Normal D-dimer levels do not exclude thrombotic complications in trauma patients

Area of Science:

• Trauma care
• Diagnostic accuracy
• Thromboembolic disease

Background:

• Deep venous thrombosis (DVT) and pulmonary embolism (PE) are frequent complications in trauma patients.
• Diagnosing DVT and PE can be challenging and resource-intensive.
• The utility of D-dimer testing in excluding these conditions in trauma patients requires further investigation.

Purpose of the Study:

• To evaluate the predictive value of D-dimer testing in excluding deep venous thrombosis (DVT) and pulmonary embolism (PE) in adult trauma patients.
• To determine the accuracy of D-dimer tests in the early post-injury phase and after the initial four days.

Main Methods:

• Adult trauma patients with Injury Severity Score > or =9 and expected stay >3 days were enrolled.
• Bilateral lower extremity duplex ultrasounds and D-dimer levels were performed at multiple time points post-admission.
• Data were collected from March 1999 to March 2001.

Main Results:

• Twenty-three patients were diagnosed with DVTs, with 18 occurring within the first week.
• Five DVT patients and one PE patient had normal D-dimer levels, indicating a 24% false negative rate for DVT.
• The negative predictive value for D-dimer was 92% overall, with all false negatives occurring within four days of admission.

Conclusions:

• A negative D-dimer test in the early post-injury phase (within 4 days) does not exclude DVT or PE.
• The negative predictive value of D-dimer testing increases to 100% after the first four days post-admission.
• Patients presenting with signs/symptoms of DVT or PE early after trauma require further diagnostic screening.