the significance of incidentally discovered venous thromboembolisms (VTE) following trauma and the role of fibrinogen breakdown in the development of post-traumatic VTE. OHSU is one of 17 centers around the country participating in this trial. The study includes collecting blood samples and data from patients following a traumatic event that requires immediate hospitalization. This project i s supported by a grant from the Defense Medical Research and Development Program and managed by the National Trauma Institute and the Coalition for National Trauma Research (CNTR).

Why do this study?

We are doing this study because we want to find out if there may be certain markers within blood that will show a higher risk of a patient developing a blood clot. Based on these study results, we may be able to help prevent patients from developing blood clots by giving them certain medications following a traumatic injury.

Who will be included?

Candidates for inclusion in the study are those patients admitted to the ICU at a participating hospital who meet the following criteria:

  • Age range 18-40 years (specified by DoD sponsor as combat age-range)
  • Expected to remain in the ICU for at least 3 days
  • Have an injury that puts a person at high risk for a VTE

What is involved?

In order to identify those patients who develop fibrinolytic shutdown, blood samples will be drawn at the following intervals following injury: 6, 12, 24, 48, and 72 hours and again on days 5 and 7 for thrombelastography testing (TEG) and other markers. The TEG provides a picture on how a person’s blood is clotting. In order to describe the association between those patients with fibrinolytic shutdown and the development of VTE a duplex venous examination will be obtained on ICU day 3. The treatment of any clot seen on ultrasound will be left to the discretion of the treating physician.

For more information, please call the Trauma Research Lab at (503) 494-4315 or email